CN115154666B - Degradable artificial ligament capable of being used for repairing nerve loop and preparation method thereof - Google Patents

Abstract

The invention relates to the technical field of medical materials, in particular to a degradable artificial ligament for repairing nerve loops and a preparation method thereof. The preparation method disclosed by the invention is integrally formed, so that the internal and external directions of chitosan and PHBV are ensured, and the additional interference of chemical solution and the uncontrollability of the fiber direction of a chemical fixing method are reduced. In addition, the invention also carries out grid-control corona polarization on the chitosan part of the surface, and the degradable artificial ligament prepared by the invention has stronger current stimulation effect and can better promote ligament tissues and nerve regeneration.

Description

Degradable artificial ligament capable of being used for repairing nerve loop and preparation method thereof

Technical Field

The invention relates to the technical field of medical materials, in particular to a degradable artificial ligament which can be used for repairing a nerve loop and a preparation method thereof.

Background

Mechanical stability decreases after anterior cruciate ligament (anterior cruciate ligament, ACL) rupture, proprioceptive afferent dysfunction ^[1] Central nervous system functional remodeling (central nervous system plasticity, CNSP) ^[2] Abnormal gait and movement posture ^[3-6] Early onset knee osteoarthritis ^[7] The resulting affliction severely affects the patient's motor and psychological well-being, greatly reducing the quality of life. Although the current conventional ACL reconstruction surgery (autologous or allogeneic tendon reconstruction and artificial ligament reconstruction) can increase the mechanical stability of the knee joint ^[8] It is difficult to restore the proprioceptive afferent function of the ACL at all, and then it is difficult to avoid CNSP. This CNSP forms a vicious circle not only as a result, but also as a cause of ACL damage ^[9,10] . Thus, CNSP is critical for recovery from ACL injury ^[11] 。

CNSP results from reduced number of proprioceptors, morphological and functional abnormalities, and proprioceptive uploading disorders following ACL injury, which in turn lead to control disorders of the central nervous system for the descending motor control system. ACL repair regeneration is the fundamental approach to restoring ACL proprioception. The better the ACL tissue regeneration, the more macroscopically the mechanical stability is restored, the microscopically the signal pathways and proprioception are restored. ACL residue-preserving reconstructive surgery is the root of ACL repair regeneration. The tissue engineering techniques of stem cells, platelet-rich plasma and the like also play a role in promoting ACL tissue repair regeneration to a certain extent ^[12] . On the basis, the ACL biological bridging enhanced repair operation mode proposed by Murray doctor in Boston children hospital in U.S. has achieved a certain effect in animal research and initial clinical research ^[13] . However, these methods of promoting repair of the stump of an ACL do not address the important issue of regeneration of neural tissue such as receptors in an ACL.

The development of material science is that nerve repair regeneration is openedA gate is provided. On the one hand: various biological and non-biological nerve conduits have achieved favorable results in basic and clinical studies related to peripheral nerve regeneration, wherein chitosan is an ideal material for constructing artificial nerve grafts due to its good adsorptivity, permeability, plasticity, biocompatibility and biodegradability ^[14-16] . On the other hand: tissue regeneration requires time, and it is difficult to avoid the reduced number of proprioceptors, morphological abnormalities, reduced function of the ACL, and consequent central nervous system remodeling, in waiting for successful tissue regeneration. During the period, the novel material is required to collect mechanical energy along with the movement of the joint, convert the mechanical energy into electric energy, meet the deformation of the knee joint during the movement sensing, generate electric impulse uploading, simulate the substitution of ACL proprioception and recover the requirement of a nerve loop ^[17] . Thus, the simulation of anterior cruciate ligament autoreceptor function is replaced by a transitional method for the period of time required for regenerative repair.

Electrets and piezoelectrets in the field of materials science can meet this requirement. (1) Electret (also called electret) refers to a dielectric that is capable of "long-term" polarization-maintaining, i.e. capable of storing excess "real" charge for a long period of time or/and maintaining an "oriented" electric dipole (i.e. a relative dielectric constant greater than 1) ^[18] . Chitosan can be polarized to become an "oriented" electric dipole electret. (2) Piezoelectric electret (also called ferroelectric electret) refers to a microporous structure electret with piezoelectric effect containing oriented "macroscopic electric dipoles ^[19] . The piezoelectric ceramic has the outstanding characteristics of light weight, thin thickness, low acoustic impedance, ultra-wide response frequency band, low relative dielectric constant, low cost, environmental friendliness and the like besides the strong piezoelectric effect of the traditional piezoelectric ceramic and the high flexibility of the ferroelectric polymer, and is an ideal sensitive material for preparing various flexible lightweight force sensors. Piezoelectric biopolymers of Poly-3-Hydroxybutyrate-3-Hydroxyvalerate (PHBV) with biodegradability, biocompatibility and strong mechanical properties ^[20] . PHBV not only can promote the regeneration of spinal cord and peripheral nerve tissues, but also can provide better environment for the adhesion, proliferation and matrix production of ligament cells ^[21] 。

In order to solve the problems of tissue regeneration and proprioception substitution at the same time, PHBV is taken as a substrate and chitosan is subjected to surface modification by the project team, and PHBV-CS absorbable nano ACL is developed ^[22,23] . PHBV-CS can absorb nano ACL, promote ligament collagen secretion, improve tissue healing capacity, have good biocompatibility and antibacterial property, have good tensile modulus and ultimate tensile stress, and can maintain mechanical stability of knee joints; can provide good environment for the growth and adhesion of schwann cells and promote the regeneration of nerves; can be successfully degraded by 50% in 14 days, and ensures that 6-week ligament heals ^[24] 。

Deep molecular mechanism capable of absorbing nano anterior cruciate ligament to regulate central remodeling relates to three levels of brain, spinal cord and ACL ^[25,26] . (1) Brain level: the project group is found in the national natural science foundation project research undertaken at present: ras homologous gene member A is in negative correlation with nerve growth related protein-43, and Ras homologous gene member A is reduced, nerve growth related protein-43 is increased and central remodeling is promoted after ACL injury; the opposite is true after ACL repair. (2) Spinal cord level: the expression of the nerve nutrient 3 and the nerve tyrosine kinase receptor 3 of the dorsal spinal cord root nerve cells after the ACL proprioceptive nerve injury is reduced, and the expression of the nerve nutrient 3 and the nerve tyrosine kinase receptor 3 in the dorsal spinal cord root nerve cells after the electric stimulation intervenes in the reflex arc of ACL-popliteal cord muscle is obviously increased ^[27] . (3) ACL level: ACL damage reduces mechano-mechanical sensitivity information, promotes alpha motor neuron activation, and further produces an effect on spinal cord level ^[28] . ACLs are capable of sensing ligament mechanical stretch stimulation in their proprioceptors. Because the proprioceptors of ACLs are dominated by Ruffini corpuscles, ACL proprioception should be of major concern. At the microscopic level, the key is an Acid-sensitive ion channel (Acid-sensing ion channel, ASIC) of Ruffini corpuscles, which is essentially a signal channel with dual chemosensitivity and mechanical sensitivity, and a molecular determinant for promoting the dynamic mechanical sensitivity of the autoreceptors ^[29,30] 。

The PHBV-CS absorbable nano anterior cruciate ligament is developed by combining the invention patent and the early research result. Firstly, preparing a PHBV-CS shell-core structure directional nanofiber scaffold by using a coaxial spinning technology; then electrically polarizing to form chitosan electret; finally, the PHBV-CS absorbable nano anterior cruciate ligament which is formed to be suitable for the surgical repair of ACL broken ends.

Chinese patent application: CN104147642B discloses a method for preparing an anti-infective artificial ligament; the method specifically comprises the following steps: ultrasonic cleaning is carried out on the PET artificial ligament to remove surface dirt; corona treatment is carried out on PET artificial ligaments; preparing a nano silver surface coating solution; coating the surface of the PET artificial ligament; cleaning and vacuum drying. The thickness of the nano silver coating on the surface of the artificial ligament is 50-300 nm, and the biocompatibility and bone conductivity of the artificial ligament can be improved, so that the artificial ligament has antibacterial and anti-inflammatory properties, and the requirements of clinical medicine on biological activity and mechanical properties are met. However, the mechanical strength of the artificial ligament described in this patent is to be improved.

The prior art comprises the following steps: development ofchitosan-crosslinked nanofi brous PHBV guide for repair ofnerve defects (Department ofBiomaterial Engineering, tonekabon Branch, islamic Azad University, tonekabon, iran,2Proteomics Research Center,Shahid Beheshti University of Medical Sciences,Tehran,Iran,and 3Tissue Engineering Department,School of Advanced Technologies inMedicine,TehranUniversityofMedical Sciences,Tehran,Iran) discloses: the aim ofthis study was to produce a chitosan-crosslinked nanofibrous biodegradable poly (3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) nerve conduit, an artificial scaffold was prepared by electrospinning, and the scaffold was subjected to evaluation microscopic, physical and mechanical analyses, and cell culture analysis of Schwann cells, analysis results showed that nerve transplantation has good elasticity and compliance, compared to uncrosslinked nanomaterials, the cross-linked nanomaterial has better cell adhesion and growth capacity, the nerve conduit has a suitable tissue engineering to perform in vivo and in vitro engineering, and the invention is a method of securing the chitosan-immobilized on the inner and outer surface of the support by the BV chemical method by the method of the present invention, additional disturbance of the chemical solution and uncontrollable chemical anchoring of the fibre direction is reduced. The degradable artificial ligament which can be used for repairing the nerve loop and the preparation method thereof are not reported at present.

Disclosure of Invention

The invention aims at overcoming the defects of the prior art and provides a degradable artificial ligament which can be used for repairing a nerve loop and a preparation method thereof.

In order to achieve the above purpose, the technical scheme adopted by the invention is as follows:

in a first aspect, the invention provides a PHBV-CS shell-core structure nanofiber scaffold material, which is prepared from hydroxybutyrate-hydroxyvalerate copolyester and chitosan, and the preparation method of the degradable artificial ligament comprises the following steps:

(1) Dissolving hydroxybutyric acid-hydroxyvalerate copolyester with mass percentage concentration of 8% -15% in chloroform to be completely dissolved, and preparing for later use;

(2) Dissolving chitosan with the mass percentage concentration of 4-8% and the deacetylation degree of more than or equal to 95% in a mixed solvent of dichloromethane and trifluoroacetic acid until the chitosan is completely dissolved, and preparing for later use;

(3) Injecting the solutions obtained in the step (1) and the step (2) into an injector respectively, and preparing the PHBV-CS core-shell fiber film according to an electrostatic spinning method;

(4) Vacuum drying the PHBV-CS core-shell fiber film obtained in the step (3) at room temperature for 1-3 days to remove the solvent, thereby obtaining the PHBV-CS core-shell structure nanofiber scaffold material;

(5) Polarizing the PHBV-CS shell-core structure nanofiber support material by adopting a grid-control corona polarization method;

(6) And rolling the polarized PHBV-CS shell-core structure nanofiber support material by taking the chitosan layer as the inner surface.

Preferably, the mass percentage concentration of the hydroxybutyric acid-hydroxyvaleric acid copolyester in the step (1) is 15%.

Preferably, the mass percentage concentration of the chitosan in the step (2) is 8%.

Preferably, the experimental conditions in the electrospinning method in step (3) are: the inner diameter of the inner tube of the coaxial spinning nozzle is 0.5mm, and the inner diameter of the outer tube is 1.2mm; the spray head is connected with positive voltage, and the receiving plate is connected with negative voltage; the spinning conditions are as follows: the size of the injector is 17mm, the rotation speed of the collector is 1500rpm, the flow rate of the outer tube is 0.04mm/min, the flow rate of the inner tube is 0.02mm/min, the distance between the head of the injector and the collector is 14cm, the positive voltage is 20kv, the negative voltage is 2kv, the temperature is 25 ℃, and the relative humidity is 30-40%.

Preferably, the experimental conditions of the polarization in step (5) are: the electrode spacing is 4cm, the corona voltage is-8 kv, the grid voltage is-1 kv, the polarization temperature is room temperature, the polarization humidity is 0-40%, and the polarization time is 5min.

Preferably, the preparation method in the step (6) is as follows: cutting the material obtained after the polarization in the step (5) into a rectangle, taking the fiber arrangement direction as the width, taking the metal rod as the axis, and rolling the material along the rectangle width by taking the chitosan layer as the inner layer.

In a second aspect, the invention provides a preparation method of a PHBV-CS shell-core structure nanofiber scaffold material, which comprises the following steps:

(1) Dissolving hydroxybutyric acid-hydroxyvalerate copolyester with mass percentage concentration of 8% -15% in chloroform to be completely dissolved, and preparing for later use;

(2) Dissolving chitosan with the mass percentage concentration of 4-8% and the deacetylation degree of more than or equal to 95% in a mixed solvent of dichloromethane and trifluoroacetic acid until the chitosan is completely dissolved, and preparing for later use;

(3) Injecting the solutions obtained in the step (1) and the step (2) into an injector respectively, and preparing the PHBV-CS core-shell fiber film according to an electrostatic spinning method;

(4) Vacuum drying the PHBV-CS core-shell fiber film obtained in the step (3) at room temperature for 1-3 days to remove the solvent, thereby obtaining the PHBV-CS core-shell structure nanofiber scaffold material;

(5) Polarizing the PHBV-CS shell-core structure nanofiber support material by adopting a grid-control corona polarization method;

(6) And rolling the polarized PHBV-CS shell-core structure nanofiber support material by taking the chitosan layer as the inner surface.

Preferably, the mass percentage concentration of the hydroxybutyric acid-hydroxyvaleric acid copolyester in the step (1) is 15%; and (3) the mass percentage concentration of the chitosan in the step (2) is 8%.

Preferably, the experimental conditions in the electrospinning method in step (3) are: the inner diameter of the inner tube of the coaxial spinning nozzle is 0.5mm, and the inner diameter of the outer tube is 1.2mm; the spray head is connected with positive voltage, and the receiving plate is connected with negative voltage; the spinning conditions are as follows: the size of the injector is 17mm, the rotating speed of the collector is 1500rpm, the flow rate of the outer tube is 0.04mm/min, the flow rate of the inner tube is 0.02mm/min, the distance between the head of the injector and the collector is 14cm, the positive voltage is 20kv, the negative voltage is 2kv, the temperature is 25 ℃, and the relative humidity is 30-40%; the experimental conditions for the polarization in step (5) are: the electrode spacing is 4cm, the corona voltage is-8 kv, the grid voltage is-1 kv, the polarization temperature is room temperature, the polarization humidity is 0-40%, and the polarization time is 5min; the preparation method in the step (6) comprises the following steps: cutting the material obtained after the polarization in the step (5) into a rectangle, taking the fiber arrangement direction as the width, taking the metal rod as the axis, and rolling the material along the rectangle width by taking the chitosan layer as the inner layer.

In a third aspect, the invention provides an application of the PHBV-CS shell-core structure nanofiber scaffold material as described above as a degradable artificial ligament.

At present, PHBV-CS can absorb how the nano anterior cruciate ligament acts on Ruffini corpuscles to make them feel stretch stimulus, and ASIC in Ruffini corpuscles generates deep molecular mechanism of proprioceptionIs unknown. Combining the literature report at home and abroad and the preliminary achievement of the national natural science foundation project, the research team of the invention proposes the hypothesis that PHBV-CS can absorb the nano-material to repair the anterior cruciate ligament to generate the proprioceptive mechanism (see figure 3): PHBV-CS can absorb nano material to promote regeneration of ACL nerve tissue and maintain ACL tension, knee joint movement stretches ACL, and substances such as collagen resisting pressure, shearing force and tension, proteoglycan keeping cell firmness and the like exist in extracellular matrix (ECM), and can transmit mechanical signals to cell membrane and extracellular H while maintaining cell stability ⁺ Together with other regulating substances, activates the ASIC channels. For cations (mainly Na ⁺ And to a lesser extent Ca ²⁺ ) The permeable ASIC produces an inward current that depolarizes the cell membrane, thereby activating voltage-gated Ca ²⁺ Channels and Na ⁺ Channels, and possibly through release of voltage dependent Mg ²⁺ Blocking may promote NMDA receptor activation. Voltage-gated Ca ²⁺ Channels and Na ⁺ The channels can promote the generation of dendritic spines and action potentials, ca ²⁺ Calmodulin-dependent protein kinase II activation and may affect other second messenger pathways. Thus, the current signal is conducted through afferent nerves, through the dorsal root ganglion to the spinal cord to form a thin bundle, and to the brain.

The invention has the advantages that:

1. the chitosan used in the invention has excellent neuroprotection and can promote the nerve regeneration, and the PHBV used in the invention has the advantages of biodegradability, biocompatibility and piezoelectric biopolymers with strong mechanical properties, can generate micro-current in pressure change, and has better capability of promoting cell proliferation and differentiation. The inventor finds that chitosan has lower mechanical strength due to its structure and mechanical instability in physiological environment, PHBV reduces proliferation and adhesion of cells due to higher surface hydrophobicity, and has higher crystallinity and higher brittleness. However, when the PHBV is used as a substrate in the preparation of artificial materials, the chitosan surface modification can make up for the advantages and disadvantages, and simultaneously, the effects of the anterior cruciate ligament proprioceptors repair and cell adhesion and the strength requirement of the ACL artificial ligament are met.

2. The PHBV-CS shell-core structure directional nanofiber scaffold is prepared by a coaxial electrostatic spinning technology, and the characteristics of specific stretching ductility, axial arrangement of fibers, porosity and the like of a ligament are considered by adopting directional spinning in the spinning process. The preparation method disclosed by the invention is integrally formed, so that the internal and external directions of chitosan and PHBV are ensured, the additional interference of chemical solution is reduced, and the uncontrollability of the fiber direction of a chemical fixing method is reduced.

3. The invention also carries out grid-control corona polarization on the chitosan part on the surface, so that the chitosan surface has charges, and the current stimulation effect of the artificial ligament is enhanced, thereby better promoting ligament tissues and nerve regeneration.

4. The mechanical properties and biological properties of the materials prepared by the experimental conditions of the invention achieve unexpected technical effects.

Drawings

FIG. 1 is a flow chart of the preparation of PHBV-CS absorbable nano anterior cruciate ligament.

FIG. 2 is a degradable artificial ligament useful for repairing nerve loops made by the method of manufacture of the present invention.

FIG. 3 is a schematic illustration of the hypothesis that PHBV-CS can absorb the mechanisms by which the anterior cruciate ligament regulates ASIC signal pathways.

FIG. 4a is the tensile test result of sample 1.

FIG. 4b shows the tensile test results of sample 2.

FIG. 4c shows the tensile test results of sample 3.

FIG. 4d shows the tensile test results of sample 4.

FIG. 4e shows the tensile test results of sample 5.

FIG. 4f shows the tensile test results of sample 6.

FIG. 4g shows the tensile test results of sample 7.

Detailed Description

The invention is further described below in conjunction with the detailed description. It is to be understood that these examples are illustrative of the present invention and are not intended to limit the scope of the present invention. Further, it is understood that various changes and modifications of the present invention may be made by those skilled in the art after reading the description of the present invention, and such equivalents are intended to fall within the scope of the claims appended hereto.

Example 1

1 materials and instruments

Hydroxybutyrate-hydroxyvalerate copolyester (PHBV), ningbo Tianan biological materials Co., ltd.

Chitosan (CS), deacetylation degree not less than 95%, MW not less than 100000, powder, anhui Kuer bioengineering Co.

Chloroform, methylene chloride, trifluoroacetic acid analytically pure, ala Ding Shiji Shanghai limited.

Coaxial electrostatic spinning equipment, SS-2535H, beijing Yongkangle industry science and technology development Co.

2 preparation method

Referring to fig. 1, a hydroxybutyric acid-hydroxyvalerate copolyester with a mass percentage concentration of 15% is dissolved in chloroform to be completely dissolved and prepared for standby; dissolving chitosan with the mass percentage concentration of 8% and the deacetylation degree of more than or equal to 95% in a mixed solvent of dichloromethane and trifluoroacetic acid until the chitosan is completely dissolved, and preparing for later use; the chitosan spinning solution and PHBV spinning solution are injected into an injector with an inner layer of 5ml, a coaxial spinning nozzle (the inner diameter of an inner pipe is 0.5mm, the inner diameter of an outer pipe is 1.2 mm) is selected, the nozzle is connected with a positive voltage, and a receiving plate is connected with a negative voltage. The spinning conditions are as follows: the size of the injector is 17mm, the rotation speed of the collector is 1500rpm, the flow rate of the outer tube is 0.04mm/min, the flow rate of the inner tube is 0.02mm/min, the distance between the head of the injector and the collector is 14cm, the positive voltage is 20kv, the negative voltage is 2kv, the temperature is 25 ℃, and the relative humidity is 30-40%. Finally, carefully separating the PHBV-CS core-shell fiber film which is electrospun from the collector, and drying in vacuum for 2 days at room temperature to completely remove solvent molecules, thereby obtaining the PHBV-CS core-shell structure nanofiber scaffold material with the outer layer of chitosan and the inner layer of PHBV. And (3) polarizing the PHBV-CS nanofiber by adopting a grid-control corona polarization method. The fibrous membrane was placed on the electrodes at a pitch of 4cm. Corona voltage-8 kv and grid voltage-1 kv. The polarization temperature is room temperature, the polarization humidity is less than 40%, and the polarization time is 5min. The polarization makes the outer chitosan possess the capacity of long-term storage of polarization and space charge, its surface carries negative charge, and it is stood in phosphate buffer solution for 9 days, and its surface potential is above 52%. Cutting a polarized PHBV-CS shell-core structure nanofiber support into a rectangle, wherein the arrangement direction of the fibers is wide, and the length of the rectangle is determined by the length of the ligament defect; the metal rod is taken as an axis, the diameter of the metal rod is selected according to the ligament diameter of an operation object, and the bracket is rolled up along a rectangular broadside by taking the chitosan layer as the inner surface, so that the chitosan artificial nerve prosthesis ACL reinforcing cable-1 is formed (see figure 2).

Example 2

1 detection method

1.1 grouping

Group one: 4% of chitosan by mass, wherein 2ml/2g of glacial acetic acid is obtained in the stirring process; PHBV mass fraction 8%, trichloromethane: absolute ethanol 9:1 dissolving, and spinning thickness is 0.14mm; the spinning conditions are as follows: the size of the injector is 17mm, the rotation speed of the collector is 250rpm, the flow speed of the inner pipe and the outer pipe is 0.7ml/h, the distance between the head of the injector and the collector is 14cm, the positive voltage is 18kv, the negative voltage is-6 kv, the temperature is 25 ℃, and the relative humidity is 30-40%.

Group II: 4% of chitosan by mass, wherein 2ml/2g of glacial acetic acid is obtained in the stirring process; PHBV mass fraction 8%, trichloromethane: absolute ethanol 9:1 dissolving, spinning thickness 0.05mm

The spinning conditions are as follows: the size of the injector is 17mm, the rotation speed of the collector is 500rpm, the flow speed of the inner pipe and the outer pipe is 0.7ml/h, the distance between the head of the injector and the collector is 14cm, the positive voltage is 18kv, the negative voltage is-6 kv, the temperature is 25 ℃, and the relative humidity is 30-40%.

Group III: 4% of chitosan by mass, wherein 2ml/2g of glacial acetic acid is obtained in the stirring process; PHBV mass fraction 8%, trichloromethane: absolute ethanol 9:1 dissolving, spinning thickness 0.3mm

The spinning conditions are as follows: the size of the injector is 17mm, the rotation speed of the collector is 250rpm, the flow speed of the inner pipe and the outer pipe is 0.7ml/h, the distance between the head of the injector and the collector is 14cm, the positive voltage is 18kv, the negative voltage is-6 kv, the temperature is 25 ℃, and the relative humidity is 30-40%.

Group four: 2 mass percent of chitosan, 2ml/2g of glacial acetic acid in the stirring process; PHBV mass fraction 8%, trichloromethane: absolute ethanol 9:1 dissolving, spinning thickness 0.14mm

The spinning conditions are as follows: the size of the injector is 17mm, the rotation speed of the collector is 250rpm, the flow speed of the inner pipe and the outer pipe is 0.7ml/h, the distance between the head of the injector and the collector is 14cm, the positive voltage is 18kv, the negative voltage is-6 kv, the temperature is 25 ℃, and the relative humidity is 30-40%.

1.2 carrying out tensile test on each group of materials, wherein the detection method is unified as a universal tensile testing machine.

2 results

The results of each group are respectively as follows:

group one: results: maximum load 16.42957N, tensile stress at a maximum load of 17.00784MPa and Young's modulus of elasticity of 662.56768MPa. (see FIGS. 4c-4d, sample 3 and sample 4)

Group II: results: maximum load 1.86248N, tensile stress at a maximum load of 2.12855MPa and Young's modulus of elasticity of 72.60026MPa. (see FIG. 4g, sample 7)

Group III: results: maximum load 3.12669N, tensile stress at a maximum load of 3.4741MPa and Young's modulus of elasticity of 111.8411MPa. (see FIGS. 4e-f, sample 5 and sample 6)

Group four: results: maximum load 9.74288N, tensile stress at a maximum load of 10.08579MPa and Young's modulus of elasticity of 564.46442MPa. (see FIGS. 4a-b, sample 1 and sample 2)

TABLE 1

TABLE 2

TABLE 3 Table 3

The foregoing is merely a preferred embodiment of the present invention and it should be noted that modifications and additions to the present invention may be made by those skilled in the art without departing from the principles of the present invention and such modifications and additions are to be considered as well as within the scope of the present invention.

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Claims (8)

1. the PHBV-CS shell-core structure nanometer degradable artificial ligament fiber scaffold material is characterized by being prepared from hydroxybutyrate-hydroxyvalerate copolyester and chitosan, and the preparation method of the degradable artificial ligament comprises the following steps:

(1) Dissolving hydroxybutyric acid-hydroxyvalerate copolyester with mass percentage concentration of 8% -15% in chloroform to be completely dissolved, and preparing for later use;

(2) Dissolving chitosan with the mass percentage concentration of 4-8% and the deacetylation degree of more than or equal to 95% in a mixed solvent of dichloromethane and trifluoroacetic acid until the chitosan is completely dissolved, and preparing for later use;

(3) Injecting the solutions obtained in the step (1) and the step (2) into an injector respectively, and preparing the PHBV-CS shell-core fiber film according to an electrostatic spinning method;

(4) Vacuum drying the PHBV-CS shell core fiber film obtained in the step (3) at room temperature for 1-3 days to remove the solvent, thus obtaining the PHBV-CS shell core structure nanofiber scaffold material;

(5) Polarizing the PHBV-CS shell-core structure nanofiber support material by adopting a grid-control corona polarization method;

(6) The polarized PHBV-CS shell-core structure nanofiber scaffold material is rolled up by taking a chitosan layer as the inner surface,

the preparation method in the step (6) comprises the following steps: cutting the material obtained after the polarization in the step (5) into a rectangle, taking the fiber arrangement direction as the width, taking the metal rod as the axis, and rolling the material along the rectangle width by taking the chitosan layer as the inner layer.

2. The PHBV-CS core-shell structured nanofiber scaffold material according to claim 1, wherein the mass percentage concentration of the hydroxybutyrate-hydroxyvalerate copolyester in step (1) is 15%.

3. The PHBV-CS core-shell structured nanofiber scaffold material according to claim 1, wherein the mass percentage concentration of chitosan in step (2) is 8%.

4. The PHBV-CS core-shell structured nanofiber scaffold material according to claim 1, wherein the experimental conditions in the electrospinning method in step (3) are: the inner diameter of the inner tube of the coaxial spinning nozzle is 0.5mm, and the inner diameter of the outer tube is 1.2mm; the spray head is connected with positive voltage, and the receiving plate is connected with negative voltage; the spinning conditions are as follows: the size of the injector is 17mm, the rotation speed of the collector is 1500rpm, the flow rate of the outer tube is 0.04mm/min, the flow rate of the inner tube is 0.02mm/min, the distance between the head of the injector and the collector is 14cm, the positive voltage is 20kV, the negative voltage is 2kV, the temperature is 25 ℃, and the relative humidity is 30-40%.

5. The PHBV-CS core-shell structured nanofiber scaffold material according to claim 1, wherein the experimental conditions of polarization in step (5) are: the electrode spacing is 4cm, the corona voltage is-8 kV, the grid voltage is-1 kV, the polarization temperature is room temperature, the polarization humidity is 0-40%, and the polarization time is 5min.

6. The preparation method of the PHBV-CS shell-core structure nanofiber scaffold material is characterized by comprising the following steps of:

(1) Dissolving hydroxybutyric acid-hydroxyvalerate copolyester with mass percentage concentration of 8% -15% in chloroform to be completely dissolved, and preparing for later use;

(2) Dissolving chitosan with the mass percentage concentration of 4-8% and the deacetylation degree of more than or equal to 95% in a mixed solvent of dichloromethane and trifluoroacetic acid until the chitosan is completely dissolved, and preparing for later use;

(3) Injecting the solutions obtained in the step (1) and the step (2) into an injector respectively, and preparing the PHBV-CS shell-core fiber film according to an electrostatic spinning method;

(4) Vacuum drying the PHBV-CS shell core fiber film obtained in the step (3) at room temperature for 1-3 days to remove the solvent, thus obtaining the PHBV-CS shell core structure nanofiber scaffold material;

(5) Polarizing the PHBV-CS shell-core structure nanofiber support material by adopting a grid-control corona polarization method;

(6) And rolling the polarized PHBV-CS shell-core structure nanofiber support material by taking the chitosan layer as the inner surface.

7. The process according to claim 6, wherein the mass percentage concentration of the hydroxybutyric acid-hydroxyvalerate copolyester in step (1) is 15%; and (3) the mass percentage concentration of the chitosan in the step (2) is 8%.

8. The method according to claim 6, wherein the experimental conditions in the electrospinning method in step (3) are as follows: the inner diameter of the inner tube of the coaxial spinning nozzle is 0.5mm, and the inner diameter of the outer tube is 1.2mm; the spray head is connected with positive voltage, and the receiving plate is connected with negative voltage; the spinning conditions are as follows: the size of the injector is 17mm, the rotating speed of the collector is 1500rpm, the flow rate of the outer tube is 0.04mm/min, the flow rate of the inner tube is 0.02mm/min, the distance between the head of the injector and the collector is 14cm, the positive voltage is 20kV, the negative voltage is 2kV, the temperature is 25 ℃, and the relative humidity is 30-40%;

the experimental conditions for the polarization in step (5) are: the electrode spacing is 4cm, the corona voltage is-8 kV, the grid voltage is-1 kV, the polarization temperature is room temperature, the polarization humidity is 0-40%, and the polarization time is 5min;

the preparation method in the step (6) comprises the following steps: cutting the material obtained after the polarization in the step (5) into a rectangle, taking the fiber arrangement direction as the width, taking the metal rod as the axis, and rolling the material along the rectangle width by taking the chitosan layer as the inner layer.

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