A modified polyester vascular stent membrane composed of composite silk fibroin and its preparation method

Abstract

The present invention discloses a modified polyester vascular stent membrane composed of silk fibroin and a preparation method thereof, including: preparing a silk fibroin solution, subjecting polyester filaments to alkali treatment for surface activation, weaving to form a seamless polyester tubular fabric, and spin-impregnating the silk fibroin solution and spin-drying it under low-temperature conditions to form a vascular stent membrane. The vascular stent membrane formed by this method can flexibly control the thickness and mechanical properties (especially toughness and compliance) of the vascular stent membrane by adjusting the polyester filament specifications, the structural parameters of the woven fabric, and the self-assembly of silk fibroin, so as to match the compliance of the autologous blood vessel, thereby reducing blood flow turbulence and stent slippage caused by non-matching compliance, maintaining the normal flow of blood, and the vascular stent membrane has good biological activity, can in-situ induce endothelial regeneration, and inhibit the formation of thrombus and inflammation.

Description

Technical Field

[0001] The present invention relates to the field of biomedical materials, and particularly to the preparation of vascular stent coatings, and more particularly to a modified polyester vascular stent coating composite with silk fibroin and a preparation method thereof. Background Art

[0002] At present, more and more clinical applications use covered stents to achieve the purpose of treating vascular occlusion. However, in the medium and long term after surgery, complications such as stent migration, endoleak, thrombosis, and restenosis are still likely to occur, resulting in a relatively high proportion of unsatisfactory interventions and the need for postoperative reintervention. These are all clinical problems that need to be urgently solved.

[0003] Silk fibroin is a natural protein derived from animals, composed of 20 amino acids, and has the same components as the extracellular matrix. Existing literature studies have shown that artificial blood vessels constructed with silk fibroin can support the adhesion, growth, and proliferation of vascular cells, can induce endothelialization after implantation to keep blood flow unobstructed, and can in situ induce the regeneration of vascular tissue, and thus has received great attention in the field of vascular tissue engineering materials. Due to its good blood compatibility, it is also a preferred material for surface modification of existing clinically applied synthetic polymers such as polyester or polytetrafluoroethylene coatings.

[0004] At present, the main coating materials for commercial covered stents are polyester and polytetrafluoroethylene. Although these two synthetic materials have excellent mechanical properties, due to their insufficient compliance, it is difficult to fully fit with the blood vessel wall after implantation, resulting in stent slippage, and it is also easy to cause blood turbulence, changing hemodynamics and inducing thrombosis and in-stent restenosis. In addition, due to the defect of its biological inertness, it is difficult to achieve endothelialization after implantation, and it cannot fundamentally solve the technical bottleneck of thrombosis, which is also the main reason for inducing postoperative complications. Especially for the elderly population, not only is the thrombosis incidence high, but their own tissue regeneration ability is weak. Therefore, higher requirements are put forward for the bioactivity of the inner surface of such synthetic polymer stent coatings - it is hoped that rapid endothelialization can be achieved while maintaining long-term mechanical support after implantation, fundamentally inhibiting the occurrence of thrombosis and inflammation. Therefore, in view of the existing clinical application bottlenecks and the application needs of the elderly, it is necessary to develop a vascular stent coating to solve the above problems. Summary of the Invention

[0005] The purpose of the present invention is to provide a modified polyester vascular stent coating composite with silk fibroin and a preparation method thereof. The prepared vascular stent coating has a tight, ultra-thin, and uniform structure, and is used to produce a vascular stent that can isolate the contact between the blood flow and the lesion site, maintain the normal blood flow, avoid blood flow turbulence and stent slippage, can rapidly induce endothelialization, and inhibit the formation of thrombosis and inflammation.

[0006] The present invention obtains a vascular stent coating with ultra-thin uniform thickness, good mechanical properties and excellent biological activity through the design and regulation of the coating structure. The technical solution to achieve the above purpose is as follows:

[0007] (1) degumming silkworm silk with boiling water, sodium carbonate, sodium bicarbonate or biological enzymes to obtain silk fibroin (hereinafter referred to as silk fibroin) fibers, and then completely dissolving the fibers in a lithium bromide solution to obtain a silk fibroin solution; pouring the silk fibroin solution into a dialysis bag, dialyzing the solution with deionized water, filtering the solution to obtain a purified silk fibroin protein aqueous solution, and evaporating and concentrating the solution to adjust the concentration of the silk fibroin protein aqueous solution to 10 to 200 mg / mL;

[0008] The silk fibroin aqueous solution is mixed with a hydrophilic flexible cross-linking agent to obtain a modified silk fibroin solution, wherein the concentration of the silk fibroin in the modified silk fibroin solution is 10 to 160 mg / mL;

[0009] (2) placing the polyester yarn in a sodium carbonate solution for a period of time, washing it with deionized water, completing the degreasing and desizing treatment, repeating the degreasing and desizing treatment several times, and finally obtaining the pretreated polyester yarn; placing the pretreated polyester yarn in a sodium hydroxide solution for surface activation treatment, and washing it with deionized water after the surface activation treatment to obtain the alkali-treated polyester yarn;

[0010] (3) placing the cylindrical auxiliary rod in the modified silk fibroin solution obtained in step (1) for rotation-immersion treatment, taking it out and placing it in an environment of 20 to 50° C. and maintaining the same rotation speed as in the solution for 10 to 30 minutes to complete one rotation-immersion treatment, and controlling the membrane surface to remain wet; repeating the rotation-immersion treatment several times to form the inner layer of the vascular stent coating;

[0011] The alkali-treated polyester yarn is braided on the outer surface of the inner layer of the stent coating by using a braiding technique to obtain a seamless polyester tubular braid;

[0012] (4) placing the seamless polyester tubular braid obtained in step (3) in the modified silk fibroin solution obtained in step (1) for rotation-immersion treatment, taking it out after treatment and placing it in an environment of 20 to 50° C. and maintaining the rotation speed in the solution for 10 to 30 minutes to complete one rotation-immersion treatment, and controlling the membrane surface to remain wet; repeating the rotation-immersion treatment several times to obtain a vascular stent coating, and then immersing the vascular stent coating in sterile deionized water to remove unreacted cross-linking agent and silk molecules, and finally obtaining a modified polyester vascular stent coating of composite silk fibroin.

[0013] Preferably, in step (1), the concentration of the lithium bromide solution is 9.3 M; the dialysis bag is a semi-permeable membrane with a molecular weight cut-off of 3 - 50 kDa, and dialysis is carried out with deionized water for 3 days; the mass ratio of silk fibroin to the cross-linking agent is 1.0:(0.3 - 1.0), and the cross-linking agent is polyethylene glycol diglycidyl ether.

[0014] Preferably, in step (2), the polyester filament is any one of polyester monofilament and polyester multifilament, with a specification of 5 - 200 D.

[0015] Preferably, in step (2), the mass concentration of the sodium carbonate solution is 1%, the temperature for desizing treatment is 95 - 100 °C, and the treatment time is 2 hours; the number of treatments is 2 - 5 times; the concentration of the sodium hydroxide solution is 20 - 50 g / L, the temperature for surface activation treatment is 30 - 80 °C, and the treatment time is 1 - 3 hours.

[0016] Preferably, in step (3), the cylindrical auxiliary rod can be selected as a stainless steel rod with a diameter of 1 - 30 mm. The rotation speed of the cylindrical auxiliary rod in the solution is 20 - 80 rpm, the rotation direction is along the circumferential direction of the auxiliary rod, the impregnation time is 10 - 60 seconds, and the impregnation area accounts for 10 - 90% of the lateral area of the stainless steel rod; the number of repeated rotation-impregnation treatments is 0 - 5 times.

[0017] Preferably, in step (3), the weaving conditions are a weaving angle of 30 - 150° and an axial weaving density of 1 - 20 threads / cm.

[0018] Preferably, in step (4), the time for rotation-impregnation treatment in the modified silk fibroin solution is 10 - 60 seconds, the rotation speed is 20 - 80 rpm, the rotation direction is along the circumferential direction of the auxiliary rod, and the impregnation area accounts for 10 - 90% of the lateral area of the stainless steel rod; the number of repeated rotation-impregnation treatments is 2 - 10 times.

[0019] Preferably, in step (4), the temperature of the sterile deionized water is 4 - 37 °C, and the soaking time is 1 - 3 days.

[0020] Regarding the modified polyester vascular stent film coated with composite silk fibroin prepared by the above method, generally speaking, the film thickness < 100 ± 5 μm, the axial tensile strength > 10.5 MPa, the elongation at break > 80%, the circumferential tensile strength > 5.3 MPa, the elongation at break > 30%, the compliance > 4.0% / 100 mmHg, and the overall water leakage < 46.8 mL / min.cm under a water pressure of 120 mmHg. 2 。

[0021] The hemolysis rate of the modified polyester vascular stent film with composite silk fibroin was measured according to the hemolysis rate test method and was <0.1%, fully meeting the standard of non-hemolytic materials (0-2%). It has no sensitization through animal experiments and the cytotoxicity is ≤1 according to national standard detection.

[0022] Beneficial effects:

[0023] The technical solution and creativity of the present invention lie in that the thickness of the composite film can be adjusted, and it has superior mechanical properties and biological activity. It has an ultra-thin and uniform thickness, excellent mechanical properties and endothelialization-promoting function, fundamentally solving the technical problems of mismatched compliance performance, easy displacement, inability to endothelialize, and still easy to generate thrombus after operation of polyester or polytetrafluoroethylene vascular stents applied clinically. The modified polyester vascular stent film with composite silk fibroin provided by the present invention can regulate the required thickness, mechanical properties (especially toughness and compliance) and endow it with good biological activity by adjusting the self-assembled layer of silk fibroin, the specifications of polyester filaments and the geometric parameters of tubular woven fabrics, etc.

[0024] The innovation of the present invention lies in the constructed ultrathin and uniform composite silk fibroin modified polyester vascular stent film with a compact structure, including a modified silk fibroin layer and a polyester core layer. The modified silk fibroin layer is a self-assembled layer at the molecular level of silk fibroin. The flowing macromolecular chains of silk fibroin flow, adhere, stretch and orient orderly with the shear force, making the macromolecules in the silk fibroin film arranged orderly. A large interaction force is formed between macromolecules within the layer and between layers. The molecular-level layer-by-layer and orderly self-assembly endows the silk fibroin film with excellent flexibility, especially radial compliance, which cannot be achieved by conventional film-forming methods such as casting method with static air drying / drying.

[0025] Polyester is a rigid fiber. The modified polyester vascular stent film coated with composite silk fibroin of the present invention has a thinner and more uniform thickness compared to the fiber-dense fabric film, and achieves significantly excellent and adjustable compliance, which can match and conform to the stress and strain generated by blood flow in blood vessels, thereby reducing blood flow turbulence caused by non-matching compliance to meet the requirements of vascular biomechanics for maintaining normal blood flow in patients of various ages and constitutions. The innovation of the present invention lies more in the self-assembled layer at the molecular level of silk fibroin in the constructed film, which completely and tightly clamps the large-mesh polyester filaments, preventing slippage between filaments and synergistically creating excellent mechanical properties and excellent anti-leakage properties. Moreover, the silk fibroin films assembled layer by layer in the vascular stent film also have satisfactory biological activity, which can promote the adhesion and proliferation of endothelial cells, in-situ induce endothelial regeneration, permanently inhibit the occurrence of thrombosis and inflammation. At the same time, the silk fibroin macromolecular chain has abundant functional groups, which can load anti-inflammatory / coagulant drugs and growth factors through methods such as hydrophilic / hydrophobic interaction, electrostatic adsorption, and chemical grafting to create a friendly microenvironment for vascular cells, guide cell behavior and endothelial regeneration, and solve the fundamental problem that existing coated stents in clinical practice cannot be endothelialized, thereby inducing the reformation of thrombosis and restenosis, which is also a problem that cannot be solved by various polyester-dense fabrics. Detailed Description of the Invention

[0026] The various exemplary embodiments of the present invention will now be described in detail. This detailed description should not be considered as a limitation of the present invention, but rather as a more detailed description of certain aspects, characteristics, and embodiments of the present invention.

[0027] It should be understood that the terms used in the present invention are only for describing specific embodiments and are not intended to limit the present invention. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by those of ordinary skill in the art to which the present invention pertains. Although the present invention only describes preferred methods and materials, any methods and materials similar or equivalent to those described herein can also be used in the implementation or testing of the present invention. All documents mentioned in this specification are incorporated by reference to disclose and describe the methods and / or materials related to the documents. In case of conflict with any incorporated document, the content of this specification shall prevail.

[0028] Without departing from the scope or spirit of the present invention, various improvements and changes can be made to the specific embodiments of the present invention specification, which are obvious to those skilled in the art. Other embodiments obtained from the specification of the present invention are obvious to those skilled in the art. The specification and examples of the present invention are only exemplary.

[0029] Example 1:

[0030] (1) The domestic silk is placed in an aqueous sodium carbonate solution with a mass concentration of 0.1% at a bath ratio of 1:50 g / mL, and treated three times at a temperature of 98 - 100 °C for 30 minutes each time. Then it is thoroughly washed with deionized water and dried in an oven at 60 °C for 12 hours to obtain degummed silk fibroin fibers. Weigh the degummed silk fibroin fibers and dissolve them completely in a 9.3 M lithium bromide solution at a bath ratio of 1:10 g / mL in a water bath environment of 65 ± 5 °C to obtain a silk fibroin solution; pour the silk fibroin solution into a dialysis bag (with a molecular weight cut-off of 14 kDa) and dialyze it with deionized water for 3 days to obtain a purified aqueous silk fibroin solution. Concentrate, adjust and measure the concentration of the purified aqueous silk fibroin solution to make the concentration of the purified aqueous silk fibroin solution 60 mg / mL.

[0031] Mix the aqueous silk fibroin solution with a hydrophilic and flexible cross-linking agent to obtain a modified silk fibroin solution. The mass ratio of silk fibroin to the cross-linking agent is 1.0:0.5. The cross-linking agent is polyethylene glycol diglycidyl ether, and the concentration of silk fibroin in the modified silk fibroin solution is 60 mg / mL.

[0032] (2) Place 120D / 1f polyester monofilaments in a sodium carbonate solution with a mass concentration of 1% at a bath ratio of 1:50 g / mL, and treat them three times at a temperature of 98 - 100 °C for 2 hours each time. Then wash them thoroughly with deionized water to obtain pretreated polyester filaments; place the pretreated polyester filaments in a 20 g / L aqueous sodium hydroxide solution at a bath ratio of 1:50 g / mL for surface activation treatment. The surface activation treatment temperature is 35 ± 5 °C, and the treatment time is 1 hour. After treatment, wash them with deionized water to obtain alkali-treated polyester filaments.

[0033] (3) Place a stainless steel rod (with a diameter of 10 mm) in the modified silk fibroin solution in a rotating-impregnating manner for rotating-impregnating treatment for 60 seconds. The impregnated area accounts for 50% of the lateral area of the stainless steel rod. The rotation speed is 20 rpm, and the rotation direction is along the circumferential direction of the stainless steel rod. After treatment, take it out and place it in an environment of 35 °C and continue to rotate at the above rotation speed and direction for 10 minutes to form the inner layer of the vascular stent coating.

[0034] Weave the alkali-treated polyester filaments obtained in step (2) on the outer surface of the inner layer of the vascular stent coating using a weaving technique to form a seamless polyester tubular woven fabric with a weaving angle of 60° and an axial weaving density of 8 roots / cm.

[0035] (4) The obtained seamless polyester tubular fabric is placed in the modified silk fibroin solution again for 60 seconds in the rotation-impregnation manner in step (3) above. The impregnated area accounts for 50% of the lateral area of the stainless steel rod. The rotation speed is 20 rpm, and the rotation direction is along the circumferential direction of the stainless steel rod. After taking it out, it is placed in an environment at 35 °C and continues to rotate for 10 minutes while maintaining the above rotation speed and rotation direction, completing one rotation-impregnation treatment, and controlling the surface of the membrane to remain wet; repeating the rotation-impregnation treatment 5 times in this way to obtain a vascular stent film coating, and then soaking the vascular stent film coating in sterile deionized water at 37 °C for 1 day to remove the unreacted cross-linking agent and silk fibroin molecules, finally obtaining a modified polyester vascular stent film coating with composite silk fibroin.

[0036] After testing, the modified polyester vascular stent film coating with the above composite silk fibroin has an ultra-thin and uniform thickness and excellent mechanical properties. The film coating thickness is measured to be 100 ± 5 μm according to the national standard testing method, the axial tensile strength is 18.2 MPa, the elongation at break is 80%, the circumferential tensile strength is 9.7 MPa, the elongation at break is 30%, the compliance is 4.0% / 100 mmHg, and the overall water leakage is 46.8 mL / min.cm under a water pressure of 120 mmHg. 2 。

[0037] The hemolysis rate of the modified polyester vascular stent film coating with the composite silk fibroin of the present invention is measured to be <0.1% according to the hemolysis rate test method, fully meeting the standard of non-hemolytic materials (0 - 2%). It has no sensitization through animal experiments, and the cytotoxicity is ≤1 according to the national standard testing.

[0038] Example 2:

[0039] (1) The domestic silk is placed in an aqueous sodium carbonate solution with a mass concentration of 0.1% at a bath ratio of 1:50 g / mL and treated three times at a temperature of 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 fibroin fibers. Weigh the degummed silk fibroin fibers and completely dissolve them in a 9.3 M lithium bromide solution in a water bath environment at 65 ± 5 °C at a bath ratio of 1:10 g / mL to obtain a silk fibroin solution. The silk fibroin solution is poured into a dialysis bag (with a cut-off molecular weight of 14 kDa) and dialyzed with deionized water for 3 days to obtain a purified aqueous silk fibroin solution. The purified aqueous silk fibroin solution is concentrated, adjusted, and the concentration is measured to make the concentration of the purified aqueous silk fibroin solution 60 mg / mL.

[0040] The aqueous silk fibroin solution is mixed with a hydrophilic and flexible cross-linking agent to obtain a modified silk fibroin solution. The mass ratio of silk fibroin to the cross-linking agent is 1.0:0.5. The cross-linking agent is polyethylene glycol diglycidyl ether, and the concentration of silk fibroin in the modified silk fibroin solution is 60 mg / mL.

[0041] (2) Place the 120D / 36f polyester multifilament in a sodium carbonate solution with a mass concentration of 1% at a bath ratio of 1:50 g / mL, and treat it three times at a temperature of 98 - 100 °C for 2 hours each time. Then, thoroughly wash it with deionized water to obtain the pretreated polyester filaments. Place the pretreated polyester filaments in a 20 g / L aqueous sodium hydroxide solution for surface activation treatment at a bath ratio of 1:50 g / mL. The surface activation treatment temperature is 35 ± 5 °C, and the treatment time is 1 hour. After treatment, wash it with deionized water to obtain the alkali-treated polyester filaments.

[0042] (3) Place the stainless steel rod (with a diameter of 10 mm) in the modified silk fibroin solution in a rotation - dipping manner for rotation - dipping treatment for 60 seconds. The dipping area accounts for 50% of the lateral area of the stainless steel rod. The rotation speed is 20 rpm, and the rotation direction is along the circumferential direction of the stainless steel rod. After taking it out, place it in an environment at 35 °C and continue to rotate for 10 minutes at the above rotation speed and rotation direction to form the inner layer of the vascular stent coating.

[0043] Weave the alkali - treated polyester filaments obtained in step (2) on the outer surface of the inner layer of the vascular stent coating using a weaving technique at a weaving angle of 60°

[0044] to form a seamless polyester tubular woven fabric with an axial weaving density of 8 filaments / cm.

[0045] (4) Place the obtained seamless polyester tubular woven fabric in the modified silk fibroin solution again in the rotation - dipping manner as in step (3) for 60 seconds. The dipping area accounts for 50% of the lateral area of the stainless steel rod. The rotation speed is 20 rpm, and the rotation direction is along the circumferential direction of the stainless steel rod. After taking it out, place it in an environment at 35 °C and continue to rotate for 10 minutes at the above rotation speed and rotation direction to complete one rotation - dipping treatment, and control the surface of the film to remain wet. Repeat the rotation - dipping treatment 5 times to obtain the vascular stent coating. Immerse the vascular stent coating in sterile deionized water at 37 °C for 1 day to remove the unreacted cross - linker and silk fibroin molecules, and obtain the modified polyester vascular stent coating with composite silk fibroin.

[0046] After testing, the above - mentioned modified polyester vascular stent coating with composite silk fibroin has an ultra - thin and uniform thickness and excellent mechanical properties. The coating thickness is measured to be 80 ± 5 μm according to the national standard testing method, the axial tensile strength is 18.8 MPa, the elongation at break is 100%, the circumferential tensile strength is 10.2 MPa, the elongation at break is 40%, the compliance is 5.3% / 100 mmHg, and the overall water leakage is 27.8 mL / min.cm under a water pressure of 120 mmHg 2 。

[0047] The composite silk protein modified polyester vascular stent coating of the present invention has a hemolysis rate of <0.1% according to the hemolysis rate test method, which fully meets the standard of non-hemolytic materials (0-2%). It has no sensitization through animal experiments and a cytotoxicity of ≤1 according to national standards.

[0048] Embodiment 3:

[0049] (1) The silkworm silk was placed in a sodium carbonate aqueous solution with a mass concentration of 0.1% at a bath ratio of 1:50 g / mL, treated at a temperature of 98-100°C for three times, each time for 30 minutes, and then fully washed with deionized water and placed in a 60°C oven for 12 hours to obtain degummed silk fibers. The degummed silk fibers were weighed and completely dissolved in a 9.3M lithium bromide solution at a bath ratio of 1:10 g / mL in a 65±5°C water bath environment to obtain a silk fibroin solution. The silk fibroin solution was poured into a dialysis bag (molecular weight cutoff of 14 kDa), and dialyzed with deionized water for 3 days to obtain a purified silk fibroin protein aqueous solution; the purified silk fibroin protein aqueous solution was concentrated, adjusted and the concentration was measured to make the concentration of the purified silk fibroin protein aqueous solution 60 mg / mL.

[0050] The silk fibroin aqueous solution is mixed with a hydrophilic flexible cross-linking agent to obtain a modified silk fibroin solution, the mass ratio of silk fibroin to the cross-linking agent is 1.0:0.5, the cross-linking agent is polyethylene glycol diglycidyl ether, and the silk fibroin concentration in the modified silk fibroin solution is 60 mg / mL.

[0051] (2) placing 40D / 36f polyester multifilament in a sodium carbonate solution with a mass concentration of 1% at a bath ratio of 1:50 g / mL, treating it three times at a temperature of 98-100° C. for 2 hours each time, and then washing it thoroughly with deionized water to obtain pretreated polyester yarn; placing the pretreated polyester yarn in a 20 g / L sodium hydroxide aqueous solution at a bath ratio of 1:50 g / mL for surface activation treatment, the surface activation treatment temperature is 35±5° C., the treatment time is 1 hour, and after treatment, washing it with deionized water to obtain alkali-treated polyester yarn.

[0052] (3) A stainless steel rod (10 mm in diameter) was placed in a modified silk fibroin solution in a rotation-immersion manner for 60 seconds, with the immersion area accounting for 50% of the side area of the stainless steel rod. The rotation speed was 20 rpm, and the rotation direction was along the circumference of the stainless steel rod. After being taken out, it was placed at 35°C and the above rotation speed and rotation direction were maintained for 10 minutes to form the inner layer of the vascular stent coating.

[0053] The polyester yarn treated with alkali in step (2) is woven at 60° on the outer surface of the inner layer of the stent coating by using a weaving technique.

[0054] A seamless polyester tubular braid with a braiding angle and an axial braiding density of 8 strands / cm.

[0055] (4) The obtained seamless polyester tubular braid was again placed in the modified silk fibroin solution for 60 seconds in the rotation-impregnation manner as in step (3) above. The impregnated area accounted for 50% of the lateral area of the stainless steel rod. The rotation speed was 20 rpm, and the rotation direction was along the circumferential direction of the stainless steel rod. After taking it out, it was placed in an environment at 35°C and continued to rotate for 10 minutes while maintaining the above rotation speed and rotation direction to complete one rotation-impregnation treatment, controlling the surface of the membrane to remain wet; repeating the rotation-impregnation treatment 5 times in this way to obtain a vascular stent film coating. The vascular stent film coating was soaked in sterile deionized water at 37°C for 1 day to remove unreacted cross-linking agents and silk fibroin molecules, and a modified polyester vascular stent film coating with composite silk fibroin was obtained.

[0056] After testing, the above-mentioned modified polyester vascular stent film coating with composite silk fibroin has an ultra-thin and uniform thickness and excellent mechanical properties. The film coating thickness was measured to be 50 ± 5 μm according to the national standard testing method, the axial tensile strength was 10.5 MPa, the elongation at break was 130%, the circumferential tensile strength was 6.2 MPa, the elongation at break was 54%, the compliance was 6.2% / 100 mmHg, and the overall water leakage was 15.5 mL / min.cm under a water pressure of 120 mmHg. 2 。

[0057] The hemolysis rate of the modified polyester vascular stent film coating with composite silk fibroin of the present invention was measured to be <0.1% according to the hemolysis rate test method, fully meeting the standard of non-hemolytic materials (0 - 2%). It has no sensitization through animal experiments, and the cytotoxicity is ≤1 according to the national standard testing.

[0058] Example 4:

[0059] (1) The domestic silk was placed in an aqueous sodium carbonate solution with a mass concentration of 0.1% at a bath ratio of 1:50 g / mL and treated three times at a temperature of 98 - 100°C for 30 minutes each time. Then it was thoroughly washed with deionized water and dried in an oven at 60°C for 12 hours to obtain degummed silk fibroin fibers. Weigh the degummed silk fibroin fibers and completely dissolve them in a 9.3 M lithium bromide solution at a bath ratio of 1:10 g / mL in a water bath environment at 65 ± 5°C to obtain a silk fibroin solution. The silk fibroin solution was poured into a dialysis bag (with a cut-off molecular weight of 14 kDa) and dialyzed with deionized water for 3 days to obtain a purified aqueous silk fibroin solution; the purified aqueous silk fibroin solution was concentrated, adjusted, and its concentration was measured to make the concentration of the purified aqueous silk fibroin solution 60 mg / mL.

[0060] Mix the aqueous solution of silk fibroin with a hydrophilic and flexible cross-linking agent to obtain a modified silk fibroin solution. The mass ratio of silk fibroin to the cross-linking agent is 1.0:0.5. The cross-linking agent is polyethylene glycol diglycidyl ether, and the concentration of silk fibroin in the modified silk fibroin solution is 60 mg / mL.

[0061] (2) Place 40D / 36f polyester multifilament in a sodium carbonate solution with a mass concentration of 1% at a bath ratio of 1:50 g / mL, and treat it three times at a temperature of 98 - 100 °C for 2 hours each time. Then wash it thoroughly with deionized water to obtain pretreated polyester filaments. Place the pretreated polyester filaments in a 20 g / L aqueous sodium hydroxide solution for surface activation treatment at a bath ratio of 1:50 g / mL. The surface activation treatment temperature is 35 ± 5 °C, and the treatment time is 1 hour. After treatment, wash it with deionized water to obtain alkali-treated polyester filaments.

[0062] (3) Place a stainless steel rod (with a diameter of 10 mm) in the modified silk fibroin solution in a rotation-impregnation manner for rotation-impregnation treatment for 60 seconds. The impregnated area accounts for 50% of the lateral area of the stainless steel rod. The rotation speed is 20 rpm, and the rotation direction is along the circumferential direction of the stainless steel rod. After taking it out, place it in an environment at 35 °C and continue to rotate for 10 minutes at the above rotation speed and rotation direction to form the inner layer of the vascular stent film.

[0063] Weave the alkali-treated polyester filaments obtained in step (2) on the outer surface of the inner layer of the vascular stent film using a weaving technique to form a seamless polyester tubular fabric with a weaving angle of 120° and an axial weaving density of 8 roots / cm.

[0064] (4) Place the obtained seamless polyester tubular fabric in the modified silk fibroin solution again in the rotation-impregnation manner as in step (3) for 60 seconds. The impregnated area accounts for 50% of the lateral area of the stainless steel rod. The rotation speed is 20 rpm, and the rotation direction is along the circumferential direction of the stainless steel rod. After taking it out, place it in an environment at 35 °C and continue to rotate for 10 minutes at the above rotation speed and rotation direction to complete one rotation-impregnation treatment, and control the surface of the film to remain wet. Repeat the rotation-impregnation treatment 5 times to obtain a vascular stent film. Immerse the vascular stent film in sterile deionized water at 37 °C for 1 day to remove the unreacted cross-linking agent and silk fibroin molecules, and obtain a modified polyester vascular stent film with composite silk fibroin.

[0065] After testing, the above-mentioned modified polyester vascular stent film with composite silk fibroin has an ultra-thin and uniform thickness and excellent mechanical properties. The film thickness is measured to be 50 ± 5 μm according to the national standard testing method, the axial tensile strength is 14.5 MPa, the elongation at break is 150%, the circumferential tensile strength is 7.7 MPa, the elongation at break is 78%, the compliance is 7.1% / 100 mmHg, and the overall water leakage is 5.7 mL / min.cm under a water pressure of 120 mmHg.2 .

[0066] The composite silk protein modified polyester vascular stent coating of the present invention has a hemolysis rate of <0.1% according to the hemolysis rate test method, which fully meets the standard of non-hemolytic materials (0-2%). It has no sensitization through animal experiments and a cytotoxicity of ≤1 according to national standards.

[0067] Embodiment 5:

[0068] (1) The silkworm silk was placed in a sodium carbonate aqueous solution with a mass concentration of 0.1% at a bath ratio of 1:50 g / mL, treated at a temperature of 98-100°C for three times, each time for 30 minutes, and then fully washed with deionized water and placed in a 60°C oven for 12 hours to obtain degummed silk fibers. The degummed silk fibers were weighed and completely dissolved in a 9.3M lithium bromide solution at a bath ratio of 1:10 g / mL in a 65±5°C water bath environment to obtain a silk fibroin solution. The silk fibroin solution was poured into a dialysis bag (molecular weight cutoff of 14 kDa), and dialyzed with deionized water for 3 days to obtain a purified silk fibroin protein aqueous solution; the purified silk fibroin protein aqueous solution was concentrated, adjusted and the concentration was measured to make the concentration of the purified silk fibroin protein aqueous solution 60 mg / mL.

[0069] The silk fibroin aqueous solution is mixed with a hydrophilic flexible cross-linking agent to obtain a modified silk fibroin solution, the mass ratio of silk fibroin to the cross-linking agent is 1.0:0.5, the cross-linking agent is polyethylene glycol diglycidyl ether, and the silk fibroin concentration in the modified silk fibroin solution is 60 mg / mL.

[0070] (2) placing 40D / 36f polyester multifilament in a sodium carbonate solution with a mass concentration of 1% at a bath ratio of 1:50 g / mL, treating it three times at a temperature of 98-100° C. for 2 hours each time, and then washing it thoroughly with deionized water to obtain pretreated polyester yarn; placing the pretreated polyester yarn in a 20 g / L sodium hydroxide aqueous solution at a bath ratio of 1:50 g / mL for surface activation treatment, the surface activation treatment temperature is 35±5° C., the treatment time is 1 hour, and after treatment, washing it with deionized water to obtain alkali-treated polyester yarn.

[0071] (3) A stainless steel rod (10 mm in diameter) was placed in a modified silk fibroin solution in a rotation-immersion manner for 60 seconds, with the immersion area accounting for 50% of the side area of the stainless steel rod. The rotation speed was 20 rpm, and the rotation direction was along the circumference of the stainless steel rod. After being taken out, it was placed at 35°C and the above rotation speed and direction were maintained for 10 minutes to form the inner layer of the stent coating.

[0072] The polyester yarn treated with alkali in step (2) is woven at 120° on the outer surface of the inner layer of the stent coating by using a weaving technique.

[0073] Seamless polyester tubular braid with braiding angle and axial braiding density of 4 strands / cm.

[0074] (4) The obtained seamless polyester tubular braid is placed in the modified silk protein solution again in the manner of rotation-immersion in the above step (3) for 60 seconds, the immersed area accounts for 50% of the side area of the stainless steel rod, the rotation speed is 20 rpm, and the rotation direction is along the circumference of the stainless steel rod. After taking it out, it is placed in a 35°C environment and maintained at the above rotation speed and rotation direction for 10 minutes to complete a rotation-immersion treatment, and the surface of the membrane is controlled to remain wet; the rotation-immersion treatment is repeated 5 times to obtain a vascular stent coating, and the vascular stent coating is immersed in 37°C sterile deionized water for 1 day to remove unreacted cross-linking agent and silk molecules to obtain a modified polyester vascular stent coating of composite silk fibroin.

[0075] After testing, the modified polyester vascular stent coating of the composite silk protein has an ultra-thin uniform thickness and excellent mechanical properties. According to the national standard testing method, the coating thickness is 50±5μm, the axial tensile strength is 12.4MPa, the elongation at break is 135%, the circumferential tensile strength is 5.3MPa, the elongation at break is 50%, the compliance is 9.0% / 100mmHg, and the overall water permeability is 9.6mL / min.cm under a water pressure of 120mmHg. 2 .

[0076] The composite silk protein modified polyester vascular stent coating of the present invention has a hemolysis rate of <0.1% according to the hemolysis rate test method, which fully meets the standard of non-hemolytic materials (0-2%). It has no sensitization through animal experiments and a cytotoxicity of ≤1 according to national standards.

[0077] Embodiment 6:

[0078] (1) The silkworm silk was placed in a sodium carbonate aqueous solution with a mass concentration of 0.1% at a bath ratio of 1:50 g / mL, treated at a temperature of 98-100°C for three times, each time for 30 minutes, and then fully washed with deionized water and placed in a 60°C oven for 12 hours to obtain degummed silk fibers. The degummed silk fibers were weighed and completely dissolved in a 9.3M lithium bromide solution at a bath ratio of 1:10 g / mL in a 65±5°C water bath environment to obtain a silk fibroin solution. The silk fibroin solution was poured into a dialysis bag (molecular weight cutoff of 14 kDa), and dialyzed with deionized water for 3 days to obtain a purified silk fibroin protein aqueous solution; the purified silk fibroin protein aqueous solution was concentrated, adjusted and the concentration was measured to make the concentration of the purified silk fibroin protein aqueous solution 60 mg / mL.

[0079] Mix the aqueous solution of silk fibroin with a hydrophilic and flexible crosslinking agent to obtain a modified silk fibroin solution. The mass ratio of silk fibroin to the crosslinking agent is 1.0:0.5. The crosslinking agent is polyethylene glycol diglycidyl ether, and the concentration of silk fibroin in the modified silk fibroin solution is 60 mg / mL.

[0080] (2) Place the 40D / 36f polyester multifilament in a sodium carbonate solution with a mass concentration of 1% at a bath ratio of 1:50 g / mL, and treat it three times at a temperature of 98 - 100 °C for 2 hours each time. Then wash it thoroughly with deionized water to obtain pretreated polyester filaments. Place the pretreated polyester filaments in a 20 g / L sodium hydroxide aqueous solution for surface activation treatment at a temperature of 35 ± 5 °C for 1 hour. After treatment, wash it with deionized water to obtain alkali-treated polyester filaments.

[0081] (3) Place a stainless steel rod (with a diameter of 10 mm) in the modified silk fibroin solution in a rotation-impregnation manner for rotation-impregnation treatment for 60 seconds. The impregnated area accounts for 50% of the lateral area of the stainless steel rod. The rotation speed is 20 rpm, and the rotation direction is along the circumferential direction of the stainless steel rod. After taking it out, place it in an environment at 35 °C and continue to rotate at the above rotation speed and rotation direction for 10 minutes to complete one rotation-impregnation treatment, and control the surface of the film to remain wet. Repeat the rotation-impregnation treatment once to form the inner layer of the vascular stent coating.

[0082] Weave the alkali-treated polyester filaments obtained in step (2) on the outer surface of the inner layer of the vascular stent coating into a polyester tubular fabric with a braiding angle of 120° and an axial braiding density of 4 roots / cm to form the middle layer of the vascular stent coating.

[0083] (4) Place the obtained seamless polyester tubular fabric in the modified silk fibroin solution again in the rotation-impregnation manner as in step (3) for 60 seconds. The impregnated area accounts for 50% of the lateral area of the stainless steel rod. The rotation speed is 20 rpm, and the rotation direction is along the circumferential direction of the stainless steel rod. After taking it out, place it in an environment at 35 °C and continue to rotate at the above rotation speed and rotation direction for 10 minutes to complete one rotation-impregnation treatment, and control the surface of the film to remain wet. Repeat the rotation-impregnation treatment 4 times to obtain the vascular stent coating. Immerse the vascular stent coating in sterile deionized water at 37 °C for 1 day to remove the unreacted crosslinking agent and silk fibroin molecules, and obtain a modified polyester vascular stent coating with composite silk fibroin.

[0084] After testing, the modified polyester vascular stent membrane with composite silk fibroin has an ultra-thin and uniform thickness and excellent mechanical properties. The membrane thickness is measured to be 60 ± 5 μm according to the national standard testing method, the axial tensile strength is 14.5 MPa, the elongation at break is 150%, the circumferential tensile strength is 6.7 MPa, the elongation at break is 75%, the compliance is 9.3% / 100 mmHg, and the overall water leakage is 1.4 mL / min.cm under a water pressure of 120 mmHg. 2 .

[0085] The modified polyester vascular stent membrane with composite silk fibroin of the present invention is measured to have a hemolysis rate < 0.1% according to the hemolysis rate test method, fully meeting the standard of non-hemolytic materials (0 - 2%). It has no sensitization through animal experiments and the cytotoxicity is ≤ 1 according to the national standard testing.

[0086] Example 7:

[0087] (1) Place the domestic silk in a sodium carbonate aqueous solution with a mass concentration of 0.1% at a bath ratio of 1:50 g / mL, and treat it three times at a temperature of 98 - 100 °C for 30 minutes each time. Then wash it thoroughly with deionized water and dry it in an oven at 60 °C for 12 hours to obtain degummed silk fibroin fibers. Weigh the degummed silk fibroin fibers and dissolve them completely in a 9.3 M lithium bromide solution at a bath ratio of 1:10 g / mL in a water bath environment of 65 ± 5 °C to obtain a silk fibroin solution. Infuse the silk fibroin solution into a dialysis bag (with a cut-off molecular weight of 14 kDa) and dialyze it with deionized water for 3 days to obtain a purified silk fibroin aqueous solution; concentrate, adjust and measure the concentration of the purified silk fibroin aqueous solution to make the concentration of the purified silk fibroin aqueous solution 60 mg / mL.

[0088] Mix the silk fibroin aqueous solution with a hydrophilic and flexible cross-linking agent to obtain a modified silk fibroin solution. The mass ratio of silk fibroin to the cross-linking agent is 1.0:0.5. The cross-linking agent is polyethylene glycol diglycidyl ether, and the concentration of silk fibroin in the modified silk fibroin solution is 60 mg / mL.

[0089] (2) Place the 40D / 36f polyester multifilament in a sodium carbonate solution with a mass concentration of 1% at a bath ratio of 1:50 g / mL, and treat it three times at a temperature of 98 - 100 °C for 2 hours each time. Then wash it thoroughly with deionized water to obtain pretreated polyester filaments; place the pretreated polyester filaments in a 20 g / L sodium hydroxide aqueous solution at a bath ratio of 1:50 g / mL for surface activation treatment. The surface activation treatment temperature is 35 ± 5 °C, and the treatment time is 1 hour. After treatment, wash it with deionized water to obtain alkali-treated polyester filaments.

[0090] (3) Place a stainless steel rod (with a diameter of 10 mm) in the modified silk fibroin solution in a rotation-impregnation manner for 60 seconds of rotation-impregnation treatment. The impregnated area accounts for 30% of the lateral area of the stainless steel rod. The rotation speed is 20 rpm, and the rotation direction is along the circumferential direction of the stainless steel rod. After taking it out, place it in an environment of 35 °C and continue to rotate for 10 minutes while maintaining the above rotation speed and rotation direction to complete one rotation-impregnation treatment, and control the film surface to remain wet; repeat the rotation-impregnation treatment 2 times in this way to form the inner layer of the vascular stent coating film.

[0091] Weave the polyester filaments after alkali treatment in step (2) on the outer surface of the inner layer of the vascular stent coating film by weaving technology into a polyester tubular fabric with a weaving angle of 120° and an axial weaving density of 4 filaments / cm to form the middle layer of the vascular stent coating film.

[0092] (4) Place the obtained seamless polyester tubular woven fabric in the modified silk fibroin solution again in the rotation-impregnation manner in step (3) for 60 seconds. The impregnated area accounts for 30% of the lateral area of the stainless steel rod. The rotation speed is 20 rpm, and the rotation direction is along the circumferential direction of the stainless steel rod; after taking it out, place it in an environment of 35 °C and continue to rotate for 10 minutes while maintaining the above rotation speed and rotation direction to complete one rotation-impregnation treatment, and control the film surface to remain wet; repeat the rotation-impregnation treatment 4 times in this way to obtain the vascular stent coating film. Immerse the vascular stent coating film in sterile deionized water at 37 °C for 1 day to remove unreacted cross-linking agents and silk fibroin molecules, and obtain a modified polyester vascular stent coating film with composite silk fibroin.

[0093] After testing, the above-mentioned modified polyester vascular stent coating film with composite silk fibroin has an ultra-thin and uniform thickness and excellent mechanical properties. The thickness of the coating film is measured to be 45 ± 5 μm according to the national standard testing method, the axial tensile strength is 14.3 MPa, the elongation at break is 147%, the circumferential tensile strength is 6.3 MPa, the elongation at break is 72%, the compliance is 9.5% / 100 mmHg, and the overall water leakage is 1.8 mL / min.cm under a water pressure of 120 mmHg. 2 。

[0094] The hemolysis rate of the modified polyester vascular stent coating film with composite silk fibroin of the present invention is measured to be <0.1% according to the hemolysis rate test method, which fully meets the standard of non-hemolytic materials (0 - 2%); there is no sensitization through animal experiments, and the cytotoxicity is ≤1 according to the national standard testing.

[0095] Example 8:

[0096] (1) Place the domestic silk in an aqueous sodium carbonate solution with a mass concentration of 0.1% at a bath ratio of 1:50 g / mL, and treat it three times at a temperature of 98 - 100 °C for 30 minutes each time. Then, wash it thoroughly with deionized water and dry it in an oven at 60 °C for 12 hours to obtain degummed silk fibroin fibers. Weigh the degummed silk fibroin fibers and dissolve them completely in a 9.3 M lithium bromide solution at a bath ratio of 1:10 g / mL in a water bath environment at 65 ± 5 °C to obtain a silk fibroin solution. Pour the silk fibroin solution into a dialysis bag (with a molecular weight cut-off of 14 kDa) and dialyze it with deionized water for 3 days to obtain a purified aqueous silk fibroin solution; concentrate, adjust, and measure the concentration of the purified aqueous silk fibroin solution to make the concentration of the purified aqueous silk fibroin solution 100 mg / mL.

[0097] Mix the aqueous silk fibroin solution with a hydrophilic and flexible cross-linking agent to obtain a modified silk fibroin solution. The mass ratio of silk fibroin to the cross-linking agent is 1.0:0.5. The cross-linking agent is polyethylene glycol diglycidyl ether, and the concentration of silk fibroin in the modified silk fibroin solution is 100 mg / mL.

[0098] (2) Place the 40D / 36f polyester multifilament in a sodium carbonate solution with a mass concentration of 1% at a bath ratio of 1:50 g / mL, and treat it three times at a temperature of 98 - 100 °C for 2 hours each time. Then, wash it thoroughly with deionized water to obtain pretreated polyester filaments; place the pretreated polyester filaments in a 20 g / L aqueous sodium hydroxide solution at a bath ratio of 1:50 g / mL for surface activation treatment. The surface activation treatment temperature is 35 ± 5 °C, and the treatment time is 1 hour. After treatment, wash it with deionized water to obtain alkali-treated polyester filaments.

[0099] (3) Place the stainless steel rod (with a diameter of 10 mm) in the modified silk fibroin solution in a rotation-impregnation manner for rotation-impregnation treatment for 60 seconds. The impregnated area accounts for 50% of the lateral area of the stainless steel rod. The rotation speed is 20 rpm, and the rotation direction is along the circumferential direction of the stainless steel rod. After taking it out, place it in an environment at 35 °C and continue to rotate at the above rotation speed and rotation direction for 10 minutes to complete one rotation-impregnation treatment, and control the surface of the film to remain wet; repeat the rotation-impregnation treatment 1 time in this way to form the inner layer of the vascular stent coating.

[0100] Weave the alkali-treated polyester filaments obtained in step (2) on the outer surface of the inner layer of the vascular stent coating into a polyester tubular fabric with a braiding angle of 120° and an axial braiding density of 4 roots / cm by using a braiding technique to form the middle layer of the vascular stent coating.

[0101] (4) The obtained seamless polyester tubular fabric is again placed in the modified silk fibroin solution for 60 seconds in the rotation-impregnation manner in step (3) above. The impregnated area accounts for 50% of the lateral area of the stainless steel rod. The rotation speed is 20 rpm, and the rotation direction is along the circumferential direction of the stainless steel rod. After taking it out, it is placed in an environment of 35 °C and continues to rotate for 10 minutes while maintaining the above rotation speed and rotation direction to complete one rotation-impregnation treatment, and the surface of the membrane is controlled to remain wet. Repeat the rotation-impregnation treatment 4 times in this way to obtain a vascular stent film. The vascular stent film is soaked in sterile deionized water at 37 °C for 1 day to remove the unreacted cross-linking agent and silk fibroin molecules, and a modified polyester vascular stent film with composite silk fibroin is obtained.

[0102] After testing, the modified polyester vascular stent film with the above composite silk fibroin has an ultra-thin and uniform thickness and excellent mechanical properties. The film thickness is measured to be 100 ± 5 μm according to the national standard testing method, the axial tensile strength is 15.2 MPa, the elongation at break is 155%, the circumferential tensile strength is 7.1 MPa, the elongation at break is 85%, the compliance is 5.4% / 100 mmHg, and the overall water leakage is 0.4 mL / min.cm under a water pressure of 120 mmHg. 2 。

[0103] The hemolysis rate of the modified polyester vascular stent film with the composite silk fibroin of the present invention is measured to be <0.1% according to the hemolysis rate test method, which fully meets the standard of non-hemolytic materials (0-2%). It has no sensitization through animal experiments, and the cytotoxicity is ≤1 according to the national standard testing.

[0104] Example 9 (control example):

[0105] (1) The domestic silk is placed in an aqueous sodium carbonate solution with a mass concentration of 0.1% at a bath ratio of 1:50 g / mL and treated three times at a temperature of 98-100 °C for 30 minutes each time. Then it is thoroughly washed with deionized water and dried in an oven at 60 °C for 12 hours to obtain degummed silk fibroin fibers. Weigh the degummed silk fibroin fibers and completely dissolve them in a 9.3 M lithium bromide solution at a bath ratio of 1:10 g / mL in a water bath environment of 65 ± 5 °C to obtain a silk fibroin solution. The silk fibroin solution is poured into a dialysis bag (with a cut-off molecular weight of 14 kDa) and dialyzed with deionized water for 3 days to obtain a purified aqueous silk fibroin solution. The purified aqueous silk fibroin solution is concentrated, adjusted and its concentration is measured to make the concentration of the purified aqueous silk fibroin solution 60 mg / mL.

[0106] The aqueous silk fibroin solution is mixed with a hydrophilic and flexible cross-linking agent to obtain a modified silk fibroin solution. The mass ratio of silk fibroin to the cross-linking agent is 1.0:0.5. The cross-linking agent is polyethylene glycol diglycidyl ether, and the concentration of silk fibroin in the modified silk fibroin solution is 60 mg / mL.

[0107] (2) Place 40D / 36f polyester multifilament in a sodium carbonate solution with a mass concentration of 1% at a bath ratio of 1:50 g / mL, and treat it three times at a temperature of 98 - 100 °C for 2 hours each time. Then wash it thoroughly with deionized water to obtain pretreated polyester filaments. Place the pretreated polyester filaments in a 20 g / L sodium hydroxide aqueous solution for surface activation treatment at a bath ratio of 1:50 g / mL. The surface activation treatment temperature is 35 ± 5 °C, and the treatment time is 1 hour. After treatment, wash it with deionized water to obtain alkali-treated polyester filaments.

[0108] (3) Place a stainless steel rod (with a diameter of 10 mm) in the modified silk fibroin solution in a rotation-impregnation manner for rotation-impregnation treatment for 60 seconds. The impregnated area accounts for 100% of the lateral area of the stainless steel rod. The rotation speed is 20 rpm, and the rotation direction is along the circumferential direction of the stainless steel rod. After taking it out, place it in an environment of 35 °C and continue to rotate for 10 minutes at the above rotation speed and rotation direction to complete one rotation-impregnation treatment, and control the surface of the film to remain wet. Repeat the rotation-impregnation treatment 1 time in this way to form the inner layer of the vascular stent coating.

[0109] Weave the alkali-treated polyester filaments in step (2) into a polyester tubular fabric with a weaving angle of 120° and an axial weaving density of 4 roots / cm on the outer surface of the inner layer of the vascular stent coating to form the middle layer of the vascular stent coating.

[0110] (4) Place the obtained seamless polyester tubular fabric in the modified silk fibroin solution in a static impregnation manner for 60 seconds. The impregnated area accounts for 100% of the lateral area of the stainless steel rod. After taking it out, place it in an environment of 35 °C for static drying or rotation drying for 10 minutes to complete one treatment. The rotation speed of rotation drying is 60 rpm, and the rotation direction is along the circumferential direction of the stainless steel rod. Control the surface of the film to remain wet. Repeat the impregnation-drying operation step 4 times in this way to obtain the vascular stent coating. Immerse the vascular stent coating in sterile deionized water at 37 °C for 1 day to remove unreacted cross-linking agents and silk fibroin molecules, and obtain a modified polyester vascular stent coating with composite silk fibroin.

[0111] According to the national standard detection method, the thickness of the modified polyester vascular stent coating with composite silk fibroin is 70 ± 50 μm (static drying) or 60 ± 15 μm (rotation drying). In the case of static drying, the solution flows downward under the action of gravity on the surface of the cylinder, and there is a serious uneven phenomenon after drying, so the thickness difference is significant.

[0112] Axial tensile strength is 6.1 MPa (static drying) or 10.0 Mpa (rotary drying), elongation at break is 60% (static drying) or 100% (rotary drying), circumferential tensile strength is 3.2 MPa (static drying) or 4.9 Mpa (rotary drying), elongation at break is 32% (static drying) or 60% (rotary drying), compliance is 2.7% / 100 mmHg (static drying) or 7.5% / 100 mmHg (rotary drying), overall water leakage is 620.0 mL / min.cm 2 (static drying) or 20.0 mL / min.cm 2 (rotary drying).

[0113] Note: The above embodiments are only used to illustrate the present invention and do not limit the technical solutions described in the present invention; therefore, although the present specification has described the present invention in detail with reference to the above respective embodiments, those of ordinary skill in the art should understand that the present invention can still be modified or equivalently replaced; and all technical solutions and their improvements that do not depart from the spirit and scope of the present invention shall be covered within the scope of the claims of the present invention.

Claims

1. A preparation method of a modified polyester vascular stent film coated with composite silk fibroin, characterized in that, It includes the following steps: (1) Degum the mulberry silk with any one of boiling water, sodium carbonate, sodium bicarbonate or bio-enzyme to obtain mulberry silk fibroin fiber, then completely dissolve it in a lithium bromide solution to obtain a silk fibroin solution. Infuse the silk fibroin solution into a dialysis bag, dialyze it with deionized water, and then filter it to obtain a purified aqueous silk fibroin solution. Evaporate and concentrate to adjust the concentration of the aqueous silk fibroin solution to 10 - 200 mg / mL; Mix the aqueous silk fibroin solution with a hydrophilic and flexible cross-linking agent to obtain a modified silk fibroin solution, and the concentration of silk fibroin in the modified silk fibroin solution is 10 - 160 mg / mL; (2) Immerse the polyester filament in a sodium carbonate solution for a period of time, then wash it with deionized water to complete the degreasing and desizing treatment. Repeat the degreasing and desizing treatment several times to finally obtain a pretreated polyester filament; Place the pretreated polyester filament in a sodium hydroxide solution for surface activation treatment. After the surface activation treatment, wash it with deionized water to obtain an alkali-treated polyester filament; (3) Place a cylindrical auxiliary rod in the modified silk fibroin solution obtained in step (1) for rotary-impregnation treatment. After taking it out, place it in an environment of 20 - 50 °C and continue to rotate at the rotation speed in the solution for 10 - 30 minutes to complete one rotary-impregnation treatment, and control the surface of the film to remain wet. Among them, the rotation speed of the cylindrical auxiliary rod in the solution is 20 - 80 rpm, the rotation direction is along the circumferential direction of the auxiliary rod, the impregnation time is 10 - 60 seconds, and the impregnation area accounts for 10 - 90% of the side area of the stainless steel rod. Repeat the rotary-impregnation treatment several times to form the inner layer of the vascular stent film; Weave the alkali-treated polyester filament on the outer surface of the inner layer of the vascular stent film by weaving technology to obtain a seamless polyester tubular woven fabric; (4) Place the seamless polyester tubular woven fabric obtained in step (3) in the modified silk fibroin solution obtained in step (1) for rotary-impregnation treatment. After taking it out, place it in an environment of 20 - 50 °C and continue to rotate at the same rotation speed as in the solution for 10 - 30 minutes to complete one rotary-impregnation treatment, and control the surface of the film to remain wet. Among them, the time for rotary-impregnation treatment in the modified silk fibroin solution is 10 - 60 seconds, the rotation speed is 20 - 80 rpm, the rotation direction is along the circumferential direction of the auxiliary rod, and the impregnation area accounts for 10 - 90% of the side area of the stainless steel rod; Repeat the rotary-impregnation treatment several times to obtain a vascular stent film, and then soak the vascular stent film in sterile deionized water to remove the unreacted cross-linking agent and silk fibroin molecules, and finally obtain a modified polyester vascular stent film with composite silk fibroin.

2. The preparation method of a modified polyester vascular stent membrane composed of composite silk fibroin according to claim 1, characterized in that, In step (1), the concentration of the lithium bromide solution is 9.3 M; the dialysis bag is a semi-permeable membrane with a cut-off molecular weight of 3 - 50 kDa, and it is dialyzed with deionized water for 3 days; the mass ratio of silk fibroin to cross-linking agent is 1.0:(0.3 - 1.0), and the cross-linking agent is polyethylene glycol diglycidyl ether.

3. The preparation method of a modified polyester vascular stent film coated with composite silk fibroin according to claim 1, characterized in that, In step (2), the polyester filament is any one of polyester monofilament and polyester multifilament, with a specification of 5 - 200 D.

4. The preparation method of a modified polyester vascular stent membrane compounded with silk fibroin according to claim 1, characterized in that, In step (2), the mass concentration of the sodium carbonate solution is 1%, the temperature for desizing treatment is 95 - 100 °C, and the treatment time is 2 hours; the number of times of the treatment is 2 - 5 times; the concentration of the sodium hydroxide solution is 20 - 50 g / L, the temperature for surface activation treatment is 30 - 80 °C, and the treatment time is 1 - 3 hours.

5. The preparation method of a modified polyester vascular stent film coated with composite silk fibroin according to claim 1, characterized in that, In step (3), the cylindrical auxiliary rod is selected as a stainless steel rod with a diameter of 1 - 30 mm, and the number of times of repeating the rotation - impregnation treatment is 0 - 5 times.

6. The preparation method of a modified polyester vascular stent film coated with composite silk fibroin according to claim 1, characterized in that, In step (3), the weaving conditions are a weaving angle of 30 - 150° and an axial weaving density of 1 - 20 strands / cm.

7. The preparation method of a modified polyester vascular stent film coated with composite silk fibroin according to claim 1, characterized in that In step (4), the number of times of repeating the rotation - impregnation treatment is 2 - 10 times.

8. The preparation method of a modified polyester vascular stent membrane composed of composite silk fibroin according to claim 1, characterized in that, In step (4), the temperature of the sterile deionized water is 4 - 37 °C, and the soaking time is 1 - 3 days.

9. A modified polyester vascular stent film coated with composite silk fibroin prepared by the method according to any one of claims 1 - 8.

10. The modified polyester vascular stent film coated with composite silk fibroin according to claim 9, characterized in that, The thickness of the film is 100±5μm or 80±5μm or 50±5μm or 60±5μm or 45±5μm, the axial tensile strength > 10.5MPa, the axial elongation at break > 80%, the circumferential tensile strength > 5.3MPa, the circumferential elongation at break > 30%, the compliance > 4.0% / 100mmHg, and the overall water leakage < 46.8mL / min.cm at a water pressure of 120mmHg 2 .