A composite vascular stent coating for regulating endothelial cell growth activity and a preparation method thereof

Abstract

The present invention provides a composite vascular stent coating for regulating the growth activity of endothelial cells and a preparation method thereof; the composite vascular stent coating of the present invention uses silk nanofiber membranes as the inner and outer layers of the composite vascular stent coating, and adopts weaving technology to weave a seamless polyester tubular fabric as the core layer on the basis of the inner layer of the composite vascular stent coating; the composite vascular stent coating has a microstructure and matrix-like components that imitate the basement membrane of natural blood vessels, which is beneficial to the mechanical engagement between the outer surface of the coating and the inner side of the diseased blood vessel, stabilizes blood flow, avoids turbulence formation, and more significantly improves the adhesion, spreading, growth and proliferation ability of endothelial cells on its inner surface, quickly forms a new endothelial layer, inhibits the occurrence of thrombosis and inflammation, maintains long-term patency of the lumen, and has good application value.

Description

Technical Field

[0001] The present invention belongs to the technical field of biomedical materials and vascular stent coating preparation, and particularly relates to a composite vascular stent coating for regulating endothelial cell growth activity and a preparation method thereof. Background Art

[0002] The incidence, morbidity, and mortality rates of cardiovascular and cerebrovascular diseases have been increasing year by year, and are becoming younger. Atherosclerosis is the main cause of cardiovascular and cerebrovascular diseases. Atherosclerosis is caused by intimal stimulation, such as lipid or sugar accumulation, which leads to thickening, hardening, and narrowing of the arterial wall, and eventually deteriorates into occlusive arterial diseases including coronary heart disease, cerebral infarction, and peripheral vascular disease. Currently, covered stents are increasingly used in clinical practice to treat vascular obstruction. However, complications such as stent migration, endoleak, thrombosis, and restenosis are still prone to occur in the mid- to long-term after surgery, resulting in a high rate of unsatisfactory interventions, requiring postoperative re-intervention, and even death in severe cases. These are clinical problems that need to be addressed urgently.

[0003] At present, the main coating materials for commercial covered stents are polyester and polytetrafluoroethylene. Although these two synthetic materials have excellent mechanical properties, they have defects such as poor compliance, biological inertness and non-degradation. In addition, it is difficult for the above two synthetic materials to achieve endothelialization after implantation in the body, which may induce secondary thrombosis, restenosis and complications. The middle-aged and elderly population not only has a high incidence of thrombosis but also has a weak ability to regenerate their own tissues. Therefore, higher requirements are placed on the biological activity of the inner surface of this type of synthetic polymer stent coating - after implantation, it is hoped that while maintaining long-term mechanical support, rapid endothelialization can be achieved, fundamentally inhibiting the occurrence of thrombosis and inflammation. Therefore, in view of the existing clinical application bottlenecks and the application needs of the middle-aged and elderly, it is necessary to develop an active stent coating that regulates endothelial cell growth to solve the above problems. Summary of the Invention

[0004] In response to the shortcomings in the existing technology, the present invention provides a composite vascular stent coating for regulating the growth activity of endothelial cells and a preparation method thereof; the composite vascular stent coating of the present invention uses silk nanofiber membrane as the inner and outer layers of the composite vascular stent coating, and adopts weaving technology to weave seamless polyester tubular fabric as the core layer on the basis of the inner layer of the composite vascular stent coating; the composite vascular stent coating has a microstructure and matrix-like components that imitate the basement membrane of natural blood vessels, which is beneficial to the mechanical engagement between the outer surface of the coating and the inner side of the diseased blood vessel, stabilizes blood flow, avoids turbulence formation, and more significantly improves the adhesion, spreading, growth and proliferation ability of endothelial cells on its inner surface, quickly forms a new endothelial layer, inhibits the occurrence of thrombosis and inflammation, maintains long-term patency of the lumen, and has good application value.

[0005] The present invention first provides a composite vascular stent covering for regulating the growth activity of endothelial cells. The silk nanofiber membrane of the composite vascular stent covering is the inner and outer layers of the composite vascular stent covering. A seamless polyester tubular fabric is woven as the core layer on the basis of the inner layer of the composite vascular stent covering using weaving technology. The composite vascular stent covering has a microstructure and matrix-like components that imitate the natural vascular basement membrane.

[0006] The present invention also provides a method for preparing the composite vascular stent coating for regulating endothelial cell growth activity, which specifically comprises the following steps:

[0007] (1) mixing a silk fibroin aqueous solution with a hydrophilic flexible cross-linking agent to obtain a modified silk fibroin solution for later use;

[0008] The polyester yarn is placed in a sodium carbonate solution for degreasing and desizing to obtain a pretreated polyester yarn, and the pretreated polyester yarn is placed in a sodium hydroxide solution for surface activation to obtain an alkali-treated polyester yarn for standby use;

[0009] (2) using the modified silk fibroin solution as the electrospinning solution to spin silk fibroin nanofibers on an auxiliary rod by electrospinning to form the inner layer of the composite vascular stent coating;

[0010] The alkali-treated polyester yarn is braided onto the inner layer of the composite vascular stent coating using a braiding technique to form a polyester tubular fabric with a braiding angle of 30 to 150 degrees and an axial braiding density of 1 to 20 strands / cm;

[0011] The polyester tubular fabric is immersed in the modified silk fibroin solution for 10 to 60 seconds, placed in an environment of 20 to 50° C. and rotated in a circular direction at a rotation speed of 10 to 100 rpm to form a film, and the dipping step is repeated 2 to 10 times to form a core layer of the vascular stent coating;

[0012] (3) Using a modified silk fibroin solution as an electrospinning liquid, electrospinning silk fibroin nanofibers on the core surface of the vascular stent coating by electrospinning to form a composite vascular stent coating that regulates endothelial cell growth activity, and immersing the composite vascular stent coating that regulates endothelial cell growth activity in sterile deionized water to remove unreacted crosslinking agent and silk fibroin molecules.

[0013] Preferably, in step (1), the method for obtaining the silk fibroin aqueous solution is: degumming silkworm raw silk using any one of boiling water, sodium carbonate, sodium bicarbonate or biological enzymes to obtain degummed silk fibroin fibers; completely dissolving the degummed silk fibroin fibers in a lithium bromide solution to obtain a silk fibroin solution, and then pouring the silk fibroin solution into a dialysis bag and dialyzing with deionized water, filtering, and evaporating to obtain the silk fibroin aqueous solution.

[0014] The concentration of the lithium bromide solution is 9.3M; the dialysis bag is a semipermeable membrane with a molecular weight cutoff of 3 to 50 kDa; the dialysis time is 3 days; and the concentration of the obtained silk fibroin aqueous solution is 10 to 200 mg / mL.

[0015] Preferably, in step (1), the mass ratio of the silk fibroin aqueous solution to the cross-linking agent is 1.0:(0.3-1.0); and the silk fibroin concentration in the modified silk fibroin solution is 20-180 mg / mL.

[0016] Preferably, in step (1), the cross-linking agent is polyethylene glycol diglycidyl ether.

[0017] Preferably, in step (1), the degreasing and desizing treatment is performed at a temperature of 95 to 100° C. for 2 hours, followed by washing with deionized water, and the steps are repeated 2 to 5 times;

[0018] The concentration of the sodium hydroxide solution is 20-50 g / L;

[0019] The surface activation temperature is 30-80° C., the treatment time is 1-3 hours, and the surface is washed with deionized water after the activation is completed.

[0020] Preferably, the auxiliary rod is a stainless steel rod.

[0021] Preferably, in step (2), the rotation speed of the auxiliary rod is 100-3000 rpm, the diameter of the auxiliary rod is 1-30 mm, the average diameter of the silk nanofibers is 100-5000 nm, the average porosity of the silk nanofibers is 35-90%, and the average orientation degree of the silk nanofibers is 30-90%.

[0022] Preferably, in step (2), the polyester yarn is any one of polyester monofilament and polyester multifilament, with a specification of 5 to 200D.

[0023] Preferably, in step (3), the soaking is: soaking the vascular stent coating in sterile deionized water at 4-37° C. for 1-3 days.

[0024] Compared with the prior art, the present invention has the following beneficial effects:

[0025] The silk fibroin used in this invention is a natural animal protein composed of 20 amino acids and shares the same composition as the extracellular matrix. Artificial blood vessels constructed with silk fibroin can support the adhesion, growth, and proliferation of vascular cells. After implantation, it can induce endothelialization, maintain smooth blood flow, and induce in situ vascular tissue regeneration. It has attracted significant attention as a material for vascular tissue engineering. Due to its excellent blood compatibility, it can be used to prepare composite vascular stent coatings that regulate endothelial cell growth activity.

[0026] The composite vascular stent coating for regulating endothelial cell growth activity described herein exhibits excellent endothelialization-promoting properties and robust coating, fundamentally resolving the challenges of clinically used polyester or polytetrafluoroethylene vascular stents, which lack endothelialization and are susceptible to thrombosis and slippage after surgery. The composite vascular stent coating for regulating endothelial cell growth activity of the present invention modulates the coating's positional stability, blood flow stability, and endothelial cell activity by adjusting the microscopic topology of the inner and outer silk fibroin layers.

[0027] The silk fibroin nanostructures on the inner and outer surfaces of the composite vascular stent coating for regulating endothelial cell growth activity mimic the microscopic morphology of the vascular basement membrane, facilitating the homing and proliferation of endothelial (progenitor) cells. As the silk fibroin gradually degrades, new endothelial tissue rapidly forms, inhibiting the formation of thrombi and inflammation, effectively maintaining blood coagulation balance, and maintaining long-term vascular patency. Furthermore, the nanofiber microstructures on the outer surface of the composite vascular stent coating for regulating endothelial cell growth activity facilitate mechanical engagement between the coating and the inner wall of the vessel, stabilizing its position and preventing slippage. DETAILED DESCRIPTION

[0028] The present invention is further described below with reference to specific embodiments, but the scope of protection of the present invention is not limited thereto. In the following embodiments, the auxiliary rod is a stainless steel rod for illustration, but the auxiliary rod can be made of any material. In the following embodiments, various processes and methods not described in detail are conventional methods well known in the art. The source of the reagents used, the trade name, and if it is necessary to list their components, are all indicated when they first appear. The same reagents used thereafter are not specifically stated and are all from the same source as the first stated; the reagents, materials, etc. involved are all obtained for commercial use unless otherwise specified.

[0029] Example 1:

[0030] (1) Bombyx mori silk was placed in a 0.1% by mass sodium carbonate aqueous solution at a bath ratio of 1:50 g / mL, treated three times at 98-100°C for 30 minutes each time, then thoroughly washed with deionized water and dried in an oven at 60°C for 12 hours to obtain degummed silk fibers.

[0031] Degummed silk fibers were weighed and completely dissolved in a 9.3 M lithium bromide solution at a bath ratio of 1:10 g / mL in a 65 ± 5°C water bath to obtain a fibroin solution. The fibroin solution was poured into a dialysis bag (molecular weight cut-off 14 kDa) and dialyzed against deionized water for three days to obtain a purified silk fibroin aqueous solution. The purified silk fibroin aqueous solution was concentrated and adjusted to the desired concentration.

[0032] The silk fibroin aqueous solution is mixed with a hydrophilic flexible cross-linking agent to obtain a modified silk fibroin solution for later use, wherein the mass ratio of silk fibroin to cross-linking agent is 1.0:0.5, and the cross-linking agent is polyethylene glycol diglycidyl ether.

[0033] The polyester yarn is placed in a 1% by mass sodium carbonate solution at a bath ratio of 1:50 g / mL, treated at a temperature of 98-100° C. for three times, each time for 2 hours, and then thoroughly washed with deionized water to obtain a pretreated polyester yarn. The pretreated polyester yarn is placed in a 20 g / L sodium hydroxide aqueous solution at a bath ratio of 1:50 g / mL for surface activation treatment at a temperature of 35±5° C. for 1 hour, and then washed with deionized water to obtain an alkali-treated polyester yarn for later use.

[0034] (2) Using a modified silk fibroin solution with a silk fibroin concentration of 60 mg / mL as the electrospinning solution, silk fibroin nanofibers were spun on a stainless steel rod (10 mm in diameter) at a rotation speed of 300 rpm by electrospinning to form the inner layer of the composite vascular stent coating that regulates the growth activity of endothelial cells.

[0035] The alkali-treated polyester filaments were woven into a polyester tubular fabric with a 120° braiding angle and an axial braiding density of 4 strands / cm on the outer surface of the inner layer of the stent coating using a braiding technique. The polyester tubular fabric was immersed in a modified silk fibroin solution with a silk fibroin concentration of 60 mg / mL for 10 seconds, taken out, and placed in a 35°C environment and rotated in a circular direction to form a film at a rotation speed of 60 rpm. This step was repeated 6 times to form a core layer of a composite vascular stent coating that regulates endothelial cell growth activity.

[0036] (3) The same method as step (2) was used to electrospin silk nanofibers on the core surface of the composite vascular stent coating that regulates endothelial cell growth activity to construct the outer layer of the composite vascular stent coating that regulates endothelial cell growth activity, and the outer layer was further immersed in sterile deionized water at 37°C for 1 day to remove unreacted cross-linking agent and silk molecules to obtain a composite vascular stent coating that can regulate endothelial cell growth activity, which was recorded as polyester braid / silk fibroin composite vascular stent coating.

[0037] Testing has shown that the polyester woven fabric / silk fibroin composite vascular stent coating of this embodiment has excellent mechanical properties and promotes endothelial cell activity. The average diameter of the silk fibroin nanofibers is 300±50nm, the porosity is 75±10%, the fiber orientation is 30±8%, the axial tensile strength is 11.5MPa, the elongation at break is 115%, the circumferential tensile strength is 5.7MPa, the elongation at break is 51%, the water burst strength is 3200mmHg, the compliance is 9.6% / 100mmHg, and the overall water leakage is less than 10mL / min.cm under a water pressure of 120mmHg. 2, hemolysis rate <0.1%.

[0038] After endothelial cells were cultured on its surface for 3 days, the average spreading area of endothelial cells on the polyester woven fabric / silk fibroin composite vascular stent coating of this embodiment increased by 38% compared with comparison example 1, the expression level of vascular endothelial growth factor increased by 35% compared with comparison example 1, and the cell proliferation rate increased by 46% compared with comparison example 1.

[0039] Example 2:

[0040] (1) Bombyx mori silk was placed in a 0.1% by mass sodium carbonate aqueous solution at a bath ratio of 1:50 g / mL, treated three times at 98-100°C for 30 minutes each time, then thoroughly washed with deionized water and dried in an oven at 60°C for 12 hours to obtain degummed silk fibers.

[0041] Degummed silk fibers were weighed and completely dissolved in a 9.3 M lithium bromide solution at a bath ratio of 1:10 g / mL in a 65 ± 5°C water bath to obtain a fibroin solution. The fibroin solution was poured into a dialysis bag (molecular weight cut-off 14 kDa) and dialyzed against deionized water for three days to obtain a purified silk fibroin aqueous solution. The purified silk fibroin aqueous solution was concentrated and adjusted to the desired concentration.

[0042] The silk fibroin aqueous solution is mixed with a hydrophilic flexible cross-linking agent to obtain a modified silk fibroin solution for later use, wherein the mass ratio of silk fibroin to cross-linking agent is 1.0:0.5, and the cross-linking agent is polyethylene glycol diglycidyl ether.

[0043] The polyester yarn is placed in a 1% by mass sodium carbonate solution at a bath ratio of 1:50 g / mL, treated at a temperature of 98-100° C. for three times, each time for 2 hours, and then thoroughly washed with deionized water to obtain a pretreated polyester yarn. The pretreated polyester yarn is placed in a 20 g / L sodium hydroxide aqueous solution at a bath ratio of 1:50 g / mL for surface activation treatment at a temperature of 35±5° C. for 1 hour, and then washed with deionized water to obtain an alkali-treated polyester yarn for later use.

[0044] (2) Using a modified silk fibroin solution with a silk fibroin concentration of 120 mg / mL as the electrospinning solution, silk fibroin nanofibers were spun on a stainless steel rod (10 mm in diameter) at a rotation speed of 300 rpm by electrospinning to form the inner layer of the composite vascular stent coating that regulates the growth activity of endothelial cells.

[0045] The alkali-treated polyester filaments were woven into a polyester tubular fabric with a 120° braiding angle and an axial braiding density of 4 strands / cm on the outer surface of the inner layer of the stent coating using a braiding technique. The polyester tubular fabric was immersed in a modified silk fibroin solution with a silk fibroin concentration of 60 mg / mL for 10 seconds, taken out, and placed in a 35°C environment and rotated in a circular direction to form a film at a rotation speed of 60 rpm. This step was repeated 6 times to form a core layer of a composite vascular stent coating that regulates endothelial cell growth activity.

[0046] (3) The same method as step (2) was used to electrospin silk nanofibers on the core surface of the composite vascular stent coating that regulates endothelial cell growth activity to construct the outer layer of the composite vascular stent coating that regulates endothelial cell growth activity, and the outer layer was further immersed in sterile deionized water at 37°C for 1 day to remove unreacted cross-linking agent and silk molecules to obtain a composite vascular stent coating that can regulate endothelial cell growth activity, which was recorded as polyester braid / silk fibroin composite vascular stent coating.

[0047] Testing showed that the polyester woven fabric / silk fibroin composite vascular stent coating of this embodiment exhibited excellent endothelial cell-stimulating activity. The silk fibroin nanofibers had an average diameter of 600±150 nm, a porosity of 60±7%, and a fiber orientation of 30±10%. After three days of endothelial cell culture on the polyester woven fabric / silk fibroin composite vascular stent coating of this embodiment, the average spreading area of the endothelial cells increased by 45% compared to the control example 1, the expression of vascular endothelial growth factor increased by 43%, and the cell proliferation rate increased by 55%.

[0048] Example 3:

[0049] (1) Bombyx mori silk was placed in a 0.1% by mass sodium carbonate aqueous solution at a bath ratio of 1:50 g / mL, treated three times at 98-100°C for 30 minutes each time, then thoroughly washed with deionized water and dried in an oven at 60°C for 12 hours to obtain degummed silk fibers.

[0050] Degummed silk fibers were weighed and completely dissolved in a 9.3 M lithium bromide solution at a bath ratio of 1:10 g / mL in a 65 ± 5°C water bath to obtain a fibroin solution. The fibroin solution was poured into a dialysis bag (molecular weight cut-off 14 kDa) and dialyzed against deionized water for three days to obtain a purified silk fibroin aqueous solution. The purified silk fibroin aqueous solution was concentrated and adjusted to the desired concentration.

[0051] The silk fibroin aqueous solution is mixed with a hydrophilic flexible cross-linking agent to obtain a modified silk fibroin solution for later use, wherein the mass ratio of silk fibroin to cross-linking agent is 1.0:0.5, and the cross-linking agent is polyethylene glycol diglycidyl ether.

[0052] The polyester yarn is placed in a 1% by mass sodium carbonate solution at a bath ratio of 1:50 g / mL, treated at a temperature of 98-100° C. for three times, each time for 2 hours, and then thoroughly washed with deionized water to obtain a pretreated polyester yarn. The pretreated polyester yarn is placed in a 20 g / L sodium hydroxide aqueous solution at a bath ratio of 1:50 g / mL for surface activation treatment at a temperature of 35±5° C. for 1 hour, and then washed with deionized water to obtain an alkali-treated polyester yarn for later use.

[0053] (2) Using a modified silk fibroin solution with a silk fibroin concentration of 120 mg / mL as the electrospinning solution, silk fibroin nanofibers were spun on a stainless steel rod (10 mm in diameter) rotating at a speed of 2000 rpm by electrospinning to form the inner layer of the composite vascular stent coating that regulates the growth activity of endothelial cells.

[0054] The alkali-treated polyester filaments were woven into a polyester tubular fabric with a 120° braiding angle and an axial braiding density of 4 strands / cm on the outer surface of the inner layer of the stent coating using a braiding technique. The polyester tubular fabric was immersed in a modified silk fibroin solution with a silk fibroin concentration of 60 mg / mL for 10 seconds, taken out, and placed in a 35°C environment and rotated in a circular direction to form a film at a rotation speed of 60 rpm. This step was repeated 6 times to form a core layer of a composite vascular stent coating that regulates endothelial cell growth activity.

[0055] (3) The same method as step (2) was used to electrospin silk nanofibers on the core surface of the composite vascular stent coating that regulates endothelial cell growth activity to construct the outer layer of the composite vascular stent coating that regulates endothelial cell growth activity, and the outer layer was further immersed in sterile deionized water at 37°C for 1 day to remove unreacted cross-linking agent and silk molecules to obtain a composite vascular stent coating that can regulate endothelial cell growth activity, which was recorded as polyester braid / silk fibroin composite vascular stent coating.

[0056] Testing showed that the polyester woven fabric / silk fibroin composite vascular stent coating of this embodiment exhibited excellent endothelial cell-stimulating activity. The average silk fibroin nanofiber diameter was 580±150 nm, the porosity was 55±10%, and the fiber orientation was 65±10%. After three days of endothelial cell culture on the polyester woven fabric / silk fibroin composite vascular stent coating of this embodiment, the average spreading area of the endothelial cells increased by 40% compared to the control example 1, the expression of vascular endothelial growth factor increased by 38%, and the cell proliferation rate increased by 45%.

[0057] Comparative Example 1:

[0058] (1) Bombyx mori silk was placed in a 0.1% by mass sodium carbonate aqueous solution at a bath ratio of 1:50 g / mL, treated three times at 98-100°C for 30 minutes each time, then thoroughly washed with deionized water and dried in an oven at 60°C for 12 hours to obtain degummed silk fibers.

[0059] Degummed silk fibers were weighed and completely dissolved in a 9.3 M lithium bromide solution at a bath ratio of 1:10 g / mL in a 65 ± 5°C water bath to obtain a fibroin solution. The fibroin solution was poured into a dialysis bag (molecular weight cut-off 14 kDa) and dialyzed against deionized water for three days to obtain a purified silk fibroin aqueous solution. The purified silk fibroin aqueous solution was concentrated and adjusted to the desired concentration.

[0060] The silk fibroin aqueous solution is mixed with a hydrophilic flexible cross-linking agent to obtain a modified silk fibroin solution for later use, wherein the mass ratio of silk fibroin to cross-linking agent is 1.0:0.5, and the cross-linking agent is polyethylene glycol diglycidyl ether.

[0061] The polyester yarn is placed in a 1% by mass sodium carbonate solution at a bath ratio of 1:50 g / mL, treated at a temperature of 98-100° C. for three times, each time for 2 hours, and then thoroughly washed with deionized water to obtain a pretreated polyester yarn. The pretreated polyester yarn is placed in a 20 g / L sodium hydroxide aqueous solution at a bath ratio of 1:50 g / mL for surface activation treatment at a temperature of 35±5° C. for 1 hour, and then washed with deionized water to obtain an alkali-treated polyester yarn for later use.

[0062] (2) The alkali-treated polyester filaments were braided on a stainless steel rod using a braiding technique to form a polyester tubular fabric with a braiding angle of 120° and an axial braiding density of 4 strands / cm. The polyester tubular fabric was immersed in a modified silk fibroin solution with a silk fibroin concentration of 60 mg / mL for 10 seconds, taken out and placed at 35°C and rotated in a circular direction to form a film at a rotation speed of 60 rpm. This step was repeated 6 times, and the fabric was further immersed in sterile deionized water at 37°C for 1 day to remove unreacted crosslinking agent and silk fibroin molecules to obtain a polyester braid / silk fibroin composite vascular stent coating.

[0063] The embodiments described are preferred implementations of the present invention, but the present invention is not limited to the above implementations. Any obvious improvements, substitutions or modifications that can be made by those skilled in the art without departing from the essence of the present invention are within the scope of protection of the present invention.

Claims

1. A method for preparing a composite vascular stent coating for regulating endothelial cell growth activity, characterized in that: include: (1) mixing the silk fibroin aqueous solution with a hydrophilic flexible cross-linking agent to obtain a modified silk fibroin solution for later use; The polyester yarn is placed in a sodium carbonate solution for degreasing and desizing to obtain a pretreated polyester yarn, and the pretreated polyester yarn is placed in a sodium hydroxide solution for surface activation to obtain an alkali-treated polyester yarn for standby use; (2) Using the modified silk fibroin solution as an electrospinning solution, spinning silk fibroin nanofibers on an auxiliary rod by electrospinning to form an inner layer of the composite vascular stent coating; the average porosity of the silk fibroin nanofibers is 35-90%, and the average orientation degree of the silk fibroin nanofibers is 30-90%; The alkali-treated polyester yarn is braided onto the inner layer of the composite vascular stent coating using a braiding technique to form a polyester tubular fabric with a braiding angle of 30-150 degrees and an axial braiding density of 1-20 strands / cm; Immerse the polyester tubular fabric in the modified silk fibroin solution of step (1) for 10 to 60 seconds, place it in an environment of 20 to 50°C, and rotate it in a circular direction to form a film at a rotation speed of 10 to 100 rpm. This is recorded as one operation step. Repeat the operation step 2 to 10 times to form a core layer of the vascular stent coating. (3) Using a modified silk fibroin solution as an electrospinning liquid, electrospinning silk fibroin nanofibers on the core surface of the vascular stent coating by electrospinning to form a composite vascular stent coating that regulates endothelial cell growth activity, and immersing the composite vascular stent coating that regulates endothelial cell growth activity in sterile deionized water to remove unreacted crosslinking agent and silk fibroin molecules.

2. The method for preparing a composite vascular stent coating for regulating endothelial cell growth activity according to claim 1, characterized in that: In step (1), the method for obtaining the silk fibroin aqueous solution is as follows: degumming silkworm raw silk using any one of boiling water, sodium carbonate, sodium bicarbonate or biological enzymes to obtain degummed silk fibroin fibers; completely dissolving the degummed silk fibroin fibers in a lithium bromide solution to obtain a silk fibroin solution, and then pouring the silk fibroin solution into a dialysis bag, dialyzing with deionized water, filtering, and evaporating to obtain the silk fibroin aqueous solution.

3. The method for preparing a composite vascular stent coating for regulating endothelial cell growth activity according to claim 1, characterized in that: In step (1), the mass ratio of the silk fibroin aqueous solution to the cross-linking agent is 1.0:(0.3-1.0); and the silk fibroin concentration in the modified silk fibroin solution is 20-180 mg / mL.

4. The method for preparing a composite vascular stent coating for regulating endothelial cell growth activity according to claim 1, characterized in that: In step (1), the cross-linking agent is polyethylene glycol diglycidyl ether.

5. The method for preparing a composite vascular stent coating for regulating endothelial cell growth activity according to claim 1, characterized in that: In step (1), the degreasing and desizing treatment is performed at a temperature of 95-100° C. for 2 hours, followed by washing with deionized water, and the steps are repeated 2-5 times; The concentration of the sodium hydroxide solution is 20-50 g / L; The surface activation temperature is 30-80° C., the treatment time is 1-3 hours, and the surface is washed with deionized water after the activation is completed.

6. The method for preparing a composite vascular stent coating for regulating endothelial cell growth activity according to claim 1, characterized in that: In step (2), the auxiliary rod is a stainless steel rod.

7. The method for preparing a composite vascular stent coating for regulating endothelial cell growth activity according to claim 1, characterized in that: In step (2), the rotation speed of the auxiliary rod is 100-3000 rpm, the diameter of the auxiliary rod is 1-30 mm, and the average diameter of the silk nanofiber is 100-5000 nm.

8. The method for preparing a composite vascular stent coating for regulating endothelial cell growth activity according to claim 1, characterized in that: In step (2), the polyester yarn is any one of polyester monofilament and polyester multifilament, and the specification is 5~200D.

9. The method for preparing a composite vascular stent coating for regulating endothelial cell growth activity according to claim 1, characterized in that: In step (3), the soaking is: soaking the vascular stent coating in sterile deionized water at 4-37°C for 1-3 days.

10. The composite vascular stent coating for regulating endothelial cell growth activity prepared according to the preparation method according to any one of claims 1 to 9, characterized in that: The composite vascular stent covering uses silk nanofiber membrane as the inner and outer layers of the composite vascular stent covering, and uses weaving technology to weave seamless polyester tubular fabric as the core layer on the basis of the inner layer of the composite vascular stent covering; the composite vascular stent covering has a microstructure and matrix-like components that imitate the natural vascular basement membrane.