CN114788892A

CN114788892A - Nerve conduit loaded with gradient density particles and preparation method

Info

Publication number: CN114788892A
Application number: CN202110092894.1A
Authority: CN
Inventors: 薛佳佳; 余逸玲; 张馨丹; 龚博文; 张立群
Original assignee: Beijing University of Chemical Technology
Current assignee: Beijing University of Chemical Technology
Priority date: 2021-01-25
Filing date: 2021-01-25
Publication date: 2022-07-26

Abstract

The invention discloses a nerve conduit loaded with gradient density active particles and a preparation method thereof. The nerve conduit comprises an inner layer and an outer layer, wherein the outer layer is an electrostatic spinning fiber layer; the inner layer is an electrostatically sprayed granular layer of bioactive particles having a gradient density. The deposition density of the bioactive particles on the surface of the inner layer structure is in gradient distribution. According to the invention, by regulating and controlling the topological structure of the spinning fiber and combining the structure of the gradient active particles, the functions of early release, time-space controllable release and the like of the active particles are realized, and the difficulty existing in the current research can be solved, so that various induction signals for promoting the peripheral nerve repair are efficiently combined, the active particles are regulated and controlled to be released from the near end to the far end in the peripheral nerve regeneration process, the axon is promoted to extend from the near end to the far end, the peripheral nerve repair is effectively accelerated, and the repair effect is improved.

Description

Nerve conduit loaded with gradient density particles and preparation method

Technical Field

The invention relates to the technical field of biological materials, in particular to a nerve conduit loaded with active particles with gradient density and a preparation method thereof.

Background

Because the number of peripheral nerve injury cases in China reaches 2000 ten thousand clinically at present, and the speed of the peripheral nerve injury cases is increased by about 200 ten thousand every year, the repair of the peripheral nerve injury becomes a great scientific problem for the research of the field of nerve repair. The clinical 'gold standard' is autologous transplantation; however, the limited source of autograft, damage to the donor area, size mismatch and secondary surgery limit its use. Therefore, there is a need to develop an artificial nerve conduit to repair nerve damage to solve the problem of autograft deficiency.

The currently clinically available nerve conduit material mainly plays a role in guiding degradation of peripheral nerve after repair is completed, but the nerve conduit material has low biological activity and is loaded with fresh active particles, so that the repair speed of peripheral nerve injury is slow. Therefore, the development of a nerve conduit capable of simulating extracellular matrix composition and structure and providing a microenvironment required for repair of peripheral nerve injury is very important for the artificial synthetic nerve conduit to repair peripheral nerve injury.

Disclosure of Invention

In order to solve the problems in the prior art, the invention provides a nerve conduit loaded with active particles with gradient density and a preparation method thereof. In the invention, by regulating and controlling the topological structure of the spinning fiber and simultaneously combining the structure of the gradient active particles, the functions of early release, time-space controllable release and the like of the active particles are realized, and the difficulty existing in the current research can be solved, so that various induction signals for promoting the repair of peripheral nerves are efficiently combined, the active particles are regulated and controlled to be released from the near end to the far end in the process of promoting the regeneration of the peripheral nerves, the extension of axons from the near end to the far end is promoted, the repair of the peripheral nerves is effectively accelerated, and the repair effect is improved.

It is an object of the present invention to provide a nerve conduit loaded with gradient density active particles.

The nerve conduit comprises an inner layer and an outer layer, wherein the outer layer is an electrostatic spinning fiber layer; the inner layer is an electrostatically sprayed granular layer of bioactive particles having a gradient density.

In a preferred embodiment of the present invention,

the deposition density of the bioactive particles on the surface of the inner layer structure is distributed in a gradient manner.

In a preferred embodiment of the present invention,

the inner diameter of the nerve conduit ranges from 0.5 mm to 2.0 mm.

The invention also provides a preparation method of the nerve conduit loaded with the active particles with gradient density.

The method comprises the following steps:

adding soluble aliphatic polyester or soluble aliphatic polyester and natural high molecular polymer into a solvent A, and fully dissolving to obtain a solution D;

step (2), performing electrostatic spinning on the solution D by using a roller rotating at a high speed as a receiver to obtain an electrospun fiber membrane with an oriented structure;

step (3), adding a natural high molecular polymer into a solvent B to obtain a shell solution E; adding a solvent C into the growth factor to obtain a nuclear layer solution F;

step (4), coaxially spraying the shell layer solution E and the core layer solution F onto the electrospun fiber membrane of the oriented structure obtained in the step (2) by using a movable baffle, and depositing bioactive particles with gradient density to obtain the electrospun fiber membrane loaded with electrostatic spray particles of the core-shell structure;

and (5) standing the electrospun fiber membrane loaded with the electrostatic spray particles with the core-shell structure, curling the electrospun fiber membrane into a tube along the direction vertical to the orientation direction, and bonding the electrospun fiber membrane with the electrostatic spray particles with the core-shell structure by using a solution D to prepare the nerve conduit loaded with the gradient density active particles.

In a preferred embodiment of the present invention,

step (1), the mass concentration of the solution D is 3-20%; preferably 4-18%; .

In a preferred embodiment of the present invention,

step (1) of carrying out a treatment,

the amount of the natural high molecular polymer is 0-100 parts by weight based on 1 part by weight of the aliphatic polyester;

the solvent A is at least one selected from hexafluoroisopropanol, trifluoroethanol, trichloromethane, methanol, dichloromethane and N, N' -dimethylformamide;

the degradable aliphatic polyester is as follows: one or a combination of polylactic acid, polycaprolactone, polylactic acid-glycolic acid copolymer and polylactic acid-glycolic acid-caprolactone copolymer;

the natural high molecular polymer is as follows: collagen, gelatin, chitosan, starch, cellulose, elastin, or a combination thereof.

In a preferred embodiment of the present invention,

a step (3) of removing the solvent,

the solvent B is at least one selected from acetic acid, hexafluoroisopropanol, trifluoroethanol, chloroform, methanol and dichloromethane;

the solvent C is at least one selected from acetic acid, water, ethanol, methanol and physiological saline; and/or the presence of a gas in the atmosphere,

the natural high molecular polymer is selected from at least one of collagen, gelatin, chitosan, starch, cellulose and elastin;

the growth factor is at least one selected from nerve growth factor, vascular endothelial growth factor, brain-derived nerve growth factor and human acidic fibroblast growth factor.

In a preferred embodiment of the present invention,

a step (3) of,

the concentration of the shell layer solution E is 5-100 mg/mL; preferably 10-50 mg/mL;

the concentration of the nuclear layer solution F is 0.1-100ug/mL, preferably 10-60 ug/mL

In a preferred embodiment of the present invention,

step (4) of carrying out a treatment,

the dosage ratio of the shell layer solution to the core layer solution is (2-5): 1;

the dosage ratio of the electrospun fiber membrane to the sum of the shell solution and the core-shell solution is as follows: 1g (5-50 mL); preferably 1g (15-50 mL).

In a preferred embodiment of the present invention,

a step (2) of carrying out a treatment,

the solution D has the advancing speed of 0.1-10mL/h, the voltage of 8-25 kV, the rotating speed of a receiver roller of 100-3000rpm, the receiving distance of 10-30 cm and the spinning time of 60-1000 min.

In a preferred embodiment of the invention

Step (4) of carrying out a treatment,

the advancing speed of the shell layer electric spraying solution is 0.1-10mL/h, the advancing speed of the core layer electric spraying solution is 0.1-8 mL/h, the voltage is 10-30 kV, the receiving distance is 10-25 cm, and the spraying time is 1-360 min;

the length of the movable baffle is 1-20cm, and the width of the movable baffle is 0.5-10 cm; the moving speed of the moving baffle is 0.1-10 cm/h.

The invention can adopt the following technical scheme:

the nerve conduit loaded with active particles comprises an inner layer and an outer layer, wherein the inner layer contains bioactive particles with gradient concentration; the deposition concentration of the bioactive particles on the surface of the inner layer structure is gradually decreased from near to far and is distributed in a gradient manner.

The preparation method specifically comprises the following steps:

step (2), performing electrostatic spinning on the solution D by using a roller rotating at a high speed within the range of 100-3000rpm to obtain an electrospun fiber membrane with an oriented structure;

step (4), coaxially and electrostatically spraying a baffle with the moving rotating speed of 1-10cm/h, the length of 1-20cm, the width of 0.5-10cm, 0.1-100mg/mL of shell layer solution E and 0.1-100ug/mL of core layer solution F onto the electrospun fiber membrane with the oriented structure obtained in the step (2), and depositing bioactive substance particles with the density reduced in an axial gradient from the near end to the far end to obtain the electrospun fiber membrane loaded with the electrostatically sprayed particles with the core-shell structure;

and (5) after the electric spraying is finished, placing the spinning membrane in a fume hood at room temperature for 3 days to fully volatilize the residual solvent. And (3) curling the fiber membrane loaded with the active particles with the gradient density into a tube, and bonding the tube by using a solution D to prepare the nerve conduit loaded with the active particles with the gradient density, wherein the inner diameter of the nerve conduit is in the range of 0.5-2.0 mm.

It is still another object of the present invention to provide the use of the nerve conduit of the gradient density active particles of the present invention as a material for repairing peripheral nerve damage.

The nerve conduit of the gradient density active particles provided by the invention contains bioactive substance particles with deposition density gradient increased so as to promote cell recruitment and migration; contains microparticles that promote peripheral nerve repair to modulate the behavior of different cells by spatio-temporally controllable delivery. The nerve conduit provided by the invention has excellent biocompatibility and degradation performance, can mediate migration, proliferation, differentiation and axon extension of cells, can accelerate axon from a near end to a far end, and improves the repairing effect of peripheral nerve injury.

Drawings

FIG. 1 is a schematic illustration of the inner layer of oriented fibers of a nerve conduit of the present invention loaded with a gradient concentration of particles of a biologically active substance; as can be seen from fig. 1, the density of the active material particles deposited on the surface of the internally oriented fibers by the electrostatic spraying technique is distributed in a gradient manner, and the deposition density is gradually decreased.

FIG. 2 is an SEM photograph of an oriented fiber obtained in step (2) of example 1.

Detailed Description

While the present invention will be described in detail and with reference to the specific embodiments thereof, it should be understood that the following detailed description is only for illustrative purposes and is not intended to limit the scope of the present invention, as those skilled in the art will appreciate numerous insubstantial modifications and variations therefrom.

The starting materials used in the examples are all commercially available.

Example 1

Dissolving polycaprolactone into dichloromethane, and magnetically stirring at room temperature for 24 hours to obtain a solution D with the mass concentration of 15%;

step (2), carrying out electrostatic spinning by using the solution D, using a roller with the rotating speed of 1000rpm as a receiver, carrying out spinning for 1000min at the advancing speed of 8.0mL/h and the voltage of 19kV and the receiving distance of 18cm to obtain the uniaxially oriented polycaprolactone nanofiber membrane;

step (3), dissolving laminin and fibronectin in an acetic acid aqueous solution, magnetically stirring at room temperature for 24 hours, and then fully mixing to obtain a shell solution E with the concentration of 15 mg/mL; adding the vascular endothelial growth factor into deionized water, fully stirring and dissolving to obtain a core-shell solution F with the concentration of 10ug/mL, wherein the dosage ratio of the polycaprolactone fiber membrane to the sum of the shell solution and the core-shell solution is as follows: 1g, 40 mL; the dosage ratio of the shell layer solution to the core layer solution is 2: 1;

step (4), using a baffle with the moving speed of 10cm/h, the length of 20cm and the width of 3cm, replacing spinning solutions into a shell layer solution E and a nuclear layer solution F, and replacing a single-shaft spinning needle head into a coaxial needle head; taking the uniaxially oriented polycaprolactone nanofiber membrane obtained in the step (2) as a receiver to perform coaxial electrostatic spraying, wherein the advancing speed of a shell layer electric spraying solution is 3.0mL/h, the advancing speed of a core layer electric spraying solution is 1.0mL/h, the voltage is 25kV, the receiving distance is 12cm, and spraying is performed for 60min to obtain the polycaprolactone fiber membrane loaded with electrostatic spraying particles of the core-shell structure; coaxially and electrostatically spraying onto the electrospun fiber membrane of the oriented structure obtained in the step (2), and depositing bioactive substance particles with axially gradient decreasing particle density from the near end to the far end to obtain the electrospun fiber membrane loaded with electrostatic spraying particles of the core-shell structure;

and (5) after the electric spraying is finished, placing the spinning membrane in a fume hood at room temperature for 3 days to fully volatilize the residual solvent. And (3) curling the fiber membrane loaded with the active particles with the gradient density into a tube, and bonding the tube by using the solution D to prepare the nerve conduit loaded with the active particles with the gradient density, wherein the inner diameter of the nerve conduit is 0.8 mm.

Example 2

Step (1), dissolving polylactic acid in trifluoroethanol, and magnetically stirring at room temperature for 20 hours to obtain a solution D with the mass concentration of 5%;

step (2), carrying out electrostatic spinning by using the solution D, using a roller with the rotating speed of 2000rpm as a receiver, enabling the solution D to have the advancing speed of 5.0mL/h, the voltage of 16kV and the receiving distance of 13cm, and spinning for 1000min to obtain the uniaxially oriented polylactic acid nanofiber membrane;

step (3), dissolving fibronectin in a shell layer in trifluoroethanol, magnetically stirring at room temperature for 24 hours, and then fully mixing to obtain a shell layer solution E with the concentration of 35 mg/mL; adding the vascular endothelial growth factor and the nerve growth factor into deionized water, fully stirring and dissolving to obtain a core-shell solution F with the concentration of 50ug/mL, wherein the dosage ratio of the polylactic acid fibrous membrane to the sum of the shell solution and the core-shell solution is as follows: 1g, 30 mL; the dosage ratio of the shell layer solution to the core layer solution is 3: 1;

step (4), using a baffle with the moving speed of 5cm/h, the length of 15cm and the width of 5cm, replacing spinning solutions into a shell layer solution E and a core layer solution F, and replacing a single-shaft spinning needle head into a coaxial needle head; taking the uniaxially oriented polylactic acid nanofiber membrane obtained in the step (2) as a receiver, and carrying out coaxial electrostatic spraying, wherein the advancing speed of a shell layer electric spraying solution is 5mL/h, the advancing speed of a core layer electric spraying solution is 2.5mL/h, the voltage is 30kV, the receiving distance is 12cm, and the polylactic acid fiber membrane is sprayed for 30min to obtain the polylactic acid nanofiber membrane loaded with the electrostatic spraying particles with the core-shell structure; coaxially and electrostatically spraying onto the electrospun fiber membrane of the oriented structure obtained in the step (2), and depositing bioactive substance particles with axially gradient decreasing particle density from the near end to the far end to obtain the electrospun fiber membrane loaded with electrostatic spraying particles of the core-shell structure;

and (5) after the electric spraying is finished, placing the spinning membrane in a fume hood at room temperature for 3 days to fully volatilize the residual solvent. And (3) curling the fiber membrane loaded with the active particles with the gradient density into a tube, and bonding the tube by using the solution D to prepare the nerve conduit loaded with the active particles with the gradient density, wherein the inner diameter range of the nerve conduit is 0.45 mm.

Example 3

Step (1), dissolving a polylactic acid-glycolic acid copolymer in chloroform and N, N' -dimethylformamide, and magnetically stirring at room temperature for 8 hours to obtain a solution D with the mass concentration of 8%;

step (2), carrying out electrostatic spinning on the solution D, using a roller with the rotating speed of 1500rpm as a receiver, enabling the solution D to have the advancing speed of 4.0mL/h, the voltage of 26kV and the receiving distance of 28cm, and spinning for 840min to obtain the uniaxially oriented polylactic acid-glycolic acid copolymer nanofiber membrane;

step (3), dissolving laminin in a sterile aqueous solution, magnetically stirring at room temperature for 24 hours, and fully mixing to obtain a shell layer solution E with the concentration of 30 mg/mL; adding brain-derived nerve growth factor and human acidic fibroblast growth factor into deionized water, fully stirring and dissolving to obtain a core-shell solution F with the concentration of 50ug/mL, wherein the dosage ratio of the polylactic acid-glycolic acid copolymer fiber membrane to the sum of the shell solution and the core-shell solution is as follows: 1g, 20 mL; the dosage ratio of the shell layer solution to the core layer solution is 4: 1;

step (4), using a baffle with the moving speed of 4cm/h, the length of 15cm and the width of 3cm, replacing spinning solutions into a shell layer solution E and a core layer solution F, and replacing a single-shaft spinning needle head into a coaxial needle head; taking the uniaxially oriented polycaprolactone nanofiber membrane obtained in the step (2) as a receiver, and carrying out coaxial electrostatic spraying, wherein the advancing speed of a shell layer electric spraying solution is 1.6mL/h, the advancing speed of a core layer electric spraying solution is 0.4mL/h, the voltage is 25KV, the receiving distance is 12cm, and the polylactic acid-glycolic acid copolymer fiber membrane loaded with core-shell structure electrostatic spraying particles is obtained after spraying for 50 min; coaxially and electrostatically spraying onto the electrospun fiber membrane of the oriented structure obtained in the step (2), and depositing bioactive substance particles with axially gradient decreasing particle density from the near end to the far end to obtain the electrospun fiber membrane loaded with electrostatic spraying particles of the core-shell structure;

and (5) after the electric spraying is finished, placing the spinning membrane in a fume hood at room temperature for 3 days to fully volatilize the residual solvent. And (3) curling the fiber membrane loaded with the active particles with the gradient density into a tube, and bonding the tube by using the solution D to prepare the nerve conduit loaded with the active particles with the gradient density, wherein the inner diameter range of the nerve conduit is 0.6 mm.

Example 4

Step (1), dissolving a polylactic acid-glycolic acid copolymer in methanol and dichloromethane, and magnetically stirring at room temperature for 18 hours to obtain a solution D with the mass concentration of 5%;

step (2), carrying out electrostatic spinning on the solution D, using a roller with the rotating speed of 1800rpm as a receiver, enabling the solution D to have the advancing speed of 4.0mL/h, the voltage of 20kV and the receiving distance of 22cm, and spinning for 1200min to obtain the uniaxially oriented polylactic acid-glycolic acid copolymer nanofiber membrane;

step (3), dissolving collagen and laminin in a sterile aqueous solution, and fully mixing after magnetically stirring for 20 hours at room temperature to obtain a shell layer solution E with the concentration of 40 mg/mL; adding nerve growth factor and human acidic fibroblast growth factor into deionized water, fully stirring and dissolving to obtain a core-shell solution F with the concentration of 60ug/mL, wherein the dosage ratio of the polylactic acid-glycolic acid copolymer fiber membrane to the sum of the shell solution and the core-shell solution is as follows: 1g, 40 mL; the dosage ratio of the shell layer solution to the core layer solution is 2.5: 1;

step (4), using a baffle with the moving speed of 3cm/h, the length of 15cm and the width of 3cm, replacing spinning solutions into a shell layer solution E and a nuclear layer solution F, and replacing a single-shaft spinning needle head into a coaxial needle head; taking the uniaxially oriented polycaprolactone nanofiber membrane obtained in the step (2) as a receiver, and carrying out coaxial electrostatic spraying, wherein the advancing speed of a shell layer electric spraying solution is 6.0mL/h, the advancing speed of a core layer electric spraying solution is 3.0mL/h, the voltage is 28kV, the receiving distance is 16cm, and the spraying is carried out for 50min to obtain the polylactic acid-glycolic acid copolymer fiber membrane loaded with the electrostatic spraying particles with the core-shell structure; coaxially and electrostatically spraying onto the electrospun fiber membrane of the oriented structure obtained in the step (2), and depositing bioactive substance particles with axially gradient decreasing particle density from the near end to the far end to obtain the electrospun fiber membrane loaded with electrostatic spraying particles of the core-shell structure;

and (5) after the electric spraying is finished, placing the spinning membrane in a fume hood at room temperature for 3 days to fully volatilize the residual solvent. And (3) curling the fiber membrane loaded with the active particles with the gradient density into a tube, and bonding the tube by using a solution D to prepare the nerve conduit loaded with the active particles with the gradient density, wherein the inner diameter range of the nerve conduit is 0.75 mm.

Example 5

Step (1), dissolving a polylactic acid-glycolic acid-caprolactone copolymer in dichloromethane and N, N' -dimethylformamide, and magnetically stirring at room temperature for 24 hours to obtain a solution D with the mass concentration of 7%;

step (2), carrying out electrostatic spinning on the solution D, using a roller with the rotating speed of 3000rpm as a receiver, enabling the solution D to have the advancing speed of 3.0mL/h, the voltage of 25kV and the receiving distance of 29cm, and spinning for 840min to obtain the uniaxially oriented polylactic acid-glycolic acid-caprolactone copolymer nanofiber membrane;

dissolving gelatin and collagen in a sterile aqueous solution, magnetically stirring at room temperature for 20 hours, and fully mixing to obtain a shell layer solution E with the concentration of 20 mg/mL; adding vascular endothelial growth factor, brain-derived nerve growth factor and human acidic fibroblast growth factor into deionized water, fully stirring and dissolving to obtain a nuclear layer solution F with the concentration of 45ug/mL, wherein the dosage ratio of the polylactic acid-glycolic acid-caprolactone copolymer fibrous membrane to the sum of the shell layer solution and the nuclear shell solution is as follows: 1g, 21 mL; the dosage ratio of the shell layer solution to the core layer solution is 3.5: 1;

step (4), using a baffle with the moving speed of 8cm/h, the length of 8cm and the width of 5cm, replacing spinning solutions into a shell layer solution E and a core layer solution F, and replacing a single-shaft spinning needle head into a coaxial needle head; taking the uniaxially oriented polycaprolactone nanofiber membrane obtained in the step (2) as a receiver to perform coaxial electrostatic spraying, wherein the advancing speed of a shell layer electric spraying solution is 3.5mL/h, the advancing speed of a core layer electric spraying solution is 2.0mL/h, the voltage is 25kV, the receiving distance is 13cm, and spraying is performed for 40min to obtain a polylactic acid-glycolic acid-caprolactone copolymer fiber membrane loaded with electrostatic spraying particles with a core-shell structure; coaxially and electrostatically spraying onto the electrospun fiber membrane of the oriented structure obtained in the step (2), and depositing bioactive substance particles with axially gradient decreasing particle density from the near end to the far end to obtain the electrospun fiber membrane loaded with electrostatic spraying particles of the core-shell structure;

and (5) after the electric spraying is finished, placing the spinning membrane in a fume hood at room temperature for 3 days to fully volatilize the residual solvent. And (3) curling the fiber membrane loaded with the active particles with the gradient density into a tube, and bonding the tube by using the solution D to prepare the nerve conduit loaded with the active particles with the gradient density, wherein the inner diameter range of the nerve conduit is 1.6 mm.

Example 6

Step (1), dissolving a polylactic acid-glycolic acid-caprolactone copolymer in hexafluoroisopropanol and trifluoroethanol, and magnetically stirring at room temperature for 30 hours to obtain a solution D with the mass concentration of 9%;

step (2), performing electrostatic spinning on the solution D, using a roller with the rotating speed of 3000rpm as a receiver, enabling the solution D to have the advancing speed of 2.5mL/h, the voltage of 24kV and the receiving distance of 13cm, and spinning for 900min to obtain the uniaxially oriented polylactic acid-glycolic acid-caprolactone copolymer nanofiber membrane;

dissolving gelatin and collagen in a sterile aqueous solution, and performing magnetic stirring at room temperature for 20 hours and then fully mixing to obtain a shell solution E with the concentration of 20 mg/mL; adding nerve growth factor, brain-derived nerve growth factor and human acidic fibroblast growth factor into deionized water, fully stirring and dissolving to obtain a core-shell solution F with the concentration of 45ug/mL, wherein the dosage ratio of the polylactic acid-glycolic acid-caprolactone copolymer fiber membrane to the sum of the shell solution and the core-shell solution is as follows: 1g, 21 mL; the dosage ratio of the shell layer solution to the core layer solution is 4.5: 1;

step (4) using a baffle with the moving speed of 6cm/h, the length of 11cm and the width of 4cm, replacing spinning solutions into a shell layer solution E and a core layer solution F, and replacing a single-shaft spinning needle head into a coaxial needle head; taking the uniaxially oriented polycaprolactone nanofiber membrane obtained in the step (2) as a receiver to perform coaxial electrostatic spraying, wherein the advancing speed of a shell layer electric spraying solution is 2.5mL/h, the advancing speed of a core layer electric spraying solution is 0.8mL/h, the voltage is 21kV, the receiving distance is 17cm, and spraying is performed for 25min to obtain a polylactic acid-glycolic acid-caprolactone copolymer fiber membrane loaded with electrostatic spraying particles with a core-shell structure; coaxially and electrostatically spraying onto the electrospun fiber membrane of the oriented structure obtained in the step (2), and depositing bioactive substance particles with the density gradient reduced from the near end to the far end in the axial direction to obtain the electrospun fiber membrane loaded with electrostatic spray particles of the core-shell structure;

and (5) after the electric spraying is finished, placing the spinning membrane in a fume hood at room temperature for 3 days to fully volatilize the residual solvent. And (3) curling the fiber membrane loaded with the active particles with the gradient density into a tube, and bonding the tube by using a solution D to prepare the nerve conduit loaded with the active particles with the gradient density, wherein the inner diameter range of the nerve conduit is 1.8 mm.

Claims

1. A gradient density active particle loaded nerve conduit, comprising:

2. A nerve conduit according to claim 1, wherein:

3. A nerve conduit according to claim 1, wherein:

the inner diameter range of the nerve conduit is 0.5-2.0 mm.

4. A method of making a gradient density active particle loaded nerve conduit according to any one of claims 1 to 3, wherein said method comprises:

step (3), adding a solvent B into the natural high molecular polymer to obtain a shell layer solution E; adding a solvent C into the growth factor to obtain a nuclear layer solution F;

step (4), coaxially spraying the shell layer solution E and the core layer solution F onto the electro-spun fiber membrane of the oriented structure obtained in the step (2) by using a movable baffle, and depositing bioactive particles with gradient density to obtain the electro-spun fiber membrane loaded with the electrostatic spraying particles of the core-shell structure;

and (5) standing the electrospun fiber membrane loaded with the electrostatic spray particles with the core-shell structure, curling the electrospun fiber membrane into a tube along the direction perpendicular to the orientation direction, and bonding the electrospun fiber membrane with the electrostatic spray particles with the core-shell structure by using a solution D to prepare the nerve conduit loaded with the active particles with the gradient density.

5. The method of claim 4, wherein:

step (1), the mass concentration of the solution D is 3-20%; preferably 4-18%; and/or the presence of a gas in the gas,

the solvent A is at least one selected from hexafluoroisopropanol, trifluoroethanol, trichloromethane, methanol, dichloromethane and N, N' -dimethylformamide; and/or the presence of a gas in the atmosphere,

the degradable aliphatic polyester is as follows: one or a combination of polylactic acid, polycaprolactone, polylactic acid-glycolic acid copolymer and polylactic acid-glycolic acid-caprolactone copolymer; and/or the presence of a gas in the atmosphere,

6. The method of claim 4, wherein:

a step (3) of,

the solvent B is at least one selected from acetic acid, hexafluoroisopropanol, trifluoroethanol, chloroform, methanol and dichloromethane; and/or the presence of a gas in the atmosphere,

the natural high molecular polymer is as follows: one or a combination of collagen, gelatin, chitosan, starch, cellulose and elastin; and/or the presence of a gas in the atmosphere,

7. The method of claim 6, wherein:

the concentration of the shell layer solution E is 5-100 mg/mL; preferably 10-50 mg/mL; and/or the presence of a gas in the atmosphere,

the concentration of the nuclear layer solution F is 0.1-100ug/mL, preferably 10-60 ug/mL.

8. The method of claim 4, wherein:

a step (4) of removing the solvent,

the dosage ratio of the shell layer solution to the core layer solution is (2-5): 1; and/or the presence of a gas in the gas,

9. The method of claim 4, wherein:

a step (2) of carrying out a treatment,

the solution D has a propulsion speed of 0.1-10mL/h, a voltage of 8-25 kV, a receiver roller rotation speed of 100-3000rpm, a receiving distance of 10-30 cm and spinning time of 10-720 min.

10. The method of claim 4, wherein:

step (4) of carrying out a treatment,

the advancing speed of the shell layer electric spraying solution is 0.1-10mL/h, the advancing speed of the core layer electric spraying solution is 0.1-5 mL/h, the voltage is 10-25 kV, the receiving distance is 10-25 cm, and the spraying time is 1-360 min;

the length of the movable baffle is 1-20cm, and the width of the movable baffle is 0.5-10 cm; the moving speed of the moving baffle is 1-10 cm/h.