Bioresorbable nonwoven fabric made of gelatin

Abstract

A nonwoven fabric includes fibers of a fiber raw material including gelatin, the fibers including at least one of an antimicrobially effective substance and an antibiotic, wherein the fibers are produced by rotational spinning.

Claims

1. A nonwoven fabric, comprising: fibers of a fiber raw material consisting essentially of at least one gelatin or derivative of gelatin, wherein the fibers comprise an antimicrobially effective substance, an antibiotic, or a mixture of two or more of any of these, wherein the fibers have a diameter from 0.3 to 500 m, wherein the fibers are produced by rotational spinning of the fiber raw material, then drawing spun fiber raw material through circular, oval, or rectangular passages, then guiding discharged fibers from the passages in a directed and non-contacting manner, wherein at least some of the fibers are twisted with one another, interlaced with one another, or have a twisted structure, so as to bond to one another as laid without further bonding measures, wherein the fabric has an open pore structure and an air permeability of at least 0.5 L/min.Math.cm.sup.2.

2. The nonwoven fabric as recited in claim 1, wherein at least some of the fibers are interlaced with one another and form at least one fiber bundle.

3. The nonwoven fabric as recited in claim 1, wherein the fibers consist of: the at least one gelatin or derivative of gelatin; and the antimicrobial substance, the antibiotic, or the mixture.

4. The nonwoven fabric as recited in claim 1, wherein the antimicrobially effective substance, the antibiotic, or the mixture is homogenously distributed in the fibers, and/or present in the fibers at a nanoscale level, and/or distributed on the fibers.

5. The nonwoven fabric as recited in claim 1, wherein the antimicrobially effective substance is present and comprises silver.

6. The nonwoven fabric as recited in claim 1, further comprising: nanofibers, comprising gelatin and/or a gelatin derivative, having a diameter of not more than 100 nm, which nanofibers are not electrically spun.

7. The nonwoven fabric as recited in claim 1, wherein the fabric has a tensile strength of at least 0.15 N/mm.sup.2 at a specific weight per unit area from 140 to 180 g/m.sup.2 in a dry state, and wherein the fabric has an elongation at break in a hydrated state of 150% to 200%.

8. A method for producing the nonwoven fabric of claim 1, the method comprising: introducing the fiber raw material into a container; introducing the antimicrobially effective substance, the antibiotic, or the mixture into the container; rotating the container so as to fluidize the fiber raw material and discharge the fluidized fiber raw material from the container by centripetal forces so as to form the fibers; and joining the fibers together in a nonwoven manner to provide the nonwoven fabric.

9. The method as recited in claim 8, further comprising: guiding the fibers being discharged from the container in a directed and non-contacting manner.

10. The method as recited in claim 9, wherein the guiding is performed using a suction device.

11. The method as recited in claim 8, wherein the fluidized fiber raw material is discharged through passages having a diameter of up to 500 m.

12. The method as recited in claim 8, wherein the rotating is carried out at a speed of up to 25,000 revolutions per minute.

13. The method as recited in claim 8, wherein the container can be heated to a temperature of 300 C.

14. The method as recited in claim 8, further comprising: laying the fibers on a laying device, wherein an electrical potential difference exists between the laying device and the container.

15. The method as recited in claim 8, further comprising: contacting the nonwoven fabric with a drug suitable for wound healing.

16. The method as recited in claim 8, further comprising: disposing the nonwoven fabric onto an end of a rod element so as to form a swab.

17. A method for producing the nonwoven fabric of claim 1, the method comprising: rotating a container comprising the fiber raw material in fluidized form, thereby discharging the fluidized fiber raw material from the container by centripetal forces so as to form the fibers; joining the fibers together to provide the nonwoven fabric; and disposing the antimicrobially effective substance, the antibiotic, or the mixture on the fibers.

18. A swab, comprising: a rod element; and the nonwoven fabric of claim 1, wherein the nonwoven fabric is disposed onto an end of the rod element.

19. The nonwoven fabric as recited in claim 1, wherein the fibers are made by a process that comprises fluidizing gelatin in a solution comprising water.

20. The nonwoven fabric as recited in claim 5, wherein the antimicrobially effective substance further comprises gold.

21. A nonwoven fabric, comprising: fibers substantially comprising gelatin; and an antimicrobially effective substance, an antibiotic, or a mixture of two or more of any of these, wherein the fibers have a diameter from 0.3 to 500 m, wherein at least some of the fibers are twisted or interlaced so as to bond to one another as laid without further bonding measures, and wherein the fabric has an air permeability of at least 0.5 L/min.Math.cm.sup.2.

22. The nonwoven fabric as recited in claim 21, further comprising: nanofibers, substantially comprising gelatin, having a diameter of not more than 100 nm, which nanofibers are not electrically spun.

23. The nonwoven fabric as recited in claim 21, wherein the fabric has a tensile strength of at least 0.15 N/mm.sup.2 at a specific weight per unit area from 140 to 180 g/m.sup.2 in a dry state, and wherein the fabric has an elongation at break in a hydrated state of 150% to 200%.

24. A nonwoven fabric, comprising: fibers substantially comprising gelatin, a gelatin derivative, or a mixture of two or more of these; and an antimicrobially effective substance, an antibiotic, or a mixture of two or more of any of these, wherein the fibers have a diameter up to 500 m, and wherein the fibers are rotationally spun, and some of the fibers are twisted or interlaced so as to bond to one another without further bonding measures, and wherein the fabric has an air permeability of at least 0.5 L/min.Math.cm.sup.2.

25. The nonwoven fabric as recited in claim 1, wherein the fabric has a tensile strength of at least 0.15 N/mm.sup.2 at a specific weight per unit area from 140 to 180 g/m.sup.2 in a dry state, and wherein the fabric has an elongation at break in a hydrated state of 150% to 200%.

26. The nonwoven fabric as recited in claim 24, wherein the fibers comprising nanofibers having a diameter of not more than 100 nm, which nanofibers are not electrically spun.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) In the drawing,

(2) FIG. 1 shows an SEM picture of a nonwoven fabric comprising gelatin, in whose fibers silver is distributed as antimicrobial substance in the form of nanoscale particles,

(3) FIG. 2 shows an SEM picture of the nonwoven fabric from FIG. 1 in magnified view,

(4) FIG. 3 shows an SEM picture of a fiber of the nonwoven fabric from FIG. 1, in magnified view, which has a diameter of 4 m, and

(5) FIG. 4 shows an SEM picture of a fiber bundle which comprises fibers interlaced with one another.

DETAILED DESCRIPTION

Working Example 1

(6) A nonwoven fabric comprising silver as an antimicrobial substance according to FIGS. 1 and 2 is produced by a rotational spinning method as follows:

(7) First, a 20% strength gelatin solution is prepared. A gelatin of type A PIGSKIN from Gelita AG is used. The gelatin is stirred into water. 1000 ppm of the solids content of a 5% strength aqueous silver solution which contains silver in the form of nanoscale particles are added to the gelatin solution. A silver solution from RENT A SCIENTIST, of the type AGPURE was used. This results in a final concentration of 50 mg of silver/(kg of gelatin solution).

(8) The gelatin solution then remains standing for about one hour in order to swell. Thereafter, the gelatin solution is dissolved in an ultrasonic bath at 60 C. and then kept at a temperature of 80-85 C. for about 2 hours. In the gelatin solution, the particles of silver can form agglomerates which are dissolved by stirring the gelatin solution. The gelatin solution thermostatted at 80-85 C. is fed by means of a peristaltic pump as fiber raw material into the container of an apparatus for rotational spinning according to DE 102005048939 A1.

(9) The container has a temperature of about 120 C. and rotates at a rotational speed of 4500 rpm. Cut-outs which are configured as holes having a diameter of 0.3 mm are present in the container. The fiber raw material is forced through the cut-outs by the centripetal force and spun into fibers which are stretched by a suction device. The suction device is present below the container.

(10) After the gelatin has formed a network, an antimicrobially effective bioresorbable nonwoven fabric comprising gelatin, namely a gelatin nonwoven fabric, is obtained.

(11) The nonwoven fabric was characterized by means of a scanning electron microscope (SEM). FIGS. 1 to 3 show SEM pictures of the nonwoven fabric described here, at different magnifications. According to a characterization based on ICP (according to EN ISO 11885), the silver concentration in the nonwoven fabric is 44 mg/kg.

(12) In FIG. 2, it is evident, particularly in the lower left quarter of the figure, that some fibers are interlaced or twisted with one another. The occurrence of these interlacings is characteristic of a nonwoven fabric which is produced by a rotational spinning method.

Working Example 2

(13) A nonwoven fabric comprising antibiotics is produced by a rotational spinning method as follows:

(14) For the production of a nonwoven fabric, first a 20% strength gelatin solution is prepared. A gelatin of the type A PIGSKIN according to example 1 is used. The gelatin is stirred into water. This gelatin solution remains standing for one hour in order to swell. Thereafter, the gelatin solution is dissolved in an ultrasonic bath at 60 C. and then kept at a temperature of 80-85 C. for about two hours.

(15) The gelatin solution thermostatted at 80-85 C. is fed by means of a peristaltic pump into the container according to DE 102005048939 A1. Shortly before the gelatin solution enters the cut-outs, an ampoule of gentamicin solution (GENTAMICIN 40 from HEXAL AG) is mixed with the gelatin solution. The container has a temperature of about 120 C. and rotates at a rotational speed of 4500 rpm. The fiber raw material is forced out of the cut-outs present on the container by the centripetal force and is spun into fibers. The fibers are stretched by a suction device which is present below the container. After the gelatin has formed a network, a nonwoven fabric having an enclosed antibiotic which has an antimicrobiotic action and at the same time is bioresorbable is obtained.

Working Example 3

(16) A nonwoven fabric with subsequent antibiotic treatment is produced by a rotational spinning method as follows:

(17) For the production of a nonwoven fabric, first a 20% strength gelatin solution is prepared. A gelatin of the type A PIGSKIN according to example 1 is used. The gelatin is stirred into water. This gelatin solution remains standing for one hour in order to swell.

(18) Thereafter, the gelatin solution is dissolved in an ultrasonic bath at 60 C. and then kept at a temperature of 80-85 C. for about two hours.

(19) The gelatin solution thermostatted at 80-85 C. is fed by means of a peristaltic pump into the container according to DE 102005048939 A1. The container has a temperature of 120 C. and rotates at a rotational speed of 4500 rpm. The fiber raw material is forced out of the cut-outs present on the container by the centripetal force and is spun into fibers. The fibers are stretched by a suction device which is present below the container. After the gelatin has formed a network, the nonwoven fabric is sprayed with a solution of gentamicin and then dried.

(20) FIG. 4 shows a nonwoven fabric which was produced analogously to working example 1. In the case of this nonwoven fabric, some fibers are interlaced with one another and form a fiber bundle. As a result of the interlacing of individual fibers, they are combined to form a fiber bundle and may be reversibly displaced relative to one another. This makes it possible to stretch the nonwoven fabric without destruction. During the stretching, individual fibers are in fact pulled and are displaced relative to other fibers. The twistings or interlacings even promote the return of the fibers to their position prior to stretching. The nonwoven fabric therefore shows high dimensional stability.

(21) Regarding further advantageous configurations and further developments of the teaching according to the invention, reference is made firstly to the general part of the description and secondly to the attached patent claims. Finally, it should be very particularly emphasized that the working examples chosen purely randomly above serve merely for discussing the teaching according to the invention but do not limit said teaching to these working examples.