Multifunctional intravascular stent capable of releasing double physiotherapy gases and preparation method of multifunctional intravascular stent

Abstract

The invention discloses a multifunctional intravascular stent capable of releasing double physiotherapy gases and a preparation method, and relates to the technical field of implantable medical instruments. Objects acted by the inner wall and the outer wall of the intravascular stent and the physiological microenvironment of the intravascular stent have obvious spatial differences. On one hand, the copper compound containing the primary amine group is grafted on the inner wall of the intravascular stent body through the coating of the phenolic hydroxyl group and the quinonyl group, and the stable NO catalytic release function is achieved. On the other hand, a drug sustained-release coating capable of releasing CO in response to hydrogen peroxide is formed on the outer wall of the intravascular stent body, the functions of regulating and controlling abnormal proliferation of smooth muscles, regulating and controlling inflammation, removing reactive oxygen free radicals and the like can be achieved, a good microenvironment is provided for focus recovery, and regeneration and repair of diseased blood vessels are promoted; and a prodrug for releasing CO is loaded in the drug-loaded slow-release coating, so that the prodrug and NO are cooperated and complemented in function, and construction of an anticoagulant, anti-inflammatory, anti-proliferative or in-situ endothelialization promoting multifunctional material surface is jointly realized.

Description

Technical Field

[0001] The present invention relates to the technical field of implantable medical devices, and in particular to a multifunctional vascular stent capable of releasing dual therapeutic gases and a preparation method thereof. Background Art

[0002] Coronary heart disease is a major disease that seriously threatens human health, and vascular stent implantation has become its main treatment. With the advancement of technology, vascular stents have evolved from bare metal stents to drug-eluting stents (DES), which effectively inhibit smooth muscle cell proliferation and significantly reduce the incidence of restenosis and related cardiovascular events. However, while DES inhibits smooth muscle proliferation, it also delays endothelial cell healing, leading to adverse events such as delayed re-endothelialization, inflammation, and late thrombosis.

[0003] Currently, most DES are only coated with a single anti-proliferative drug. However, after the vascular stent is implanted in the diseased blood vessel, the microenvironment of its inner and outer surfaces is different. Specifically, the outer surface of the stent is in direct contact with the diseased vascular tissue, while the inner surface is in contact with the blood, which means that the inner and outer surfaces of the vascular stent should have different functions to cope with different pathological environments. Therefore, according to the "spatial differences" in the actual microenvironment of the inner and outer walls of the vascular stent and the biological specificity of the actual pathological response events, the functional modification of the inner and outer walls of the vascular stent should be "customized" to achieve the best therapeutic effect.

[0004] In view of this, the present invention is proposed. Summary of the invention

[0005] The purpose of the present invention is to provide a multifunctional vascular stent for releasing dual therapeutic gases and a preparation method thereof, so as to enable the inner wall and the outer wall of the vascular stent to release different therapeutic gases respectively, so as to achieve a better therapeutic effect.

[0006] Specifically, the present invention provides a multifunctional vascular stent that releases dual therapeutic gases, thereby improving stent endothelialization, inhibiting intimal hyperplasia, regulating inflammation within lesions, and scavenging reactive oxygen free radicals, thereby reducing the incidence of late thrombosis and restenosis within the stent, and achieving lesion repair and self-healing.

[0007] The present invention is achieved in that: In a first aspect, the present invention provides a multifunctional vascular stent for releasing dual therapeutic gases, comprising a vascular stent body, an inner wall of the vascular stent body having an NO-releasing coating, and an outer wall of the vascular stent body having a CO-releasing coating; The NO-releasing coating comprises a coating containing phenolic hydroxyl groups and quinone groups and a catalytic functional coating, wherein the catalytic functional coating is formed by in-situ grafting and re-crosslinking a copper complex containing a primary amine group onto the coating containing phenolic hydroxyl groups and quinone groups; The CO-releasing coating contains CO drug molecules that release CO gas in response to hydrogen peroxide.

[0008] In an optional embodiment, the compound used to form the coating containing phenolic hydroxyl groups and quinone groups is selected from at least one of melanin, dopamine, dihydroxyindole, adrenaline, norepinephrine, levodopa, tannic acid, dextrodopa, gallic acid, pyrogallol, epicatechin gallate, epigallocatechin and epigallocatechin gallate.

[0009] In an optional embodiment, the functional molecule having NO catalytic activity and containing a primary amine group has a ligand structure of a macrocyclic polyamine and has a nitrogen-containing heterocycle and a plurality of carboxyl groups; The ligand of the macrocyclic polyamine is at least one selected from 1,4,7-triazacyclononanecarboxylic acid or its derivatives, 1,4,7,10-tetraazacyclododecanecarboxylic acid or its derivatives and 1,4,8,11-tetraazacyclotetradecanecarboxylic acid or its derivatives.

[0010] In an optional embodiment, the CO drug molecule is selected from at least one of a metal carbonyl compound, an organic molecule type, and an enzyme catalytic activation type; Among them, metal carbonyl compounds include CORM-1, CORM-2, CORM-3, CORM-A1, CORM-F10, CORM-F11, CORM-F12, CORM-RM20, CORM-E2, CORM-RM20, Mn(CO)5Br and CORM-401; The organic molecular types include CORM-S1, CORM-S2, CORM-AM, CORM-polymer 1, and CORM-polymer 2; Enzyme catalytic activation types include Fe(CO)4I2, Fe(CO)3I2(PPh3), Fe(CO)3I2(Py), CpFe(CO)2Cl, CpFe(CO)2I, CpFe(CO)2Br, Fe2(μ-S)2(CO), Fe2(μ-SCH2CH3)(CO)6, Fe2(μ-S)2(CO)6 and Fe2(μ-SCH2CHOHCH2OH)2(CO)6.

[0011] In an optional embodiment, the CO-releasing coating further comprises a carrier for loading CO drug molecules, and the carrier is a degradable polymer; The degradable polymer is selected from at least one of polytrimethylene carbonate, polylactic acid, polycaprolactone, polyglycolic acid, polylactic acid-co-glycolic acid, glycolide-lactide copolymer, glycolide-caprolactone copolymer, lactide-caprolactone copolymer, polylactic acid-polyethylene glycol copolymer, polyhydroxybutyrate, polyhydroxyvalerate, polyamino acids and polyanhydrides; The molecular weight of the degradable polymer is 50,000-1 million Daltons.

[0012] In an optional embodiment, the thickness of the CO-releasing coating is 0.1 nm-10000 nm; and / or, the coating layer containing phenolic hydroxyl groups and quinone groups has a thickness of 5 nm to 25 nm, and the thickness of the catalytic functional coating layer has a thickness of 5 nm to 180 nm; And / or, the material of the vascular stent body is at least one of stainless steel, cobalt and its alloys, titanium and its alloys, platinum and its alloys, magnesium and its alloys, iron and its alloys, and zinc and its alloys.

[0013] In a second aspect, the present invention provides a method for preparing any one of the aforementioned multifunctional vascular stents, comprising: forming an NO-releasing coating on the inner wall of the vascular stent body, and forming a CO-releasing coating on the outer wall of the vascular stent body.

[0014] In an optional embodiment, the process of forming the NO-releasing coating comprises: immersing the vascular stent body in a solution containing phenolic hydroxyl groups and quinone groups to assemble and form a coating containing phenolic hydroxyl groups and quinone groups, and then in-situ grafting and cross-linking a copper complex containing a primary amine group; The preparation process of the copper complex containing primary amine groups includes: adding soluble copper salt to a ligand solution having macrocyclic polyamine to form a copper-containing complex, and then adding a primary amine compound for reaction dialysis, the reaction temperature is 1°C-60°C, and the reaction time is 0.5h-200h.

[0015] In an optional embodiment, the primary amine compound is selected from at least one of polyallylamine, polyethyleneamine, polylysine, polyethylene glycol diamine, polyetheramine, polyamide, melamine, poly-N-isopropylacrylamide, chitosan and derivatives thereof; and / or, the soluble copper salt is selected from at least one of copper sulfate, cupric chloride, cuprous chloride, cupric acetate, cupric acetate, copper fluoride, cupric bromide, cuprous bromide, cupric iodide, cuprous iodide, copper citrate, copper tartrate, copper propionate, copper nitrate and ammonia copper ion; and / or, the molar ratio of the copper-containing complex to the primary amine compound is (0.01-100):1; and / or, the molar ratio of primary amine group to phenolic hydroxyl group is (0.03-30):1; And / or, the molar ratio of the ligand to the copper salt for forming the copper-containing complex is (0.01-100):1.

[0016] And / or, when the copper complex containing primary amine groups is grafted and cross-linked in situ, the reaction temperature is controlled to be 1° C.-60° C. and the reaction time is controlled to be 0.5 h-200 h.

[0017] In an optional embodiment, the process of forming the CO release coating includes: covering and protecting the inner wall of the vascular stent body by a clamp, spraying the CO drug sustained-release solution on the outer wall of the vascular stent body by ultrasonic atomization spraying, and then drying; The preparation process of the CO drug sustained-release solution includes: mixing a degradable polymer, CO drug molecules and an organic solvent; The mass fraction of CO drug molecules in the CO drug sustained-release solution is 5%-30%; The mass ratio of the degradable polymer and the CO drug molecule is (50-99): (1-50); The organic solvent is selected from at least one of ethyl acetate, dichloromethane, chloroform, N-methylpyrrolidone, dimethyl sulfoxide, tetrahydrofuran, acetone, ether and ethanol.

[0018] The present invention has the following beneficial effects: based on the fact that the main target of the inner wall of the vascular stent is blood and cells migrated from the blood vessels, while the outer wall of the vascular stent directly acts on the lesion vascular tissue, the targets acted on by the inner and outer walls and the physiological microenvironment in which they are located have obvious "spatial" differences. In view of the above differences, on the one hand, the present invention realizes the function of stable NO catalytic release by grafting a copper complex containing a primary amine group on the inner wall of the vascular stent body through a coating of phenolic hydroxyl and quinone groups. On the other hand, a drug sustained-release coating that releases CO in response to hydrogen peroxide is formed on the outer wall of the vascular stent body, which can play the role of regulating abnormal smooth muscle proliferation, regulating inflammation and scavenging active oxygen free radicals, providing a good microenvironment for lesion recovery, and promoting the regeneration and repair of diseased blood vessels; a prodrug (i.e., CO drug molecule) that releases CO is loaded inside the drug-loaded sustained-release coating to cooperate and complement with the NO function, and jointly realize the construction of a multifunctional material surface that is anticoagulant, anti-inflammatory, anti-proliferative or promotes in situ endothelialization.

[0019] Therefore, targeted design of the inner and outer walls of the stent based on the spatial differences between the inner and outer surfaces of the stent and the different response requirements of pathological molecules can achieve a more efficient synergistic treatment effect after stent implantation, and ultimately accelerate the repair process of atherosclerotic plaques. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings required for use in the embodiments are briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present invention and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without creative work.

[0021] Figure 1 This is the SEM morphology of the inner and outer wall coating of the vascular stent in Example 2 of this application; Figure 2 This is a mapping result diagram of the inner and outer walls of the vascular stent in Example 2 of the present application; Figure 3 This is a NO and CO release curve diagram of the vascular stent in Example 2 of the present application; Figure 4 This is a graph showing the endothelial cell activity results of Example 1 and Comparative Examples 2 and 3 in this application; Figure 5 This is a graph showing the smooth muscle cell activity results of Example 1 and Comparative Examples 2 and 3 in this application; Figure 6 This is a graph showing the macrophage activity results of Example 1 and Comparative Examples 2 and 3 in this application; Figure 7 ELISA test result diagram of Example 1 and Comparative Examples 2 and 3 in this application; Figure 8 The endothelial cell activity result diagram of Example 1, Example 7, and Example 8 in this application; Fig. 9 This is a graph showing the ELISA test results of Example 1 and Examples 9-12 in this application. DETAILED DESCRIPTION

[0022] In order to make the purpose, technical scheme and advantages of the embodiments of the present invention clearer, the technical scheme in the embodiments of the present invention will be described clearly and completely below. If the specific conditions are not specified in the embodiments, they are carried out according to conventional conditions or conditions recommended by the manufacturer. If the manufacturer of the reagents or instruments used is not specified, they are all conventional products that can be purchased commercially.

[0023] By analyzing the existing vascular stents, the inventors found that in actual clinical applications, the inner wall of the vascular stent mainly acts on blood and cells migrating from blood vessels, while the outer wall of the stent directly acts on the diseased vascular tissue. The objects acted by the inner and outer walls and the physiological microenvironment in which they are located have obvious "spatial" differences. Therefore, an ideal vascular stent needs to make reasonable use of the stent surface and carry out targeted design of the inner and outer walls of the stent to exert a more efficient synergistic treatment effect under pathological conditions.

[0024] NO is an important signaling molecule secreted by endothelial cells. It is mainly produced by L-arginine catalyzed by eNOS (endothelial nitric oxide synthase) in vascular ECs (endothelial cells), and plays an important role in maintaining vascular homeostasis. NO has the functions of vasodilation, promoting endothelial cell proliferation, inhibiting platelet and smooth muscle proliferation, and regulating inflammation. CO is the second gas signaling molecule discovered after NO, which has anti-inflammatory, scavenging reactive oxygen, inhibiting smooth muscle proliferation and myocardial protection functions. The multiple effects of NO and CO make them ideal modification molecules for vascular stents. Therefore, for the outer wall of the stent in contact with the diseased vascular tissue, it is planned to adopt a hydrogen peroxide-responsive CO release coating for functional modification, and use "ultrasonic atomization spraying technology" to construct a CO drug sustained-release coating, which continuously consumes the inflammatory oxidative H2O2 free radicals at the vascular lesions as a driving force to respond to the decomposition of CO prodrugs to release physiotherapeutic gas CO, thereby selectively inhibiting the proliferation of SMCs (smooth muscle cells) and regulating the inflammatory response. The inner wall of the stent is modified with a NO in situ catalytic release functional coating, and a conversion coating with NO catalytic activity is constructed based on mussel inspiration and phenolamine chemistry to achieve anti-coagulation and promote endothelial cell regeneration and repair. Therefore, the multifunctional vascular stent finally constructed will be able to release NO and CO in response to the environment, promote the regeneration of new intimal tissue with physiological functions, and achieve regeneration and repair of atherosclerotic diseased blood vessels.

[0025] The embodiment of the present invention provides a multifunctional vascular stent that releases dual therapeutic gases, including a vascular stent body, an NO-releasing coating on the inner wall of the vascular stent body, and a CO-releasing coating on the outer wall of the vascular stent body. The vascular stent body can respond to the environment and release NO and CO simultaneously to adapt to the physiological microenvironment in which the stent is located. The stable release of NO and CO is achieved through the coordinated cooperation of the inner and outer surfaces of the vascular stent body, and the functions of the double-sided modified coating in synergistic anti-coagulation, anti-inflammatory, and promotion of regeneration and repair of diseased vascular tissue are innovatively exerted.

[0026] Furthermore, the NO-releasing coating includes a coating containing phenolic hydroxyl groups and quinone groups and a catalytic functional coating, and the catalytic functional coating is formed by in-situ grafting and re-crosslinking a copper complex containing primary amine groups on the coating containing phenolic hydroxyl groups and quinone groups. Aiming at the microenvironment of the inner wall of the vascular stent, by setting a phenolic hydroxyl group and quinone group coating on the inner wall of the vascular stent body and grafting a copper complex containing primary amine groups, the copper ions in the copper complex have similar properties to GPx (glutathione peroxidase) in the presence of a reducing agent GSH (glutathione). GPx can catalyze endogenous NO donors (nitrosothiols) in the human body, so that endogenous NO donors can release NO stably and for a long time, avoiding the problem of excessive NO release in the early stage causing toxicity to cells and insufficient NO release in the later stage causing functional loss.

[0027] In addition, the coating of the phenolic hydroxyl and quinone groups on the inner wall of the stent body contains primary amine groups, which can act as reaction sites to undergo carbodiimide chemical cross-linking reactions with copper-containing complexes. Therefore, the primary amine groups can covalently graft the copper-containing complexes, making the copper-containing complexes more firmly grafted on the surface of the phenolic hydroxyl and quinone coatings, thereby enabling the stent to continuously and controllably catalyze NO release. In addition, the ortho-phenolic hydroxyl groups can undergo self-polymerization reactions under weak alkaline conditions to generate oligomers, and some of the oligomers are further cross-linked to generate polymers with cross-linked structures. The cross-linked structure can react with compounds containing two or more amino groups in the molecular structure, and introduce a large number of amino groups to the surface for secondary grafting.

[0028] The phenolic hydroxyl and quinone-based coatings on the inner wall of the vascular stent body have ortho-phenolic hydroxyl groups, which can achieve effective adhesion on almost all surfaces by virtue of their characteristics of self-polymerization reaction when encountering oxygen under weak alkaline conditions (through coordination, hydrogen bonding, charge transfer, π-π stacking and other binding effects). Subsequently, under alkaline conditions, the phenolic hydroxyl groups exposed by the dissociation of the adhesion layer and the converted quinone groups are used to react with the copper complex grafted with primary amine groups for Schiff base reaction and Michael addition, so as to achieve in-situ re-crosslinking of the copper-containing complex with stable NO catalytic release function, thereby achieving long-term, stable and sustained release of NO and improving the pathological microenvironment.

[0029] Furthermore, the CO release coating contains CO drug molecules that release CO gas in response to hydrogen peroxide. In view of the microenvironment that the outer wall of the vascular stent contacts, a CO drug sustained-release coating that releases ROS (reactive oxygen species) in response is sprayed on the outer wall of the vascular stent body. CO and NO complement each other in function and jointly realize the construction of a multifunctional material surface that is anti-coagulation, anti-inflammatory, anti-proliferation or promotes in situ endothelialization.

[0030] In some embodiments, the compound used to form the coating containing phenolic hydroxyl groups and quinone groups is selected from at least one of melanin, dopamine, dihydroxyindole, epinephrine, norepinephrine, levodopa, tannic acid, dextrodopa, gallic acid, pyrogallol, epicatechin gallate, epigallocatechin and epigallocatechin gallate. The coating containing phenolic hydroxyl groups and quinone groups can be prepared by one or more of the above compounds.

[0031] In some embodiments, the functional molecules with NO catalytic activity containing primary amine groups have a ligand structure of macrocyclic polyamines, and have nitrogen-containing heterocyclic rings and multiple carboxyl groups. The size of the cavity formed by the structure of macrocyclic polyamines is very consistent with copper ions, and the nitrogen atoms on the heterocyclic rings are also easy to form coordination bonds with copper ions to generate thermodynamically stable complexes. At the same time, the multiple reactive carboxyl functional groups on the molecules of these macrocyclic polyamines can make them more easily and stably fixed on the surface of the coating of phenolic hydroxyl and quinone groups rich in amine groups.

[0032] Further, the ligand having a macrocyclic polyamine structure in the copper-containing complex grafted with a primary amine group is selected from at least one of 1,4,7-triazacyclononanecarboxylic acid or a derivative thereof, 1,4,7,10-tetraazacyclododecanecarboxylic acid or a derivative thereof, and 1,4,8,11-tetraazacyclotetradecanecarboxylic acid or a derivative thereof, and the ligand may be any one or more of the above. For example, it may be 1,4,7-triazacyclononane-1,4,7-triacetic acid, 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid (1,4,7,10-Tetraazacyclododecane-N,N',N",N'-tetraacetic acid, DOTA), 1,4,8,11-tetraazacyclotetradecane-1,4,8,11-tetraacetic acid, and the like. The size of the cavity formed by the above-mentioned ligand having the structure of macrocyclic polyamine is very compatible with lanthanide metal ions or copper ions. At the same time, the nitrogen atoms on the heterocyclic rings are also easy to form coordination bonds with copper ions to generate thermodynamically stable complexes. At the same time, these macrocyclic polyamine molecules also have multiple reactive carboxyl functional groups, which can make it easier and more stable to fix them on the surface of amine-rich phenolic hydroxyl and quinone-based coatings.

[0033] It should be noted that when the copper complex Cu-DOTA and the primary amine compound combined with it select PAM, the unique adhesion of the ortho-phenolic hydroxyl groups in the phenolic hydroxyl and quinone-based coatings is assembled to the coating surface, and the Cu-DOTA / PAA can be further fixed by Schiff base reaction and Michael addition, so that the copper complex is more firmly grafted on the surface of the phenolic hydroxyl and quinone-based coatings. In addition, the ortho-phenolic hydroxyl groups can undergo self-polymerization reaction under weak alkaline conditions to generate oligomers, and some oligomers are further cross-linked to generate polymers with cross-linked structures, and then react with compounds containing two or more amino groups in the molecular structure to introduce a large number of amino groups to the surface for secondary grafting. In addition, the various groups in the phenolic hydroxyl and quinone-based coatings can also enhance the binding ability of the coating through physical effects such as intermolecular interactions and hydrogen bonding.

[0034] Furthermore, the CO drug molecules in the CO-releasing coating are selected from at least one of metal carbonyl compounds, organic molecules and enzyme catalytic activation types, and may contain any one or more of the above drugs. Among them, metal carbonyl compounds include CORM-1, CORM-2, CORM-3, CORM-A1, CORM-F10, CORM-F11, CORM-F12, CORM-RM20, CORM-E2, CORM-RM20, Mn(CO)5Br and CORM-401; organic molecular types include CORM-S1, CORM-S2, CORM-AM, CORM-polymer 1 and CORM-polymer 2; enzyme catalytic activation types include Fe(CO)4I2, Fe(CO)3I2(PPh3), Fe(CO)3I2(Py), CpFe(CO)2Cl, CpFe(CO)2I, CpFe(CO)2Br, Fe2(μ-S)2(CO), Fe2(μ-SCH2CH3)(CO)6, Fe2(μ-S)2(CO)6 and Fe2(μ-SCH2CHOHCH2OH)2(CO)6. Preferably, the CO drug molecule is selected from at least one of CORM-2, CORM-3, CORM-A1 and CORM-401. The CO prodrug releases CO slowly under normal conditions, but in the presence of hydrogen peroxide, hydrogen peroxide can significantly accelerate the release of CO and is responsive to hydrogen peroxide.

[0035] For example, when CORM-401 is selected as a sustained-release drug, the sustained-release CORM-401 can release CO in response to ROS in the lesion, and CO can inhibit the inflammatory response and has an anti-inflammatory effect. Secondly, CO can reduce the level of ROS, thereby exerting an antioxidant effect and protecting cells from damage by oxidative stress. In addition, CO can protect cells from damage through a variety of signaling pathways, including inhibiting cell apoptosis and promoting cell survival. Moreover, CO plays a protective role in the cardiovascular system, including regulating vascular tension and inhibiting the proliferation and migration of vascular smooth muscle cells. CO can cooperate with NO to achieve anti-inflammatory, antioxidant, anticoagulant, and anti-proliferative effects. The two complement each other in function and have more material diversity.

[0036] In some embodiments, the CO release coating further contains a carrier for loading CO drug molecules, the carrier is a degradable polymer, the type of degradable polymer is not limited, and can be selected from at least one of polytrimethylene carbonate, polylactic acid, polycaprolactone, polyglycolic acid, polylactic acid-glycolic acid copolymer (PLGA), glycolide-lactide copolymer, glycolide-caprolactone copolymer, lactide-caprolactone copolymer, polylactic acid-polyethylene glycol copolymer, polyhydroxybutyrate, polyhydroxyvalerate, polyamino acids and polyanhydrides, and the degradable polymer can be any one or more of the above. The molecular weight of the degradable polymer can be 50,000-1 million Daltons, such as 50,000 Daltons, 100,000 Daltons, 300,000 Daltons, 500,000 Daltons, 800,000 Daltons, 1 million Daltons, etc. Preferably, the degradable polymer is PLGA, which has the advantages of good biocompatibility, non-toxicity and good film-forming properties, and can achieve long-term controllable release of CO-free prodrugs.

[0037] Furthermore, the thickness of the CO release coating is 0.1nm-10000nm, such as 0.1nm, 1.0nm, 5.0nm, 10.0nm, 20.0nm, 50.0nm, 100nm, 500nm, 1000nm, 3000nm, 5000nm, 8000nm, 10000nm, etc., preferably 5nm-200nm, more preferably 5nm-20nm. The thickness of the CO release coating is controlled within a reasonable range, which can effectively improve the pathological microenvironment.

[0038] Further, the coating layer containing phenolic hydroxyl and quinone groups has a thickness of 5nm-25nm, such as 5nm, 10nm, 15nm, 17nm, 18nm, 20nm, 22nm, 25nm, etc., preferably 5nm-20nm; the thickness of the catalytic functional coating layer is 5nm-180nm, such as 5nm, 10nm, 60nm, 80nm, 100nm, 160nm, 180nm, etc., preferably 5nm-160nm, more preferably 60nm-100nm. Such coating layers of phenolic hydroxyl and quinone groups have suitable and uniform thickness, good secondary graftability, strong applicability, less affected by the molecular size, activity and conformation of secondary grafting, and are not easily inactivated or lost in large quantities during service. They can catalyze the long-term and stable release of NO by the human body, and NO can regulate the hydrolysis of guanosine triphosphate (GTP) into cyclic guanosine monophosphate (cGMP), thereby inhibiting the activation and adhesion of platelets and promoting the repair of blood vessels.

[0039] Furthermore, the material of the vascular stent body is at least one of stainless steel, cobalt and its alloys, titanium and its alloys, platinum and its alloys, magnesium and its alloys, iron and its alloys, and zinc and its alloys. The material of the vascular stent body can be any one or more of the above materials. The above materials have good biocompatibility, certain strength and toughness, and are not prone to cracking or breakage.

[0040] The embodiment of the present invention also provides a method for preparing a multifunctional vascular stent capable of releasing dual therapeutic gases, comprising the following steps: S100, cleaning the vascular stent body The vascular stent body is ultrasonically cleaned using organic solvents such as acetone and ethanol and deionized water, and then dried for later use.

[0041] S200, depositing a coating containing phenolic hydroxyl and quinone groups on the inner wall of the stent body The vascular stent body is immersed in a solution containing phenolic hydroxyl groups and quinone groups to assemble and form a coating containing phenolic hydroxyl groups and quinone groups.

[0042] In some embodiments, the solution containing phenolic hydroxyl groups and quinone groups can be a buffer solution containing ortho-phenolic hydroxyl groups, and the reaction time is 0.5h-200h to generate a coating of phenolic hydroxyl groups and quinone groups. The reaction time can preferably be 10h-100h, more preferably 20h-80h, for example, 15h, 24h, 30h, 36h, 50h or 80h. In this step, the reaction temperature also needs to be controlled at 1°C-60°C, preferably 10-50°C, and more preferably 30-40°C.

[0043] The buffer solution can be a common buffer system such as Tris-buffer (tris(hydroxymethyl)aminomethane), the pH of which is generally between 6 and 12, which can provide a relatively stable pH value for the reaction environment and is conducive to the formation of phenolic hydroxyl and quinone-based coatings.

[0044] Further, the compound providing ortho-phenolic hydroxyl groups may be at least one or more of melanin, dopamine, dihydroxyindole, adrenaline, norepinephrine, levodopa, tannic acid, dextrodopa, gallic acid, pyrogallol, epicatechin gallate, epigallocatechin and epigallocatechin gallate, and the concentration is generally 0.01-10 mg / mL.

[0045] S300, grafting copper complex containing primary amine groups on the surface of phenolic hydroxyl and quinone-based coatings After forming the coating containing phenolic hydroxyl and quinone groups, the copper complex containing primary amine groups is grafted and cross-linked in situ. The preparation process of the copper complex containing primary amine groups includes: adding soluble copper salt to the ligand solution with macrocyclic polyamine to form a copper-containing complex, and then adding primary amine compounds for reaction dialysis, the reaction temperature is 1℃-60℃ (such as 1℃, 10℃, 20℃, 30℃, 40℃, 50℃, 60℃, etc.), and the reaction time is 0.5h-200h. Copper salt can provide the central atom-copper for the copper-containing complex, and then copper ions or cuprous ions can chelate with ligands to form copper-containing complexes and grafted on the surface of the coating containing phenolic hydroxyl and quinone groups, and cooperate with GSH in the human body to catalyze the long-term and stable release of NO by NO donors such as nitrosothiol in the human body to promote the repair of vascular tissue.

[0046] The types of ligands of macrocyclic polyamines can refer to the product introduction of multifunctional vascular stents. The primary amine compound is selected from at least one of polyallylamine (PAM), polyethyleneamine, polylysine, polyethylene glycol diamine, polyetheramine, polyamide, melamine, poly-N-isopropylacrylamide, chitosan and its derivatives, and the primary amine compound can be any one or more of the above. The soluble copper salt is selected from at least one of copper sulfate (CuSO4), copper chloride (CuCl2), cuprous chloride (CuCl), copper acetate (Cu(CH3COO)2), copper acetate (Cu(C2H3O2)2), copper fluoride (CuF2), copper bromide (CuBr), cuprous bromide (CuBr2), copper iodide (CuI), cuprous iodide (CuI2), copper citrate (C6H6CuO7), copper tartrate (C4H4CuO6·3H2O), copper propionate (Cu(CO2CH3CH2)2), copper nitrate (Cu(NO3)2) and ammonia copper ion ([Cu(NH3)4]²⁺), and the soluble copper salt can be any one or more of the above. Preferably, the soluble copper salt is selected from at least one of copper sulfate (CuSO4), copper chloride (CuCl2) and cuprous chloride (CuCl).

[0047] Furthermore, the molar ratio of the copper-containing complex to the primary amine compound is (0.01-100):1, such as 0.01:1, 0.10:1, 1.00:1, 10.00:1, 20.00:1, 25.00:1, 30.00:1, 50.00:1, 80.00:1, 100.00:1, etc., preferably (20-30):1, and more preferably 25:1. The molar ratio of the ligand to the copper salt for forming the copper-containing complex is (0.01-100):1, such as 0.01:1, 0.10:1, 1.00:1, 10.00:1, 20.00:1, 25.00:1, 30.00:1, 50.00:1, 80.00:1, 100.00:1, etc., preferably (0.5-3):1, more preferably (1-3):1. The molar ratio of the primary amine group to the phenolic hydroxyl group is (0.03-30):1, such as 0.03:1, 0.10:1, 1.00:1, 5.00:1, 10.00:1, 20.00:1, 30.00:1, etc., preferably 3:1.

[0048] Furthermore, when in-situ grafting and re-crosslinking the copper complex containing primary amine groups, the reaction temperature is controlled to be 1°C-60°C, such as 1°C, 10°C, 20°C, 30°C, 40°C, 50°C, 60°C, etc., preferably 10°C-50°C, and more preferably 30°C-40°C; the reaction time is 0.5h-200h, such as 0.5h, 1.0h, 5.0h, 10.0h, 15.0h, 20.0h, 24.0h, 50.0h, 80.0h, 100.0h, 150.0h, 200.0h, etc., preferably 10h-100h, and more preferably 20h-80h.

[0049] For example, a copper complex having 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid as a ligand and grafted with polyallylamine can be used as an example to explain the steps in detail: Specifically, a polyallylamine solution is added to a DOTA solution containing copper salt and the reaction is dialyzed for 0.5 to 200 hours to generate a Cu-DOTA / PAM solution with secondary graftability; the vascular stent body in S200 is placed in the above Cu-DOTA / PAM solution for reaction for 0.5h-200h to achieve in situ re-crosslinking of Cu-DOTA / PAM with the phenolic hydroxyl and quinone-based coatings. The size of the cavity formed by the twelve-membered ring in the DOTA molecule is very consistent with the size of the copper ion, and the nitrogen atom on its heterocyclic ring is also easy to form a coordination bond with the copper ion to generate a thermodynamically stable complex. At the same time, the reactive primary amine functional group of the Cu-DOTA / PAM molecule can make it easier and more stably fixed on the coating containing phenolic hydroxyl and quinone groups.

[0050] In addition, the concentration of copper salt in the Cu-DOTA / PAM solution is generally 0.02 to 20 mg / mL, and the concentration of the primary amine compound is generally 0.01 to 10 mg / mL.

[0051] In some other embodiments, copper complexes of other ligands may also be grafted. The operation steps thereof are different from the above process, and the main difference lies in the type of ligand solution, which will not be described in detail in this application.

[0052] It should be noted that at this time, a coating of phenolic hydroxyl and quinone groups fixedly grafted with a copper-containing complex is formed on both the inner and outer walls of the stent body, and the outer wall coating is subsequently covered with a CO drug sustained-release coating.

[0053] In other embodiments, the CO releasing coating may be formed first and then the NO releasing coating may be formed, and the NO releasing coating may be formed to protect the outer wall of the vascular stent body.

[0054] S400, forming a CO release coating A CO release coating is formed on the outer wall of the vascular stent body. The process of forming the CO release coating includes: covering and protecting the inner wall of the vascular stent body by a clamp, spraying a CO drug sustained-release solution on the outer wall of the vascular stent body by an ultrasonic atomization spraying method, and then drying. The ultrasonic atomization spraying method can form a uniform CO release coating.

[0055] The preparation process of the CO drug sustained-release solution includes: uniformly mixing a degradable polymer, a CO drug molecule and an organic solvent, wherein the types of the degradable polymer and the CO drug molecule refer to the introduction of the multifunctional vascular stent product; the organic solvent is selected from at least one of ethyl acetate, dichloromethane, chloroform, N-methylpyrrolidone, dimethyl sulfoxide, tetrahydrofuran, acetone, ether and ethanol, and the organic solvent may be any one or more of the above.

[0056] Furthermore, the mass fraction of CO drug molecules in the CO drug sustained-release solution is 5%-30%, such as 5%, 10%, 15%, 20%, 25%, 30%, etc.; the mass ratio of the degradable polymer to the CO drug molecules is (50-99): (1-50), that is, the degradable polymer is 50-99 parts by weight, and the CO drug molecules are 1-50 parts by weight. Specifically, the mass ratio of the degradable polymer to the CO drug molecules can be 50:50, 60:40, 70:30, 80:20, 90:10, 99:1, etc.

[0057] This step takes the sustained-release drug as CORM-401, the degradable polymer as the carrier as polylactic acid-glycolic acid copolymer, and the organic solvent as tetrahydrofuran as an example to explain the step in detail. Specifically, after mixing 50-99 parts of PLGA and 1-50 parts of CORM-401 by weight, add tetrahydrofuran and stir thoroughly for 1-200 hours to form a CORM-401 concentration of 0.1-50 mg / mL solution; place the stent on a customized fixture, and use an ultrasonic atomization spray method to spray the solution on the outer wall surface of the stent body; then dry it. The number of spray cycles can be 1-30 cycles, the extrusion rate can be 0.001-0.5 mL / min, and the forward rate can be 0.001-1 cm / min. It should be noted that the customized fixture is a clamp that can cover the inner wall.

[0058] In this step S400, the sprayed drug solution is only applied on the outer surface of the stent body to form a CO prodrug sustained-release coating, which covers the outer wall of the vascular stent body and can be used in combination with the Cu chelate to more effectively improve the pathological microenvironment and promote the repair of vascular tissue.

[0059] The features and performance of the present invention are further described in detail below in conjunction with the embodiments.

[0060] Example 1 This embodiment provides a multifunctional vascular stent, and the preparation method thereof is as follows: S100, ultrasonically clean the stainless steel stent body with acetone, ethanol, and deionized water for 50 minutes in sequence, and blow dry in a nitrogen environment to obtain a clean stainless steel stent body for use.

[0061] S200, placing the vascular stent body in S100 in a Tris-buffer system with a pH value of 8.4, then adding dopamine to the system to a concentration of 1 mg / mL, and reacting at 37° C. for 24 hours to form a coating of phenolic hydroxyl and quinone groups.

[0062] S300, dissolve copper chloride dihydrate and DOTA in a buffer solution (pH = 5.6) composed of EDC, NHS and MES to obtain a Cu-DOTA solution, in which the concentration of copper chloride dihydrate is 0.9 mg / mL and the concentration of DOTA is 2.14 mg / mL. PAM is added to the Cu-DOTA solution to make the PAM concentration 3 mg / mL, and the reaction is dialyzed for 24 hours to generate a Cu-DOTA / PAM solution with secondary graftability; the sample obtained in S200 is washed with deionized water and blown dry, placed in a Cu-DOTA / PAM solution, and reacted at 24°C for 24 hours, so that Cu-DOTA / PAM is grafted on the surface of the coating with phenolic hydroxyl and quinone groups.

[0063] S400, CORM-401, PLGA and tetrahydrofuran were mixed to obtain a CO drug sustained-release solution, in which the concentration of CORM-401 was 2 mg / mL, the concentration of PLGA was 2 mg / mL, and the loading amount of CORM-401 was 10% (mass fraction, the same below). The sample obtained in S300 was washed and dried with deionized water, and the inner surface of the sample was protected by a clamp. The CORM-401 sustained-release solution with a loading amount of 10% was sprayed onto the outer surface of the stent by ultrasonic atomization spraying technology, and the vascular stent was obtained after drying.

[0064] In the vascular stent of this embodiment, the coating thickness of phenolic hydroxyl and quinone groups is 20nm; the grafted Cu-DOTA / PAM coating thickness is 60nm, wherein the molar ratio of CuCl2·H2O to DOTA is 1:1, and the molar ratio of Cu-DOTA to PAM is 25:1. The thickness of the drug-loaded sustained-release coating is 5μm, and the ultrasonic atomization spraying is controlled as follows: the number of spraying cycles is 15 cycles, the extrusion rate is 0.075mL / min, and the forward rate is 0.075cm / min.

[0065] Example 2 This embodiment provides a multifunctional vascular stent that releases dual therapeutic gas molecules in response to an environment. The preparation method thereof is different from that of Embodiment 1 in the following aspects: In step S100, the stainless steel vascular stent is replaced with a cobalt-chromium alloy stent. In step S200, dopamine is added to the system to a concentration of 1 mg / mL and reacted at 37°C for 48 hours. In step S400, a 1 mg / mL CORM-3 dichloromethane solution is used as a drug sustained-release solution.

[0066] The vascular stent of this embodiment has a phenolic hydroxyl and quinone-based coating with a thickness of 20 nm, and a grafted Cu-DOTA / PAM thickness of 80 nm, wherein the molar ratio of CuCl2·H2O to DOTA is 1:1, and the molar ratio of Cu-DOTA to PAM is 25:1; the thickness of the drug-loaded sustained-release coating is 10 μm, the number of spraying cycles is 18 cycles, the extrusion rate is 0.05 mL / min, and the forward rate is 0.05 cm / min.

[0067] Example 3 This embodiment provides a multifunctional vascular stent that releases dual therapeutic gas molecules in response to an environment. The main differences between the preparation method and that of Embodiment 1 are as follows: In step S300, a 1 mg / mL polyallylamine solution was added and reacted at 37°C for 12 hours; in step S400, a 1.5 mg / mL CORM-A1 dichloromethane solution was used as a drug sustained-release solution.

[0068] The vascular stent of this embodiment has a phenolic hydroxyl and quinone-based coating with a thickness of 10 nm, and a grafted Cu-DOTA / PAM thickness of 60 nm, wherein the molar ratio of CuCl2·H2O to DOTA is 1:1, and the molar ratio of Cu-DOTA to PAM is 75:1; the thickness of the drug-loaded sustained-release coating is 7 μm, the number of spraying cycles is 12 cycles, the extrusion rate is 0.075 mL / min, and the forward rate is 0.05 cm / min.

[0069] Example 4 This embodiment provides a multifunctional vascular stent that releases dual therapeutic gas molecules in response to an environment. The preparation method thereof is different from that of Embodiment 1 in the following aspects: In step S200, dopamine is added to the system to a concentration of 2 mg / mL, and the reaction is carried out at 37°C for 12 hours; in step S400, 2 mg / mL of PTMC is used as the drug-carrying polymer.

[0070] The vascular stent of this embodiment has a phenolic hydroxyl and quinone-based coating with a thickness of 18 nm, and a grafted Cu-DOTA / PAM thickness of 45 nm, wherein the molar ratio of CuCl2·H2O to DOTA is 1:1, and the molar ratio of Cu-DOTA to PAM is 25:1; the thickness of the drug-loaded sustained-release coating is 10 μm, the number of spraying cycles is 12 cycles, the extrusion rate is 0.075 mL / min, and the forward rate is 0.05 cm / min.

[0071] Example 5 The present embodiment provides a multifunctional vascular stent that releases dual therapeutic gas molecules in response to an environment. The main differences between the preparation method thereof and that of Example 1 are as follows: in step S300, 3 mg / mL of polyvinylamine solution is added and reacted at 37°C for 36 hours; in step S400, 3 mg / mL of polylactic acid is used as a drug carrier to prepare a 2 mg / mL chloroform solution of CORM-2 as a drug sustained-release solution.

[0072] The vascular stent of this embodiment has a phenolic hydroxyl and quinone coating thickness of 15 nm, a grafted Cu-DOTA / PAM thickness of 60 nm, wherein the molar ratio of CuCl2·H2O to DOTA is 1:1, and the molar ratio of Cu-DOTA to PAM is 25:1; the thickness of the drug-loaded sustained-release coating is 15 μm, the number of spraying cycles is 18 cycles, the extrusion rate is 0.05 mL / min, and the forward rate is 0.05 cm / min.

[0073] Example 6 This embodiment provides a multifunctional vascular stent that releases dual therapeutic gas molecules in response to an environment. The main differences between the preparation method thereof and that of Embodiment 1 are as follows: in step S200, dopamine is added to the system to a concentration of 2.5 mg / mL, and the reaction is carried out at 24°C for 24 hours; in step S300, the reaction is carried out at 37°C for 24 hours.

[0074] The vascular stent of this embodiment has a coating thickness of phenolic hydroxyl and quinone groups of 10 nm; the thickness of the grafted Cu-DOTA / PAM is 35 nm, wherein the molar ratio of CuCl2·H2O to DOTA is 1:1, and the molar ratio of Cu-DOTA to PAM is 25:1; the thickness of the drug-loaded sustained-release coating is 8 μm, the number of spraying cycles is 15 cycles, the extrusion rate is 0.075 mL / min, and the forward rate is 0.075 cm / min.

[0075] Example 7 This embodiment provides another vascular stent, and the preparation method thereof is different from that of embodiment 1 in that: in step S400, the loading amount of CORM-401 is 30%. The vascular stent of this embodiment has a coating thickness of phenolic hydroxyl and quinone groups of 20 nm; a grafted Cu-DOTA / PAM thickness of 60 nm, wherein the molar ratio of CuCl2·H2O to DOTA is 1:1, and the molar ratio of Cu-DOTA to PAM is 25:1; a drug-loaded sustained-release coating thickness of 12 μm, a spraying cycle number of 15 cycles, an extrusion rate of 0.075 mL / min, and a forward rate of 0.075 cm / min.

[0076] Example 8 This embodiment provides another vascular stent, and the preparation method thereof is different from that of embodiment 1 in that: in step S400, the loading amount of CORM-401 is 50%. In the vascular stent of this embodiment, the coating thickness of the phenolic hydroxyl group and the quinone group is 20nm; the thickness of the grafted Cu-DOTA / PAM is 60nm, wherein the molar ratio of CuCl2·H2O to DOTA is 1:1, and the molar ratio of Cu-DOTA to PAM is 25:1; the thickness of the drug-loaded sustained-release coating is 15μm, the number of spraying cycles is 15 cycles, the extrusion rate is 0.075mL / min, and the forward rate is 0.075cm / min.

[0077] Example 9 This embodiment provides another vascular stent, and the preparation method thereof is different from that of embodiment 1 in that: in step S400, CpFe(CO)2I is used instead of CORM-401. In the vascular stent of this embodiment, the coating thickness of the phenolic hydroxyl group and the quinone group is 20 nm; the thickness of the grafted Cu-DOTA / PAM is 60 nm, wherein the molar ratio of CuCl2·H2O to DOTA is 1:1, and the molar ratio of Cu-DOTA to PAM is 25:1; the thickness of the drug-loaded sustained-release coating is 9 μm, the number of spraying cycles is 15 cycles, the extrusion rate is 0.075 mL / min, and the forward rate is 0.075 cm / min.

[0078] Example 10 This embodiment provides another vascular stent, and the preparation method thereof is different from that of embodiment 1 mainly in that: in step S400, CORM-2 is used instead of CORM-401. The vascular stent of this embodiment has a coating thickness of phenolic hydroxyl and quinone groups of 20 nm; a grafted Cu-DOTA / PAM thickness of 60 nm, wherein the molar ratio of CuCl2·H2O to DOTA is 1:1, and the molar ratio of Cu-DOTA to PAM is 25:1; a drug-loaded sustained-release coating thickness of 9 μm, a spraying cycle number of 15 cycles, an extrusion rate of 0.075 mL / min, and a forward rate of 0.075 cm / min.

[0079] Embodiment 11 This embodiment provides another vascular stent, and the preparation method thereof is different from that of embodiment 1 in that: in step S400, CORM-3 is used instead of CORM-401. The vascular stent of this embodiment has a coating thickness of phenolic hydroxyl and quinone groups of 20 nm; a grafted Cu-DOTA / PAM thickness of 60 nm, wherein the molar ratio of CuCl2·H2O to DOTA is 1:1, and the molar ratio of Cu-DOTA to PAM is 25:1; a drug-loaded sustained-release coating thickness of 9 μm, a spraying cycle number of 15 cycles, an extrusion rate of 0.075 mL / min, and a forward rate of 0.075 cm / min.

[0080] Example 12 This embodiment provides another vascular stent, and the preparation method thereof is different from that of embodiment 1 mainly in that: in step S400, CORM-A1 is used instead of CORM-401. The vascular stent of this embodiment has a coating thickness of phenolic hydroxyl and quinone groups of 20 nm; a grafted Cu-DOTA / PAM thickness of 60 nm, wherein the molar ratio of CuCl2·H2O to DOTA is 1:1, and the molar ratio of Cu-DOTA to PAM is 25:1; a drug-loaded sustained-release coating thickness of 9 μm, a spraying cycle number of 15 cycles, an extrusion rate of 0.075 mL / min, and a forward rate of 0.075 cm / min.

[0081] Comparative Example 1 This comparative example provides another vascular stent, and its preparation method is as follows: S100. The stent body made of magnesium alloy is ultrasonically cleaned with acetone, ethanol and deionized water for 50 minutes respectively, and blown dry in a nitrogen environment to obtain a clean stainless steel stent body for use.

[0082] S200, add PAM to the Cu-DOTA solution to a concentration of 3 mg / mL, and dialyze for 24 hours to generate a Cu-DOTA / PAM solution with secondary graftability; wash the sample obtained in S100 with deionized water, blow dry, place it in the Cu-DOTA / PAM solution, and react at 24°C for 24 hours. In the Cu-DOTA solution, the concentration of copper chloride dihydrate is 0.9 mg / mL, and the concentration of DOTA is 2.14 mg / mL.

[0083] S300, prepare CORM-401 concentration of 2 mg / mL, PLGA concentration of 2 mg / mL, solvent is tetrahydrofuran solution, CORM-401 loading amount is 10%. Wash the sample obtained in S200 with deionized water and blow dry, use a clamp to protect the inner surface of the sample, spray PLGA loaded CORM-401 onto the outer surface of the stent by ultrasonic atomization spraying technology, and obtain the vascular stent after drying.

[0084] The vascular stent of the comparative example has an inner wall of a stent body without a coating of phenolic hydroxyl and quinone groups, a grafted Cu-DOTA / PAM thickness of 0 nm, wherein the molar ratio of CuCl2·H2O to DOTA is 1:1, and the molar ratio of Cu-DOTA to PAM is 25:1; the thickness of the drug-loaded sustained-release coating is 5 μm, the number of spraying cycles is 15 cycles, the extrusion rate is 0.075 mL / min, and the forward rate is 0.075 cm / min.

[0085] Comparative Example 2 This comparative example provides another vascular stent, and its preparation method does not contain step S300 compared with Example 1. The vascular stent of this comparative example has a phenolic hydroxyl and quinone-based coating on the inner wall of the stent body, and Cu-DOTA / PAM is not grafted on the surface. The vascular stent of this comparative example has only phenolic hydroxyl and quinone-based coatings on the inner wall of the stent; the thickness of the drug-loaded sustained-release coating is 5 μm, the number of spraying cycles is 15 cycles, the extrusion rate is 0.075 mL / min, and the forward rate is 0.075 cm / min.

[0086] Comparative Example 3 This comparative example provides another vascular stent, and its preparation method does not contain step S400 compared with Example 1.

[0087] The vascular stent of this embodiment has a coating thickness of phenolic hydroxyl and quinone groups of 20 nm; the grafted Cu-DOTA / PAM has a thickness of 60 nm, wherein the molar ratio of CuCl2·H2O to DOTA is 1:1, and the molar ratio of Cu-DOTA to PAM is 25:1; and there is no drug-loaded sustained-release coating on the outer wall of the stent.

[0088] Experimental example 1. Morphology test The microscopic morphology of the surface coating of the medical cobalt-chromium alloy vascular stent prepared in Example 2 was tested using a scanning electron microscope (SEM). The results are as follows: Figure 1 As shown, it can be seen that the coating on the inner wall of the stent maintains good adhesion on the surface of the stent and is deposited evenly, and the outer wall of the stent is sprayed evenly without obvious cracking, which proves that the coating can fully adapt to the deformation of the stent during expansion and compression.

[0089] The distribution of Co, Cr, and Cu elements on the inner and outer walls of the vascular stent in Example 2 and the coverage of the drug-loaded coating were tested using EDS energy spectrum. Figure 2 As shown in the figure, it can be seen that in Example 2, the inner wall Cu-DOTTA / PAM molecules were successfully grafted and the outer wall was successfully covered with the drug-loaded sustained-release coating.

[0090] 2. Characterization of NO and CO Release Behavior The NO catalytic release capacity and CO release capacity of the medical cobalt-chromium alloy vascular stent prepared in Example 2 were tested using a NO detector and a CO detector, respectively. The results are as follows: Figure 3 As shown in Figure 2, the scaffold has the ability to stably release NO and CO, and the NO catalytic rate is 1.64 mol cm -2 min -1 , the CO release rate was above 0.1 μM, showing potential therapeutic prospects.

[0091] 3. Cell Test Endothelial cells, smooth muscle cells and macrophages were 2×10 4 cells / cm 2 , 2×10 4 cells / cm 2 , 2×10 4 cells / cm 2 The cell density of Example 1, Comparative Examples 1, 2 and 3 and Examples 7, 8, 9, 10, 11 and 12 was planted on the sample surface, and the cell proliferation and activity were detected and analyzed using the CCK-8 kit method after the cells were cultured on the sample surface for 24 and 72 hours respectively.

[0092] Figure 4 , Figure 5 , Figure 6 As shown, Example 1 has better ability to promote endothelial cell proliferation and inhibit smooth muscle cell and macrophage proliferation. At the same time, the supernatant of macrophages was extracted and its anti-inflammatory property was tested using ELISA reagent test kit.

[0093] Figure 7 As shown, Example 1 has a better ability to inhibit the secretion of the pro-inflammatory factor IL-1β and promote the secretion of the anti-inflammatory factor IL-10.

[0094] Figure 8 As shown, in Experimental Example 1, a drug loading amount of 10% of CORM-401 has a promoting effect on endothelial cells, while a drug loading amount greater than 10% has an inhibitory effect on endothelial cells.

[0095] Fig. 9 As shown, Example 1 has better ability to inhibit the secretion of pro-inflammatory factor IL-6 and promote the secretion of anti-inflammatory factor TGF-β. This shows that CORM-401 with a loading amount of 10% in Experimental Example 1 has better biocompatibility.

[0096] By comparing the vascular stents of the embodiments and the comparative examples, it can be found that only the vascular stent of the embodiments of the present application can achieve a relatively good therapeutic effect.

[0097] In summary, the vascular stent can achieve the effects of regulating inflammatory response, promoting endothelial cell proliferation, rapid endothelialization, anti-thrombosis, stabilizing or reversing neoatherosclerosis, and reducing the occurrence of late stent thrombosis. The vascular stent has the advantages of multifunctionality and wide applicability, and its preparation method has the advantages of easy operation and low cost.

[0098] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A multifunctional vascular stent for releasing dual therapeutic gases, characterized in that: It comprises a vascular stent body, wherein the inner wall of the vascular stent body has an NO release coating, and the outer wall of the vascular stent body has a CO release coating; The NO-releasing coating comprises a coating containing phenolic hydroxyl groups and quinone groups and a catalytic functional coating, wherein the catalytic functional coating is formed by in-situ grafting and re-crosslinking a copper complex containing a primary amine group to the coating containing phenolic hydroxyl groups and quinone groups; The CO-releasing coating contains CO drug molecules that release CO gas in response to hydrogen peroxide.

2. The multifunctional vascular stent according to claim 1, characterized in that: The compound used to form the coating containing phenolic hydroxyl groups and quinone groups is selected from at least one of melanin, dopamine, dihydroxyindole, adrenaline, norepinephrine, levodopa, tannic acid, dextrodopa, gallic acid, pyrogallol, epicatechin gallate, epigallocatechin and epigallocatechin gallate.

3. The multifunctional vascular stent according to claim 1 or 2, characterized in that: The primary amine-containing functional molecule with NO catalytic activity has a ligand structure of macrocyclic polyamines, and has a nitrogen-containing heterocycle and multiple carboxyl groups; The ligand of the macrocyclic polyamine is at least one selected from 1,4,7-triazacyclononanecarboxylic acid or its derivatives, 1,4,7,10-tetraazacyclododecanecarboxylic acid or its derivatives and 1,4,8,11-tetraazacyclotetradecanecarboxylic acid or its derivatives.

4. The multifunctional vascular stent according to claim 1, characterized in that: The CO drug molecule is selected from at least one of a metal carbonyl compound, an organic molecule type and an enzyme catalytic activation type; Wherein, the metal carbonyl compounds include CORM-1, CORM-2, CORM-3, CORM-A1, CORM-F10, CORM-F11, CORM-F12, CORM-RM20, CORM-E2, CORM-RM20, Mn(CO)5Br and CORM-401; The organic molecular types include CORM-S1, CORM-S2, CORM-AM, CORM-polymer 1 and CORM-polymer 2; The enzyme catalytic activation types include Fe(CO)4I2, Fe(CO)3I2(PPh3), Fe(CO)3I2(Py), CpFe(CO)2Cl, CpFe(CO)2I, CpFe(CO)2Br, Fe2(μ-S)2(CO), Fe2(μ-SCH2CH3)(CO)6, Fe2(μ-S)2(CO)6 and Fe2(μ-SCH2CHOHCH2OH)2(CO)6.

5. The multifunctional vascular stent according to claim 1 or 4, characterized in that: The CO release coating also contains a carrier for loading the CO drug molecules, and the carrier is a degradable polymer; The degradable polymer is selected from at least one of polytrimethylene carbonate, polylactic acid, polycaprolactone, polyglycolic acid, polylactic acid-co-glycolic acid, glycolide-lactide copolymer, glycolide-caprolactone copolymer, lactide-caprolactone copolymer, polylactic acid-polyethylene glycol copolymer, polyhydroxybutyrate, polyhydroxyvalerate, polyamino acids and polyanhydrides; The molecular weight of the degradable polymer is 50,000-1,000,000 Daltons.

6. The multifunctional vascular stent according to claim 1, characterized in that: The thickness of the CO release coating is 0.1nm-10000nm; and / or, the coating layer containing phenolic hydroxyl groups and quinone groups has a thickness of 5 nm to 25 nm, and the thickness of the catalytic functional coating layer has a thickness of 5 nm to 180 nm; And / or, the material of the vascular stent body is at least one of stainless steel, cobalt and its alloys, titanium and its alloys, platinum and its alloys, magnesium and its alloys, iron and its alloys, and zinc and its alloys.

7. A method for preparing the multifunctional vascular stent according to any one of claims 1 to 6, characterized in that: include: The NO releasing coating is formed on the inner wall of the vascular stent body, and the CO releasing coating is formed on the outer wall of the vascular stent body.

8. The preparation method according to claim 7, characterized in that: The process of forming the NO-releasing coating comprises: immersing the vascular stent body in a solution containing phenolic hydroxyl groups and quinone groups to assemble and form the coating containing phenolic hydroxyl groups and quinone groups, and then in-situ grafting and cross-linking a copper complex containing primary amine groups; The preparation process of the copper complex containing primary amine groups includes: adding soluble copper salt to a ligand solution containing macrocyclic polyamine to form a copper-containing complex, and then adding a primary amine compound for reaction dialysis, the reaction temperature is 1°C-60°C, and the reaction time is 0.5h-200h.

9. The preparation method according to claim 8, characterized in that: The primary amine compound is selected from at least one of polyallylamine, polyethyleneamine, polylysine, polyethylene glycol diamine, polyetheramine, polyamide, melamine, poly-N-isopropylacrylamide, chitosan and derivatives thereof; And / or, the soluble copper salt is selected from at least one of copper sulfate, copper chloride, cuprous chloride, copper acetate, copper acetate, copper fluoride, copper bromide, cuprous bromide, copper iodide, cuprous iodide, copper citrate, copper tartrate, copper propionate, copper nitrate and ammonia copper ion; and / or, the molar ratio of the copper-containing complex to the primary amine compound is (0.01-100): 1; and / or, the molar ratio of the ligand and the copper salt forming the copper-containing complex is (0.01-100): 1; and / or, the molar ratio of primary amine group to phenolic hydroxyl group is (0.03-30):1; And / or, when the copper complex containing primary amine groups is grafted and cross-linked in situ, the reaction temperature is controlled to be 1° C.-60° C. and the reaction time is controlled to be 0.5 h-200 h.

10. The preparation method according to claim 7, characterized in that: The process of forming the CO release coating includes: covering and protecting the inner wall of the vascular stent body by a fixture, spraying a CO drug sustained-release solution on the outer wall of the vascular stent body by an ultrasonic atomization spraying method, and then drying; The preparation process of the CO drug sustained-release solution includes: mixing a degradable polymer, CO drug molecules and an organic solvent; The mass fraction of the CO drug molecules in the CO drug sustained-release solution is 5%-30%; The mass ratio of the degradable polymer to the CO drug molecule is (50-99): (1-50); The organic solvent is selected from at least one of ethyl acetate, dichloromethane, chloroform, N-methylpyrrolidone, dimethyl sulfoxide, tetrahydrofuran, acetone, ether and ethanol.

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