Negative poisson ratio structure myocardial patch with conductive stability and preparation method thereof
阅读说明：本技术 一种导电稳定性的负泊松比结构心肌补片及其制备方法 (Negative poisson ratio structure myocardial patch with conductive stability and preparation method thereof ) 是由 毛吉富 李沂蒙 高娅娅 李超婧 王富军 王璐 于 2020-06-24 设计创作，主要内容包括：本发明涉及一种导电稳定性的负泊松比结构心肌补片及其制备方法,该方法是采用机织或者针织织造具有内凹多边形为最小结构单元的心肌补片基材,并在基材表面涂覆导电涂层制得导电稳定性的负泊松比结构心肌补片；或者,先将纱线进行处理制成导电涂层纱线,再以导电涂层纱线为原料采用机织或者针织织造具有内凹多边形为最小结构单元的导电稳定性的负泊松比结构心肌补片；制得的心肌补片在50％拉伸变形下,电阻变化率低于5％,所述最小结构单元的拉伸率在50％以内,织物呈现负泊松比结构,且在拉伸载荷的垂直方向膨胀,织物展现出负泊松比效应和杨氏模量的各向异性,与正常心肌组织机械行为相匹配。(The invention relates to a negative Poisson ratio structure myocardial patch with conductive stability and a preparation method thereof, the method is to adopt weaving or knitting to weave a myocardial patch base material with a concave polygon as a minimum structural unit, and coat a conductive coating on the surface of the base material to prepare the negative Poisson ratio structure myocardial patch with conductive stability; or, the yarns are processed to be conductive coating yarns, and then the conductive coating yarns are used as raw materials to weave the negative Poisson ratio structure myocardial patch with the conductive stability and the inward concave polygon as the minimum structural unit by weaving or knitting; the prepared myocardial patch has the resistance change rate of less than 5 percent under 50 percent of tensile deformation, the tensile rate of the minimum structural unit is within 50 percent, the fabric presents a negative Poisson's ratio structure and expands in the vertical direction of tensile load, and the fabric presents the anisotropy of the negative Poisson's ratio effect and the Young modulus and is matched with the mechanical behavior of normal myocardial tissues.)
1. The utility model provides a negative poisson's ratio structure cardiac muscle patch of electrically conductive stability which characterized by: a knitted fabric or a woven fabric which takes the concave polygon as a minimum structural unit; the knitted fabric or woven fabric is composed of yarns and a conductive coating on the surface of the yarns;
the initial conductivity of the myocardial patch is 1-10S/m, the resistance change rate is lower than 5% under 50% stretching deformation, the stretching rate of the minimum structural unit is within 50%, the minimum Poisson ratio of the knitted fabric is-0.5, and the minimum Poisson ratio of the woven fabric is-0.1; and expands in the direction perpendicular to the tensile load, and the anisotropic ratio of the Young's modulus of the myocardial patch is 1.99 to 5.71.
2. The conductive-stabilized negative poisson's ratio structural myocardial patch according to claim 1, wherein said minimal structural unit is composed of yarns with different contractility, and the tissue formed by the yarns with strong contractility pulls the surrounding tissue to contract and fold.
3. An electrically conductive stabilized negative poisson's ratio structural myocardial patch as claimed in claim 1 or 2, wherein the smallest structural units in said woven fabric are formed by yarns of different contractility into a concave polygonal pattern comprising patterns 1, 2 and 3; wherein the tissue structure densities of the tissues 1, 2 and 3 are different, and the tissue 1 is more than the tissue 2 is more than the tissue 3;
the minimum structural unit in the knitted fabric is half of the row where the elastic yarn is located to form a loop and half of the row floats.
4. The conductive-stability negative poisson's ratio structure myocardial patch according to claim 3, wherein the weave 1 is a plain weave, the weave 2 is a twill or satin weave, and the weave 3 is a weave in which warp yarns alternately float over weft yarns.
5. The conductive-stability negative poisson's ratio structural myocardial patch according to claim 3, wherein warp yarns of the woven fabric are composed of elastic yarns and inelastic yarns with the number of 1:1, and weft yarns are composed of elastic yarns or elastic yarns and inelastic yarns with the number of 1: 1;
the yarns in the knitted fabric consist of inelastic yarns and elastic yarns with the number of 2: 1.
6. The negative poisson's ratio structural myocardial patch of conductive stability according to claim 5, wherein the elastic yarn is made of polycaprolactone or polyurethane, and the inelastic yarn is polylactic acid yarn.
7. The electrically conductive stable negative poisson's ratio structural myocardial patch of claim 1, wherein the concave polygon is a concave quadrilateral, an inward concave quadrilateral, or a concave hexagon.
8. The electrically conductive stable negative poisson's ratio structural myocardial patch of claim 1, wherein the electrically conductive coating is formed primarily from a polymerization reaction of a monomer of electrically conductive material, a dopant, and an oxidant.
9. The negative poisson's ratio structural myocardial patch of conductive stability of claim 8, wherein when the conductive material monomer is pyrrole, the dopant is sodium dodecyl benzene sulfonate or cetyl trimethyl ammonium bromide, and the oxidant is ammonium persulfate or ferric chloride;
or when the conductive material monomer is aniline, the doping agent is hydrochloric acid, sulfuric acid, nitric acid, camphorsulfonic acid or sodium dodecyl benzene sulfonate, and the oxidant is ammonium persulfate, potassium dichromate, ferric trichloride or potassium iodate;
or when the conductive material monomer is thiophene, the dopant is sodium dodecyl benzene sulfonate or hexadecyl trimethyl ammonium bromide, and the oxidant is ferric trichloride, copper perchlorate, aluminum trichloride or ammonium sulfate.
10. A method of preparing an electrically conductive stable negative poisson's ratio structural myocardial patch as claimed in any one of claims 1 to 9, wherein: weaving or knitting a cardiac muscle patch base material with a concave polygon as a minimum structural unit, and then processing a conductive material on the base material by adopting a surface coating or in-situ polymerization method to prepare a negative poisson's ratio structural cardiac muscle patch with conductive stability;
or, the conductive material is processed on the yarn by adopting a surface coating or in-situ polymerization method to prepare conductive coating yarn, and then the conductive coating yarn is used as a raw material to weave the negative Poisson ratio structure myocardial patch with the conductive stability and the inward concave polygon as the minimum structural unit by adopting weaving or knitting.
11. The method for preparing the conductive-stable negative poisson's ratio structural myocardial patch as claimed in claim 10, wherein the in-situ polymerization process for processing the conductive material onto the substrate comprises:
(1) adding an oxidant and a doping agent into a 10-40 wt% polyurethane solution, and uniformly stirring to obtain a solution;
(2) coating the solution on the surface of the substrate for 1-10 times;
(3) conducting conductive material monomer fumigation on the coated substrate at the temperature of 0-60 ℃ for 1-24 hours to prepare the negative poisson's ratio structural myocardial patch with the conductive stability;
the in-situ polymerization method comprises the following steps of treating a conductive material onto yarns:
(1) adding a conductive material monomer and a doping agent into a 10-40 wt% polyurethane solution, and uniformly stirring to obtain a mixed solution;
(2) immersing or coating the yarn in the mixed solution for 1-30 minutes;
(3) immersing or coating the yarn in an oxidant solution at 0-60 ℃ for 1-24 hours;
(4) washing with deionized water for 1-5 times, and drying to obtain conductive coating yarns;
the surface coating process comprises the following steps:
(1) adding a conductive material monomer and a doping agent into an oxidant solution, and stirring, wherein the polymerization time is 3-6 h;
(2) after the polymerization reaction is finished, filtering and drying to obtain conductive material powder;
(3) adding a certain mass fraction of conductive material powder into a 10-40 wt% polyurethane solution, and uniformly stirring to obtain a solution;
(4) and coating the solution on the surface of the substrate or the yarn for 1-10 times, and naturally drying to obtain the conductive stable negative poisson ratio structural myocardial patch or conductive coating yarn.
12. The method for preparing the conductive-stable negative poisson's ratio structural myocardial patch according to claim 10, wherein when the weaving is adopted, the specific steps are as follows:
(1) weaving the yarns or the conductive coating yarns on a weaving machine with 1 or 2 weft yarn supplying and opening mechanisms according to the minimum structural unit to obtain a fabric;
(2) after the fabric is taken off the machine, soaking the fabric in deionized water at the temperature of 50-70 ℃ for 20-60 min, and drying the fabric in a roller at the temperature of 60-100 ℃ for 30-60 min;
(3) loosening the fabric for 12-24 hours to obtain a woven fabric;
when knitting weaving is adopted, the method comprises the following specific steps:
(1) a double-needle-plate latch needle weft knitting machine is adopted to convey the yarns or the conductive coating yarns to a knitting area, and the knitting machine performs knitting according to the minimum structural unit to obtain a fabric;
(2) after the fabric is taken off the machine, soaking the fabric in deionized water at the temperature of 50-70 ℃ for 20-60 min, and drying the fabric in a roller at the temperature of 60-100 ℃ for 30-60 min;
(3) and loosening the fabric for 12-24 hours to obtain the knitted fabric.
Technical Field
The invention belongs to the technical field of biomedical materials, and relates to a negative poisson's ratio structural myocardial patch with conductive stability and a preparation method thereof.
Background
Cardiovascular disease is one of the leading diseases causing human death worldwide, accounting for over 40% of deaths, with myocardial infarction and other types of ischemic heart disease being the leading causes of death. The number of people who die of myocardial infarction and complications thereof in China exceeds 100 million every year, and the incidence rate rises year by year. Although the existing interventional therapy and thrombolytic agent reinjection therapy remarkably reduce the death rate of myocardial infarction in the acute stage. However, myocardial tissues at the diseased region are necrotic and can not regenerate, and can be replaced by surrounding connective tissues to form scar tissues, so that the scar tissues can not be repaired by surgical operation, and the fatality rate of complications at the later recovery stage of myocardial infarction still remains high. The tissue engineering myocardial patch is prepared by compounding seed cells capable of forming myocardial cells and a scaffold material and constructing a biological material capable of being used for transplanting, repairing or replacing autologous myocardium. The tissue engineered myocardial patch provides a very potential technology for repairing damaged myocardium.
Electrical conductivity is an important factor in maintaining cardiac function. The formation of scar tissue after a myocardial infarction interferes with the propagation of the electrical signal. Studies have shown that the introduction of conductive polymers into myocardial patches aids in electrical signal conduction and revascularization in areas of myocardial infarction. However, the existing research ignores that the electrical resistance of the conductive myocardial patch changes along with the strain generated by the heart after the conductive myocardial patch is implanted into the heart. The study shows that the conductive performance of the conductive myocardial patch is applied to the amplitude and frequency of the electrical signal transmission of myocardial cells and Ca2+Transient frequencies have a significant impact. The change in the electrical conductivity of the myocardial patch may cause a difference in the contraction frequency of myocardial tissue. Due to the fact thatThis, the stability of the electrical conduction is crucial for maintaining the synchronous contractility of the myocardial tissue.
Furthermore, the mechanical properties of the myocardial patch are also crucial for the cardiac pulse function. It is generally accepted that the mechanical properties of a myocardial patch should be matched to healthy myocardial tissue. The natural heart has a Young's modulus varying between 0.02 and 0.5MPa and a pronounced mechanical anisotropy. Furthermore, poisson's ratio is an important mechanical property that is often ignored. Most materials have a positive poisson's ratio and when stretched longitudinally, they contract laterally. A material with a negative poisson's ratio may expand in multiple directions simultaneously, thereby affecting co-directional curvature, shear strength, etc. It has been shown that biomaterials with negative or zero poisson's ratio may be best suited to mimic the behavior of natural tissues.
At present, the existing conductive myocardial patch is mainly used for restoring the electrical signal conduction of a myocardial infarction part, only the matching of the conductive performance of the myocardial patch and myocardial tissues in a static state is considered, and the corresponding resistance change of the traditional conductive myocardial patch caused by the deformation of the heart pulse is ignored, so that the consistency of the transmission of the electrical signal and the myocardial contraction frequency is influenced. In the existing research, the myocardial patch is endowed with conductive performance mainly through two modes, the most common mode is to deposit a conductive layer on the surface of the myocardial patch material, and in order to ensure good biocompatibility, conductive materials mostly adopt conductive high polymers. But the conductive high polymer material has small tensile deformation and is difficult to match with the tensile property of the myocardial patch base material. This difference causes the conductive myocardial patch to be prone to rupture when stretched, which results in a change in the resistance of the conductive myocardial patch and affects the transmission of electrical signals. In more serious cases, the conductive coating can be completely broken, so that the conductive cardiac muscle patch completely loses the electric signal transmission capability during the beating of the cardiac muscle; the other method is to blend the conductive material and the myocardial patch base material and prepare the conductive myocardial patch through a spinning or gel process. The conductive material is uniformly dispersed in the myocardial patch in such a way, the conductive material has conductivity under the permeation action in the fiber or gel, the problem that the mechanical properties of the conductive material and the stent material are not matched is solved, and the conductive property can be still maintained under large deformation. However, when stretched, the conductive material undergoes changes in elongation in the direction of stretching and shrinkage in the direction perpendicular to the direction of stretching with the substrate. Before and after stretching, the total path length of electrons passing through the bracket is obviously increased, and the cross-sectional area is obviously reduced, so that the conductivity of the bracket is reduced, and the transmission of electric signals is influenced. In addition, in order to ensure the biocompatibility of the myocardial patch, the conventional myocardial patch is mostly made of materials such as collagen and alginate, and the mechanical property of the conventional myocardial patch is difficult to meet the requirement of generating pulling force during the heart beating. Even if the myocardial patch with good mechanical properties is prepared by the electrostatic spinning technology, the matching problem of the mechanical anisotropy and Poisson's ratio of the myocardial patch with natural myocardial tissues is ignored.
Therefore, it is very important to research a preparation method of a myocardial patch having conductive stability and matching with the electrical and mechanical properties of natural myocardial tissue and a product thereof.
Disclosure of Invention
The invention provides a negative Poisson ratio structure myocardial patch with conductive stability and a preparation method thereof, and aims to solve the problems that the conductive myocardial patch in the prior art is difficult to maintain stable conductive performance after being implanted and the myocardial patch is difficult to match the electrical and mechanical behaviors of normal natural myocardial tissues.
In order to achieve the purpose, the technical scheme adopted by the invention is as follows:
a negative Poisson ratio structure myocardial patch with conductive stability is a knitted fabric or a woven fabric with an internally concave polygon as a minimum structural unit; the knitted fabric or woven fabric is composed of yarns and a conductive coating on the surface of the yarns; the minimum structure unit structure is unbalanced and can be contracted and folded to form an inwards concave polygonal structure after being taken off the machine. The knitted fabric or the woven fabric can be woven in a large scale, and in practical application, corresponding cutting is carried out according to the myocardial infarction area of a patient; the fabric with corresponding size can also be woven according to the myocardial infarction area of the patient.
The initial conductivity of the myocardial patch is 1-10S/m, and the myocardial patch shows stable conductivity when beating with the heart, namely 50%Under tensile deformation, the resistance change rate is less than 5 percent, and the resistivity change rate is (R-R)0)/R0(wherein, R0 is the resistance before stretching, R is the resistance after stretching), the deformation rate of normal myocardial tissue is about 10-20%, the stretching rate of the minimum structural unit is within 50%, the fabric presents a negative Poisson ratio structure, the Poisson ratio of the fabric is gradually increased along with the increase of the stretching rate, the minimum Poisson ratio is-0.5 (the minimum Poisson ratio of the knitted fabric is-0.5, the woven fabric is-0.1), and expands in the vertical direction of the tensile load, the anisotropy ratio of the mechanical property of the natural myocardial tissue is 1.9-3.9, the myocardial patch shows the anisotropy of the negative Poisson ratio effect and the Young modulus, the anisotropy ratio is 1.99-5.71, the Young modulus of the myocardial patch is 0.4-8 MPa, the Young modulus of the myocardial patch is matched with the mechanical behavior of normal myocardial tissues, the biological material with the negative or zero Poisson ratio is most suitable for simulating the behavior of natural tissues, and the normal myocardial tissues show obvious mechanical anisotropy. The myocardial patch has a stable conductive coating, can effectively recover an electric signal path of damaged myocardial tissue and stably transmit an electric signal under the dynamic environment of heart pulsation, when the conductive coating is stretched to a certain degree, the concave folding structure is unfolded, and a reconstruction phenomenon occurs in space, but the path and the cross-sectional area of electrons passing through the conductive myocardial patch do not have significant changes, so that the conductive myocardial patch shows strain insensitivity.
As a preferred technical scheme:
the conductive stable negative poisson's ratio structural myocardial patch is characterized in that the minimum structural unit is formed by yarns with different contractility, and the tissues formed by the yarns with strong contractility pull the surrounding tissues to shrink and fold.
The conductive-stability negative poisson ratio structural myocardial patch is characterized in that the smallest structural unit in the woven fabric is a concave polygonal structure comprising structures 1, 2 and 3 and is formed by yarns with different contractibility; wherein the tissue structure densities of the tissues 1, 2 and 3 are different, and the tissue 1 is more than the tissue 2 is more than the tissue 3;
the minimum structural unit in the knitted fabric is half of a row where the elastic yarn is located to form a loop and half of the row floats; the under-machine shrinkage of the elastic yarns forming the floats is stronger than the shrinkage of the yarns at the loop formation.
According to the conductive-stability negative poisson ratio structure myocardial patch, the weave 1 is a plain weave, the weave 2 is a twill or satin weave, and the weave 3 is a weave with warp yarns alternately floating on weft yarns.
The warp and weft densities are preferably 30 and 25 threads/cm.
The weave 1 is a plain weave with tight weaving; the weave 2 is a twill weave (preferably an upper and a lower twill weave) or a satin weave (preferably a five-flying-weft-surface satin weave), and the weave structure of the weave 2 is relatively loose compared with a plain weave; the warp yarns of the part of the weave 3 are not interwoven, but alternately appear to float above the weft yarns, and the weave structure is loosest.
After the fabric is off the machine, the tissue 3 can shrink maximally, surrounding tissues are pulled, the tissue 1 is interwoven most tightly, and the fabric is prevented from shrinking too much, so that an inwards concave polygonal structure is realized.
The conductive stable negative poisson ratio structural myocardial patch is characterized in that warp yarns of the woven fabric are composed of elastic yarns and non-elastic yarns with the number of 1:1 (alternate arrangement), and weft yarns are composed of elastic yarns or elastic yarns and non-elastic yarns with the number of 1:1 (alternate arrangement);
the yarns in the knitted fabric consist of inelastic yarns and elastic yarns with the number of 2: 1.
The concave structure of the minimum structure unit in the knitted fabric is realized by the difference of the contractibility of elastic yarns on a row and the difference of the stitch density on different wales; taking the concave hexagon as an example, the elastic yarn is in large contractibility at the floating thread position of the transverse row, the elastic yarn and the surrounding tissues at the looping position can be drawn to contract and fold towards the floating thread position to form a concave structure, and the plain stitch structures of the upper and lower lines of the inelastic yarn of the elastic yarn are compact to prevent the fabric from excessively contracting.
The negative poisson's ratio structure myocardium patch with the conductive stability is characterized in that the elastic yarn is made of polycaprolactone or polyurethane, and the non-elastic yarn is polylactic acid yarn.
The negative poisson's ratio structural myocardial patch with conductive stability as described above, wherein the concave polygon is a concave quadrilateral, an inward concave quadrilateral or a concave hexagon.
When the pattern is an inward concave quadrangle or an inward concave quadrangle, the tissue 3 is taken off the machine and then generates large shrinkage deformation, and the shrinkage along the radial direction of the fabric is generated, so that an inward concave quadrangle structure is formed; when the pattern is an inwards concave hexagon, the tissues 3 contract and deform maximally, surrounding tissues are pulled, the structure of the tissues 1 is the most compact, the fabric is prevented from contracting along the radial direction, and therefore the inwards concave hexagon structure contracting along the weft direction of the fabric is realized.
The conductive-stable negative poisson's ratio structural myocardial patch is characterized in that the conductive coating is mainly prepared by polymerizing a conductive material monomer, a dopant and an oxidant.
According to the conductive stable negative poisson's ratio structure myocardial patch, when a conductive material monomer is pyrrole, a doping agent is sodium dodecyl benzene sulfonate or hexadecyl trimethyl ammonium bromide, and an oxidizing agent is ammonium persulfate or ferric trichloride;
or when the conductive material monomer is aniline, the doping agent is hydrochloric acid, sulfuric acid, nitric acid, camphorsulfonic acid or sodium dodecyl benzene sulfonate, and the oxidant is ammonium persulfate, potassium dichromate, ferric trichloride or potassium iodate;
or when the conductive material monomer is thiophene, the dopant is sodium dodecyl benzene sulfonate or hexadecyl trimethyl ammonium bromide, and the oxidant is ferric trichloride, copper perchlorate, aluminum trichloride or ammonium sulfate.
The invention also provides a method for preparing the negative Poisson ratio structure myocardial patch with the conductive stability, which comprises the steps of weaving or knitting the myocardial patch base material with the concave polygon as the minimum structural unit, and coating a conductive coating on the surface of the base material to prepare the negative Poisson ratio structure myocardial patch with the conductive stability;
or the yarns are processed to be made into conductive coating yarns, and then the conductive coating yarns are used as raw materials to weave the conductive stable negative Poisson ratio structural myocardial patch with the concave polygon as the minimum structural unit by weaving or knitting.
The coating method is an in-situ polymerization method, namely, an oxidant and a dopant are coated on the fabric or the yarn, and then a conductive material monomer is introduced for polymerization by a liquid phase or gas phase polymerization method; or the conductive material monomer and the doping agent are coated on the fabric or the yarn, and then the oxidizing agent is coated for polymerization.
Or adding a conductive material monomer into an oxidant and a reducing agent for reaction and polymerization, and then drying to prepare conductive material powder; finally, the conductive material powder is coated on the fabric or the yarn.
As a preferred technical scheme:
the preparation method of the conductive-stable negative poisson's ratio structural myocardial patch comprises the following steps:
(1) adding an oxidant and a doping agent (the mass ratio is 1: 1-5: 1) into 10-40 wt% (preferably 30 wt%) of a polyurethane solution, and uniformly stirring to obtain a solution;
(2) coating the solution on the surface of the substrate for 1-10 times (preferably 5 times);
(3) conducting conductive material monomer fumigation on the coated substrate for 1-24 h (preferably 12h) at 0-60 ℃ (preferably 4 ℃) to prepare the negative poisson ratio structural myocardial patch with conductive stability; taking off the machine, and naturally contracting and folding;
the in-situ polymerization method comprises the following steps of treating a conductive material onto yarns:
(1) adding a conductive material monomer and a doping agent (the mass ratio is 1: 3-1: 1) into 10-40 wt% (preferably 30 wt%) of a polyurethane solution, and uniformly stirring to obtain a mixed solution;
(2) immersing or coating the yarn in the mixed solution for 1-30 minutes (preferably 5 minutes);
(3) immersing or coating the yarn in an oxidant solution (with the concentration of 0.1-1M) for 1-24 h (preferably 12h) at 0-60 ℃ (preferably 4 ℃);
(4) washing with deionized water for 1-5 times (preferably 3 times), and drying to obtain the conductive coating yarn.
The process of coating after preparing the conductive material powder comprises the following steps:
(1) adding a conductive material monomer and a doping agent (the mass ratio is 1: 4-1: 1) into an oxidant solution (the concentration is 0.1-1M) and stirring, wherein the polymerization time is 3-6h (preferably 4 h);
(2) after the polymerization reaction is finished, filtering and drying to obtain conductive material powder;
(3) adding a certain mass fraction (preferably 20 wt%) of conductive material powder into 10-40 wt% (preferably 30 wt%) of polyurethane solution, and uniformly stirring to obtain a solution;
(4) and coating the solution on the surface of the substrate or the yarn for 1-10 times (preferably 5 times), and naturally drying to obtain the conductive coating myocardial patch or the conductive coating yarn.
The preparation method of the negative poisson's ratio structure myocardial patch with the conductive stability comprises the following specific steps when the negative poisson's ratio structure myocardial patch is woven and weaved:
(1) weaving yarns or conductive coating yarns on a loom (preferably, a rapier loom, an air jet loom, etc.) having 2 weft supplying and shedding mechanisms (the shedding mechanism is a dobby shedding mechanism, a jacquard shedding mechanism, etc., preferably, the number of heald frames required for the inward-concave quadrilateral structure is 13, and the number of heald frames required for the inward-concave hexagonal structure is 16) according to a minimum structural unit to obtain a fabric;
by using a combined interlaced pattern of loose and tight weaves with different shrinkage characteristics, different shrinkage effects can be produced in the weft direction. The elastic yarns introduce elasticity into the fabric structure and act as return springs. The non-elastic yarns act as stabilizing elements, combining a loosely and tightly woven staggered pattern to introduce bulkiness into the fabric structure and help maintain the cross-direction dimensions of the fabric when stretched;
(2) after the fabric is taken off the machine, soaking the fabric in deionized water at the temperature of 50-70 ℃ (preferably 60 ℃) for 20-60 min (preferably 45min), and drying the fabric in a roller at the temperature of 60-100 ℃ (preferably 70 ℃) for 30-60 min (preferably 60 min);
(3) the fabric is relaxed for 12-24 hours to promote different tissues to generate different contraction effects in a woven fabric structure, and the geometric shape of a negative Poisson ratio structure is realized to obtain the woven fabric.
When weaving, the warp yarns of different part tissues pass through different heald frames in sequence, and the heald frames move to drive the warp yarns and the weft yarns to form interweaving. The fabric is repeatedly woven in the radial direction (width direction) as follows: the warp yarns pass through the heald frames in sequence according to the sequence of the elastic yarns and the inelastic yarns, and when a minimum structural unit is reached, the drafting technology is repeated.
The weft (length direction) is repeatedly woven as follows: the warp yarns are separated up and down under the action of the heald frame to form a weaving opening, then weft insertion is carried out, and then the heald frame moves and interweaves to form a tissue. When a minimum structural unit is knitted, the heald frame repeats the above movement and the next unit is woven.
When knitting weaving is adopted, the weft knitting weaving comprises the following specific steps:
(1) and (3) adopting a double-needle-plate latch needle weft knitting machine to convey the yarn or the conductive coating yarn to a knitting area, and knitting the yarn or the conductive coating yarn by the double-needle-plate latch needle weft knitting machine according to the minimum structural unit to obtain the fabric.
(2) After the fabric is taken off the machine, soaking the fabric in deionized water at the temperature of 50-70 ℃ for 20-60 min, and drying the fabric in a roller at the temperature of 60-100 ℃ for 30-60 min;
(3) and loosening the fabric for 12-24 hours to obtain the knitted fabric.
The specific application steps of the myocardial repair by adopting the conductive stable negative poisson ratio structural myocardial patch are as follows:
(1) the human pluripotent stem cell source cardiac muscle cells are inoculated on the cardiac muscle patch with the negative Poisson ratio structure with the conductive stability. Cardiomyocytes were cultured in high glucose modified Eagle medium supplemented with 15% fetal bovine serum (FBS, GIBCO), 100U/ml penicillin and 100ug/ml streptomycin. All cells were maintained at 37 ℃ with 5% CO2The culture medium was changed every two days in the incubator of (1).
(2) The conductive myocardial patch loaded with myocardial cells and having a negative poisson's ratio structure is surgically implanted into the myocardial infarction area of a patient, and after the implantation of the biomaterial, the muscle and skin are sutured together with sutures.
Preferably, the operation method of the conductive cardiac muscle patch for cardiac muscle repair is open chest operation or thoracoscopic assisted operation and the like.
The principle of the invention is as follows:
the myocardial patch is made of fabric with unbalanced structure by weaving or knitting forming technology, the fabric can be naturally contracted and folded after being off the machine to form an inwards concave polygonal structure, and the negative Poisson ratio effect of the fabric is realized. Furthermore, the negative poisson's ratio structural fabric has mechanical anisotropy, i.e. the young's modulus differs in different directions. Before the fabric is off-machine, the fabric is subjected to conductive coating or is woven by using conductive fibers, and after the fabric is off-machine, the conductive layer or the conductive yarns can be correspondingly contracted and deformed to form an effect of a concave polygonal structure. When the conductive myocardial patch is subjected to strain such as stretching, the conductive coating or the conductive yarns can be unfolded along with the concave folding structure of the myocardial patch, and are reconstructed in space, but obvious stretching deformation cannot be generated. When the electric signal is transmitted, the cross section and the total path of the electric signal flowing through the conductive coating do not change obviously, and the conductive stability is shown. The electrical conductivity of the myocardial patch of the invention can not obviously change along with the heart pulsation, and the electrical and mechanical properties of the myocardial patch are matched with those of natural myocardial tissues, thus effectively promoting the regeneration and functional recovery of the myocardial tissues.
Has the advantages that:
(1) the negative poisson ratio structural myocardial patch with the conductive stability has stable conductive performance when being influenced by strain caused by heart beating, and avoids the problems of myocardial cell contraction frequency change and the like caused by the conductive performance change of the conductive myocardial patch along with the heart beating in the process of effectively recovering an electric signal path of damaged myocardial tissue;
(2) the negative poisson ratio structure myocardial patch with the conductive stability has excellent mechanical performance, a negative poisson ratio structure and mechanical anisotropy, meets the requirement of heart beating pulling force, and is matched with the mechanical behavior of normal myocardial tissues;
(3) the negative poisson's ratio structure myocardial patch with the conductive stability can provide a thought for solving the problems of complex process of open-chest surgery, postoperative complications, long recovery time and the like by matching implantation of the negative poisson's ratio structure myocardial patch into a human myocardial infarction part through thoracoscopic surgery;
(4) the preparation method of the negative poisson's ratio structure myocardial patch with the conductive stability adopts the molding and surface finishing technology to prepare the myocardial patch, is simple, saves the cost and is easy to realize industrialization.
Drawings
FIG. 1 is a schematic diagram of a negative Poisson's ratio structural model in the present invention;
FIG. 2 is a schematic view of a woven concave polygonal negative Poisson's ratio structural myocardial patch of the present invention, wherein a-concave quadrilateral, b-internal concave quadrilateral, c-concave hexagon, 1-tissue 1, 2 in FIG. 3-tissue 2, 3 in FIG. 3-tissue 3 in FIG. 3;
FIG. 3 is a tissue diagram of each tissue unit in the woven inner negative Poisson ratio structure myocardial patch of the invention, wherein, a is a tissue 1, b is a tissue 2, and c is a tissue 3;
fig. 4 is a weaving diagram of the knitted concave hexagonal negative poisson's ratio structural myocardial patch in the invention.
Detailed Description
The invention will be further illustrated with reference to specific embodiments. It should be understood that these examples are for illustrative purposes only and are not intended to limit the scope of the present invention. Further, it should be understood that various changes or modifications of the present invention may be made by those skilled in the art after reading the teaching of the present invention, and such equivalents may fall within the scope of the present invention as defined in the appended claims.
A negative Poisson ratio structure myocardial patch with conductive stability is a knitted fabric or a woven fabric with an internally concave polygon as a minimum structural unit; the knitted fabric or woven fabric is composed of yarns and a conductive coating on the surface of the yarns;
the initial conductivity of the myocardial patch is 1-10S/m, the resistance change rate is lower than 5% under 50% stretching deformation, the stretching rate of the minimum structural unit is within 50%, the minimum Poisson ratio of the knitted fabric is-0.5, and the minimum Poisson ratio of the woven fabric is-0.1; and expands in the direction perpendicular to the tensile load, and the anisotropy ratio of the Young's modulus of the fabric is 1.99 to 5.71.
The minimum structural unit is composed of yarns with different contractibility, and the tissues formed by the yarns with strong contractibility pull the surrounding tissues to contract and fold.
The minimum structural unit in the woven fabric is a concave polygonal structure comprising structures 1, 2 and 3, which is formed by yarns with different contractibility; wherein the tissue structure densities of the tissues 1, 2 and 3 are different, and the tissue 1 is more than the tissue 2 is more than the tissue 3;
the minimum structural unit in the knitted fabric is half of the row where the elastic yarn is located to form a loop and half of the row floats.
The weave 1 is a plain weave, the weave 2 is a twill or satin weave, and the weave 3 is a weave in which warp yarns alternately float over weft yarns.
The warp yarns of the woven fabric consist of elastic yarns and non-elastic yarns with the number of 1:1, and the weft yarns consist of elastic yarns or elastic yarns and non-elastic yarns with the number of 1: 1;
the yarns in the knitted fabric consist of inelastic yarns and elastic yarns with the number of 2: 1.
The elastic yarn is made of polycaprolactone or polyurethane, and the non-elastic yarn is polylactic acid yarn;
the concave polygon is a concave quadrangle, an inward concave quadrangle or a concave hexagon.
The conductive coating is mainly prepared by conducting polymerization reaction on a conductive material monomer, a doping agent and an oxidizing agent.
When the conductive material monomer is pyrrole, the dopant is sodium dodecyl benzene sulfonate or hexadecyl trimethyl ammonium bromide, and the oxidant is ammonium persulfate or ferric trichloride;
or when the conductive material monomer is aniline, the doping agent is hydrochloric acid, sulfuric acid, nitric acid, camphorsulfonic acid or sodium dodecyl benzene sulfonate, and the oxidant is ammonium persulfate, potassium dichromate, ferric trichloride or potassium iodate;
or when the conductive material monomer is thiophene, the dopant is sodium dodecyl benzene sulfonate or hexadecyl trimethyl ammonium bromide, and the oxidant is ferric trichloride, copper perchlorate, aluminum trichloride or ammonium sulfate.
The method for preparing the conductive-stability negative Poisson ratio structural myocardial patch comprises the steps of weaving or knitting a myocardial patch base material with a concave polygon as a minimum structural unit, and processing a conductive material on the base material by adopting a surface coating or in-situ polymerization method to prepare the conductive-stability negative Poisson ratio structural myocardial patch;
or, the conductive material is processed on the yarn by adopting a surface coating or in-situ polymerization method to prepare conductive coating yarn, and then the conductive coating yarn is used as a raw material to weave the negative Poisson ratio structure myocardial patch with the conductive stability and the inward concave polygon as the minimum structural unit by adopting weaving or knitting.
The in-situ polymerization method comprises the following steps of treating a conductive material on a base material:
(1) adding an oxidant and a doping agent into a 10-40 wt% polyurethane solution, and uniformly stirring to obtain a solution;
(2) coating the solution on the surface of the substrate for 1-10 times;
(3) conducting conductive material monomer fumigation on the coated substrate at the temperature of 0-60 ℃ for 1-24 hours to prepare the negative poisson's ratio structural myocardial patch with the conductive stability;
the in-situ polymerization method comprises the following steps of treating a conductive material onto yarns:
(1) adding a conductive material monomer and a doping agent into a 10-40 wt% polyurethane solution, and uniformly stirring to obtain a mixed solution;
(2) immersing or coating the yarn in the mixed solution for 1-30 minutes;
(3) immersing or coating the yarn in an oxidant solution at 0-60 ℃ for 1-24 hours;
(4) washing with deionized water for 1-5 times, and drying to obtain conductive coating yarns;
the surface coating process comprises the following steps:
(1) adding a conductive material monomer and a doping agent into an oxidant solution, and stirring, wherein the polymerization time is 3-6 h;
(2) after the polymerization reaction is finished, filtering and drying to obtain conductive material powder;
(3) uniformly stirring 10-40 wt% of polyurethane solution of conductive material powder with a certain mass fraction to obtain a solution;
(4) and coating the solution on the surface of the substrate or the yarn for 1-10 times, and naturally drying to obtain the conductive stable negative poisson ratio structural myocardial patch or conductive coating yarn.
When the weaving is adopted, the specific steps are as follows:
(1) weaving the yarns or the conductive coating yarns on a weaving machine with 2 weft supplying and opening mechanisms according to the minimum structural unit to obtain a fabric;
(2) after the fabric is taken off the machine, soaking the fabric in deionized water at the temperature of 50-70 ℃ for 20-60 min, and drying the fabric in a roller at the temperature of 60-100 ℃ for 30-60 min;
(3) and (5) loosening the fabric for 12-24 hours to obtain the woven fabric.
When knitting weaving is adopted, the weft knitting weaving comprises the following specific steps:
(1) a double-needle-plate latch needle weft knitting machine is adopted to convey the yarns or the conductive coating yarns to a knitting area, and the knitting machine performs knitting according to the minimum structural unit to obtain a fabric;
(2) after the fabric is taken off the machine, soaking the fabric in deionized water at the temperature of 50-70 ℃ for 20-60 min, and drying the fabric in a roller at the temperature of 60-100 ℃ for 30-60 min;
(3) and loosening the fabric for 12-24 hours to obtain the knitted fabric.
FIG. 1 is a schematic diagram of a negative Poisson ratio structural model in the present invention, and it can be seen from the diagram: when the negative Poisson material with the concave polygonal structure is stretched, the expansion and expansion effects can be generated in the direction perpendicular to the stretching direction.