Textile products having a sealant or coating and method of manufacture
11666683 · 2023-06-06
Assignee
Inventors
Cpc classification
A61F2002/077
HUMAN NECESSITIES
International classification
A61L27/50
HUMAN NECESSITIES
Abstract
A medical textile product includes a textile substrate having opposed first and second surfaces with the textile substrate including a textile construction of one or more yarns. The second surface includes a coating of a substantially water-insoluble, non-porous elastomeric sealant. The one or more yarns at the first surface are pre-treated with a removable composition, such that the water-insoluble elastomeric sealant encapsulates a portion of fibers of the one or more yarns at the second surface of the textile substrate. The textile substrate is substantially impermeable to fluid. The first surface is substantially free of the substantially water-insoluble elastomeric sealant. The textile substrate may be a non-tubular substrate, such as a planar sheet, a shaped sheet, and a tape, or a tubular substrate, such as a cylindrical conduit, a tubular conduit, a Y-shaped, a T-shaped conduit, a multi-channel conduit, and a bulbous shaped conduit.
Claims
1. A medical textile product comprising: a textile substrate having opposed first and second surfaces, the textile substrate comprising a textile construction of one or more yarns; wherein the second surface comprises a coating of a substantially water-insoluble, non-porous elastomeric sealant, disposed thereon; wherein the one or more yarns at the first surface are pre-treated with a removable composition, which removable composition is substantially removed prior to use or implantation, such that the water-insoluble elastomeric sealant encapsulates a portion of fibers of the one or more yarns at the second surface of the textile substrate; wherein the textile substrate is substantially impermeable to fluid; and wherein the first surface is substantially free of the substantially water-insoluble elastomeric sealant.
2. The medical textile product of claim 1, wherein the first surface is at least 70% free of the substantially water-insoluble elastomeric sealant.
3. The medical textile product of claim 1, wherein the first surface is at least 80% free of the substantially water-insoluble elastomeric sealant.
4. The medical textile product of claim 1, wherein the first surface is at least 90% free of the substantially water-insoluble elastomeric sealant.
5. The medical textile product of claim 1, wherein the first surface is at least 95% free of the substantially water-insoluble elastomeric sealant.
6. The medical textile product of claim 1, wherein the textile construction is selected from the group consisting of a weave of the one or more yarns, a knit of the one or more yarns, a braid of the one or more yarns, a web of the one or more yarns, a felt of the one or more yarns, and a mesh of the one or more yarns.
7. The medical textile product of claim 1, wherein the coating is disposed within an intermediate portion of the non-tubular textile substrate between the second surface and the first surface.
8. The medical textile product of claim 1, wherein the substantially water-insoluble elastomeric sealant is a material selected from the group consisting of silicones, polyurethanes, polycarbonates, thermoplastic elastomers, and combinations thereof.
9. The medical textile product of claim 1, wherein the removable composition is a water-soluble material is selected from the group consisting of polyvinylpyrrolidone, glycerol, methyl cellulose, poly(ethylene glycol), poly(ethylene glycol) hydrogel, polyethylene oxide, and combinations thereof.
10. The medical textile product of claim 1, wherein one portion of the textile substrate has a first level of the substantially water-insoluble elastomeric sealant to provide a first soft, flexible zone; wherein another portion of the textile substrate has a second level of the substantially water-insoluble elastomeric sealant to provide a second zone having a stiffness greater than the first zone; and wherein the second level the substantially water-insoluble elastomeric sealant is greater than the first level of the substantially water-insoluble sealant.
11. The medical textile product of claim 10, wherein the textile substrate has a plurality of portions having different levels of the substantially water-insoluble elastomeric sealants to provide a plurality of portions having different levels of stiffnesses.
12. The medical textile product of claim 1, wherein the coating of the substantially water-insoluble elastomeric sealant is disposed within an intermediate portion of the textile substrate between the second surface and the first surface.
13. The medical textile product of claim of claim 1, wherein the textile substrate is a non-tubular substrate.
14. The medical textile product of claim 13, wherein the non-tubular textile substrate is selected from the group consisting a planar sheet, a shaped sheet, and a tape.
15. The medical textile product of claim 13, wherein the medical textile product is selected from the group consisting a mesh, a patch, a hernia plug, and vascular wrap.
16. The medical textile product of claim 1, wherein the substantially water-insoluble elastomeric sealant further comprises a material selected from the group consisting of a colorant, a dye, a pigment, and a fluorescent indicator.
17. The medical textile product of claim 13, wherein the substantially water-insoluble elastomeric sealant further comprises a material selected from the group consisting of a colorant, a dye, a pigment, and a fluorescent indicator.
18. The medical textile product of claim 1, wherein the textile substrate is a tubular substrate.
19. The medical textile product of claim 18, wherein the tubular textile substrate is a conduit selected from the group consisting of a cylindrical conduit, a tubular conduit, a Y-shaped, a T-shaped conduit, a multi-channel conduit, a bulbous shaped conduit, and combinations thereof.
20. The medical textile product of claim 19, wherein the textile construction of one or more yarns defines the tubular textile wall, wherein the first surface is an inner surface of the tubular textile wall; and wherein the second surface is an outer surface of the tubular textile wall.
21. The medical textile product of claim 20, further comprising a support member disposed about the tubular textile wall.
22. The medical textile product of claim 21, wherein the support member is disposed about the outer surface of the tubular textile wall.
23. The medical textile product of claim 22, wherein the support member is wrapped around the outer surface of the tubular textile wall.
24. The medical textile product of claim 20, wherein the tubular textile wall comprises a plurality of crimps, and the support member is arranged to nest between the plurality of crimps.
25. The medical textile product of claim 21, wherein the support member is a flexible, polymer member.
26. The medical textile product of claim 21, wherein the support member is a metallic member.
27. The medical textile product of claim 13, further comprising a support member disposed along a portion of the second surface of the textile substrate.
28. The medical textile product of claim 13, further comprising a support member disposed along a portion of the first surface of the textile substrate.
29. The medical textile product of claim 28, further comprising a support member disposed along a portion of the first surface of the textile substrate.
30. The medical textile product of claim 1, wherein the removable composition is a coating or layer.
Description
BRIEF DESCRIPTION OF THE DRAWINGS
(1) Embodiments of the invention will now be described, by way of example, with reference to the drawings, in which:
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DESCRIPTION OF EMBODIMENTS
(29) As used herein the term “substantially” and its equivalents refer to being at least 70% of a stated value, desirably within at least 80% of a stated value, and more desirably within 90% or 95% of a stated value.
(30) As used herein the terms “about” or “approximate” and their equivalents refer to being within (plus and/or minus) at least 20% of a stated value, desirably within at least 10% of a stated value, and more desirably within 5% of a stated value.
(31) As used herein the terms “layer” and “coating” may be used interchangeably to refer to a deposition of material over, underneath, or within a substrate, such as a textile substrate.
(32) As used herein masking agent shall refer to any suitable non-biological, e.g., synthetic, hydrophilic polymer and any suitable biological hydrophilic polymer. However, it should be understood that other masking agents may be used.
(33) With reference to
(34)
(35) The conduit 10 comprises polyethylene terephthalate (PET). However, it should be understood that the conduit 10 could comprise other materials, such as polytetrafluoroethylene (PTFE). Other suitable polymers for medical textile applications may include, but are not limited to polyolefin, polyester, poly(ether amide), poly(ether ester), poly(ether urethane), poly(ester urethane), poly(ethylene-styrene/butylene-styrene), and other block copolymers.
(36) In the embodiment illustrated and described here, the weft yarn pick-rate of the conduit 10 is approximately 45 ppcm. However, it should be understood that the weft yarn pick-rate of the conduit 10 could be between approximately 25 ppcm and approximately 50 ppcm.
(37) The conduit 10 is moveable between a contracted state and an extended state.
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(39) The conduit 10 depicted in
(40) In the embodiment illustrated here, the conduit 10 has a substantially uniform cross section throughout. However, it should be understood that the conduit 10 could have an irregular cross section throughout. For example, if the conduit 10 is to be connected between a further prosthesis, such as a heart valve, and an end of a severed blood vessel, the conduit 10 could have an irregular cross section throughout. As described in more detail below, in some embodiments the conduit 10 could be configured to have differing degrees of flexibility, either by selectively adding sealant 14 to different sections of the conduit 10, or in other ways.
(41) As described above, it is desirable for the inner surface 10a of the wall 10f of the conduit 10 to remain free from, or substantially devoid of, the material used to seal the conduit 10. The reason for this is to ensure that the inner surface 10a of the wall 10f of the conduit 10, remains of a porous 10e, woven nature, to ensure that when the vascular prosthesis 16 is implanted in the human or animal body, biological tissue will grow into the inner surface 10a of the wall 10f of the conduit 10. This is important to ensure that ingrowing biological tissue forms a pseudointima (an example of an inner biological tissue layer within a vascular prosthesis). Furthermore, in addition to the promotion of biological tissue growth on the inner surface 10a of the wall 10f of the conduit 10, it is also advantageous if the biological tissue layer growing on the inner surface 10a of the wall 10f of the conduit 10 has good adhesion to the inner surface 10a. If the adhesion between the biological tissue layer and the inner surface 10a is insufficient, complications can arise such as haemorrhagic dissection.
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(43) Prior to the addition of the masking agent 12 to the conduit 10, the conduit 10 is weighed. The weight of the conduit 10 is then used, at least in part, to determine the amount of masking agent 12 to add to the conduit 10.
(44) In this embodiment, the masking agent 12 is applied from a masking agent solution. The masking agent solution is a polymer solution. In the embodiment illustrated and described here, the polymer solution comprises approximately 7% w/v PVP (an example of a water-soluble polymer) in water (an example of a solvent). However, it should be understood that other polymers, such as glycerol, methyl cellulose and/or PEG could be used. Furthermore, it will be understood that the polymer solution could comprise between approximately 5% w/v PVP in solution and approximately 30% w/v PVP in solution. Moreover, the polymer solution could comprise between approximately 5% w/v polymer in solution and approximately 30% w/v polymer in solution. It should be understood that the masking agent 12 could comprise approximately 1% w/v of glycerol in solution. Without wishing to be bound by theory, it is thought that an advantage of adding glycerol to the masking agent 12 is that it mitigates cracking of the masking agent 12 when the masking agent 12 is added to the conduit 10.
(45) In the embodiment described here, the masking agent 12 comprises PVP with a molecular weight of approximately 10,000 g/mol. However, it should be understood that the masking agent 12 could comprise PVP with a molecular weight of between approximately 6,000 g/mol and approximately 15,000 g/mol.
(46) While in the embodiment described here the masking agent 12 comprises PVP, it should be understood that the masking agent 12 could comprise glycerol, methyl cellulose, PEG, PEO, and/or PEG hydrogel.
(47) In the embodiment illustrated and described here, the masking agent 12 is biocompatible. However, it should be understood that, in some embodiments the masking agent 12 need not be biocompatible. For example, as described in more detail below, if substantially all of the masking agent 12 is to be removed from the conduit 10, then the masking agent 12 need not be biocompatible. In some embodiments, the masking agent 12 need not be removed, and in some embodiments only a part of the masking agent 12 is removed. In these arrangements, it is advantageous that the masking agent 12 is biocompatible, which allows the conduit 10 to be implanted in the human or animal body.
(48) In this embodiment, the masking agent 12 is biodegradable. Therefore, any residual masking agent 12 present on the conduit 10 will biodegrade when the conduit 10 is implanted in the human or animal body. However, the masking agent 12 could be non-biodegradable. In this embodiment, substantially all of the masking agent 12 is removed from the conduit 10 prior to implantation, and therefore it is not necessary for the masking agent 12 to be biodegradable. In some embodiments, it may be advantageous for the masking agent 12 to be biodegradable.
(49) With reference to
(50) In this embodiment, the masking agent solution is applied to the conduit 10 by immersing the conduit 10 in the masking agent solution for approximately 1 minute, while agitating the conduit 10. However, it should be understood that the masking agent solution could be added to the conduit 10 in other ways, such as by dipping, spray coating, or by brushing. Furthermore, it should be understood that the masking agent 12 could be added to the conduit 10 without agitating the conduit 10. During the step of immersing the conduit 10 in the masking agent solution, the conduit 10 is moved between the contracted state and the extended state. However, it should be understood that the conduit 10 could be immersed in the masking agent solution while the conduit 10 is in the contracted state and/or the extended state.
(51) In this embodiment, when the masking agent solution is added to the conduit 10, solvent is then evaporated from the masking agent solution. Solvent is therefore removed from the masking agent solution, and the masking agent 12 remains on the conduit 10.
(52) In this embodiment, during the addition of the masking agent 12 to the conduit 10, a directed flow of air (an example of a gas) is provided to the conduit 10. The directed flow of air is directed towards the outer surface 10b of the wall 10f of the conduit 10, such that the masking agent 12 is preferentially formed on the inner surface 10a of the wall 10f of the conduit 10. It should be understood that while directed air flow is used here, other gases could be used.
(53) In this embodiment, the masking agent 12 is formed, or added, substantially on the inner surface 10a of the wall 10f of the conduit 10. However, it should be understood that the masking agent 12 could be added to the outer surface 10b of the wall 10f of the conduit 10. The masking agent 12 is added to the porous section 10e of the conduit 10, although in other embodiments the masking agent 12 could be added to at least a part of the porous section 10e of the conduit 10. In this embodiment, the masking agent 12 forms a masking agent layer substantially on the inner surface 10a of the wall 10f of the conduit 10. However, it should be understood that the masking agent 12 could be added to other parts of the conduit 10, and that the masking agent 12 could form a masking agent layer on other parts of the conduit 10.
(54) In the manufacturing process illustrated and described here, the residual masking agent 12 on the outer surface 10b of the wall 10f of the conduit 10 is removed prior to the addition of the sealant 14, in order to improve the adhesion between the sealant 14 (when applied to the conduit 10) and the outer surface 10b of the wall 10f of the conduit 10. In this embodiment, the residual masking agent 12 on the outer surface 10b is removed by ablating (an example of a first masking agent removal step). However, it should be understood that the masking agent 12 could be removed by applying a solvent, by heating, by etching, by plasma etching, by abrading, and/or by other techniques.
(55) In the embodiment shown in
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(57) When the sealant solution is applied to the conduit 10, solvent is evaporated from the sealant solution, which results in the formation of the sealant 14.
(58) While in the embodiment illustrated and described here the sealant 14 is added to the conduit 10 from a sealant solution, it will be understood that the sealant 14 could be added to the conduit 10 in other ways and need not be added from a sealant solution.
(59) The sealant 14 is added to the porous section 10e of the conduit 10. Therefore, in this embodiment, the sealant 14 is added to substantially all of the conduit 10, as in this embodiment the conduit 10 is entirely porous 10e. In other embodiments, the sealant 14 could be added to a part of the porous section 10e.
(60) The presence of the masking agent 12 prevents the sealant 14 from adhering, or forming on, the inner surface 10a of the wall 10f of the conduit 10. The sealant 14 is applied to the conduit 10 by spraying the sealant 14 onto the outer section 10b of the conduit 10. However, it should be understood that other techniques for adding the sealant 14 to the conduit 10 could be used, such as brushing, wiping, immersing, dipping, vapour depositing, such as chemical vapour depositing, electrostatic spinning, and/or by casting.
(61) In this embodiment, the sealant 14 is applied to the conduit 10, while the conduit 10 is in the extended state. However, it should be understood that the sealant 14 could be applied to the conduit 10 while the conduit 10 is in the contracted state or when the conduit 10 is moved between the contracted state and the extended state.
(62) In this embodiment, the sealant 14 is added to the conduit 10 while the conduit 10 is rotated about its longitudinal axis at approximately 60 rpm. However, it should be understood that the conduit 10 could be rotated about its longitudinal axis at up to approximately 2,000 rpm.
(63) In the embodiment described here, the sealant 14 comprises approximately 8 mg/cm.sup.2 of silicone. However, it should be understood that the sealant could comprise between approximately 4 mg/cm.sup.2 of silicone and approximately 19 mg/cm.sup.2 of silicone.
(64) Spraying and/or brushing the sealant 14 onto the outer surface 10b of the wall 10f of the conduit 10 is advantageous over some sealant application techniques because the sealant 14 is applied substantially only to the outer surface 10b of the conduit 10 and is not substantially applied to the inner surface 10a of the conduit 10. In this arrangement, the masking agent 12, and the addition of the sealant 14 to the conduit 10 by way of spraying, and/or brushing, the sealant 14 onto the conduit 10, mitigate presence of the sealant 14 on the inner surface 10a of the wall 10f of the conduit 10. However, it should be understood that other sealant 14 application techniques, such as wiping the sealant 14 onto the conduit 10, could be used.
(65) In the embodiment illustrated and described here, it is advantageous if, when the sealant 14 is applied to the conduit 10, the masking agent 12 is not substantially covered, or blocked, by the sealant 14. The reason for this is that, if at least a part of the masking agent 12 is to be removed from the conduit 10, it is easier to remove the masking agent 12 if at least some of the masking agent 12 is exposed. For example, when removing at least a part of the masking agent 12 from the conduit 10 by applying a solvent, it is easier to do so if at least some of the masking agent 12 is exposed. In the embodiments described here, a significant amount of the masking agent 12 is exposed, and it is therefore relatively straightforward to use a variety of masking agent 12 removal techniques.
(66) In this embodiment, the addition of the sealant 14 to the porous section 10e of the conduit 10 forms a sealing layer on the outer surface 10b of the wall 10f of the conduit 10. In this embodiment, the sealant 14 is biocompatible.
(67) In this embodiment, the sealant 14, when applied to the conduit 10, is configured to mitigate against environmental stress cracking.
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(69) In the embodiment described here and shown in
(70) In the embodiment depicted in
(71) In the embodiment illustrated and described here, the step of removing substantially all of the masking agent 12 from the conduit 10 does not result in the removal of the sealant 14 from the conduit 10.
(72) As described in detail above, the manufacturing process comprises a first masking agent removal step, designed to improve the adhesion of the sealant 14 to the conduit 10, and a second masking agent removal step, designed primarily to remove the masking agent 12 from the inner surface 10a of the wall 10f of the conduit 10. However, it will be understood that multiple masking agent removal steps could be carried out. It should also be understood that for some embodiments of the invention it may not be necessary to carry out a masking agent removal step.
(73) In the embodiment illustrated and described here, the vascular prosthesis 16 is reversibly sealable. That is, the sealant 14 could be removed from the conduit 10 and the sealant 14 could be applied to the conduit 10. For example, this could be necessary in the event of a manufacturing error. Similarly, the masking agent 12 may be added, and removed from, and subsequently added to the conduit 10. This could be necessary when carrying out more than one masking agent addition step.
(74) In the embodiment illustrated and described here, the vascular prosthesis 16 can be sterilised by way of a gamma sterilisation process. However, it should be understood that the vascular prosthesis 16 could be sterilised by way of an electron beam sterilisation process. Another option for sterilising the vascular prosthesis 16 is to carry out ethylene oxide sterilisation. It will be appreciated that other sterilisation techniques could be applied to the vascular graft 16, either as an alternative to, or in addition to those described here.
(75) The vascular prosthesis 16 depicted in
(76) The vascular prosthesis 16 illustrated in
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(78) The woven nature of the conduit 10 means that it is flexible. After applying the masking agent 12 and the sealing layer 14, the vascular graft 16 remains flexible, which helps to make the vascular graft 16 easier to manipulate and handle by, for example, a medical practitioner.
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(80) In the embodiment shown in
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(86) In the embodiment shown in
(87) One desirable feature for a sealed graft is that it may have sufficiently low levels of permeability to remain predominantly leak proof during the implant procedure. The applicable test method, as prescribed in ISO 7198, Whole Graft Permeability recommends testing using reverse osmosis (RO) filtered water at a test pressure of 120 mmHg. This parameter was based on a de facto standard established by the manufacturers of biologically sealed grafts (gelatin and collagen). A limit of 0.16 ml/min/cm.sup.2 may be used to ensure that the graft meets and exceeds sealing capability of aforementioned grafts. Different applications, however, may have different permeability requirements, and such different permeability requirements are within the scope of the present invention.
(88) Further embodiments were prepared according to the manufacturing process illustrated in
(89) Commercial textile vascular grafts were used for the tests described hereinafter. Details for commercial graft samples are described below:
(90) First Commercial Samples of Woven Graft Fabrics:
(91) (a) Warp yarn: twisted, texturized, PET, 2 ply/44 denier per ply (or bundle)/27 filaments per ply or bundle.
(92) (b) Weft yarn: twisted, texturized, PET, 2 ply/44 denier per ply (or bundle)/27 filaments per ply or bundle.
(93) (c) Picks per cm, about 40 to 46.
(94) Second Commercial Samples of Woven Graft Fabrics:
(95) (a) Warp yarn: 80 Denier, 2 ply/40 denier per ply (or bundle)/27 filaments per ply (or bundle), PET, Spun Draw, texturized, 7.5 Twists per inch, Z twist.
(96) (b) Weft yarn: 2 ply/40 Denier per ply (or bundle), 2 ply/40 denier per ply (or bundle)/27 filaments per ply or bundle, PET, TXT, S & Z Twist.
(97) (c) Picks per inch, about 155.
(98) The tests done below in Table 1 were performed on the first commercial samples of woven graft fabrics.
(99) TABLE-US-00001 TABLE 1 Sealant Sealant Leak Rate Masking Agent Sealant Coating Coverage Leak Rate ≤0.16 Polymer Solvent Polymer Solvent Method (mg/cm.sup.2) (ml/min/cm.sup.2) ml/min/cm.sup.2 7% w/v Water 30% w/v Xylene Brush × 1 11.33 0.19 No PVP Silicone 7% w/v Water 30% w/v Xylene Brush × 1 8.30 0.19 No PVP Silicone 4% w/v Water TPU and THF Brush × 1 2.00 5.79 No PVP Silicone 4% w/v Water TPU and THF Brush × 2 3.70 0.46 No PVP Silicone 30% w/v Water 30% w/v Xylene Brush × 1 5.3 1.78 No PVP Silicone 30% w/v Water 30% w/v Xylene Brush × 1 5.2 3.49 No PVP Silicone 30% w/v Water 30% w/v Xylene Brush × 1 7.6 >12.24 No PVP Silicone 25% w/v Water 30% w/v Xylene Brush × 1 — — No PVP and Silicone 18% w/v Glycerol 7% w/v Water 30% w/v Xylene Brush × 1 4.8 0 Yes PVP Silicone 7% w/v Water 30% w/v Xylene Brush × 2 8.9 0 Yes PVP Silicone 7% w/v Water 30% w/v Xylene Brush × 3 8.3 0 Yes PVP Silicone 7% w/v Water 30% w/v Heptane Brush × 1 7.6 0.69 No PVP Silicone 7% w/v Water 30% w/v Heptane Brush × 2 13.8 0.02 Yes PVP Silicone 7% w/v Water 30% w/v Heptane Brush × 3 18.6 0 Yes PVP Silicone 7% w/v Water 30% w/v Xylene Brush × 1 8.0 0.09 Yes PVP Silicone 7% w/v Water 30% w/v Xylene Brush × 2 11.5 0.14 Yes PVP Silicone 7% w/v Water 30% w/v Xylene Brush × 2 11.5 0.05 Yes PVP Silicone 7% w/v Water 30% w/v Xylene Brush × 3 15.6 0 Yes PVP Silicone 7% w/v Water 30% w/v Xylene Brush × 1 7.1 0.01 Yes PVP Silicone 7% w/v Water 30% w/v Xylene Brush × 2 9.7 0.03 Yes PVP Silicone 7% w/v Water 30% w/v Xylene Brush × 2 9.1 0.03 Yes PVP Silicone 7% w/v Water 30% w/v Xylene Brush × 3 12.6 0.02 Yes PVP Silicone 7% w/v Water 30% w/v Xylene Brush × 1 6.0 0.22 No PVP Silicone 7% w/v Water 30% w/v Xylene Brush × 2 14.3 0.03 Yes PVP Silicone 7% w/v Water 30% w/v Xylene Brush × 2 9.8 0.10 Yes PVP Silicone 7% w/v Water 30% w/v Xylene Brush × 3 13.8 0.06 Yes PVP Silicone 12% w/v Water 30% w/v Xylene Brush × 2 11.0 6.25 No PVP Silicone 12% w/v Water 30% w/v Xylene Brush × 2 11.3 1.81 No PVP Silicone 7% w/v Water 15% w/v Xylene Spray × 1 3.5 7.24 No PVP Silicone 7% w/v Water 15% w/v Xylene Spray × 2 5.6 0.07 Yes PVP Silicone 7% w/v Water 15% w/v Xylene Spray × 3 5.3 0.57 No PVP Silicone 7% w/v Water 15% w/v Xylene Spray × 1 6.7 5.11 No PVP Silicone 7% w/v Water 15% w/v Xylene Spray × 1 8.7 0.01 Yes PVP Silicone 7% w/v Water 15% w/v Xylene Spray × 1 6.4 0.02 Yes PVP Silicone 7% w/v Water 15% w/v Xylene Spray × 1 4 8.41 No PVP Silicone 7% w/v Water 15% w/v Xylene Spray × 1 6.3 8.99 No PVP Silicone 7% w/v Water 15% w/v Xylene Spray × 1 3.8 5.05 No PVP Silicone 7% w/v Water 15% w/v Xylene Spray × 1 8.1 1.17 No PVP Silicone 7% w/v Water 15% w/v Xylene Spray × 1 7.9 0.14 Yes PVP Silicone 7% w/v Water 15% w/v Xylene Spray × 1 8.2 5.94 No PVP Silicone 7% w/v Water 15% w/v Xylene Spray × 1 8.8 1.08 No PVP Silicone 7% w/v Water 15% w/v Xylene Spray × 1 11.4 0.01 Yes PVP Silicone 7% w/v Water 15% w/v Xylene Spray × 1 6.8 5.93 No PVP Silicone 7% w/v Water 15% w/v Xylene Spray × 1 7.4 0.16 Yes PVP Silicone 7% w/v Water 15% w/v Xylene Spray × 1 11.9 0 Yes PVP Silicone 6% w/v Water 15% w/v Xylene Spray × 1 7.8 0.04 Yes PVP and Silicone 1% w/v Glycerol
(100) A hobby spray gun was used for all spray application tests where sealants were sprayed onto graft samples. The spray distance from the graft samples was approximately 50 mm. Grafts were held horizontally on mandrel and rotated in a rotisserie. Spray rates were not measured but were controlled by a combination of the nozzle traverse rate (estimated at 2 seconds/cm), graft rotation speed (estimated between one and three revolutions per second) and overall spray volume rate. Craft bristle brushes were used for all brush application tests where sealants were brushed onto graft samples.
(101) As indicated in Table 1, if the wall 10f has a Leak Rate ≤0.16 ml/min/cm.sup.2 then the conduit 10 is considered suitable for implantation and is considered substantially impermeable. In some further embodiments, the masking agent 12 comprises glycerol. Without wishing to be bound by theory, the presence of glycerol in the masking agent 12 is thought to mitigate cracking of the masking agent 12 when applied to the conduit 10.
(102) Masking agents described herein prevent sealants, such as the liquid silicone elastomer dispersion, from penetrating throughout the thickness of the graft wall and reaching the lumen or blood contacting surface of the graft. Sealants, such as silicone, are believed to adhere to graft fibres on the external surface of the graft through two mechanisms: a. Where graft fibres have had the mask agent ablated or otherwise free of the masking agents, the liquid silicone elastomer dispersion adheres to the surface of the graft fibres, such as PET fibres. b. Where surface fibres are individually sheathed by the masking agent, these fibres are encapsulated and a mechanical interlocking takes place rather than surface adhesion.
(103) Silicone will adhere to the PET fibre surface where there is no masking agent, but will also encapsulate PET fibres which are sheathed in masking agent.
(104) The masking agent is believed to act like a slurry when applied to a textile and can flow and cover gaps between the yarn bundles and also seep between the yarn fibers. It acts as a viscous mixture moving through the fabric and settling and collecting at areas of low energy. Rather than attaching to individual fibers it continues to move and pool until a masking agent drying process initiates and through the evaporation of its solvent, such as water, the masking agent then solidifies wherever it has gathered.
(105) The elastomeric sealant (e.g., silicone) may not adequately attach to the textile surface where excessive concentrations of masking agent are present. If the masking agent is too viscous and has fully encapsulated an area of fabric and then dried, there may be no exposed yarn filaments for the silicone to mechanically encapsulate and lock onto. Without this mechanical encapsulation of the yarn by the silicone, then the adhesion may be poor and possibly non-existent once the masking agent is removed.
(106) While the masking agent may appear to thinly coat the individual filaments as it moves or washes through the textile, the concentrations remaining in these washed through areas after drying are not sufficient to prevent subsequent encapsulation and adhesion of the silicone adhesive to the yarn bundles.
(107) Any synthetic hydrophilic polymer and any biological hydrophilic polymer, e.g., gelatin, partially hydrolysed collagen, dextran, hyaluronic acid, alginates and starches (e.g., hydroxyethyl starch) and chitosan may be used as masking agents. Pluronic F127 PEG, which is soluble in cold water but insoluble in warm water, may also be used as a masking agent. Desirably, masking agents derived from animal products may are removed prior to vascular applications. As such, the masking agents, including animal derived masking agents, if any, are removed from the final product, such grafts may suitable be used in vascular applications. Furthermore, as the masking agents are removed from the textile graft prior to any applications with a patient, including vascular applications, the masking agents need not be biocompatible.
(108) Desirably, the masking agent is highly soluble in water. It can be any polymer which can swell in a liquid which has a Hildebrand Solubility Parameter (Delta SI units) of 24 or higher.
(109) Masking agents useful with the present invention may have molecular weights from about 400 or 1,000 to about 1,000,000. Desirably, the molecular weight may vary from about 3,000 to about 30,000, and more desirably from about 6,000 to about 15,000
(110) One useful sealant may be a dispersion of silicone in a nonpolar ‘solvent’ or carrier medium. Useful cross linking is through acetoxy ‘room temp vulcanisation’ chemistry but two part platinum cure chemistry could also be used as well as ultraviolet (UV) curing.
(111) For samples employing a polymer supplied as a dispersion, for example NuSil MED 6605 and Med 6606, discrete amounts of polymer dispersion were decanted by weight into individual pots for either direct coating onto the graft or further addition of solvent, by weight.
(112) All silicone dispersions used were acetoxy curing. Curing schedules are recommended at 72 hours, however due to the extremely thin cross section/large surface area of the graft, full cures have been observed apparent within 24 hours. Subsequent washing of the device in water may speed up the curing and ensure full cross linking. These times are, however, non-limiting, and other cure times and conditions may suitably be used.
(113) The preferred polymers for coating, in order to achieve a soft and flexible graft with handling characteristics similar to that of a gelatin sealed graft, are those with very low Shore hardness values. The preferred silicone elastomers, MED 6605 and MED 6605 have Durometer Type A values of 25 and 20 respectively. Both of these grades can provide grafts with suitable flexibility and handling characteristics, when thin coatings are applied. As multiple coatings are applied, stiffness may increase and flexibility may reduce.
(114) Harder grades can be used as an alternative to thicker coatings in order to create stiffer grafts if required.
(115) Alternative coatings, such as TPU-Silicones (Advansource Chronosil 75 A or Aor-Tech Elast-Eon E5-130) can be used however, these have Durometer Hardness of 75 A and 77 A respectively, therefore may create grafts which may be stiffer, if desired, than current gelatin sealed grafts. Such stiffer grafts may have some benefits for specific applications, however, may not meet expectations for conventional surgeon handling.
(116) Additional useful sealant materials include, but are not limited to:
(117) (a) Applied Silicone Corporation, PN 40021, Implant grade high strength RTV Silicone Elastomer Dispersion in Xylene. This material is suitable for use in fabricating high strength, elastic membranes of any shape and thickness using processes such as dipping, casting, spraying or brushing. After evaporating the solvent, the silicone is room temperature vulcanized (RTV) by exposure to ambient air. The key features of this material are high strength, low durometer, (Shore A 24) and is supported by ISO 10993 testing and compendium to support regulatory submissions.
(b) AdvanSource Biomaterials Corporation, ChronoFlex AR, polycarbonate based thermoplastic urethanes. These materials may be used for moulding, casting and dip-coating and are fully synthesized in liquid providing high strength & elongation while maintaining the inherent polycarbonate advantage of long-term permanent durability and resistance to environmental stress cracking (ESC). Additionally, they may be electrospun or used in water emulsion processes. Examples of specific useful materials include, but are not limited to, ChronoFlex C80 A 5% and ChronoFlex AR 23%.
(118) Suitable sealants are low durometer elastomers (desirably less than or equal to about 40 A durometer or shore hardness 40 A, more desirably less than or equal to about 30 A durometer or shore hardness 30 A, even more desirably less than or equal to about 20 A durometer or shore hardness 20 A) and have good biostability.
(119) One parameter which may be considered in the choice of sealant is the stiffness or elastic modulus. Usually with elastomers the modulus is not linear thus at each elongation the stress (or force) is measured. A material with lower stress @ % strain will provide less resistance to extension and will therefore feel more flexible and closer to matching the handling of a gelatin sealed graft.
(120) Preferred materials are low stress silicone rubbers, such as NuSil MED 6605 and MED 6606, with Stress @ Strain values <180 @ 200%.
(121) Useful Polyurethane and Silicone-polyurethane grades, include, but are not limited to:
(122) TABLE-US-00002 TABLE 2 Stress (psi) at Material Manufacturer Grade % elongation Silicone Rubber NuSil MED 6606 50 @ 100% Silicone Rubber NuSil MED 6605 160 @ 300% Silicone Rubber Applied Dispersion PN 170 @ 300% Silicone 40021 TPU - Silicone Advansource ChronoSil adjusted 570 @ 200% TPU - silicone Biomerics Quadrasil Elast- 725 @ 200% EON E5-130 TPU - aliphatic Advansource Chronoflex AL 800 @ 200% polycarbonate 75A TPU - 10% silicone Advansource ChronoSil 75A 834 @ 200% 10% Si
(123) The present invention is not limited to the use of silicone as the polymeric sealant. Other useful coating materials for both medical and non-medical textiles may include, for example, polytetrafluoroethylene, polyethylene, poly(hydroxyethly methacrylate), poly(vinyl alcohol), polycaprolactone, poly(D, L-lactic acid), poly(L-lactic acid), poly(lactide-co-glycolide), poly(hydroxybutyrate), poly(hydroxybutyrate-co-valerate), polydioxanone, polyorthoester, polyanhydride, poly(glycolic acid), poly(glycolic acid-cotrimethylene carbonate), polyphosphoester, polyphosphoester urethane, poly(amino acids), cyanoacrylates, poly(trimethylene carbonate), poly(iminocarbonate), copoly(ether-esters), polyalkylene oxalates, polyphosphazenes, polyiminocarbonates, aliphatic polycarbonate, polyethylene oxide, polyethylene gylcol, poly(propylene oxide), polyacrylamide, polyacrylic acid (30-60% solution), polymethacrylic acid, poly(N-vinyl-2-pyrollidone), polyurethane, poly(aminoacid), cellulosic polymer (e.g. sodium carboxymethyl cellulose, hydroxyethyl celluslose), collagen, carrageenan, alginate, starch, dextrin, gelatin, poly(lactide), poly(glycolide), polydioxanone, polycaprolactone, polyhydroxybutyrate, poly(phospazazene), poly(phosphate ester), poly(lactide-co-glycolide), poly(glycolide-co-trimethylene carbonate), poly(glycolide-co-caprolactone), polyanhydride, polyamide, polyesters, polyether, polyketone, polyether elastomer, parylene, polyether amide elastomers, polyacrylate-based elastomer, polyethylene, polypropylene, and/or and derivatives thereof. Other useful coating materials, in particular for but not limited to non-medical textiles, may include natural rubbers, natural gums, acrylic polymers, polybutadienes, styrene-butadiene copolymers or rubbers, butadiene-acrylonitrile copolymers, polyisobutylenes, isoprene-isobutylene copolymers, polysulfide rubbers, chloroprene rubbers (neoprene), chlorosulfonated polyethylene, fluorinated polymers, vinyl resins, and the like. Further, coating materials may include metallic materials and powdered materials.
(124)
(125) The support member 18 is a flexible, polymer wire, which in this embodiment is wrapped around the outer surface 10b of the wall 10f of the conduit 10 and is arranged to nest between the crimps 10g of the conduit 10. One of the advantages of adding the support member 18 to the conduit 10, as illustrated and described here, is that the conduit 10 is made more robust while retaining much of its flexible characteristics. As stated above, the conduit 10 is able to be manipulated by a medical practitioner in a more efficient way because the conduit 10 is flexible.
(126) In the embodiment illustrated in
(127)
(128) An example of how the vascular graft 16 may be used will now be provided.
(129) The vascular graft 16 described in
(130) The masking agent 12 is configured to biodegrade in the body. Therefore, any residual masking agent 12 present on the conduit 10 will biodegrade in the body. However, as described in more detail above, the masking agent 12 need not be biodegradable, as in some embodiments the masking agent 12 will be removed substantially entirely from the conduit 10. In other embodiments, the masking agent 12 need not be removed from the conduit 10.
(131) The vascular graft 16 can be used to bypass a region, or a section of a blood vessel. For example, if a medical practitioner identifies a blocked, a diseased region or partially blocked region of a blood vessel, they may decide to bypass that region by using the vascular graft 16. In this example, the inlet 10c of the vascular graft 16 may be attached to one point of the blood vessel, and the outlet 10d of the vascular graft 16 may be attached to another point of the blood vessel. In another example, the blood vessel could be diseased, or have been severed or bisected in order to connect the vascular graft 16 to two ends of the severed blood vessel. Because the vascular graft 16 is sealed, blood may flow through the vascular graft 16 in order to bypass the blocked, diseased, or partially blocked region of the blood vessel, and the leaking of blood through the walls 10f of the conduit 10 is mitigated by the presence of the sealant 14.
(132) Once the vascular graft 16 is in place, biological tissue will grow into the inner section 10a of the vascular graft 16 in order to form a pseudointima. Over time, the psuedointima will form, adhering to the inner section 10a of the vascular graft 16. During this time, the vascular graft 16 prevents leakage of blood through the wall 10f and acts as a scaffold for the ingrowing biological tissue.
(133) The vascular graft 16 may also be used to connect a further prosthesis, such as a heart assist device, a biological heart valve or a synthetic heart valve, to a blood vessel. For example, the inlet 10c of the vascular graft 16 may be connected to an outlet of a synthetic heart valve, and the outlet 10d of the vascular graft 16 may be connected to an end of a blood vessel. The advantage of this use of the vascular graft 16 is that a heart assist component can be used with a wide variety of shapes and sizes of blood vessels, as the vascular graft 16 can be provided in a range of sizes. The medical practitioner is then able to select which particular vascular graft 16 will interface well with the synthetic heart valve and the blood vessel. This avoids the need for a range of different configurations of heart assist device to be used, as a standard part can be used and customised by adding different types and sizes of vascular graft 16. It will be appreciated that, depending on the nature of the heart assist device, multiple vascular grafts 16 could be used with the heart assist device.
(134) While the embodiments illustrated and described here show a cylindrical conduit 10 with an inlet 10c and an outlet 10d, other shapes of conduit 10 could be used. For example, a Y shaped, T-shaped, or a multi-channel conduit 10 could be used.
(135)
(136) The mandrel 20 may be used for a variety of purposes. For example, the mandrel 20 could be used to deliver the masking agent or the water-soluble material to a tubular textile, such as a graft. In such a use, a tubular textile (not shown) may be disposed over the outer surface 22 of the mandrel 20. The masking agent or the water-soluble material may be delivered into the open lumen 24 of the mandrel 20, for example into the open lumen 24 via an open end 26. The opposed end may be closed or open, such as in the case of a circulating system for the fluid masking agent or water-soluble material. The fluid masking agent or water-soluble material would flow through the perforations or holes 23 and onto and into the graft (not shown) disposed over the mandrel 20.
(137) The mandrel 20 may have a controlled amount of fluid masking agent or water-soluble material within the lumen 24 to control the amount of fluid masking agent or water-soluble material exposed to the graft (not shown). The fluid masking agent or water-soluble material contained within the mandrel 20 may be forced onto the graft through the use of a pressure differential (higher pressure within the lumen 24 than outside the lumen 24) or through rotational forces when the mandrel 20 is disposed on or within a rotating or spinning device.
(138) A mandrel not having the perforations 20 (not shown) may be used to dispose a layer of fluid masking agent or water-soluble material over the outer surface of the mandrel. The masking layer may be viscous enough or partially cured to remain on the mandrel until a graft is disposed over the mandrel. The masking layer may then be releasably disposed over the inner surface of the graft.
(139) The mandrel 20 may also be used for control of fluid migration. For example, the pressure within the lumen 24 may be lower than the pressure outside of the lumen 24. Such a negative pressure or vacuum may be used to migrate the masking agent or water-soluble material away from the outer surface of a graft (not shown).
(140) The mandrel 20 may also be used for drying the fluid masking agent or water-soluble material. A warm gas, such as air, may be introduced into the lumen 24, flow through the perforations or holes 23, and dry the fluid masking agent or water-soluble material. Alternatively, a heat source may be disposed outside of the mandrel 20, and the flow of heat, such as heated air, may be controlled through the application of a negative pressure at the lumen 24.
(141) A mandrel, either the same or different, may be used throughout different applications and techniques described herein, such as, but not limited to, masking agent application and/or dispersion, masking agent drying, sealant application and/or dispersion, sealant drying and/or curing, textile washing, and the like. A tubular textile may be substantially disposed over a mandrel or only a portion of the tubular textile may be disposed over a mandrel. For example, one end of a tubular textile may be supported by a mandrel and the other end of the tubular textile may be supported by a different mandrel, and the like.
(142) The substantially water-insoluble sealant may also be applied to the graft while the graft is on a solid or non-perforated mandrel or on a perforated mandrel 20. The substantially water-insoluble sealant may be applied to the graft by any suitable means, such as by brushing, spraying, roller coating, spinning the substantially water-insoluble sealant thereon.
(143) Furthermore, if desired the substantially water-insoluble sealant may be cured with the graft disposed over a mandrel.
(144) Further, other materials, such as colorants, therapeutic agents, dyes, fluorescent indicators, and the like maybe applied to the graft.
(145) Therapeutic agents may include, but are not limited to: anti-thrombogenic agents (such as heparin, heparin derivatives, urokinase, and PPack (dextrophenylalanine proline arginine chloromethylketone); anti-proliferative agents (such as enoxaprin, angiopeptin, or monoclonal antibodies capable of blocking smooth muscle cell proliferation, hirudin, and acetylsalicylic acid); anti-inflammatory agents (such as dexamethasone, prednisolone, corticosterone, budesonide, estrogen, sulfasalazine, and mesalamine); antineoplastic/antiproliferative/anti-miotic agents (such as paclitaxel, 5-fluorouracil, cisplatin, vinblastine, vincristine, epothilones, endostatin, angiostatin and thymidine kinase inhibitors); anesthetic agents (such as lidocaine, bupivacaine, and ropivacaine); anti-coagulants (such as D-Phe-Pro-Arg chloromethyl keton, an RGD peptide-containing compound, heparin, antithrombin compounds, platelet receptor antagonists, anti-thrombin antibodies, anti-platelet receptor antibodies, aspirin, prostaglandin inhibitors, platelet inhibitors and tick antiplatelet peptides); vascular cell growth promoters (such as growth factor inhibitors, growth factor receptor antagonists, transcriptional activators, and translational promotors); vascular cell growth inhibitors (such as growth factor inhibitors, growth factor receptor antagonists, transcriptional repressors, translational repressors, replication inhibitors, inhibitory antibodies, antibodies directed against growth factors, bifunctional molecules consisting of a growth factor and a cytotoxin, bifunctional molecules consisting of an antibody and a cytotoxin); cholesterol-lowering agents; vasodilating agents; agents which interfere with endogenous or vascoactive mechanisms; and combinations thereof.
(146) Masking Agent Drying and Uniformity Tests
(147) Tests were performed to determine how long it took for a standard woven graft immersed in PVP to dry at different concentrations, and if PVP dried in a homogeneous fashion throughout the textile. A series of tests at different concentrations of PVP were done to determine if the concentration made a difference on the drying nature of the substance.
(148) The tests used 15%, 10% & 5% PVP solution profiles. First, a 15% solution of PVP was made with 15 g of PVP and 100 mL of water. This was agitated until PVP was fully dissolved into solution. Graft samples were prepared by cutting approximately 50 mm of a commercial tubular graft. The graft samples were, if necessary, dried and were weighed. Graft samples were then soaked in the 15% PVP solution. The wet grafts were weighed to provide initial weights. The samples were placed vertically near a running fan. The graft samples were weighed at 5-minute intervals until there was a constant weight being displayed. The graft samples were cut into 4 labelled pieces. Each quarter piece was weighed. The quarter pieces were then washed, dried, re-weighed when fully dry. The lengths of the dry-washed graft were measured.
(149) Next, 50 mL of water was added to the 15% PVP solution in order to make a 10% PVP solution. The above textile processing steps were repeated for the 10% PVP solution
(150) Next 150 mL of water was added to the 10% PVP solution to make a 5% PVP solution. The above textile processing steps were repeated for the 5% PVP solution.
(151) Results: 15% PVP Profile
(152) TABLE-US-00003 TABLE 3 Time (min) Weight (g) Dry 1.709 0 4.817 5 4.229 10 3.81 15 3.399 20 3.056 25 2.775 30 2.543 35 2.36 40 2.235 45 2.152 50 2.122 55 2.117 60 2.113 65 2.113 Length measured Length (mm) Initial 51 Final 52 Quarter With PVP Without PVP wt % PVP in piece 1 0.507 0.418 17.6 2 0.519 0.421 18.9 3 0.569 0.461 19.0 4 0.516 0.427 17.2 Total 2.111 1.727 18.2 Total expected 2.113 1.709
(153) Table 3 showed that the 15% PVP coated graft took over an hour to dry fully in ambient air, it also showed that there was a slight increase in the length of the graft after being coated, washed and dried. After drying, the samples averaged 18.2 weight percent PVP. Further, the distribution of PVP among the samples was substantially consistent. Graft samples or pieces 2 and 3 had slightly higher PVP levels. These pieces had a seam of the graft on them, so it appeared that the seam was probably absorbing more PVP. Thus, about 15 to about 21 weight percent PVP was deposited onto the graft when immersed in the 15% PVP solution.
(154) Results: 10% PVP Profile
(155) TABLE-US-00004 TABLE 4 Time (min) Weight (g) Dry 1.699 0 4.891 5 4.292 10 3.881 15 3.491 20 3.159 25 2.849 30 2.580 35 2.124 40 2.040 45 2.000 50 1.994 55 1.994 Length measured Length (mm) Initial 48 Final 51 Quarter With PVP Without PVP wt % PVP in piece 1 0.543 0.469 13.6 2 0.598 0.51 14.7 3 0.394 0.334 15.2 4 0.459 0.394 14.2 Total 1.994 1.707 14.4 Total expected 1.994 1.699
(156) Table 4 showed that the 10% PVP covered graft took just under an hour to dry completely, and that the 10% PVP solution covering, washing and drying had also caused a slight increase in the length of the graft. The slightly higher weight % of PVP in pieces 2 and 3 also suggested that the seam of the graft absorbed more of the PVP than the rest of the graft. After drying, the samples averaged 14.4 weight percent PVP. Thus, about 10 to about 18 weight percent PVP was deposited onto the graft when immersed in the 10% PVP solution.
(157) Results: 5% PVP Profile
(158) TABLE-US-00005 TABLE 5 Time (min) Weight (g) Dry 1.514 0 3.197 5 2.735 10 2.385 15 2.070 20 1.820 25 1.650 30 1.590 35 1.588 40 1.588 Length measured Length (mm) Initial 47 Final 47 Quarter With PVP Without PVP wt % PVP in piece 1 0.357 0.348 2.5 2 0.423 0.406 4.0 3 0.432 0.412 4.6 4 0.371 0.354 4.6 Total 1.583 1.52 4.0 Total expected 1.588 1.514
(159) Table 5 showed that the 5% PVP covered graft took the least time to dry completely, and that its length did not seem to alter after coating, washing and drying, the PVP did to a minor degree to ‘sink’ to the bottom of this graft. Thus, about 2 to about 8 weight percent PVP was deposited onto the graft when immersed in the 5% PVP solution.
(160) Conclusions
(161) The 15% PVP covered graft took the most time to dry by approximately 25 minutes. In terms of drying evenly anyone of these concentrations was acceptable.
(162) Various drying techniques are suitable for use with the present invention. For example, textile grafts and/or textile substrates may be dried at room temperature to remove the solvent(s) from the deposited masking agent solution and/or from the sealant solution. Forced air, such as use of a fan or fans or other sources of air movement and/or sources of pressurized air, may be used to facilitate drying. The forced air, if any, may be applied at any suitable angle or combination of angles. The air may or may not flow into the interior lumen of the graft. For example, forced air may be directed towards outer surface of a tubular graft, either perpendicularly, substantially perpendicularly, at an acute angle, and/or at an obtuse angle. Moreover, forced air may be directed towards the interior lumen of the tubular graft, such as towards one open end of the tubular graft, or even from within the interior lumen of the tubular graft. The direction of air flow and the amount of extend of the air flow may be varied to control drying times and even to control resultant physical properties of the graft. Forced air flow may also be useful in aiding migration of the masking agent towards the interior portions of the graft and away from exterior portions of the graft. In other words the masking agent desirably retracts when drying. This would aid in the securement of the sealant material at the exterior portions of the textile graft while also aiding in the blocking of sealant migration towards the interior portions of the graft. The present invention, however, is not limited to the use of air as a drying medium, and other suitable media, including gaseous media, may be used. Further, the present invention is not limited to room temperature drying, and elevated drying temperatures above room temperature may suitably be used.
(163) Moreover, a fluid, such as water, including heated water, may be used with the present invention as described below. The use of heated water aids in the removal of the water-soluble masking agent from the textile product. Further, the use of heated water may also aid in curing of the sealant or sealing agent.
(164) Furthermore, drying and/or curing the sealant material may also be controlled using forced air or other medium, ambient forced air or other medium, heated forced air or other medium, non-forced ambient air or other medium, non-forced heated air or other medium, and the like. Not only may curing times of the sealant material be controlled, but also, to some extent, the properties of the sealant layer may be controlled. The sealant material may be selected, dried or cured, and or selectively deposited, such that the sealant material, as is cures, shrinks about the textile substrate, e.g., the outer surface of the textile graft.
(165) Masking Agent Removal Tests
(166) Different washing methods for the grafts were performed to determine which method would extract the highest levels of PVP and if the chosen method has any effect on the length and crimp of the graft.
(167) Two wash processes were considered, an Ultrawave ultrasonic bath and a domestic washing machine.
(168) Procedures
(169) Part 1: No Sealant Coating
(170) This trial was first done on 6 grafts that were not coated with silicone in order to establish if 100% of the PVP could be removed with the chosen washing methods.
(171) Grafts were prepared by cutting approximately 6×60 mm lengths of commercial woven grafts. All 6 grafts were measured, weighed, and labelled with notches cut into the side. A 15% PVP solution was made with 15 g of PVP and 100 mL of water. All 6 samples were submerged in the 15% PVP in solution. All 6 samples were dried vertically near a running fan. All dried samples were weighed.
(172) An ultrasonic bath was set to 40 degrees Celsius. Samples 1, 2, and 3 were submerged into the ultrasonic bath. Samples 1-3 were left in the ultrasonic bath for 15 minutes. These samples were removed from the ultrasonic bath and were dried vertically near a fan. The dried 1-3 samples were weighed and their lengths were measured and recorded.
(173) Samples 4, 5, and 6 were placed in a washing bag and then into a washing machine. The washing machine was set to a 40 degrees Celsius, 800 RPM, 51 minute wool wash setting. Samples 4-6 were removed from the washing machine and were allowed to dry. Samples 4-6 were weighed and their lengths were recorded.
(174) Part 2: Silicone in Heptane Sprayed Sealant Coating
(175) Samples 1-3 were re-washed, dried, measured and weighed. Samples 1-3 were then submerged in the 15% PVP solution. All 6 samples were dried vertically near a running fan. The dried samples were weighed.
(176) All 6 samples were stretched out and sprayed with silicone in heptane coating. The 6 samples were then allowed to return to their relaxed states under a fume hood and were allowed to dry. An ultrasonic water bath was set to 40 degrees Celsius. Once dry, samples 1-3 were submerged in the ultrasonic bath for 15 minutes. These samples were removed from the bath and were dried vertically near a fan. The dried samples 1-3 were weighed, and their lengths were measured and recorded.
(177) Once dry, samples 4-6 were placed in a washing bag and then into a washing machine. The washing machine was set to a 40 degree Celsius, 800 RPM, 51 minute wool wash setting. The samples were removed from the washing machine and were allowed to dry. Once dry, the samples 4-6 were weighed, and their lengths were measured and recorded.
(178) Results
(179) TABLE-US-00006 TABLE 6 No Sealant Coating Ultrasonic Bath at 40 Washing Machine Wool Degrees Setting Sample Sample Sample Sample Sample Sample Measurement 1 2 3 4 5 6 Initial 2.747 3.177 2.456 2.641 2.772 2.846 Weight (g) Dried PVP 3.508 4.048 3.179 3.445 3.568 3.658 weight (g) Washed 2.779 3.212 2.467 2.641 2.772 2.847 Weight (g) PVP left (g) 0.032 0.035 0.011 0.000 0.000 0.001 Initial 62.5 61 57 57 56 63.5 Length (mm) Final Length 62.5 62 57 57 56 63.5 (mm)
(180) The majority of the samples that were put in the washing machine were cleared of PVP while the samples that were put in the ultrasonic bath all still had some minor PVP on them after washing.
(181) TABLE-US-00007 TABLE 7 Silicone in Heptane Sprayed Sealant Coating Ultrasonic Bath at 40 Degrees Washing Machine Wool Setting Sample Measurement Sample 1 Sample 2 Sample 3 4 Sample 5 Sample 6 Initial Weight 2.747 3.177 2.456 2.641 2.772 2.847 (g) Dried PVP 3.510 3.911 3.123 3.389 3.538 3.57 weight (g) Dried PVP + 3.737 4.08 3.323 3.583 3.843 3.825 Coating weight (g) Washed 2.779 3.212 2.467 2.641 2.772 2.847 Weight (g) Silicone 0.227 0.169 0.200 0.194 0.305 0.255 applied (g) PVP + silicone 0.252 0.186 0.214 0.206 0.312 0.266 left on graft (g) PVP left (g) 0.025 0.017 0.014 0.012 0.007 0.011 Initial Length 62.5 61 57 57 56 63.5 (mm) Length after 81 79 73 79 79 79 coating (mm) Final Length 70 66 62 61 64 65 (mm) Ratio of PVP 3.4 4.3 3.3 3.9 2.5 2.8 Applied to Silicone Applied, wt./wt. Ratio of 0.29 0.23 0.30 0.26 0.40 0.36 Silicone Applied to PVP Applied, wt./wt. Percent PVP 96.7 97.7 97.9 98.4 99.1 98.5 Removed, wt. %
(182) Although there was some PVP left on the grafts that went in the washing machine, there is significantly less PVP left on them as opposed to the grafts washed in the ultrasonic bath. In all cases, greater than about 90 weight percent of the PVP was removed. Indeed, in all cases greater than about 95 weight percent of the PVP was removed.
(183) In Table 7, the weight ratio of PVP to silicone applied varied from about 2.5:1.0 to about 4.3:1.0. Conversely, the weight ratio of silicone to PVP applied varied from about 0.40:1.0 to about 0.23:1.0.
(184) Further, ratios are described in Table 11 below.
(185) The ratios described in Tables 7 and 11 are non-limiting.
(186) The weight ratio of PVP (or other masking agents) to silicone (or other sealant agents) may vary from about 10:1 wt. PVP (or other masking agents)/wt. silicone (or other sealant agents) to about 0.01:1 wt. PVP (or other masking agents)/wt. silicone (or other sealant agents), desirably from about 1:1 wt. PVP (or other masking agents)/wt. silicone (or other sealant agents) to about 0.05:1 wt. PVP (or other masking agents)/wt. silicone (or other sealant agents), more desirably from about 0.5:1 wt. PVP (or other masking agents)/wt. silicone (or other sealant agents) to about 0.1:1 wt. PVP/wt. silicone.
(187) Conversely, the weight ratio of silicone (or other sealant agents) to PVP (or other masking agents) may vary from about 0.1:1.0 wt. silicone (or other sealant agents)/wt. PVP (or other masking agents) to about 100:1 wt. silicone (or other sealant agents)/wt. PVP (or other masking agents, desirably from about 1:1 wt. silicone (or other sealant agents)/wt. PVP (or other masking agents to about 20:1 wt. silicone (or other sealant agents)/wt. PVP (or other masking agents, more desirably from about 2:1 wt. silicone (or other sealant agents)/wt. PVP (or other masking agents to about 10:1 wt. silicone (or other sealant agents)/wt. PVP (or other masking agents.
(188) Mask and Dye Tests
(189) Materials
(190) Fabric—Diameter 22 mm, flat tube twill weave and Diameter 10 mm. Crimped twill weave.
(191) Silicone—NuSil Med16-6606 (Temporary implant grade).
(192) Solvent—n-Heptane, 50:50 with silicone dispersion.
(193) Dye—Easy Composites Royal blue pigment for RTV silicone, mixed to approx. 10% of silicone solid content.
(194) Sample Description
(195) For Flat 22 mm fabric samples, the following masking agent formulations were used:
(196) #71 A—Bare Fabric
(197) #71 B—6% PVP
(198) #71 C—6% PVP+1.5% Glycerol (by volume of Mask solution)
(199) #71 D—6% PVP+1.5% Glycerol+4% PVP (Total 10% PVP)
(200) The #71B-D flat fabric samples were immersed into the PVP solution and then removed. All #71 samples were mounted on suspended mandrels (Post masking, Pre-coating).
(201) For Crimped Diameter 10 mm fabric samples, the following masking agent formulations were used:
(202) #70 A—Bare Fabric
(203) #70 B—6% PVP
(204) #70 C—6% PVP+1.5% Glycerol (by volume of Mask solution)
(205) #70 D—6% PVP+1.5% Glycerol+4% PVP (Total 10% PVP)
(206) The #70B-D crimped fabric samples were immersed into the PVP solution and then removed. All #70 samples were mounted on suspended mandrels (Post masking, Pre-coating).
(207) Masking Agent Preparation
(208) Masking agents were prepared using the same method as described above, with the additional steps to add glycerol for samples B and C (both #70 and #71) and then additional PVP for samples D (both #70 and #71).
(209) Measured the target weight of PVP into plastic beaker on scale balance. A 100 ml masking agent solution was prepared therefore target mass of 4 g PVP required (4% concentration). Measured the target volume of de-ionised water into a 100 ml plastic measuring cylinder. A 100 ml Mask solution to be prepared therefore target volume of 96 ml required. Added de-ionised water into the PVP in plastic beaker. Placed magnetic stirrer in the water and place the beaker on the magnetic stirrer. Turned the magnetic stirrer on at a speed of 350-450 RPM, ensuring the stirrer is centred in the beaker. The stirring was done at room temperature. Stirring was continued until there was no visible PVP solute, or for a minimum of at least 2 minutes. After stirring the masking agent solution was removed from stirrer and used for graft preparation, samples B.
(210) Additional steps were used for samples C, i.e. added glycerol. Returned the plastic beaker to scale balance, tared, and added required quantity of glycerol to the mask agent solution. The target glycerol content was 1.5% by volume of masking agent solution. This corresponded to a target weight of 1.5 g. (Note this corresponded to 25% Glycerol to PVP). Set beaker on stirrer and stirred for at least 2 minutes. This masking agent solution used for samples C.
(211) Additional steps were used for samples D, i.e., additional PVP. Returned the plastic beaker to scale balance, tared, and added the required quantity of PVP to the masking agent solution. The target PVP content was 10% by volume of Mask solution. This corresponded to an additional 4 g PVP added. (Note this effectively reduced the glycerol to PVP ratio from 25% to 15%). This masking agent solution was used for samples D.
(212) Sealant Preparation
(213) The silicone sealant dispersion as-supplied had a 30% solid content, the dispersion was diluted by an additional 100% of solvent. This reduced the solid content to 15%. Additionally, a blue dye was added to the silicone dispersion to provide a visual indication of the coverage and depth of penetration of silicone into the fabric structure.
(214) In particular, 20 ml of silicone dispersion was measured out from its container, in the as-supplied state, and placed into a plastic beaker. An additional 20 ml of n-Heptane solvent was added. The mixture was beaked and was set on scales, tared, and drops of dye were added using dropper. The recommended dye concentration range was 0.3% to 5%, depending of section thickness, therefore a target of 5% was set in order to provide a strong blue colour for visualization. A deviation from this target was due to a calculation of the solid content being at 30% rather than 15%, therefore the actual concentration of dye to silicone was 10% rather than 5%.
(215) Sample Preparation
(216) The individual samples were prepared with masking agent formulations according to the following table.
(217) TABLE-US-00008 TABLE 8 10% PVP + No 6% 6% PVP + Glycerol Glycerol (@15% Mask PVP (@25% of PVP) of PVP) Flat Fabric 71A 71B 71C 71D Crimped 70A 70B 70C 70D Fabric
(218) Samples B-D were immersed in the mask agent solution, as per the above table. The samples were assembled onto mandrel such that each fabric was held at diameter by sized end bungs, but remained unsupported on the inner surface. The inner surface of each fabric was not in contact with the mandrel to avoid affecting mask performance, location and concentrations.
(219) Dispersion drop assessment was undertaken as described below.
(220) Each sample was fully coated with at least 2 coats of silicone dispersion. The intention was to ensure sufficient silicone was present on the outer surface to effect a suitable coverage without concerns for lack of silicone during visual evaluations. Brush coating was done onto a rotating graft on rotisserie at approximately one revolution per second. Grafts were left overnight for solvent evaporation. Grafts were left to fully cure for recommended 72 hrs before being removed from mandrel for washing. The grafts were then placed in a delicate bag and put on 95° C. Tumble Machine Wash cycle for approximately 2 hours 30 mins.
(221) Samples were masked, coated, washed and cut opened flat.
(222) Dispersion Drop Assessment
(223) Prior to full coating, a single drop of polymer dispersion was applied to each sample, and video recorded in order to visually assess if there were noticeable differences in the behaviour of the dispersion on the masked fabric.
(224) Sample A—No Mask. Slow spread of the single drop of polymer dispersion across fabric. Appeared to be soaking into and through fabric
(225) Sample B—6% PVP Mask. Rapid spread of the single drop of polymer dispersion across fabric. Appeared to spread more readily than soaking into and through fabric
(226) Sample C—6% PVP+1.5% Glycerol Mask. First drop of the single drop of polymer dispersion had rapid spread across fabric. The second drop of the single drop of polymer dispersion was inconclusive, possibly due to sagging fabric holding the pool.
(227) Sample D—10% PVP+1.5% Glycerol Mask. Inconclusive—possibly due to sagging fabric holding the pool
(228) Dispersion Drop Assessment across face of the graft
(229) Sample A—No Mask. Slower spread of the single drop of polymer dispersion across fabric. Appeared to soak into fabric.
(230) Sample B—6% PVP Mask. Rapid spread of the single drop of polymer dispersion across fabric. Coverage was more uneven with pooling of dispersion in valleys.
(231) Sample C—6% PVP+1.5% Glycerol Mask. Fabric clearly resisted dispersion soaking in.
(232) Sample D—10% PVP+1.5% Glycerol Mask. Fabric clearly resisted dispersion soaking in.
(233) In summary, this Dispersion Droplet Assessment showed that even the lower concentration of masking agent, (Samples B, 6% PVP), appeared to initiate a significantly different response when compared to a non-masked fabric.
(234) A “pooling” effect was seen on the flat fabrics, samples 71C, 71D, was most likely a result of the excess dispersion being unable to run off the fabric or through the fabric. This effect was perhaps also evident in the crimped fabric, particularly Samples 70B, 70D, where there was pooling of the dispersion in the valleys, highlighted by the darker colour, unlike the non-masked sample 70 A, which appears far more uniform in colour/coverage.
(235) Assessment of Sealant Coverage and Penetration
(236) Following the wash cycle to remove the masking agent the grafts were cut lengthways to provide visualization of inner and outer surfaces. Each graft was visualized under optical microscopy on: (a) the outer surface—to confirm presence and uniformity of sealant coating; (b) the inner surface—to confirm presence or ingress of blue silicone, either through the fabric or between the yarn filaments; and (c) sectional view—to assess the level of penetration through the yarn bundles.
(237) Results
(238) Both samples without mask appeared to have permitted the dyed blue silicone dispersion into the yarn bundles and penetrate to the inner surface while the application of the mask appears to have prevented this ingress on all samples.
(239) TABLE-US-00009 TABLE 9 Penetration of Polymer to Mask Applied Inner Surface Flat Fabric Samples 71A None Yes 71B 6% PVP No 71C 6% PVP + Glycerol No 71D 10% PVP + Glycerol No Crimped Fabric Samples 70A None Yes 70B 6% PVP No 70C 6% PVP + Glycerol No 70D 10% PVP + Glycerol No
(240) Photographs of crimped fabric sample 70D are provided in
(241)
(242) The masking agent solution may encapsulate whole yarn bundles and individual yarn fibers, depending on the concentration of the masking agent solution. The higher concentrated masking agent solution (i.e. >30% w/w PVP, >20% w/w of PVP glycerol in water) seems to be too thick to flow into the yarn bundles and coat individual fibers, as seen in
(243) The overall mechanism of masking agent may include two main concepts, depending on the size of the void or gap: (1) a physical effect for macro pathways (i.e. voids between yarn bundles) and (2) chemical effect for micro pathways (i.e. voids between fibers and voids in micro cracks within the masking layer).
(244) (1) Physical Effect: Filling macro pathways is based on the physical ability for the masking agent solution to penetrate and flow into large voids between the yarn bundles. When the yarn bundles are completely encapsulated with a masking agent layer, the masking agent layer fills the voids between each yarn bundle and blocks entry into the yarn bundle. In turn, the sealant would not be able to penetrate within the macro pathways between each yarn or micro pathways between each fiber due to the presence of masking to fill these voids.
(245) (2) Chemical Effect: For micro pathways throughout the textile, whether micro pathways refer to micro cracks within the masking layer, micro voids between the yarn bundles or micro voids between individual fibers, the chemical mechanism of the masking solution's repulsion effect or ability to repel away from the sealant causes the sealant not to fill the micro voids. The repelling mechanism occurs when the oleophobic sealant tries to come into contact or close proximity with the highly hydrophilic masking layer. This is proven using solution solubility theory and solubility parameters developed by Joel H. Hildebrand. SI Hildebrand values (∂[SI]) demonstrate the masking solution and sealant solubility parameters indicating the solvency behavior of their specific solvents when they come into contact with one another. As noted in the Handbook of Solubility Parameters, CRC Press, 1983, the solvents in the masking solution (water and glycerol) are on the hydrophilic end of the solubility parameter range, whereas the solvent of the sealant (Heptane) is on the opposite end of the solubility parameter range. The ∂[SI] of water is 48.0, ∂[SI] of glycerol is 36.2, and ∂[SI] n-Heptane is 15.3.
(246) Thus, the masking agents of the present invention hinder undesirable migration of the sealant through, physical (e.g., blocking) and repulsion mechanisms. Thus, it may be desirable to use a sealant(s) whose solvent(s) has a solubility parameter of less than about 20 ∂[SI], for example from about 10 ∂[SI] to about 20 ∂[SI] and a masking agent solution(s) whose solvent(s) has a solubility parameter of greater than about 30 ∂[SI], for example from about 30 ∂[SI] to about 50 ∂[SI].
(247) Conclusions
(248) The use of blue dye in the silicone dispersion provided an excellent visual assessment of silicone penetration into the fabric. Both samples coated without prior mask application demonstrated substantial ingress of blue silicone sealant through the fabric to the inner surface. All three masking agent formulations appeared to substantially prevent ingress of silicone to the inner surface.
(249) Silicone Sealing Tests for Commercial Vascular Grafts
(250) The following equipment and materials were used to test sealing commercial grafts according to the present invention.
(251) 8 mm crimped polyester fabric commercial graft
(252) 14 mm crimped polyester fabric commercial graft
(253) Polyvinylpyrrolidone (PVP) Powder
(254) NuSil MED-6606 RTV Silicone
(255) N-Heptane
(256) Royal Blue Pigment
(257) De-ionised water
(258) Magnetic Stirrer
(259) Coating Variable Ranges
(260) The following values were used for the testing of the inventive sealing techniques of the present invention. PVP concentration in de-ionised water was varied on a weight basis at 1%, 2%, 4%, 6%, 8%, 10%, 15%, 20%, 25%, and 30%. Glycerol and silicone dispersion concentration was tested at PVP concentrations of 4%, 8%, 15%, and 30%. Glycerol concentrations were used on PVP concentrations of 5%, 15%, and 30%. These concentrations were percentage of glycerol to PVP.
(261) The variations of PVP, glycerol, and silicone tested were as follows:
(262) TABLE-US-00010 TABLE 10 Glycerol Silicone Concentration Concentration PVP Concentration (%) (% of PVP) (%) Sample 1 2 4 6 8 10 15 20 25 30 5 15 30 15 30 1 X X 2 X X 3 X X *4 X X 5 X X 6 X X *7 X X 8 X X 9 X X *10 X X *11 X X X 12 X X X 13 X X X 14 X X X 15 X X X *16 X X X 17 X X X 18 X X X *19 X X X 20 X X X 21 X X X 22 X X X 23 X X X 24 X X X 25 X X X *26 X X X *Denotes samples to be applied to both types of grafts, i.e., First and Second graft samples.
(263) Sample Preparation
(264) Each sample was made from of a section of the commercial grafts. The grafts were first cut to length by first fully stretching the graft to remove the crimps, and then a section of 180 mm length was cut with a single edge razor blade. Each sample was weighed.
(265) Mask Preparation
(266) A measured amount of de-ionised water was placed into a 100 ml plastic beaker. A magnetic stirrer was placed into the de-ionised water. While stirring, PVP and glycerol (if any) were added. Stirring continued until there was no solute visible.
(267) Masking Agent Application
(268) The graft samples were coated by immersing the graft samples within the mask solution and agitating the graft by gloved hands, so the samples were fully coated inside and out.
(269) Once the grafts were fully coated, excess mask solution, if any, was removed. Next, each graft was attached to a mandrel by using cable ties. One end of the graft was secured to the mandrel by a cable tie, then the graft was extended to 60% of its overall extended length (108 mm), and the other end of the graft was secured to the mandrel by another cable tie. The mandrel was then placed horizontally on a rotating mount and allowed to air dry. Once dry, the masked grafts were weighed.
(270) Sealant Preparation
(271) The silicone dispersion was supplied as a 30% solid content. Additional amounts of n-Heptane were added to reduce that solid content to 22.5% then 15. A blue dye was added to the silicone dispersion.
(272) Sealant Application
(273) The mandrel with the graft mounted was be placed on the rotary motor to slowly spin the graft. The sealant was applied with a paint brush starting at one end and working to the other end. This was repeated until there was an excess of sealant dispersion on the graft. Once the targeted level of silicone was applied onto the graft, the graft was transferred to a rotating mount and allowed to air dry. Once dry, the sealed graft was weighed.
(274) Masking Agent Removal
(275) Once the grafts were fully dried, the masking agents were removed. This was done by washing the grafts in a washing machine on a 90° C. wash (with no detergent). This caused the PVP to dissolve in the water and thus be removed from the graft. The 90° C. temperature also aided in complete curing of the silicone. When the wash was complete, the grafts were hung up to air dry. After drying, the finished grafts were weighed.
(276) Silicone Adherence
(277) A good coating adhesion can also be demonstrated if the graft coating maintains its integrity in a high pressurised state. Pressure can be used as a measure over all sizes of grafts because most of the overall hoop stress is borne by the stiffer fabric material of the graft. Furthermore, most of the forces acting on the silicone coating for delaminating it happen in the gaps between bundles of fibres as the weave structure does not change for different diameters of graft, then this area and consequently the force acting on that area will be consistent. Therefore, irrespective of the size of graft the same pressure will produce the same force to delaminate the silicone coating.
(278) To ensure the position of the bundles within the fabric are as uniform as possible over all diameters, the fabric was crimp removed so the graft is in its fully extended shape. In accomplishing this, the pressure applied was above the pressure that it takes to fully extend the graft. Since this pressure will be different for each size of graft, the graft that needs the highest pressure to fully extend itself (i.e., the one of smallest diameter) will be used as a worst-case scenario. Once this worst-case pressure is determined, a factor of safety (FOS) is applied and it is this FOS corrected pressure that is used as a minimum requirement for all grafts. If the graft can be pressurised to this FOS corrected pressure with no visual signs of the coating delaminating (bubbles forming), then it can be deduced that the coating has sufficient and acceptable adhesion/integrity.
(279) One method of testing for delamination is as follows: Connect the graft to a pressure rig, ensuring one end is plugged; Slowly apply pressure to the graft; Stop at 120 mmHg (clinical pressure) and look for signs of delamination (bubbles); Measure the leak rate and record it in mm/cm.sup.2/min; Increase the pressure in increments up to the FOS corrected figure is reached; If any signs of delamination are visible at any point stop the test, mark as failed; Hold at the FOS corrected pressure for 1 min; and If no signs of delamination are present, mark graft as pass.
(280) The following pressure tests were conducted:
(281) The grafts were pressurised with water to observe if there were any signs of the silicone losing its bond from the graft. The pressure was to be increased slowly to a maximum pressure of 600 mmHg. The adherence was noted as follows:
(282) 0—Silicone is well adhered to graft and showing no signs of failure;
(283) 1—Graft reached the maximum pressure, but the leak rate has visibly increased;
(284) 2—Silicone coating has started to fail, showing jets of water coming from the graft; and
(285) 3—Silicone coating has failed, and a bubble has appeared on the surface.
(286) Penetration Depth
(287) The effectiveness of the mask was determined by how far the silicone wicked through the fabric. Desirably, the silicone will sit on the outside surface of the graft and not unduly penetrate the graft structure. If the masking agent was not effective, then the silicone was visible within the fabrics and on the inside edge. To visualise this, the grafts were cut lengthways and a cross section was examined under high magnification.
(288) The degree of penetration was noted as follows;
(289) 0—Silicone only visible on the outer surface of the graft;
(290) 1—Silicone is visible between fibres of the graft but only up to 50% of the thickness;
(291) 2—Silicone is visible penetrating to the inside surface; and
(292) 3—Silicone visible everywhere, the entire graft structure is blue.
(293) Test Results Summaries
(294) TABLE-US-00011 TABLE 11 WEIGHT SUMMARIES Weight of Graft Segment Amount Ratio of After After After of Amount Sealant Masking Sealant Washing Masking of to and and and Agent Sealant Masking Sample Initial Drying Curing Drying Applied Applied Agent Name (g) (g) (g) (g) (g) (g) (g/g) 1 0.703 0.714 1.496 1.485 0.011 0.782 71.1 2 0.714 0.739 1.484 1.46 0.025 0.745 29.8 3 0.741 0.779 1.436 1.392 0.038 0.657 17.3 4 0.673 0.721 1.239 1.182 0.048 0.518 10.8 A4 1.089 1.159 2.31 2.229 0.07 1.151 16.4 5 0.689 0.778 1.199 1.1 0.089 0.421 4.7 6 0.698 0.778 1.216 1.129 0.08 0.438 5.5 7 0.694 0.813 1.454 1.319 0.119 0.641 5.4 A7 1.026 1.198 2.047 1.86 0.172 0.849 4.9 8 0.695 0.864 1.492 1.31 0.169 0.628 3.7 9 0.688 0.939 1.541 1.276 0.251 0.602 2.4 10 0.663 0.969 1.537 1.207 0.306 0.568 1.9 11 0.739 0.778 1.382 1.339 0.039 0.604 15.5 A11 1.08 1.119 2.086 2.041 0.039 0.967 24.8 12 0.658 0.712 1.262 1.201 0.054 0.55 10.2 13 0.717 0.83 1.486 1.368 0.113 0.656 5.8 14 0.719 0.816 1.463 1.357 0.097 0.647 3.7 15 0.717 0.853 1.513 1.367 0.136 0.66 4.9 16 0.701 0.888 1.502 1.298 0.187 0.614 3.3 A16 0.896 1.103 1.731 1.503 0.207 0.628 3.0 17 0.738 1.067 1.879 1.531 0.329 0.812 2.5 18 0.719 1.183 1.881 1.395 0.464 0.698 1.5 19 0.705 0.754 1.502 1.446 0.049 0.748 15.3 A19 0.878 0.924 1.682 1.632 0.046 0.758 16.5 20 0.717 0.759 2.063 2.016 0.042 1.304 31.0 21 0.709 0.809 1.46 1.355 0.1 0.651 6.5 22 0.741 0.844 2.121 2.007 0.103 1.277 12.4 23 0.715 0.855 1.487 1.333 0.14 0.632 4.5 24 0.688 0.867 2.03 1.846 0.179 1.163 6.5 25 0.711 1.057 1.818 1.451 0.346 0.761 2.2 26 0.699 1.038 2.464 2.115 0.339 1.426 4.2 A26 1.356 2.058 4.448 3.689 0.702 2.39 3.4
(295) The ratio of sealant to masking agent on a gram to gram or weight dry basis varied from about 1:1 to about 70:1. Useful ratios also include ratios of sealant to masking agent from about 2:1 to about 20:1, including from about 2:1 to about 10:1, on a dry weight basis. These ratios, however are non-limiting. The weight ratio of silicone (or other sealant agents) to PVP (or other masking agents) may vary from about 0.1:1.0 wt. silicone (or other sealant agents)/wt. PVP (or other masking agents) to about 100:1 wt. silicon (or other sealant agents)/wt. PVP (or other masking agents, desirably from about 1:1 wt. silicone (or other sealant agents)/wt. PVP (or other masking agents to about 20:1 wt. silicone (or other sealant agents)/wt. PVP (or other masking agents, more desirably from about 2:1 wt. silicone (or other sealant agents)/wt. PVP (or other masking agents to about 10:1 wt. silicone (or other sealant agents)/wt. PVP (or other masking agents.
(296) TABLE-US-00012 TABLE 12 PENETRATION TEST RESULTS Glycerol Penetration Sample PVP as % of Grading Number % PVP Scale 0-3 Comment 1 1 0 3 2 2 0 3 3 4 0 2 4 6 0 2 A4 6 0 2 5 8 0 2 6 10 0 1 7 15 0 2 A7 15 0 2 8 20 0 2 9 25 0 0 Delaminated 10 30 0 0 Delaminated A10 30 0 Not Made 11 4 5 2 A11 4 5 2 12 4 30 2 13 8 5 2 14 8 30 2 15 15 5 1 16 15 30 0 A16 15 30 1 17 30 5 0 Delaminated 18 30 30 0 Delaminated 19 4 15 2 A19 4 15 2 20 4 15 2 21 8 15 2 22 8 15 1 23 15 15 1 24 15 15 1 25 30 15 0 Delaminated 26 30 15 0 Delaminated A26 30 15 0 Delaminated
(297) The results, which are tabulated in order of PVP masking agent concentrations, showed a clear correlation between higher levels of PVP and reduced penetration of the silicone sealant into the inner lumen of the graft samples.
(298) In general, PVP mask concentration of 10% or greater prevented the bulk penetration of silicone to more than 50% into the fabric thickness. In some samples, they were small “fingers” or “slivers” of silicone evident between the yarn bundles at the interstices created by warp and weft yarn bundles. Such interstitial silicone represented a very small percentage of the overall inner surface area of the fabric.
(299) Adhesion Test Results
(300) TABLE-US-00013 TABLE 13 Measured Measured Leakage Leakage (ml/min) (ml/min) Glycerol @120 @600 Adhesion Sample PVP as % of mmHg mmHg grading Number (g) PVP Result 1 Result 3 Scale 0-3 1 1 0 0 0 0 2 2 0 0 0 0 3 4 0 0 0 0 4 6 0 0 4 0 A4 6 0 33 3 5 8 0 19 1 6 10 0 40 1 7 15 0 4 14 0 A7 15 0 31 1 8 20 0 12 46 1 9 25 0 Delaminated 3 10 30 0 >500 3 A10 30 0 11 4 5 0 1 0 A11 4 5 0 5 0 12 4 30 0 0 0 13 8 5 9 86 2 14 8 30 1 22 1 15 15 5 3 22 1 16 15 30 1.5 1 A16 15 30 34 190 1 17 30 5 >1000 3 18 30 30 >1001 3 19 4 15 0 0 0 A19 4 15 4 27 0 20 4 15 0 0 0 21 8 15 0.5 5 0 22 8 15 0 3 23 15 15 1.5 11 0 24 15 15 0 3 25 30 15 Delaminated 3 26 30 15 Delaminated 3 A26 30 15 Delaminated 3
(301) The above results, which are tabulated in order of PVP masking agent concentrations, show a clear correlation between higher levels of PVP and reduced adhesion of the silicone sealant to the fabric. Two mechanisms by which silicone penetrated into the inner surface of the fabric were observed, i.e., either through the yarn bundle fibers or by passing between the gaps in the yarn bundles. The lower concentrations of mask agent (>4% PVP) appeared to inhibit the flow of polymer through the yarn fibers, however it was not in all cases sufficient to substantially prevent the ingress of small “fingers” or “slivers” of silicone polymer between the gaps in the bundles, i.e., interstitial spaces between proximately juxtaposed yarns within the textile pattern. It appeared that slightly larger concentrations of mask agent (>15%) was required to completely block the passage of silicone polymer through between the gaps in the fiber bundles.
(302) Assessment of Handling
(303) The handling characteristics of grafts are the result of a series of complex interactions between the fabric structure, the graft diameter, the crimp pitch and form, the thickness profile of the polymer sealant and the amount of penetration of the sealant into the yarn bundles.
(304) The below assessment parameters, although subjective, aim to consider all of the following: bend radius at kink formation, flexibility, hoop stiffness (ability to remain fully open) and stretching.
(305) A grading score (1-4) was be used to assess handling characteristics;
(306) 1—Graft judged more flexible than reference sample.
(307) 2—Graft judged comparable to reference sample.
(308) 3—Graft judged to be stiffer than reference sample but with useable characteristics.
(309) 4—Graft judged too stiff for comparable use.
(310) The reference sample was considered to have excellent overall handling and at least comparable to currently commercially available gelatin sealed grafts.
(311) Polymer Sealant Coverage
(312) The amount of polymer sealant coverage on each sample was reported in mg/cm.sup.2 and was calculated by dividing the overall mass of polymer applied to each individual graft by the surface area of the graft. Previous crimped prototypes have demonstrated both effective sealing and suitable handling characteristics with polymer coverages of at least about 8 mg/cm.sup.2 ranging up to about 14 mg/cm.sup.2. Coverage levels above 14 mg/cm.sup.2 increased the overall stiffness of the handling characteristics beyond that of a standard gelatin sealed graft, however increase stiffness and therefore increased amount of polymer coverage may be advantageous for some graft applications.
(313) Tensile Extension Force
(314) Samples were mounted between jaws of Lloyd Tensile Test machine with jaws spacing of 80 mm. The machine was zeroed and the jaws extended by 20% (16 mm) and the maximum measured force was recorded.
(315) The results recorded are tabulated below, ranked in order from low to high for force-to-extend by 20%.
(316) These results demonstrated a strong correlation between handling assessment and force-to-extend, with lower extension forces corresponding to improved handling characteristics.
(317) A review of the polymer coverage values indicated that coverage levels of up to 40 mg/cm.sup.2 might be considered in order to achieve comparable handling characteristics to the reference sample (grading 2), as indicated by graft sample #15.
(318) All grafts which demonstrated delamination of the polymer sealant during pressurized adhesion tests are by a note (1) highlighted in italics. This list indicates that poor adhesion can result in low Extension Forces and improved handling characteristics. This result supports the theory that acceptable handling characteristics rely on lower levels of penetration of sealant into the yarn bundles.
(319) TABLE-US-00014 TABLE 14 Handling Force to Extended Surface Polymer Assessment Extend Sample Dia, Length, Area, Coverage, Grading, by 20% No. mm mm cm.sup.2 mg/cm.sup.2 1 to 4 (N) 18 (1) 8 130 32.7 43 1 0.29986 10 (1) 8 125 31.4 38 1 0.37938 5 8 120 30.1 36 1 0.4067 25 (1) 8 130 32.7 44 1 0.41064 6 8 135 33.9 33 2 0.48247 16 8 130 32.7 40 2 0.48938 17 (1) 8 140 35.2 44 1 0.52805 8 8 130 32.7 40 2 0.53074 7 8 132 33.2 40 2 0.54057 9 (1) 8 125 31.4 41 1 0.57061 13 8 140 35.2 39 2 0.58817 4 8 125 31.4 38 2 0.60156 12 8 135 33.9 35 3 0.69369 15 8 135 33.9 40 2 0.71933 14 8 130 32.7 42 3 0.76625 3 8 135 33.9 41 3 0.78701 11 8 130 32.7 41 3 0.90773 1 8 135 33.9 44 3 1.0072 19 8 135 33.9 43 3 1.0302 23 8 140 35.2 38 3 1.0372 2 8 140 35.2 41 3 1.1116 21 8 125 31.4 43 3 1.1234 26 (1) 8 134 33.7 63 4 1.1571 22 8 125 31.4 64 4 1.8936 24 (1) 8 111 27.9 66 4 2.1711 20 8 115 28.9 70 4 3.0235 64B 10 620 194.7 12.1 Reference Sample Note: (1) demonstrated delamination of the polymer sealant during pressurized adhesion tests
(320) Conclusions
(321) Acceptable handling characteristics were achieved with lower levels of penetration of sealant into the yarn bundles. The use of the masking agents to limit the amount of polymer penetration into textile fabric can be utilized for improved handling characteristics. Polymer coverage levels of up to 40 mg/cm.sup.2 were demonstrated to achieve comparable handling characteristics to the reference sample as assessed by surgeon users.
(322) Photographs of select samples from Tables 10-14 are reproduced in
(323)
(324)
(325)
(326)
(327)
(328)
(329)
(330) Measured Leakage at 120 mmHg: 3 ml/min; Measured Leakage at 600 mmHg: 22 ml/min; Handling Assessment: 2 (Graft judged comparable to Reference Sample 64B); and Tensile Force to Extend Graft by 20%: 0.719 N.
(331)
(332) Glycerol Hydration of Masking Agents
(333) The use of glycerol within different masking agent formulations has been demonstrated on multiple formulations with the aim of hydrating or plasticizing the (PVP) masking agent and improving its ability to cover and fill the yarn structure and prevent the sealant dispersion from ingress to the inner surface.
(334) Masking Agent Sample Preparation
(335) Masking agents were prepared using following method:
(336) A target weight of PVP (MW 10,000) was introduced in a plastic beaker on a scale balance. A 100 ml masking agent solution was prepared at a target mass of 10 g PVP (10% concentration). The target volume of de-ionised water was introduced into a 100 ml plastic measuring cylinder. A target volume of 90 ml was required. The de-ionised water was added into the PVP in plastic beaker. A magnetic stirrer rod was placed in the water, and the beaker was placed on the magnetic stirrer. The magnetic stirrer was turned on at a speed of 350-450 RPM, the stirrer was centered in the beaker. The stirring was done at room temperature. Stirring continued until there was no visible PVP solute, but for at least 2 minutes. After stirring the masking agent solution, it can be removed from stirrer and used for control sample preparation.
(337) Additional steps were used for subsequent samples with added glycerol. The plastic beaker was returned to scale balance, tared, and the required quantity of glycerol was added to the masking agent solution. The target glycerol content was calculated as a percentage by mass of the PVP. The target weight of Glycerol added at each stage was 1 g, corresponding to cumulative weights of 1, 2, 3, 4, 5, 6, 7, 8, 9 and 10 g. Each beaker was stirred for at least 2 minutes after each added quantity of Glycerol.
(338) A summary of the samples prepared are shown below.
(339) TABLE-US-00015 TABLE 15 Volume PVP PVP % Glycerol Glycerol as Sample Ref. of water Weight w/v Weight % of PVP Control 90 ml 10 g 10% 0 0 A) 10% Glycerol 90 ml 10 g 9.9% 1 g 10% B) 20% Glycerol 90 ml 10 g 9.8% 2 g 20% C) 30% Glycerol 90 ml 10 g 9.7% 3 g 30% D) 40% Glycerol 90 ml 10 g 9.6% 4 g 40% E) 50% Glycerol 90 ml 10 g 9.5% 5 g 50% F) 60% Glycerol 90 ml 10 g 9.4% 6 g 60% G) 70% Glycerol 90 ml 10 g 9.3% 7 g 70% H) 80% Glycerol 90 ml 10 g 9.3% 8 g 80% I) 90% Glycerol 90 ml 10 g 9.2% 9 g 90% J) 100% Glycerol 90 ml 10 g 9% 10 g 100%
(340) Dispersion Drop Castings
(341) Three individual drops of each masking agent formulation were cast onto a dark coloured sheet to allow visual observation during the drying process. The drying was accelerated by using a desk fan at room temperature
(342) Assessments of the masking agents after drying were as follows:
(343) TABLE-US-00016 TABLE 16 Assessment Assessment Sample Ref. after 12 hours after 96 hours Control Looked white, Dry, Brittle Dry to touch A) 10% Glycerol Looked hydrated, Looked Dry to touch hydrated, Dry to touch B) 20% Glycerol Hydrated, Soft, Hydrated, Soft, Tacky to touch Tacky to touch C) 30% Glycerol Very Sticky to Sticky to touch touch D) 40% Glycerol Sticky, still wet Sticky, still wet E) 50% Glycerol Wet to touch Wet to touch F) 60% Glycerol Wet to touch Wet to touch G) 70% Glycerol Wet to touch Wet to touch H) 80% Glycerol Wet to touch Wet to touch I) 90% Glycerol Wet to touch Wet to touch J) 100% Glycerol Wet to touch Wet to touch
(344) Conclusions
(345) The control masking agent formulation (e.g., PVP-only) dried out fully within a few hours and became brittle. Use of this PVP-only masking agent may result in a stiff graft structure once mask is applied and dried. The use of 10% glycerol helped to hydrate the PVP masking agent solution, and appeared dry after 12 hours. A masking agent solution consisting of 20% glycerol retains some hydration at 12 hours and is soft/deformable to touch. A range of between about 1% and about 30% glycerol to PVP, by weight, provides appropriate ranges for use with the present invention.
(346) Moreover, the present invention is not limited to vascular prostheses in conduit-type shapes. The methods, coatings, and masking agents of the present invention may suitably be used with other textile products, including medical and non-medical (e.g., non-implantable) textile products. Other medical products may include ventricular assist devices, artificial heart conduits, medical sheets, patches, meshes, and the like. Non-medical textiles may include, but are not limited to, clothing, geotextiles, transportation textiles, military and/or defense textiles, safety and/or protective textiles, sports and/or recreation textiles, and the like. Further, textile products are not limited to tubular conduits, but may be of any shape including, but not limited to for example, sheets and/or tapes (e.g., two-dimensional products), or even three-dimensional shaped products other than conduit-shaped products.
(347) Useful polymeric materials and/or for fibers for non-medical or non-implantable textiles may include, but are not limited to, polyethylene terephthalate (PET), polytetrafluoroethylene (PTFE), expanded polytetrafluoroethylene (ePFTE), polyolefins, polyesters, poly(ether amides), poly(ether esters), poly(ether urethanes), poly(ester urethanes), poly(ethylene-styrene/butylene-styrenes), and other block copolymers. Useful animal fibers for the non-medical or non-implantable textiles of the present invention may include, but are not limited to, wool, alpaca, angora, mohair, llama, cashmere, and silk. Useful natural fibers may include, but are not limited to, linen, cotton bamboo, hemp, corn, nettle, soy fiber, and the like.
(348) The masking agents and/or the sealants may be applied by brushing, spray-coating, dipping or immersing, and the like. The present invention, however is not limited to such techniques, and other techniques, such as chemical deposition, vapor deposition, chemical vapor deposition, physical vapor deposition, printing and the like, may suitably be used. These techniques are generally suitable for medical textiles. However, for large commercial scale textile production, including non-medical textiles, other techniques may also be used. For example, coating and/or masking materials for textile sheets or substrates may be applied by squeegee type coating, roller coating, knife coating, nip coating, dip coating, cast coating, chemical deposition, vapor deposition, and the like. Moreover, printing techniques, such as roller printing, stencil printing, screen printing, inkjet printing, lithographic printing, 3D printing, and the like may be used with the present invention for applying the masking agents and/or the sealing agents. Furthermore, mechanical devices may be employed to control the depth of penetration of the masking agent and/or sealing agent into the wall of the textile substrate of graft. For example, with a tubular graft an expandable balloon may be to control the depth of penetration of the masking agent into the graft wall.
(349) Modifications may be made to the foregoing embodiments within the scope of the present invention.
(350) The following embodiments or aspects of the invention may be combined in any fashion and combination and be within the scope of the present invention, as follows:
(351) Embodiment 1. A method of manufacturing a tubular graft comprising the steps of:
(352) providing a textile comprising a tubular wall disposed between a first open end and an opposed second open end, an inner surface and an opposed outer surface defining an interior wall portion therein between, the tubular wall comprising a textile construction of one or more filaments or yarns, the textile construction by itself being permeable to liquid;
(353) applying a substantially water-soluble material to at least a portion of the tubular wall; and
(354) applying a substantially water-insoluble sealant to at least a part of the outer surface of the tubular wall, the substantially water-insoluble sealant being configured to mitigate movement of fluid through the wall of the conduit;
(355) wherein the water-soluble material is configured to mitigate penetration of the sealant to the inner surface of the conduit.
(356) Embodiment 2. The method of embodiment 1, wherein the step of applying the water-soluble material to at least a portion of the tubular wall comprises applying the water-soluble material to at least a portion of the inner surface and a portion of the interior portion of the tubular wall.
(357) Embodiment 3. The method of embodiment 1 or 2, wherein the step of applying the water-soluble material to at least a portion of the tubular wall comprises applying the water-soluble material to at least a portion of the outer surface of the tubular wall.
(358) Embodiment 4. The method of any preceding embodiment, wherein the water-soluble material is a solution of the water-soluble material and a solvent.
(359) Embodiment 5. The method of any preceding embodiment, wherein the solvent is selected form the group consisting of water, lower alcohols, and combinations thereof.
(360) Embodiment 6. The method of any preceding embodiment, wherein the solvent is at least partially removed prior to applying the substantially water-insoluble sealant.
(361) Embodiment 7. The method of any preceding embodiment, further comprising removal of at least a portion of the water-soluble material is by dissolution, abrading, peeling, degrading, and combinations thereof.
(362) Embodiment 8. The method of any preceding embodiment, wherein the water-soluble material is selected from the group consisting of polyvinylpyrrolidone, glycerol, methyl cellulose, poly(ethylene glycol), poly(ethylene glycol) hydrogel, polyethylene oxide, and combinations thereof.
(363) Embodiment 9. The method of any preceding embodiment, wherein the substantially water-insoluble sealant is an elastomeric material selected from the group consisting of moisture curing, light curing, thermo-curing, platinum catalyzed, anaerobic curing materials or a combination of these curing mechanisms.
(364) Embodiment 10. The method of embodiment 9, wherein the elastomeric material is selected from the group consisting of silicones, polyurethanes, polycarbonates, thermoplastic elastomers, and combinations thereof.
(365) Embodiment 11. The method of any preceding embodiment, wherein one of more of the substantially water-soluble coating or the substantially water-insoluble coating further comprises a component selected from the group consisting of a colorant, a therapeutic agent, a dye, and a fluorescent indicator.
(366) Embodiment 12. The method of any preceding embodiment, wherein the water-soluble material comprises polyvinylpyrrolidone having a molecular weight of between approximately 6,000 g/mol and approximately 15,000 g/mol.
(367) Embodiment 13. The method of any preceding embodiment, wherein applying the water-soluble material forms layer on substantially all of the inner surface of the tubular wall.
(368) Embodiment 14. The method of any preceding embodiment, further comprising curing the substantially water-insoluble sealant.
(369) Embodiment 15. The method of any preceding embodiment, further comprising curing the substantially water-insoluble sealant; and thereafter removing at least a portion of the water-soluble material.
(370) Embodiment 16. The method of embodiment 14, further comprising removing substantially all of the water-soluble material from the inner surface of the tubular wall.
(371) Embodiment 17. The method of any preceding embodiment, further comprising:
(372) removing at least a part of the water-soluble material from at least a part of the outer surface of the tubular wall prior to the applying the substantially water-insoluble sealant.
(373) Embodiment 18. The method of any one of embodiments 15 to 17, wherein the removing at least the portion of the water-soluble material is carried out at a temperature of between approximately 15° C. and approximately 140° C.
(374) Embodiment 19. The method of any one of embodiments 15 to 18, wherein the removing at least the portion of the water-soluble material further comprises the step of applying a solvent thereto.
(375) Embodiment 20. The method of embodiment 19, wherein the solvent comprises water, lower alcohols, and combinations thereof.
(376) Embodiment 21. The method of any one of embodiments 15 to 20, wherein the tubular textile is agitated, rotated, spun, and shaken, or the like, during the removal of the water-soluble material.
(377) Embodiment 22. The method of any one of embodiments 15 to 21, wherein the removal of the water-soluble material comprises dissolving, etching, plasma etching, ablating, abrading and combinations thereof of the water-soluble material.
(378) Embodiment 23. The method of any preceding embodiment, wherein the step of applying the water-soluble material further comprises spraying the water-soluble material, brushing the water-soluble material, immersing at least a portion of the tubular wall into a solution of the water-soluble material, and combinations thereof.
(379) Embodiment 24. The method of any preceding embodiment, wherein the substantially water-insoluble sealant is a polymer solution.
(380) Embodiment 25. The method of embodiment 24, wherein the polymer solution comprises an organic solvent.
(381) Embodiment 26. The method of embodiment 25, wherein the organic solvent comprises at least one of heptane and xylene.
(382) Embodiment 27. The method of any preceding embodiment, wherein the substantially water-insoluble sealant is applied by brushing, spraying, roller coating the substantially water-insoluble sealant thereon.
(383) Embodiment 28. The method of any preceding embodiment, wherein the method comprises one or more steps of selectively applying the substantially water-insoluble sealant to one or more portions of the tubular wall, such that the tubular wall comprises at least two sections having substantially different amounts of the substantially water-insoluble sealant thereon.
(384) Embodiment 29. The method of any one of embodiments 14 to 28, wherein the tubular wall having the coating of the substantially water-insoluble sealant is, after curing thereof, substantially impermeable to liquid.
(385) Embodiment 30. The method of any preceding embodiment, wherein, after curing of the substantially water-insoluble sealant, the tubular wall has a water permeability of about 0.16 ml/min/cm.sup.2 at 120 mm Hg pressure or less than 0.16 ml/min/cm.sup.2 at 120 mm Hg pressure.
(386) Embodiment 31. A textile comprising:
(387) a tubular wall disposed between a first open end and an opposed second open end and having an inner surface and an opposed outer surface, the tubular wall comprising a textile construction of one or more filaments or yarns, the textile construction by itself being permeable to liquid;
(388) wherein a portion of the inner surface comprises a coating of a substantially water-soluble material thereon;
(389) wherein the outer surface further comprises a coating of a substantially water-insoluble sealant disposed thereon; and
(390) wherein the tubular wall having the coating of the substantially water-insoluble sealant is, after curing thereof, substantially impermeable to liquid.
(391) Embodiment 32. The textile of embodiment 31, wherein the water-soluble material is selected from the group consisting of polyvinylpyrrolidone, glycerol, methyl cellulose, poly(ethylene glycol) poly(ethylene glycol) hydrogel, polyethylene oxide, and combinations thereof.
(392) Embodiment 33. The textile of embodiment 31 or 32, wherein the coating of the water-soluble material comprises an oleophobic layer.
(393) Embodiment 34. The textile of any one of embodiments 31 to 33, wherein the water-soluble material comprises polyvinylpyrrolidone having a molecular weight of between approximately 6,000 g/mol and approximately 15,000 g/mol.
(394) Embodiment 35. The textile of any one of embodiments 31 to 34, the water-soluble material comprises polyvinylpyrrolidone and glycerol.
(395) Embodiment 36. The textile of any one of embodiments 31 to 35, wherein the substantially water-insoluble sealant is an elastomeric material selected from the group consisting of moisture curing, light curing, thermo-curing, platinum catalyzed, anaerobic curing materials or a combination of these curing mechanisms.
(396) Embodiment 37. The textile of embodiment 36, wherein the elastomeric material is selected from the group consisting of silicones, polyurethanes, polycarbonates, thermoplastic elastomers, and combinations thereof.
(397) Embodiment 38. The textile of any one of embodiments 31 to 37, wherein one of more of the substantially water-soluble coating or the substantially water-insoluble coating comprises a component selected from the group consisting of a colorant, a therapeutic agent, a dye, and a fluorescent indicator.
(398) Embodiment 39. The textile of any one of embodiments 31 to 38, wherein, after curing of the substantially water-insoluble sealant, the tubular wall has a water permeability of about 0.16 ml/min/cm.sup.2 at 120 mm Hg pressure or less than 0.16 ml/min/cm.sup.2 at 120 mm Hg pressure.
(399) Embodiment 40. The textile of any one of embodiments 31 to 39, wherein the textile construction is selected from the group consisting of a weave of the one or more filaments or yarns, a knit of the one or more filaments or yarns, a braid of the one or more filaments or yarns, and a web of the one or more filaments or yarns.
(400) Embodiment 41. The textile of any one of embodiments 31 to 40, wherein the tubular wall is a crimped wall having a series of peaks and valleys.
(401) Embodiment 42. The textile of embodiment 41, wherein the substantially water-insoluble sealant is disposed at about 8 mg/cm.sup.2 of area of the tubular wall or greater than 8 mg/cm.sup.2 of area of the tubular wall.
(402) Embodiment 43. The textile of any one of embodiments 31 to 40, wherein the tubular wall is a non-crimped wall being substantially free of peaks and valleys.
(403) Embodiment 44. The textile of embodiment 43, wherein the substantially water-insoluble sealant is disposed at about 4 mg/cm.sup.2 of area of the tubular wall or greater than 4 mg/cm.sup.2 of area of the tubular wall.
(404) Embodiment 45. The textile of any one of embodiments 31 to 44, wherein the substantially water-insoluble sealant is disposed at about 14 mg/cm.sup.2 of area of the tubular wall or less than 14 mg/cm.sup.2 of area of the tubular wall.
(405) Embodiment 46. The textile of any one of embodiments 31 to 45,
(406) wherein one portion of the tubular wall has a first level of the substantially water-insoluble sealant to provide a first soft, flexible zone;
(407) wherein another portion of the tubular wall has a second level of the substantially water-insoluble sealant to provide a second zone having a stiffness greater than the first zone; and
(408) wherein the second level the substantially water-insoluble sealant is greater than the first level of the substantially water-insoluble sealant.
(409) Embodiment 47. The textile of any one of embodiments 31 to 46, wherein at least a portion of the coating of the substantially water-insoluble sealant engages at least a portion of the one or more filaments or yarns.
(410) Embodiment 48. The textile of any one of embodiments 31 to 47, where in the textile is an implantable medical device.
(411) Embodiment 49. The textile of embodiment 48, wherein the implantable medical device is selected from the group consisting of surgical vascular grafts, and endovascular graphs, meshes, patches, hernia plugs, vascular wraps, heart valves, filters, and the like.
(412) Embodiment 50. The textile of any one of embodiments 31 to 49, wherein the textile is a delivery medical device.
(413) Embodiment 51. The textile of embodiment 50, wherein the delivery medical device is a catheter.
(414) Embodiment 52. A textile structure comprising:
(415) a fluid permeable polymeric textile layer having opposing first and second surfaces and a length;
(416) a cross-linkable water-insoluble elastomeric layer on the first textile surface configured to render the liquid permeable polymeric textile layer substantially impermeable to fluid when cured; and
(417) a substantially dried water-soluble polymer layer on the second textile surface;
(418) wherein water-soluble polymer layer substantially inhibits migration of the water-insoluble elastomeric layer onto the second surface; and
(419) wherein the water-soluble polymer layer is substantially removable by exposure to water.
(420) Embodiment 53. The textile structure of embodiment 52, wherein the weight ratio of the cross-linkable water-insoluble elastomeric polymer to the water-soluble polymer is from about 0.1:1 to about 100:1.
(421) Embodiment 54. The textile structure of embodiment 53, wherein the weight ratio of the cross-linkable water-insoluble elastomeric polymer to the water-soluble polymer is from about 1:1 to about 20:1.
(422) Embodiment 55. A textile structure comprising:
(423) a fluid permeable polymeric textile layer having opposing first and second surfaces and a length;
(424) a crosslinked water-insoluble elastomeric polymer layer on the first textile surface forming a substantially fluid impermeable barrier, wherein the crosslinked water-insoluble elastomeric layer is adhered to the first textile surface by elastomeric shrinkage; and
(425) a water dissolvable polymer layer dried on the second textile surface;
(426) wherein the weight ratio of the crosslinked water-insoluble elastomeric polymer to the water dissolvable polymer is from about 0.1:1 to about 100:1.
(427) Embodiment 56. The textile construction of embodiment 55, wherein the weight ratio of the crosslinked water-insoluble elastomeric polymer to the water dissolvable polymer is from about 1:1 to about 20:1.
(428) Embodiment 57. A graft comprising:
(429) a tubular wall disposed between a first open end and an opposed second open end and having an inner surface and an opposed outer surface, the tubular wall comprising a textile construction of one or more filaments or yarns;
(430) wherein the outer surface comprises a coating of a substantially water-insoluble sealant disposed thereon;
(431) wherein the inner surface is substantially free of the substantially water-insoluble sealant; and
(432) wherein the tubular wall has a water permeability of about 0.16 ml/min/cm.sup.2 at 120 mm Hg pressure or less than 0.16 ml/min/cm.sup.2 at 120 mm Hg pressure.
(433) Embodiment 58. The graft of embodiment 57, wherein the textile construction is selected from the group consisting of a weave of the one or more filaments or yarns, a knit of the one or more filaments or yarns, a braid of the one or more filaments or yarns, and a web of the one or more filaments or yarns.
(434) Embodiment 59. The graft of embodiment 57 or 58, wherein the coating is disposed within an intermediate portion of the tubular wall between the inner surface and the opposed outer surface.
(435) Embodiment 60. The graft of any one of embodiments 57 to 59, wherein the tubular wall is a crimped wall having a series of peaks and valleys.
(436) Embodiment 61. The graft of any one of embodiments 57 to 60, wherein the substantially water-insoluble sealant is disposed at about 8 mg/cm.sup.2 of area of the tubular wall or greater than 8 mg/cm.sup.2 of area of the tubular wall.
(437) Embodiment 62. The graft of any one of embodiments 57 to 59, wherein the tubular wall is a non-crimped wall being substantially free of peaks and valleys.
(438) Embodiment 63. The graft of any one of embodiments 57 to 62, wherein the substantially water-insoluble sealant is disposed at about 4 mg/cm.sup.2 of area of the tubular wall or greater than 4 mg/cm.sup.2 of area of the tubular wall.
(439) Embodiment 64. The graft of any one of embodiments 57 to 63, wherein the substantially water-insoluble sealant is disposed at about 14 mg/cm.sup.2 of area of the tubular wall or less than 14 mg/cm.sup.2 of area of the tubular wall.
(440) Embodiment 65. The graft of any one of embodiments 57 to 64, wherein the substantially water-insoluble sealant is an elastomeric material selected from the group consisting of moisture curing, light curing, thermo-curing, platinum catalyzed, anaerobic curing materials or a combination of these curing mechanisms.
(441) Embodiment 66. The graft of embodiment 65, wherein the elastomeric material is selected from the group consisting of silicones, polyurethanes, polycarbonates, thermoplastic elastomers, and combinations thereof.
(442) Embodiment 67. The graft of any one of embodiments 57 to 66, wherein one of more of the substantially water-soluble coating or the substantially water-insoluble coating comprises a component selected from the group consisting of a colorant, a therapeutic agent, a dye, and a fluorescent indicator.
(443) Embodiment 68. The graft of any one of embodiments 57 to 67, wherein the substantially water-insoluble sealant is selected from the group consisting of silicone, room temperature vulcanizing silicone, thermoplastic polyurethane, aliphatic polycarbonate, one or more thermoplastic elastomers, polycarbonate, and combinations thereof.
(444) Embodiment 69. The graft of any one of embodiments 57 to 69,
(445) wherein one portion of the tubular wall has a first level of the substantially water-insoluble sealant to provide a first soft, flexible zone;
(446) wherein another portion of the tubular wall has a second level of the substantially water-insoluble sealant to provide a second zone having a stiffness greater than the first zone; and
(447) wherein the second level the substantially water-insoluble sealant is greater than the first level of the substantially water-insoluble sealant.
(448) Embodiment 70. An implantable or deliverable medical textile comprising:
(449) a wall having a textile construction and having a first surface and an opposed second surface;
(450) wherein the second surface comprises a coating of a substantially water-insoluble sealant disposed thereon;
(451) wherein the first surface is substantially free of the substantially water-insoluble sealant; and
(452) wherein the wall has a water permeability of about 0.16 ml/min/cm.sup.2 at 120 mm Hg pressure or less than 0.16 ml/min/cm.sup.2 at 120 mm Hg pressure.
(453) Embodiment 71. An assembly for producing an implantable or deliverable medical textile having a selectively applied water-insoluble sealant layer, comprising:
(454) a mandrel having a length, a hollow lumen disposed within a portion of the length, at least one open end, and a plurality of perforations through a wall of the mandrel;
(455) a reservoir in fluid communication with the open lumen of the mandrel; and
(456) a water-soluble polymer disposed within the reservoir.
(457) Embodiment 72. The assembly of embodiment 71, further comprising a tubular graft securably disposed over a portion of the mandrel having the plurality of perforations.
(458) Embodiment 73. The assembly of embodiment 71 or 72, further comprising a vacuum source in fluid communication with the hollow lumen of the mandrel.
(459) Embodiment 74. The assembly of embodiment 73, further comprising a manifold configured to provide selective fluid communication between the hollow lumen of the mandrel and the reservoir and/or the vacuum source.
(460) Embodiment 75. The assembly of any one of embodiments 71 to 74, further comprising a source of pressurized and/or blown air.
(461) Embodiment 76. The assembly of embodiment 75, wherein the pressurized and/or blown air is in fluid communication with the hollow lumen of the mandrel.
(462) Embodiment 77. The method, textile, graft, device or assembly of any preceding embodiment, further including a support member.
(463) Embodiment 78. The method of any one of embodiments 1 to 30, wherein the support member is added to the outer surface of the wall of the conduit.
(464) Embodiment 79. The method of embodiment 78, wherein the support member is wrapped around the outer surface of the wall of the conduit.
(465) Embodiment 80. The method of embodiment 79, wherein the conduit comprises a plurality of crimps, and the support member is arranged to nest between the plurality of crimps.
(466) Embodiment 81. The method of any one of embodiments 78 to 80, wherein a step of adding the support member to the conduit is carried out prior to the step of adding the sealant to the conduit.
(467) Embodiment 82. The method of any one of embodiments 78 to 81, wherein a step of adding the sealant to the conduit is used, at least in part, to attach the support member to the conduit.
(468) Embodiment 83. The method of any one of embodiments 78 to 82, wherein the support member is a flexible, polymer member.
(469) Embodiment 84. The method of any one of embodiments 78 to 83, wherein the flexible support member is present on a portion of the length of the graft.
(470) Embodiment 85. A method of manufacturing a vascular prosthesis, the method comprising the steps of:
(471) (i) providing a conduit comprising a wall, the wall of the conduit comprising an inner surface and an outer surface, at least a section of the conduit being porous;
(472) (ii) adding a masking agent to at least a part of the porous section of the conduit; and
(473) (iii) adding a sealant to at least a part of the porous section of the conduit, the sealant being configured to mitigate movement of fluid through the wall of the conduit;
(474) wherein the masking agent is configured to mitigate presence of the sealant on the inner surface of the conduit.
(475) Embodiment 86. The method of embodiment 85, wherein the sealant forms a sealing layer on at least a part of the outer surface of the wall of the conduit.
(476) Embodiment 87. The method of embodiment 85 or embodiment 86, wherein the sealant forms a sealing layer on substantially all of the outer surface of the wall of the conduit.
(477) Embodiment 88. The method of any preceding embodiments 85 to 87, wherein the masking agent forms a masking agent layer on at least a part of the inner surface of the wall of the conduit.
(478) Embodiment 89. The method of any preceding embodiments 85 to 88, wherein the masking agent forms a masking agent layer on substantially all of the inner surface of the wall of the conduit.
(479) Embodiment 90. The method of any preceding embodiments 85 to 89, wherein substantially all of the conduit is porous.
(480) Embodiment 91. The method of any preceding embodiments 85 to 90, wherein the method comprises one or more masking agent removal steps, the, or each, masking agent removal step comprising the step of removing at least a part of the masking agent from the conduit.
(481) Embodiment 92. The method of embodiment 91, wherein the method comprises the step of removing at least a part of the masking agent from at least a part of the outer surface of the wall of the conduit prior to the step of adding the sealant to the porous section of the conduit.
(482) Embodiment 93. The method of embodiment 91 or embodiment 92, wherein the method comprises the step of removing at least a part of the masking agent from the inner surface of the wall of the conduit subsequent to the step of adding the sealant to at least a part of the porous section of the conduit.
(483) Embodiment 94. The method of any one of embodiments 91 to 93, wherein the method comprises the step of removing substantially all of the masking agent from the conduit subsequent to the step of adding the sealant to at least a part of the porous section of the conduit.
(484) Embodiment 95. The method of any one of embodiments 91 to 94, wherein at least one of the masking agent removal steps is carried out at a temperature of between approximately 15° C. and approximately 140° C.
(485) Embodiment 96. The method of any one of embodiments 91 to 95, wherein at least one of the masking agent removal steps comprises the step of removing at least a part of the masking agent by applying a solvent thereto.
(486) Embodiment 97. The method of embodiment 96, wherein the solvent comprises water.
(487) Embodiment 98. The method of any one of embodiments 91 to 97, wherein the conduit is at least one of: agitated, rotated, spun, and shaken, or the like, during at least one of the masking agent removal steps.
(488) Embodiment 99. The method of any one of embodiments 91 to 98, wherein at least one of the masking agent removal steps is carried out by etching, plasma etching, ablating and/or abrading the masking agent.
(489) Embodiment 100. The method of any preceding embodiments 85 to 99, wherein the inner surface of the wall of the conduit is configured to promote the growth of biological tissue thereon.
(490) Embodiment 101. The method of any preceding embodiments 85 to 100, wherein the masking agent comprises a polymer.
(491) Embodiment 102. The method of embodiment 101, wherein the masking agent comprises a water-soluble polymer.
(492) Embodiment 103. The method of embodiment 101 or embodiment 102, wherein the masking agent comprises at least one of: polyvinylpyrrolidone, glycerol, methyl cellulose, poly(ethylene glycol), and poly(ethylene glycol) hydrogel.
(493) Embodiment 104. The method of any preceding embodiments 85 to 103, wherein the masking agent is biocompatible.
(494) Embodiment 105. The method of any preceding embodiments 85 to 104, wherein the masking agent forms a biocompatible masking agent layer when added to the conduit.
(495) Embodiment 106. The method of any preceding embodiments 85 to 105, wherein the masking agent is added to at least a part of the porous section of the conduit from a masking agent solution.
(496) Embodiment 107. The method of embodiment 106, wherein the masking agent solution is a polymer solution.
(497) Embodiment 108. The method of embodiment 106 or embodiment 107, wherein the step of adding the masking agent to at least a part of the porous section of the conduit is performed by spraying the masking agent solution onto at least a part of the porous section of the conduit.
(498) Embodiment 109. The method of embodiment 108, wherein the masking agent solution is added to the conduit by spraying the masking agent onto at least a part of the inner surface of the wall of the conduit.
(499) Embodiment 110. The method of any one of embodiments 106 to embodiment 109, wherein the step of adding the masking agent to at least a part of the porous section of the conduit is performed by immersing at least a part of the porous section of the conduit in the masking agent solution.
(500) Embodiment 111. The method of embodiment 110, wherein substantially all of the conduit is immersed in the masking agent solution.
(501) Embodiment 112. The method of any one of embodiments 106 to 111, wherein the masking agent solution comprises between approximately 5% weight/volume (w/v) of polymer in solution and approximately 30% w/v of polymer in solution.
(502) Embodiment 113. The method of any preceding embodiments 85 to 112, wherein the step of adding the sealant to at least a part of the porous section of the conduit does not result in the removal of the masking agent from the porous section of the conduit.
(503) Embodiment 114. The method of any preceding embodiments 85 to 113, wherein the masking agent is configured to biodegrade when the vascular prosthesis is implanted inside the human or animal body.
(504) Embodiment 115. The method of any preceding embodiments 85 to 114, wherein the conduit is a woven fibrous polymer conduit.
(505) Embodiment 116. The method of any preceding embodiments 85 to 115, wherein the sealant comprises a polymer.
(506) Embodiment 117. The method of embodiment 116, wherein the sealant is a water-insoluble polymer.
(507) Embodiment 118. The method of any preceding embodiments 85 to 117, wherein the sealant forms a sealing layer when added to the conduit, the sealing layer being a polymer layer.
(508) Embodiment 119. The method of any one of embodiments 116 to 118, wherein the sealant comprises at least one of: silicone, room temperature vulcanising silicone, thermoplastic polyurethane, aliphatic polycarbonate, one or more thermoplastic elastomers, and polycarbonate.
(509) Embodiment 120. The method of any preceding embodiments 85 to 119, wherein the sealant is added to the conduit from a sealant solution.
(510) Embodiment 121. The method of embodiment 120 wherein the sealant solution is a polymer solution.
(511) Embodiment 122. The method of embodiment 120 or embodiment 121, wherein the sealant solution comprises an organic solvent.
(512) Embodiment 123. The method of embodiment 122, wherein the sealant solution comprises at least one of heptane and xylene.
(513) Embodiment 124. The method of any preceding embodiments 85 to 123, wherein the sealant is added to at least a part of the porous section of the conduit by brushing and/or spraying the sealant thereon.
(514) Embodiment 125. The method of any preceding embodiments 85 to 124, wherein the sealant is configured to mitigate movement of blood through the wall of the conduit.
(515) Embodiment 126. The method of any preceding embodiments 85 to 125, comprising the further step of sterilising the vascular prosthesis.
(516) Embodiment 127. The method of embodiment 126, wherein the vascular prosthesis is sterilised by way of at least one of: a gamma sterilisation process, an electron beam sterilisation process, and an ethylene oxide sterilisation process.
(517) Embodiment 128. The method of any preceding embodiments 85 to 127, wherein the conduit is moveable between a contracted state and an extended state.
(518) Embodiment 129. The method of embodiment 128, wherein the step of adding the masking agent to at least a part of the porous section of the conduit is carried out, at least in part, while the conduit is in the contracted state, in the extended state, and/or when moved between the contracted state and the extended state.
(519) Embodiment 130. The method of embodiment 128 or embodiment 129, wherein the step of adding the sealant to at least a part of the porous section of the conduit is carried out, at least in part, while the conduit is in the contracted state, in the extended state, and/or when moved between the contracted state and the extended state.
(520) Embodiment 131. The method of any preceding embodiments 85 to 130, the method comprising one or more steps of weighing the conduit and/or measuring the length of the conduit, to determine, at least in part, the amount of masking agent, and/or or the amount of sealant, to add to at least a part of the porous section of the conduit.
(521) Embodiment 132. The method of any preceding embodiments 85 to 131, wherein the step of adding the masking agent to at least a part of the porous section of the conduit comprises the step of providing gas to the conduit.
(522) Embodiment 133. The method of embodiment 132, wherein the gas is directed towards the outer surface of the wall of the conduit.
(523) Embodiment 134. The method of embodiment 132 or embodiment 133, wherein the gas is air.
(524) Embodiment 135. The method of any preceding embodiments 85 to 134, wherein the method comprises the step of adding a support member to the conduit.
(525) Embodiment 136. The method of embodiment 135, wherein the support member is added to the outer surface of the wall of the conduit.
(526) Embodiment 137. The method of embodiment 136, wherein the support member is wrapped around the outer surface of the wall of the conduit.
(527) Embodiment 138. The method of embodiment 137, wherein the conduit comprises a plurality of crimps, and the support member is arranged to nest between the plurality of crimps.
(528) Embodiment 139. The method of any one of embodiments 135 to 138, wherein the step of adding the support member to the conduit is carried out prior to the step of adding the sealant to the conduit.
(529) Embodiment 140. The method of any one of embodiments 135 to 139, wherein the step of adding the sealant to the conduit is used, at least in part, to attach the support member to the conduit.
(530) Embodiment 141. The method of any one of embodiments 135 to 140, wherein the support member is a flexible, polymer member.
(531) Embodiment 142. The method of any preceding embodiments 85 to 141, wherein the method comprises one or more steps of selectively adding sealant to one or more sections of the conduit, such that the conduit comprises at least two sections comprising substantially different amounts of sealant thereon.
(532) Embodiment 143. A vascular prosthesis comprising:
(533) a conduit comprising a wall, the wall of the conduit comprising an inner surface and an outer surface, at least a section of the conduit being porous;
(534) wherein at least a part of the porous section comprises a sealant configured to mitigate movement of fluid through the wall of the conduit; and
(535) wherein the inner surface of the wall of the conduit is substantially devoid of the sealant.
(536) Embodiment 144. The vascular prosthesis of embodiment 143, wherein the sealant forms a sealing layer on at least a part of the outer surface of the wall of the conduit.
(537) Embodiment 145. The vascular prosthesis of embodiment 143 or embodiment 144, wherein the sealant forms a sealing layer on substantially all of the outer surface of the wall of the conduit.
(538) Embodiment 146. The vascular prosthesis of any one of embodiments 143 to 145, wherein substantially all of the conduit is porous.
(539) Embodiment 147. The vascular prosthesis of any one of embodiments 143 to 146, wherein the inner surface of the wall of the conduit is configured to promote the ingrowth of biological tissue thereon.
(540) Embodiment 148. The vascular prosthesis of any one of embodiments 143 to 147, wherein the conduit is a woven fibrous polymer conduit.
(541) Embodiment 149. The vascular prosthesis of any one of embodiments 143 to 148, wherein the sealant forms a sealing layer, the sealing layer being a polymer layer.
(542) Embodiment 150. The vascular prosthesis of any one of embodiments 143 to 149, wherein the sealant comprises at least one of: silicone, room temperature vulcanising silicone, thermoplastic polyurethane, aliphatic polycarbonate, one or more thermoplastic elastomers, and polycarbonate.
(543) Embodiment 151. The vascular prosthesis of any one of embodiments 143 to 150, wherein the sealant is configured to mitigate movement of blood through the wall of the conduit.
(544) Embodiment 152. The vascular prosthesis of any one of embodiments 143 to 151, wherein the vascular prosthesis is sterilised.
(545) Embodiment 153. The vascular prosthesis of embodiment 152, wherein the vascular prosthesis is sterilised by way of at least one of the following: a gamma sterilisation process, an ethylene oxide sterilisation process, and an electron beam sterilisation process.
(546) Embodiment 154. The vascular prosthesis of any one of embodiments 143 to 153, wherein the conduit is moveable between a contracted state and an extended state.
(547) Embodiment 155. The vascular prosthesis of any one of embodiments 143 to 154, wherein the conduit comprises a support member.
(548) Embodiment 156. The vascular prosthesis of embodiment 155, wherein the support member is located substantially adjacent to the outer surface of the wall of the conduit.
(549) Embodiment 157. The vascular prosthesis of embodiment 156, wherein the support member is wrapped around the outer surface of the wall of the conduit.
(550) Embodiment 158. The vascular prosthesis of embodiment 157, wherein the conduit comprises a plurality of crimps, the support member being arranged to nest between the plurality of crimps.
(551) Embodiment 159. The vascular prosthesis of any one of embodiments 155 to 158, wherein the sealant is arranged to, at least in part, attach the support member to the conduit.
(552) Embodiment 160. The vascular prosthesis of any one of embodiments 155 to 159, wherein the support member is a flexible, polymer member.
(553) Embodiment 161. The vascular prosthesis of any one of embodiments 143 to 160, wherein the conduit is configured to have at least two sections having substantially different amounts of sealant thereon.
(554) Embodiment 162. A kit of parts for manufacturing a vascular prosthesis, the kit of parts comprising:
(555) (i) a conduit comprising a wall, the wall of the conduit comprising an inner surface and an outer surface, at least a section of the conduit being porous;
(556) (ii) a masking agent; and
(557) (iii) a sealant;
(558) when applied to at least a part of the porous section of the conduit, the masking agent being configured to mitigate presence of the sealant on the inner surface of the conduit; and when applied to at least a part of the porous section of the conduit, the sealant being configured to mitigate movement of fluid through the wall of the conduit.
(559) Embodiment 163. The kit of parts of embodiment 162, wherein addition of the sealant to at least a part of the porous section of the conduit forms a sealing layer on at least a part of the outer surface of the wall of the conduit.
(560) Embodiment 164. The kit of parts of embodiment 162 or embodiment 163, wherein addition of the masking agent to at least a part of the porous section of the conduit forms a masking agent layer on at least part of the inner surface of the wall of the conduit.
(561) Embodiment 165. The kit of parts of any one of embodiments 162 to 164, wherein substantially all of the conduit is porous.
(562) Embodiment 166. The kit of parts of any one of embodiments 162 to 165, the kit of parts comprising a masking agent remover, the masking agent remover being operable to remove applied masking agent from the conduit.
(563) Embodiment 167. The kit of parts of embodiment 166, wherein the masking agent remover comprises a solvent.
(564) Embodiment 168. The kit of parts of embodiment 167, wherein the solvent comprises water.
(565) Embodiment 169. The kit of parts of any one of embodiments 166 to 168, wherein the masking agent remover is operable to remove applied masking agent from the conduit at a temperature of between approximately 15° C. and approximately 140° C.
(566) Embodiment 170. The kit of parts of any one of embodiments 162 to 169, the kit of parts comprising an abrading tool, the abrading tool being operable to remove applied masking agent from the conduit.
(567) Embodiment 171. The kit of parts of any one of embodiments 162 to 170, wherein the inner surface of the wall of the conduit is configured to promote the ingrowth of biological tissue thereon.
(568) Embodiment 172. The kit of parts of any one of embodiments 162 to 171, wherein the masking agent comprises a polymer.
(569) Embodiment 173. The kit of parts of embodiment 172, wherein the masking agent comprises a water-soluble polymer.
(570) Embodiment 174. The kit of parts of any one of embodiments 162 to 173, wherein masking agent applied to the conduit forms a masking agent layer, the masking agent layer being a polymer layer.
(571) Embodiment 175. The kit of parts of any one of embodiments 172 to 174, wherein the masking agent comprises at least one of: polyvinylpyrrolidone, glycerol, methyl cellulose, and poly(ethylene glycol) hydrogel.
(572) Embodiment 176. The kit of parts of any one of embodiments 162 to 175, wherein the masking agent is biocompatible.
(573) Embodiment 177. The kit of parts of any one of embodiments 162 to 176, wherein masking agent applied to the conduit forms a biocompatible masking agent layer.
(574) Embodiment 178. The kit of parts of any one of embodiments 162 to 177, wherein the kit of parts comprises a masking agent solution, the masking agent solution being operable to apply masking agent to the conduit.
(575) Embodiment 179. The kit of parts of embodiment 178, wherein the masking agent solution is a polymer solution.
(576) Embodiment 180. The kit of parts of embodiment 178 or embodiment 179, wherein the conduit is immersible in the masking agent solution.
(577) Embodiment 181. The kit of parts of any one of embodiments 178 to 180, wherein the masking agent solution comprises between approximately 5% w/v of polymer in solution and approximately 30% w/v of polymer in solution.
(578) Embodiment 182. The kit of parts of any one of embodiments 162 to 181, wherein when the masking agent and the sealant are applied to the conduit, the sealant is configured such that addition of the sealant to the conduit does not result in the removal of the applied masking agent from the conduit.
(579) Embodiment 183. The kit of parts of any one of embodiments 162 to 182, wherein the masking agent is configured to biodegrade when implanted inside the human or animal body.
(580) Embodiment 184. The kit of parts of any one of embodiments 162 to 183, wherein the conduit is a woven fibrous polymer conduit.
(581) Embodiment 185. The kit of parts of any one of embodiments 162 to 184, wherein the sealant comprises a polymer, optionally a water-insoluble polymer.
(582) Embodiment 186. The kit of parts of any one of embodiments 162 to 185, wherein the sealant, when applied to the conduit, forms a sealing layer, the sealing layer being a polymer layer.
(583) Embodiment 187. The kit of parts of embodiment 185 or embodiment 186, wherein the sealant comprises at least one of: silicone, room temperature vulcanising silicone, thermoplastic polyurethane, aliphatic polycarbonate, one or more thermoplastic elastomers, and polycarbonate.
(584) Embodiment 188. The kit of parts of any one of embodiments 162 to 187, wherein the kit of parts comprises a sealant solution operable to apply sealant to the conduit.
(585) Embodiment 189. The kit of parts of embodiment 188, wherein the sealant solution is a polymer solution.
(586) Embodiment 190. The kit of parts of embodiment 188 or embodiment 189, wherein the sealant solution comprises an organic solvent.
(587) Embodiment 191. The kit of parts of embodiment 190, wherein the sealant solution comprises at least one of heptane and xylene.
(588) Embodiment 192. The kit of parts of any one of embodiments 162 to 191, the kit of parts comprising a sealant applicator operable to apply sealant to the conduit, and/or a masking agent applicator operable to apply masking agent to the conduit.
(589) Embodiment 193. The kit of parts of embodiment 192, wherein the sealant applicator is an apparatus for spray coating the sealant, and/or a brush, or the like.
(590) Embodiment 194. The kit of parts of embodiment 192 or embodiment 193, wherein the masking agent applicator is a brush, an apparatus for spray-coating the masking agent, an apparatus for dipping or immersing the conduit in the masking agent, and/or an apparatus for wiping the masking agent onto the conduit.
(591) Embodiment 195. The kit of parts of any one of embodiments 162 to 194, wherein the sealant, when applied to at least a part of the porous section of the conduit, is configured to mitigate movement of blood through the wall of the conduit.
(592) Embodiment 196. The kit of parts of any one of embodiments 162 to 195, wherein the conduit is moveable between a contracted state and an extended state.
(593) Embodiment 197. The kit of parts of any one of embodiments 162 to 196, the kit of parts comprising a further prosthesis.
(594) Embodiment 198. The kit of parts of embodiment 197, wherein the further prosthesis is at least one of: a biological heart valve, a synthetic heart valve, a cardiac assist device, and a ventricular assist device, or the like.
(595) Embodiment 199. The kit of parts of any one of embodiments 162 to 198, the kit of parts comprising a weighing device and/or a device for measuring the length of the conduit.
(596) Embodiment 200. The kit of parts of any one of embodiments 162 to 199, the kit of parts comprising a gas flow apparatus operable to provide gas flow to the conduit.
(597) Embodiment 201. The kit of parts of embodiment 200, wherein the gas is air.
(598) Embodiment 202. A vascular system, the vascular system comprising:
(599) a vascular prosthesis manufactured according to any one of embodiments 85 to 142; and
(600) a further prosthesis;
(601) wherein the vascular prosthesis is connected to the further prosthesis, such that fluid can flow between the vascular prosthesis and the further prosthesis.
(602) Embodiment 203. The vascular system of embodiment 202, wherein the further prosthesis is at least one of: a biological heart valve, a synthetic heart valve, a cardiac assist device, and a ventricular assist device, or the like.
(603) Embodiment 204. A method of implanting a vascular prosthesis, the method comprising the steps of:
(604) providing a vascular prosthesis manufactured using the method of any one of embodiments 85 to 142;
(605) connecting an inlet of the vascular prosthesis to a first blood vessel; and
(606) connecting an outlet of the vascular prosthesis to a second blood vessel;
(607) such that blood can flow between the first and second blood vessels through the vascular prosthesis.
(608) Embodiment 205. The method of embodiment 204, wherein the first and second blood vessels are formed from a blood vessel which is diseased, or has been severed, bisected, or the like.
(609) Embodiment 206. A method of implanting a vascular prosthesis, the method comprising the steps of:
(610) providing a vascular prosthesis according to any one of embodiments 143 to 161;
(611) connecting the vascular prosthesis to a first blood vessel; and
(612) connecting the vascular prosthesis to a second blood vessel;
(613) such that blood can flow between the first and second blood vessels through the vascular prosthesis.
(614) Embodiment 207. The method of embodiment 206, wherein the first and second blood vessels are formed from a blood vessel which is diseased, or has been severed, bisected, or the like.
(615) Embodiment 207. A method of implanting a vascular system, the method comprising the steps of:
(616) providing a vascular system, the vascular system comprising:
(617) a vascular prosthesis manufactured according to any one of embodiments 85 to 142; and
(618) a further prosthesis;
(619) wherein the vascular prosthesis is connectable to the further prosthesis;
(620) connecting the vascular prosthesis to the further prosthesis, such that blood can flow therebetween;
(621) connecting an end of a blood vessel to the vascular prosthesis; and
(622) connecting the further prosthesis to the heart;
(623) such that blood can flow between the blood vessel and the heart through the vascular system.
(624) Embodiment 209. The method of embodiment 208, wherein the further prosthesis is at least one of: a biological heart valve, a synthetic heart valve, a cardiac assist device, and a ventricular assist device, or the like.