STABLE CONDUCTIVE MYOCARDIAL PATCH WITH NEGATIVE POISSON'S RATIO STRUCTURE AND PREPARATION METHOD THEREOF

Abstract

A stable conductive myocardial patch with a negative Poisson's ratio structure is provided. The preparation method includes preparing a myocardial patch substrate with concave polygons as the structural units by weaving or knitting, and then a conductive coating is coated on the surface of the substrate. Alternatively, the yarns can be processed into conductive coated yarns first, and then used as the raw material to weave or knit a stable conductive myocardial patch with a negative Poisson's ratio structure. The prepared myocardial patch has a relative resistance change of less than 5% at 50% tensile strain. When the strain of the structural units is within 50%, the fabric exhibits a negative Poisson's ratio structure, which expands in the perpendicular direction of the tensile load. The fabric exhibits a negative Poisson's ratio effect and anisotropy of Young's modulus, which matches the mechanical behavior of natural myocardium.

Claims

1. A stable conductive myocardial patch with a negative Poisson's ratio structure, comprising a knitted fabric or a woven fabric with a concave polygon as a structural unit; wherein the knitted fabric or the woven fabric is composed of yarns with a conductive coating on a surface of the yarns; wherein an initial conductivity of the stable conductive myocardial patch is 1-10 S/m, and a relative resistance change is less than 5% at 50% tensile strain; when a strain of the structural unit is within 50%, a minimum Poisson's ratio of the knitted fabric is −0.5, a minimum Poisson's ratio of the woven fabric is −0.1; and the stable conductive myocardial patch expands in a perpendicular direction of a tensile load, and an anisotropy ratio of Young's modulus of the stable conductive myocardial patch is 1.99-5.71; wherein the structural unit in the woven fabric is composed of a first weave, a second weave, and a third weave interwoven by yarns with different contractility; wherein, the first weave, the second weave and the third weave have sequentially decreasing fabric densities; and the structural unit in the knitted fabric is half loops and half floats in a course where elastic yarns are located.

2. The stable conductive myocardial patch with the negative Poisson's ratio structure according to claim 1, wherein the structural unit is composed of yarns with different elasticities, and the structural unit formed by the elastic yarns pulls surrounding units to shrink and fold.

3. The stable conductive myocardial patch with the negative Poisson's ratio structure according to claim 1, wherein the first weave is a plain weave, the second weave is a twill weave or a satin weave, and the third weave is a weave having warp yarns alternately floating on weft yarns.

4. The stable conductive myocardial patch with the negative Poisson's ratio structure according to claim 1, wherein warp yarns of the woven fabric are composed of the elastic yarns and inelastic yarns with a number ratio of 1:1, and the weft yarns are composed of the elastic yarns separately or are composed of the elastic yarns and the inelastic yarns with a number ratio of 1:1; and the yarns in the knitted fabric are composed of inelastic yarns and the elastic yarns with a number ratio of 2:1.

5. The stable conductive myocardial patch with the negative Poisson's ratio structure according to claim 4, wherein a chemical composition of the elastic yarns is polycaprolactone or polyurethane, and a chemical composition of the inelastic yarns is polylactic acid.

6. The stable conductive myocardial patch with the negative Poisson's ratio structure according to claim 1, wherein the concave polygon is a concave quadrilateral, a symmetrical concave quadrilateral, or a concave hexagon.

7. The stable conductive myocardial patch with the negative Poisson's ratio structure according to claim 1, wherein the conductive coating is mainly synthesized by a polymerization reaction of a conductive polymer monomer, a dopant, and an oxidant.

8. The stable conductive myocardial patch with the negative Poisson's ratio structure according to claim 7, wherein when the conductive polymer monomer is pyrrole, the dopant is sodium dodecylbenzene sulfonate or cetyltrimethylammonium bromide, and the oxidant is ammonium persulfate or ferric chloride; or, when the conductive polymer monomer is aniline, the dopant is hydrochloric acid, sulfuric acid, nitric acid, camphorsulfonic acid or sodium dodecylbenzene sulfonate, and the oxidant is ammonium persulfate, potassium dichromate, ferric chloride, or potassium iodate; or, when the conductive polymer monomer is thiophene, the dopant is sodium dodecylbenzene sulfonate or cetyltrimethylammonium bromide, and the oxidant is iron trichloride, copper perchlorate, aluminum trichloride, or ammonium sulfate.

9. A method for preparing the stable conductive myocardial patch with the negative Poisson's ratio structure according to claim 1, comprising manufacturing a myocardial patch substrate with concave polygonal structural units by weaving or knitting, and then applying the conductive coating on a surface of the myocardial patch substrate by coating and in-situ polymerization to obtain the stable conductive myocardial patch with the negative Poisson's ratio structure; or, applying the conductive coating on the yarns first by coating and the in-situ polymerization to obtain conductive coated yarns, and then using the conductive coated yarns as a raw material to weave or knit the stable conductive myocardial patch with the negative Poisson's ratio structure.

10. The method according to claim 9, wherein the step of fabricating the conductive coating of the myocardial patch substrate by the in-situ polymerization comprises: (1) adding an oxidant and a dopant to a 10-40 wt % polyurethane solution and stirring evenly; (2) coating the surface of the myocardial patch substrate with the 10-40 wt % polyurethane solution 1-10 times to obtain a coated substrate; and (3) fumigating the coated substrate with a conductive material monomer at 0-60° C. for 1-24 h; the process of fabricating a conductive polymer coating of the yarns by the in-situ polymerization method comprises: (1) adding the conductive polymer monomer and the dopant to the 10-40 wt % polyurethane solution and stirring evenly to obtain a mixed solution ; (2) immersing the yarns with the mixed solution for 1-30 min to obtain coated yarns; (3) immersing or coating the coated yarns in an oxidant solution at 0-60° C. for 1-24 h to obtain the conductive coated yarns; and (4) after washing with deionized water 1 to 5 times, the conductive coated yarns are dried and collected; and the process of surface coating comprises: (1) adding the conductive polymer monomer and the dopant to the oxidant solution and stirring, and then performing a polymerization for 3-6 h; (2) after the polymerization, obtaining a conductive polymer powder by filtration and drying; (3) adding a certain mass of the conductive polymer powder to the 10-40 wt % polyurethane solution and stirring evenly to obtain a homogenous suspension; (4) coating the surface of the myocardial patch substrate or the yarns with the homogenous suspension 1 to 10 times, and drying to prepare the stable conductive myocardial patch or the conductive coated yarns with the negative Poisson's ratio structure.

11. The method according to claim 9, wherein the weaving comprises the following steps: (1) weaving the yarns or the conductive coated yarns on a loom to obtain a fabric; (2) soaking the fabric in deionized water at a temperature of 50-70° C. for 20-60 min, and drying in a drum at 60-100° C. for 30-60 min; (3) relaxing the fabric for 12-24 h to obtain a woven fabric; and the knitting comprises the following steps: (1) feeding and knitting the yarns or the conductive coated yarns on a computerized flat knitting machine to obtain the fabric; (2) soaking the fabric in the deionized water at the temperature of 50-70° C. for 20-60 min, and drum-drying at 60-100° C. for 30-60 min; (3) allowing the fabric to relax for 12-24 h to obtain a knitted fabric.

12. The method according to claim 9, wherein the structural unit is composed of yarns with different elasticities, and the structural unit formed by the elastic yarns pull surrounding units to shrink and fold.

13. The method according to claim 9, wherein the first weave is a plain weave, the second weave is a twill weave or a satin weave, and the third weave is a weave in which warp yarns alternately float on weft yarns.

14. The method according to claim 9, wherein warp yarns of the woven fabric are composed of the elastic yarns and inelastic yarns with a number ratio of 1:1, and the weft yarns are composed of the elastic yarns separately or are composed of the elastic yarns and the inelastic yarns with a number ratio of 1:1; and the yarns in the knitted fabric are composed of inelastic yarns and the elastic yarns with a number ratio of 2:1.

15. The method according to claim 14, wherein a chemical composition of the elastic yarns is polycaprolactone or polyurethane, and a chemical composition of the inelastic yarns is polylactic acid.

16. The method according to claim 9, wherein the concave polygon is a concave quadrilateral, a symmetrical concave quadrilateral, or a concave hexagon.

17. The method according to claim 9, wherein the conductive coating is mainly synthesized by a polymerization reaction of a conductive polymer monomer, a dopant, and an oxidant.

18. The method according to claim 17, wherein when the conductive polymer monomer is pyrrole, the dopant is sodium dodecylbenzene sulfonate or cetyltrimethylammonium bromide, and the oxidant is ammonium persulfate or ferric chloride; or, when the conductive polymer monomer is aniline, the dopant is hydrochloric acid, sulfuric acid, nitric acid, camphorsulfonic acid or sodium dodecylbenzene sulfonate, and the oxidant is ammonium persulfate, potassium dichromate, ferric chloride, or potassium iodate; or, when the conductive polymer monomer is thiophene, the dopant is sodium dodecylbenzene sulfonate or cetyltrimethylammonium bromide, and the oxidant is iron trichloride, copper perchlorate, aluminum trichloride, or ammonium sulfate.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0067] FIG. 1 shows a schematic diagram of negative Poisson's ratio structural model;

[0068] FIGS. 2A-2C show schematic diagrams of woven concave polygonal negative Poisson's ratio myocardial patch, wherein FIG. 2A shows a concave quadrilateral patch, FIG. 2B shows a symmetrical concave quadrilateral patch, and FIG. 2C shows a concave hexagon patch, 1 indicates weave 1 in FIG. 3, 2 indicates weave 2 in FIGS. 3, and 3 indicates weave 3 in FIG. 3;

[0069] FIGS. 3A-3C show fabric weave charts, in which FIG. 3A shows a fabric weave chart of plain weave, FIG. 3B shows a fabric weave chart of twill weave, and FIG. 3C shows a fabric weave chart of satin weave;

[0070] FIG. 4 shows a knitting diagram of the myocardial patch with a concave hexagonal negative Poisson's ratio structure.

DETAILED DESCRIPTION OF THE EMBODIMENTS

[0071] This invention is further explained below in conjunction with specific embodiments. It should be understood that these embodiments are only used to illustrate the present invention and not to limit the scope of the present invention. In addition, it should be understood that after reading the teachings of the present invention, those skilled in the art can make various changes or modifications to the present invention, and these equivalent forms also fall within the scope defined by the appended claims of the present application.

[0072] A stable conductive myocardial patch with a negative Poisson's ratio structure is a knitted fabric or woven fabric with a concave polygon as a structural unit; the knitted fabric or woven fabric is composed of yarns with conductive coatings on its surface.

[0073] The initial conductivity of the myocardial patch is 1-10 S/m, and the relative resistance change is less than 5% at 50% tensile strain. When the strain of the structural units is within 50%, the minimum Poisson's ratio of the knitted fabric is −0.5, and the minimum Poisson's ratio of the woven fabric is −0.1; and it expands in the perpendicular direction of the tensile load. The anisotropy ratio of Young's modulus of the myocardial patch is 1.99-5.71.

[0074] The structural unit is composed of yarns with different elasticities, and the weaves formed by the elastic yarns pull the surrounding weaves to shrink and fold.

[0075] The concave polygonal structural units in the woven fabric are composed of weaves 1, 2, and 3 of yarns with different contractility; among them, weaves 1, 2, and 3 have sequentially decreasing fabric densities; the structural units in the knitted fabric are half loops and half floats in the course where the elastic yarns are located.

[0076] Weave 1 is a plain weave, weave 2 is a twill weave or a satin weave, and weave 3 is a weave in which the warp yarns alternately float on the weft yarns.

[0077] The warp yarns of the woven fabric are composed of elastic yarns and inelastic yarns with a number ratio of 1:1, and the weft yarns are composed of elastic yarns or are composed of elastic yarns and inelastic yarns with a number ratio of 1:1; the yarns in the knitted fabric are composed of inelastic yarns and elastic yarns with a number ratio of 2:1.

[0078] The chemical composition of the elastic yarn is polycaprolactone or polyurethane, and the non-elastic yarn is polylactic acid.

[0079] The concave polygon is a concave quadrilateral, a symmetrical concave quadrilateral, or a concave hexagon.

[0080] The conductive coating is mainly made by the polymerization reaction of conductive polymer monomers, dopants, and oxidants.

[0081] When the conductive material monomer is pyrrole, the dopant is sodium dodecylbenzene sulfonate or cetyltrimethylammonium bromide, and the oxidant is ammonium persulfate or ferric chloride;

[0082] or, when the conductive material monomer is aniline, the dopant is hydrochloric acid, sulfuric acid, nitric acid, camphorsulfonic acid or sodium dodecylbenzene sulfonate, and the oxidant is ammonium persulfate, potassium dichromate, ferric chloride, or potassium iodate;

[0083] or, when the conductive material monomer is thiophene, the dopant is sodium dodecylbenzene sulfonate or cetyltrimethylammonium bromide, and the oxidant is iron trichloride, copper perchlorate, aluminum trichloride, or ammonium sulfate.

[0084] The method for preparing a stable conductive myocardial patch with a negative Poisson's ratio structure characterized in that: the myocardial patch substrate with concave polygonal structural units is manufactured by weaving or knitting, and then a conductive coating is coated on the surface of the substrate by coating and in-situ polymerization to obtain a conductive and stable myocardial patch with a negative Poisson's ratio structure;

[0085] or, the yarns can be processed into conductive yarns first by coating and in-situ polymerization, and then the conductive yarns are used as the raw material to weave or knit a stable conductive myocardial patch with a negative Poisson's ratio structure.

[0086] The process of processing the conductive polymer onto the myocardial patch substrate by the in-situ polymerization method is:

[0087] (1) The oxidant and dopant are added to the 10-40 wt % polyurethane solution and stirred evenly;

[0088] (2) The surface of the myocardial patch substrate is coated with polyurethane solution 1-10 times;

[0089] (3) The coated substrate is fumigated with conductive material monomer at 0-60° C. for 1-24 h.

[0090] The process of fabricating the conductive polymer onto the yarns by the in-situ polymerization method is:

[0091] (1) The conductive polymer monomer and dopant are added to the 10-40 wt % polyurethane solution and stirred evenly;

[0092] (2) The yarns are immersed in the mixed solution for 1-30 min;

[0093] (3) The coated yarns are immersed in or coated with the oxidant solution at 0-60° C. for 1-24 h.

[0094] (4) After washing with deionized water 1 to 5 times, the conductive yarns are obtained after being dried;

[0095] The process of surface coating is:

[0096] (1) The conductive polymer monomer and dopant are added to the oxidant solution and stirred, and then allowed to polymerize for 3-6 h;

[0097] (2) After polymerization, the conductive polymer powder is obtained by filtration and drying;

[0098] (3) A certain mass of conductive polymer powder is added to the 10-40 wt % polyurethane solution and stirred evenly;

[0099] (4) The surface of the myocardial patch substrates or yarns are coated with the solution 1 to 10 times, and a stable conductive myocardial patch or conductive yarns with a negative Poisson's ratio structure are prepared after being dried.

[0100] The method for preparing a stable conductive myocardial patch with a negative Poisson's ratio structure characterized in that when weaving technology is used, the specific steps are as follows:

[0101] (1) The yarns or conductive yarns are woven on a loom to obtain a fabric;

[0102] (2) The fabric is soaked in deionized water at a temperature of 50-70° C. for 20-60 min, and dried in a drum at 60-100° C. for 30-60 min;

[0103] (3) The fabric is relaxed for 12-24 h to obtain a woven fabric.

[0104] When using knitting technology, the specific steps are as follow:

[0105] (1) The yarns or conductive yarns is fed in and knitted on the computerized flat knitting machine to obtain the fabric;

[0106] (2) The fabric is soaked in deionized water at a temperature of 50-70° C. for 20-60 min, and drum-dried at 60-100° C. for 30-60 min;

[0107] (3) The fabric is relaxed for 12-24 h to obtain a knitted fabric.

[0108] FIG. 1 shows a schematic diagram of the negative Poisson's ratio structure model. It can be seen from the figure that when a negative Poisson material with a concave polygonal structure is stretched, it will expand in the perpendicular direction of the stretching load.

EXAMPLE 1

[0109] The method for preparing a stable conductive myocardial patch with a negative Poisson's ratio structure, including the following steps :

[0110] (1) The pyrrole monomer is added to the FeCl.sub.3 solution and stirred for 4 h; after polymerization, the polypyrrole powder is obtained by filtration and drying (The molar ratio of FeCl.sub.3 to pyrrole monomer is 2.3:1);

[0111] (2) The polypyrrole powder is added to the 30 wt % polyurethane solution and stirred to obtain a homogenous 30 wt % polypyrrole suspension;

[0112] (3) Polyurethane yarns and polylactic acid yarns are immersed in the above suspension for 5 minutes.

[0113] (4) The polypyrrole-coated polyurethane yarns and the polypyrrole-coated polylactic acid yarns are prepared after washing and drying;

[0114] (5) The conductive yarns are fed in and knitted on the computerized flat knitting machine according to the knitting diagram shown in FIG. 4 to obtain the fabric (the polypyrrole-coated polylactic acid yarns and polypyrrole-coated polyurethane yarns are arranged alternately in number ratio of 2:1);

[0115] (6) After being relaxed from the machine, the fabric naturally shrinks and folds to form a stable conductive myocardial patch with a negative Poisson's ratio structure;

[0116] The initial conductivity of the myocardial patch is 3 S/m, and the relative resistance change is less than 5% at 50% tensile strain. When the strain of the structural units is within 50%, the minimum Poisson's ratio of the fabric is −0.5 and it expands in the perpendicular direction of the tensile load. The anisotropy ratio of Young's modulus of the myocardial patch is 3.8.

EXAMPLE 2

[0117] The method for preparing a stable conductive myocardial patch with a negative Poisson's ratio structure, including the following steps :

[0118] (1) The polycaprolactone yarns and polylactic acid yarns are fed in and knitted on the computerized flat knitting machine according to the knitting diagram shown in FIG. 4 to obtain the fabric (the polypyrrole-coated polylactic acid yarns and polypyrrole-coated polyurethane yarns are arranged alternately in number ratio of 2:1);

[0119] (2) Before being relaxed from the machine, the fabric is coated by the polyurethane solution (10% w/v) containing sodium dodecylbenzene sulfonate (1% w/v) and ammonium persulfate (3% w/v) three times;

[0120] (3) The coated fabric is fumigated with pyrrole monomer at 4° C. for 12 h;

[0121] (4) After being relaxed from the machine, the fabric is soaked in deionized water at 60° C. for 40 min, and dried in a drum at 70° C. for 60 min;

[0122] (5) The fabric is relaxed for 24 h to obtain a knitted fabric.

[0123] The initial conductivity of the myocardial patch is 5 S/m, and the relative resistance change is less than 3% at 50% tensile strain. When the strain of the structural units is within 50%, the minimum Poisson's ratio of the fabric is −0.5 and it expands in the perpendicular direction of the tensile load. The anisotropy ratio of Young's modulus of the myocardial patch is 2.78.

EXAMPLE 3

[0124] The method for preparing a stable conductive myocardial patch with a negative Poisson's ratio structure, including the following steps :

[0125] (1) Polycaprolactone yarn is used as elastic yarn raw material, and polylactic acid yarn is used as inelastic yarn, and a rapier loom with two kinds of weft yarn supplies and dobby shedding mechanism is used;

[0126] (2) The warp yarns (polycaprolactone yarns and polylactic acid yarns arranged alternatively at a number ratio of 1:1) are used for winding, warping, sizing, and drawing-in, and polycaprolactone yarn is selected as the weft yarn. The myocardial patch substrate is prepared according to FIG. 2A and FIGS. 3A-3C.

[0127] (3) Before being relaxed from the machine, the fabric is coated by the polyurethane solution (10% w/v) containing sodium dodecylbenzene sulfonate (1% w/v) and ammonium persulfate (3% w/v) three times;

[0128] (4) The coated fabric is fumigated with pyrrole monomer at 4° C. for 12 h;

[0129] (5) After being relaxed from the machine, the fabric is soaked in deionized water at 60° C. for 40 min, and dried in a drum at 70° C. for 60 min;

[0130] (6) The fabric is relaxed for 24 h to obtain a woven fabric.

[0131] The initial conductivity of the myocardial patch is 8 S/m, and the relative resistance change is less than 3% at 50% tensile strain. When the strain of the structural units is within 50%, the minimum Poisson's ratio of the fabric is −0.08 and it expands in the perpendicular direction of the tensile load. The anisotropy ratio of Young's modulus of the myocardial patch is 1.99.

EXAMPLE 4

[0132] The method for preparing a stable conductive myocardial patch with a negative Poisson's ratio structure, including the following steps :

[0133] (1) Polycaprolactone yarn is used as elastic yarn raw material, and polylactic acid yarn is used as inelastic yarn, and a rapier loom with two kinds of weft yarn supplies and dobby shedding mechanism is used;

[0134] (2) The warp yarns (polycaprolactone yarns and polylactic acid yarns arranged alternatively at a number ratio of 1:1) are used for winding, warping, sizing, and drawing-in, and polycaprolactone yarn is selected as the weft yarn. The myocardial patch substrate is prepared according to FIG. 2B and FIGS. 3A-3C.

[0135] (3) Before being relaxed from the machine, the fabric is coated by the polyurethane solution (10% w/v) containing sodium dodecylbenzene sulfonate (1% w/v) and ammonium persulfate (3% w/v) three times;

[0136] (4) The coated fabric is fumigated with pyrrole monomer at 4° C. for 12 h;

[0137] (5) After being relaxed from the machine, the fabric is soaked in deionized water at 60° C. for 40 min, and dried in a drum at 70° C. for 60 min;

[0138] (6) The fabric is relaxed for 24 h to obtain a woven fabric.

[0139] The initial conductivity of the myocardial patch is 8 S/m, and the relative resistance change is less than 5% at 50% tensile strain. When the strain of the structural units is within 50%, the minimum Poisson's ratio of the fabric is −0.1 and it expands in the perpendicular direction of the tensile load. The anisotropy ratio of Young's modulus of the myocardial patch is 2.35.

EXAMPLE 5

[0140] The method for preparing a stable conductive myocardial patch with a negative Poisson's ratio structure, including the following steps :

[0141] (1) Polycaprolactone yarn is used as elastic yarn raw material, and polylactic acid yarn is used as inelastic yarn, and a rapier loom with two kinds of weft yarn supplies and dobby shedding mechanism is used;

[0142] (2) The warp yarns (polycaprolactone yarns and polylactic acid yarns arranged alternatively at a number ratio of 1:1) are used for winding, warping, sizing, and drawing-in, and polycaprolactone yarn is selected as the weft yarn. The myocardial patch substrate is prepared according to FIG. 2C and FIGS. 3A-3C.

[0143] (3) Before being relaxed from the machine, the fabric is coated by the polyurethane solution (10% w/v) containing sodium dodecylbenzene sulfonate (1% w/v) and ammonium persulfate (3% w/v) three times;

[0144] (4) The coated fabric is fumigated with pyrrole monomer at 4° C. for 12 h;

[0145] (5) After being relaxed from the machine, the fabric is soaked in deionized water at 60° C. for 40 min, and dried in a drum at 70° C. for 60 min;

[0146] (6) The fabric is relaxed for 24 h to obtain a woven fabric.

[0147] The initial conductivity of the myocardial patch is 8 S/m, and the relative resistance change is less than 5% at 50% tensile strain. When the strain of the structural units is within 50%, the minimum Poisson's ratio of the fabric is −0.08 and it expands in the perpendicular direction of the tensile load. The anisotropy ratio of Young's modulus of the myocardial patch is 2.41.

EXAMPLE 6

[0148] The method for preparing a stable conductive myocardial patch with a negative Poisson's ratio structure is the same as in Example 5. The difference lies in the methods for conductive coating on the fabric in steps (3) to (6), specifically as follows:

[0149] (3) The pyrrole monomer and sodium dodecylbenzene sulfonate are added to the ammonium persulfate solution and stirred for 5 h; after polymerization, the polypyrrole powder is obtained by filtration and drying (The molar ratio of pyrrole monomer, sodium dodecylbenzene sulfonate, and ammonium persulfate is 1:0.8:1);

[0150] (4) The polypyrrole powder is added to the 30 wt % polyurethane solution and stirred to obtain a homogenous 30 wt % polypyrrole suspension;

[0151] (5) The surface of the substrate is coated with the solution 3 times. And after air drying, a conductive and stable myocardial patch with a negative Poisson's ratio structure is prepared;

[0152] The initial conductivity of the myocardial patch is 8 S/m, and the relative resistance change is less than 5% at 50% tensile strain. When the strain of the structural units is within 50%, the minimum Poisson's ratio of the fabric is −0.08 and it expands in the perpendicular direction of the tensile load. The anisotropy ratio of Young's modulus of the myocardial patch is 2.41.

EXAMPLE 7

[0153] To explore the effect of a myocardial patch matching the electrical and mechanical behavior of normal myocardium on myocardial repair in Examples 1 to 6, the steps are as follows:

[0154] (1) Sprague-Dawley rats are anesthetized with moderate ether, followed by left thoracic incisions to expose the heart, and then the left coronary arteries are ligated with 8-0 #sutures 2 mm below the left atrial appendage to establish rat myocardial infarction models;

[0155] (2) Myocardial infarcted Sprague-Dawley rats are divided into two groups: the sham group and the experimental group in which each rat is transplanted with a conductive myocardial patch with a negative Poisson's ratio structure;

[0156] (3) After 2 weeks, the heart function of the rats is observed using echocardiography. The rats are euthanized and their heart tissues are collected and fixed in 4% paraformaldehyde at 4° C. and dehydrated in ethanol. Masson's trichrome staining is performed on the frozen sections to observe the changes in fibrotic tissue, infarct area, and left ventricular wall thickness.

[0157] Experimental results showed that implanting a conductive fabric with a negative Poisson's ratio structure into the heart of rats with myocardial infarction can significantly increase the cardiac ejection fraction and the shortening fraction of the left ventricular axis, and significantly reduce the size of the left ventricle during systole as well as the size of the fibrotic tissue and infarct area.

EXAMPLE 8

[0158] To explore the effect of a myocardial patch matching the electrical and mechanical behavior of normal myocardium on myocardial repair in Examples 1 to 6, the steps are as follows:

[0159] (1) Neonatal rat cardiomyocytes are seeded on a conductive myocardial patch with a negative Poisson's ratio structure at a density of 5×10.sup.6 cells/cm.sup.2. Cardiomyocytes are cultured in high-glucose Dulbecco's modified Eagle medium supplemented with 15% fetal bovine serum, 100 U/ml penicillin, and 100 ug/ml streptomycin. Cells are incubated at 37° C. under 5% CO.sub.2, and the medium is changed every two days.

[0160] (2) After the cardiomyocytes are cultured for 7 days, the viability of the cardiomyocytes on the myocardial patch is measured by live/dead cell staining.

[0161] (3) Sprague-Dawley rats are anesthetized with moderate ether, followed by left thoracic incisions to expose the heart, and then the left coronary arteries are ligated with 8-0 #sutures 2 mm below the left atrial appendage to establish rat myocardial infarction models. Myocardial infarcted Sprague-Dawley rats are divided into two groups: the sham group and the experimental group in which each rat is transplanted with a cardiomyocytes-loaded conductive myocardial patch with a negative Poisson's ratio structure;

[0162] (4) The echocardiography system is used to evaluate the left ventricular function of rats at 3, 7, 14, and 28 days after surgery.

[0163] (5) After 4 weeks, the heart function of the rats is observed using echocardiography. The rats are euthanized, and their heart tissues are collected and fixed in 4% paraformaldehyde at 4° C. and dehydrated in ethanol. Masson's trichrome staining is performed on the frozen sections to observe the changes in fibrotic tissue, infarct area, and left ventricular wall thickness.

[0164] The experimental results showed that the viability of cardiomyocytes cultured on the myocardial patch was not significantly different from that cultured on the petri dish, and the myocardial patch had good biocompatibility. After the patch was implanted into the myocardial infarcted rats, the cardiac ejection fraction and the shortening fraction of the left ventricular short-axis were significantly increased. The internal size of the left ventricle decreased significantly during systole, and the size of fibrotic tissue and infarct area were also reduced.