Intravascular stent coating as well as preparation method and application thereof

Abstract

The invention discloses an intravascular stent coating as well as a preparation method and application thereof, and belongs to the technical field of biological materials. The intravascular stent coating is obtained by reaction of a porous coating and an anion solution containing drug molecules, the porous coating contains micro-nano albumin-polypeptide particles stacked on the surface of a stent matrix, and the micro-nano albumin-polypeptide particles are formed by co-assembly of albumin and polypeptide containing hydrophobic amino acid under induction of an oxidizing agent; the porosity of the intravascular stent coating is smaller than that of the porous coating. The intravascular stent coating has excellent biocompatibility and can achieve high loading of drugs, along with degradation of the intravascular stent coating, the released polypeptide and drugs can play dual effects, and the degradation process is beneficial to prolonging the treatment effect of the intravascular stent. The intravascular stent with the intravascular stent coating can reduce or avoid inflammatory response and postoperative complications, and has high application value.

Description

Technical Field

[0001] The present invention relates to the technical field of biomaterials, and in particular to a vascular stent coating and a preparation method and application thereof. Background Art

[0002] Cardiovascular diseases (CVDs) are currently the leading cause of death, and coronary artery disease (CAD) is the most important cause of disability and mortality among all cardiovascular diseases. Clinical treatments for CAD include medication and interventional therapy. For patients with advanced or late-stage CAD, percutaneous coronary intervention (PCI) is the most effective treatment.

[0003] Drug-eluting stents (DES) are currently the most commonly used vascular stents in clinical practice, and they can significantly improve patients' quality of life. However, multiple clinical studies have shown that patients who undergo stent implantation do not survive significantly longer than those who do not. This is because DES-loaded drugs, such as rapamycin and paclitaxel, are inherently anticancer agents that effectively inhibit inflammation and smooth muscle cell proliferation in the diseased vessel where the stent is implanted, significantly reducing early in-stent restenosis. However, these drugs are not cell-selective. While inhibiting inflammation and smooth muscle cells, they also inhibit endothelial cell growth, delaying endothelialization and increasing the risk of late thrombosis. Furthermore, the degradation products of the polylactic acid drug carrier used in DES are acidic, which can easily induce an inflammatory response, leading to various postoperative complications such as in-stent thrombosis, neoatherosclerosis, and neointimal thickening.

[0004] Therefore, there is an urgent need to develop novel stent drug-eluting coating technologies that precisely regulate cell repair, promote endothelialization, and exhibit enhanced biocompatibility. Albumin-based drug-eluting coatings offer an innovative solution. As a multifunctional carrier protein naturally present in the human body, albumin not only possesses excellent biodegradability and biocompatibility, but its abundant surface binding sites also enable efficient loading and controlled release of pro-repair drugs through molecular engineering techniques.

[0005] In view of this, the present invention is proposed. Summary of the Invention

[0006] The purpose of the present invention is to provide a vascular stent coating and a preparation method and application thereof, so as to solve or improve the above technical problems.

[0007] The present invention can be achieved like this: In a first aspect, the present invention provides a vascular stent coating, wherein the vascular stent coating is obtained by reacting a porous coating with an anionic solution containing drug molecules, wherein the porous coating contains micro-nano albumin-polypeptide particles stacked on the surface of the stent matrix, and the micro-nano albumin-polypeptide particles are formed by co-assembly of albumin and a polypeptide containing hydrophobic amino acids under the induction of an oxidant; The porosity of the vascular stent coating is smaller than that of the porous coating.

[0008] In an optional embodiment, the particle size of the micro-nano albumin-polypeptide particles is 800 nm to 2000 nm.

[0009] In an optional embodiment, the number of layers of the porous coating layer is 1 to 10 layers.

[0010] In an optional embodiment, the number of layers of the porous coating layer is 2 to 3 layers.

[0011] In a second aspect, the present invention provides a method for preparing a vascular stent coating as described in any of the aforementioned embodiments, comprising the following steps: mixing a stent matrix with a mixed solution containing an oxidant, albumin, and a polypeptide, so that the albumin and the polypeptide containing hydrophobic amino acids co-assemble under the induction of the oxidant to obtain a porous coating containing micro-nano albumin-polypeptide particles stacked on the surface of the stent matrix; and reacting the porous coating with an anionic solution containing drug molecules to obtain the vascular stent coating.

[0012] In an optional embodiment, when the number of layers of the porous coating is greater than or equal to 2, after obtaining the x-th layer of the porous coating, the obtained x-th layer of the porous coating is washed and continued to be placed in a new mixed solution without drying, and the next layer of the porous coating is prepared under the same co-assembly reaction conditions until the last layer of the porous coating is obtained; the number of layers of the last layer of the porous coating is defined as y, x<y.

[0013] In an optional embodiment, the co-assembly reaction has at least one of the following characteristics: Feature 1: The temperature of the co-assembly reaction is 15°C~60°C; Feature 2: The co-assembly reaction time is ≥ 2 h; Feature 3: The pH value of the co-assembly reaction is 3~8.

[0014] In an optional embodiment, the temperature of the co-assembly reaction is 35°C to 50°C.

[0015] In an optional embodiment, the co-assembly reaction time is 2 hours to 72 hours.

[0016] In an optional embodiment, the co-assembly reaction time is 4 hours to 12 hours.

[0017] In an optional embodiment, the pH value of the mixed solution is 3-8.

[0018] In an optional embodiment, the mixed solution is obtained by mixing an oxidant solution, an albumin solution, and a polypeptide solution; The volume ratio of the oxidant solution, the albumin solution and the polypeptide solution is 1:1:0.01 to 1:1:2; the concentration of the oxidant solution is 0.01 mg / mL~100 mg / mL, the concentration of the albumin solution is 0.01 mg / mL~100 mg / mL, and the concentration of the polypeptide solution is 0.01 mg / mL~100 mg / mL.

[0019] In an optional embodiment, the concentration of the oxidant solution is 1 mg / mL to 10 mg / mL.

[0020] In an optional embodiment, the concentration of the oxidant solution is 1 mg / mL to 5 mg / mL.

[0021] In an optional embodiment, the concentration of the albumin solution is 0.5 mg / mL to 10 mg / mL.

[0022] In an optional embodiment, the concentration of the albumin solution is 1 mg / mL to 2 mg / mL.

[0023] In an optional embodiment, the concentration of the polypeptide solution is 0.01 mg / mL to 10 mg / mL.

[0024] In an alternative embodiment, the concentration of the polypeptide solution is 0.05 mg / mL to 2 mg / mL. In an alternative embodiment, the total concentration of albumin and polypeptide in the mixed solution is 0.01 mmol / L to 10 mmol / L, and the molar ratio of albumin to polypeptide is 0.01:1 to 10:1.

[0025] In an optional embodiment, the total concentration of albumin and polypeptide in the mixed solution is 0.01 mmol / L to 5 mmol / L.

[0026] In an alternative embodiment, the molar ratio of albumin to polypeptide is from 0.05:1 to 5:1.

[0027] In an alternative embodiment, the oxidant comprises at least one of an inorganic oxidant and an organic oxidant.

[0028] In an alternative embodiment, the inorganic oxidizing agent comprises at least one of persulfate, chlorate, perchlorate, perchlorate, dichromate, periodate, permanganate, nitrate, and an inorganic peroxide.

[0029] In an alternative embodiment, the organic oxidant comprises at least one of dichlorine peroxide and peracetic acid.

[0030] In an optional embodiment, the isoelectric point of the polypeptide is 3-6.5.

[0031] In an optional embodiment, the polypeptide includes an anticoagulant functional polypeptide, an anti-inflammatory functional polypeptide, and a cell growth promoting polypeptide.

[0032] In an alternative embodiment, the polypeptide includes a polypeptide having anticoagulant function and having hydrophobic amino acids.

[0033] In an optional embodiment, the anticoagulant functional polypeptide comprises at least one of a thrombomodulin-derived peptide, a snake venom anticoagulant peptide, and bivalirudin; And / or, the anti-inflammatory functional polypeptide includes at least one of thymosin and antimicrobial peptide; And / or the cell growth promoting polypeptide includes at least one of insulin, growth hormone, somatostatin, VEGF-derived peptide, EGF, bFGF and IGF-1.

[0034] In an optional embodiment, the cleaning liquid used for cleaning is distilled water.

[0035] In an optional embodiment, after the final porous coating layer is obtained, the entire porous coating layer is first cleaned and dried, and then reacted with the anion solution containing drug molecules.

[0036] In an optional embodiment, the drying is performed at 10°C to 45°C.

[0037] In an alternative embodiment, the reaction of the porous coating with the anionic solution containing drug molecules includes at least one of the following features: Feature 4: The reaction temperature of the porous coating and the anionic solution containing drug molecules is -20°C to 50°C; Feature 5: The reaction time between the porous coating and the anionic solution containing drug molecules is ≥ 1 min; Feature 6: The pH value of the reaction between the porous coating and the anionic solution containing drug molecules is 1~14.

[0038] In an optional embodiment, the reaction time of the porous coating and the anion solution containing drug molecules is 5 min to 60 min.

[0039] In an optional embodiment, the concentration of the anion solution is 0.1 mmol / L to 10 mmol / L.

[0040] In an optional embodiment, the concentration of the anion solution is 2 mmol / L to 6 mmol / L.

[0041] In an optional embodiment, the anion solution includes at least one of a phosphoric acid solution, a phosphate solution, a hydrogen phosphate solution, and a dihydrogen phosphate solution.

[0042] In an alternative embodiment, the anion solution comprises a phosphate solution.

[0043] In an optional embodiment, the temperature of the anion solution containing drug molecules is 0°C to 37°C.

[0044] In an optional embodiment, the temperature of the anion solution containing drug molecules is 4°C to 25°C.

[0045] In an optional embodiment, the concentration of the drug molecules in the anionic solution is 0.1 mmol / L to 10 mmol / L.

[0046] In an optional embodiment, the concentration of the drug molecules in the anionic solution is 1 mmol / L to 5 mmol / L.

[0047] In an optional embodiment, the anionic solution containing the drug molecules is obtained by mixing the drug solution with the anionic solution; Among them, the drug solution is obtained by dissolving drug molecules in a solvent.

[0048] In an optional embodiment, the concentration of the drug solution is 0.01 mg / mL to 100 mg / mL.

[0049] In an optional embodiment, the concentration of the drug solution is 0.01 mg / mL to 10 mg / mL.

[0050] In an optional embodiment, the concentration of the drug solution is 1 mg / mL to 5 mg / mL.

[0051] In an optional embodiment, the solvent in the drug solution includes at least one of ultrapure water, physiological saline, alcohol, anhydrous ethanol, phosphate buffered saline and dimethyl sulfoxide.

[0052] In an optional embodiment, the drug molecule includes at least one of a chemically synthesized drug, a biomass drug, a gene therapy drug, an antibody, a Chinese herbal medicine, and a plant extract.

[0053] In an optional embodiment, the chemically synthesized drug includes at least one of an anti-inflammatory drug, a statin, an antibiotic, and an anti-tumor drug.

[0054] In an optional embodiment, the anti-tumor drug includes at least one of rapamycin, paclitaxel and a targeted drug.

[0055] In an optional embodiment, the biomass medicine includes at least one of a monoclonal antibody, a vaccine, a cytokine, and an exosome.

[0056] In an optional embodiment, the gene therapy drug includes at least one of a drug for targeting gene expression and a drug for gene repair.

[0057] In an optional embodiment, the Chinese herbal medicine and plant extracts include at least one of artemisinin and its derivatives, colchicine and its derivatives, oregano and its derivatives, and allicin and its derivatives.

[0058] In an optional embodiment, the scaffold matrix includes at least one of a metal material, an inorganic material, a polymer material, a natural biological material, and an artificially synthesized polypeptide hydrogel material.

[0059] In an optional embodiment, the metal material includes at least one of cobalt-based alloys, titanium and its alloys, nickel-titanium alloys, platinum and its alloys, magnesium and its alloys, iron and its alloys, and zinc and its alloys.

[0060] In an optional embodiment, the inorganic material includes at least one of titanium oxide and its nanotubes, carbon materials, silicon, silicon dioxide, calcium phosphate, silicon nitride, silicon carbide, aluminosilicate, calcium aluminum system, bioglass, titanium nitride and biomedical micro-nanoparticles.

[0061] In an optional embodiment, the biomedical micro-nanoparticles include at least one of ferroferric oxide nanoparticles, silicon dioxide nanoparticles, titanium oxide nanoparticles, and zinc oxide nanoparticles.

[0062] In an optional embodiment, the polymer material includes at least one of polyester, polyethylene, polyvinyl chloride, polytetrafluoroethylene, polyurethane, polystyrene, polyvinyl alcohol, polypropylene, polyoxymethylene, polycarbonate, carbon copolymer, polyglycolic acid, polymethyl methacrylate, polyvinyl acetate, polylactic acid, glycolide-lactide copolymer, polytrimethylene carbonate, polycaprolactone, polyhydroxyalkanoate, polybutylene succinate, polyamide, polydioxanone, epoxy resin, silicone rubber, silicone gel, polyacrylic acid and its derivatives, polyethylene glycol and its derivatives.

[0063] In an alternative embodiment, the natural biomaterial comprises at least one of decellularized tissues and organs of animal origin, gelatin, collagen, fibrin, silk protein, keratin, and polysaccharide.

[0064] In alternative embodiments, the animal-derived decellularized tissues and organs include at least one of blood vessels, valves, hearts, bones, lungs, ligaments, bladders, mucosa, and corneas.

[0065] In an optional embodiment, the polysaccharide includes at least one of sodium hyaluronate, sodium alginate, agarose, plastic starch material, cellulose, hemicellulose, lignin, chitin and derivatives thereof.

[0066] In an optional embodiment, the artificially synthesized polypeptide hydrogel material includes at least one of L-lysine and poly-L-glutamic acid.

[0067] In a third aspect, the present invention provides a vascular stent, which comprises a stent matrix and a vascular stent coating according to any one of the aforementioned embodiments.

[0068] The beneficial effects of the present invention include: The vascular stent coating provided by the present invention is obtained by reacting a porous coating with an anionic solution containing drug molecules. The porous coating contains micro-nano albumin-polypeptide particles stacked on the surface of the stent matrix. The micro-nano albumin-polypeptide particles are formed by co-assembly of albumin and a polypeptide containing hydrophobic amino acids under the induction of an oxidant. The porosity of the vascular stent coating is less than that of the porous coating.

[0069] This porous coating exhibits excellent biocompatibility, and its degradation products, similar in nature to those of protein degradation products in the human body, rarely induce an immune response, thereby reducing or avoiding inflammatory responses and postoperative complications, making it an excellent drug carrier. Albumin, as a transport protein in the body, effectively protects drugs from immune recognition and degradation, providing a degree of "immune escape" and extending their half-life. Furthermore, albumin exhibits excellent passive anti-adhesion properties. Combined with anticoagulant peptides or drugs, it can further enhance the long-lasting anticoagulant effect of the stent coating. Furthermore, the coating's porous structure reconstitutes and self-encapsulates in anionic solutions containing drug molecules, facilitating efficient drug loading. This loading process has minimal impact on drug activity, thereby enhancing drug bioavailability. Furthermore, the drug and peptide can be slowly released into the localized lesion as the stent coating degrades, exerting their dual efficacy and long-term physiological regulation of the lesion. This coating holds promise as a drug-eluting stent coating with promising applications. BRIEF DESCRIPTION OF THE DRAWINGS

[0070] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for use in the embodiments. It should be understood that the following drawings only illustrate certain embodiments of the present invention and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other relevant drawings can be obtained based on these drawings without paying any creative work.

[0071] Figure 1 This is a scanning electron microscope image of the porous coating and the vascular stent coating provided in Example 1 of Experimental Example 1; Figure 2 This is a scanning electron micrograph of the porous coating and the vascular stent coating provided by the control group in Experimental Example 1; Figure 3 This is a result diagram of the vascular stent in step 1 and step 2 provided in Example 1 of Experimental Example 1 under a 3D profilometer; Figure 4 This is a graph showing the thrombin time test results of each sample after the immersion experiment in Experimental Example 2; Figure 5 This is a graph showing the thrombin time test results of each soaking solution after the soaking experiment in Experimental Example 2; Figure 6 This is a graph showing the colchicine release results of each sample in Experiment 3 (1) when immersed in an anionic solution for different time periods; Figure 7 This is a graph showing the colchicine release results of each sample in Experiment 3 (2) when immersed in anionic solution for the same time; Figure 8 The graph is a graph showing the colchicine release results of each sample in Experimental Example 4 when immersed in anionic solution for the same time; Figure 9 This is a graph showing the colchicine release results for each sample in Experimental Example 5 when immersed in anionic solution for the same time; Figure 10 The graph is a graph showing the colchicine release results of each sample in Experimental Example 6 when immersed in anionic solution for the same time; Figure 11 This is a graph showing the colchicine release results for each sample in Experimental Example 7 when immersed in anionic solution for the same time. DETAILED DESCRIPTION

[0072] To make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention are described clearly and completely below. Where specific conditions are not specified in the embodiments, conventional conditions or conditions recommended by the manufacturer are used. Where the manufacturer of the reagents or instruments is not specified, all are conventional products that can be purchased commercially.

[0073] The vascular stent coating provided by the present invention and its preparation method and application are described in detail below.

[0074] The invention provides a vascular stent coating, which is obtained by reacting a porous coating with an anion solution containing drug molecules.

[0075] The porous coating contains micro-nano albumin-polypeptide particles stacked on the surface of the scaffold matrix. The micro-nano albumin-polypeptide particles are co-assembled by albumin and polypeptides containing hydrophobic amino acids under the induction of oxidants. Specifically, under the induction of oxygen free radicals, the disulfide bonds in the albumin molecules are broken and oxidized to form stable intermediate sulfides. In this process, the protein structure stretches and its side chains expose a large number of hydrophobic groups. In an aqueous solution system, the hydrophobic groups of albumin and the hydrophobic groups of the hydrophobic amino acids in the polypeptide combine with each other, thereby assembling together to form hydrophobic nucleation sites that are easier to avoid water. The co-assembled micro-nano albumin-polypeptide particles are deposited and stacked on the surface of the matrix, and micro-nano pores are formed between the particles, thereby obtaining a porous coating with higher stability. During the co-assembly process, the peptide can be inserted into the reaction between the oxidant and albumin, thereby increasing the degree of intermolecular aggregation. Within a short period of time (4 hours), it can quickly assemble and aggregate to form large-sized particles. After the particles are formed, they quickly stack on the substrate surface due to gravity, which is more conducive to the formation of micro-nanopore structures between the particles. Particles formed solely by the oxidant and protein require a longer time to assemble and aggregate to form particles. During this process, they mainly deposit small particles on the material surface, stack, assemble and fuse, and form a uniform and dense coating.

[0076] In some optional embodiments, the particle size of the micro-nano albumin-polypeptide particles can be 800 nm to 2000 nm.

[0077] Furthermore, based on the loose and porous characteristics of the porous coating, the porous coating undergoes reassembly in an anionic solution containing drug molecules to achieve drug loading and encapsulation. In this process, the drug molecule solution enters the interior of the porous coating through the capillary effect and is adsorbed in the protein-polypeptide pore structure based on hydrogen bonding, hydrophobicity, electrostatic interactions, etc. At the same time, due to the hydrophilic effect of the anionic groups, the hydrophobic core of the porous coating further gathers internally, and the hydrophilic groups extend in the solution, inducing the reconstruction of the protein-polypeptide pore structure. Under the trend of thermodynamics and minimum interfacial energy, the porous coating is reassembled from a loose porous structure into a dense and firm coating. Therefore, the porosity of the vascular stent coating is less than that of the porous coating, that is, the density of the vascular stent coating is higher than that of the porous coating.

[0078] In some optional embodiments, the number of layers of the porous coating layer may be 1 to 10 layers, and illustratively, the number of layers may be 1, 2, 3, 4, 5, 6, 7, 8, 9, or 10. In some other optional embodiments, it is not excluded that the number of layers of the porous coating layer exceeds 10. In some preferred embodiments, the number of layers of the porous coating layer may be 2 to 3 layers.

[0079] As mentioned above, the porous coating provided by the present invention has excellent biocompatibility, and the degradation products are similar in nature to the protein degradation products in the human body, and will hardly induce the body's immune response, thereby reducing or avoiding inflammatory reactions and postoperative complications, becoming an excellent drug carrier. Among them, albumin acts as a transport protein in the body, which can effectively protect drugs from being recognized and degraded by the immune system, has a certain "immune escape" function, and can prolong the half-life of drugs. In addition, albumin has an excellent passive anti-adhesion effect, and when combined with polypeptides or drugs with anticoagulant function, it can further exert the long-term anticoagulant effect of the vascular stent coating. In addition, the porous structure of the coating is reconstructed and self-encapsulated in an anionic solution containing drug molecules, which is conducive to the efficient loading of drugs, and the drug loading process has almost no effect on the activity of the drug, which can improve the bioavailability of the drug. In addition, the drug and polypeptide can be slowly released to the local lesion as the vascular stent coating degrades, exerting the dual efficacy of the drug and polypeptide, and exerting the physiological function of regulating the lesion for a long time, and is expected to be a drug-eluting stent coating with potential application value.

[0080] Accordingly, the present invention also provides a method for preparing the above-mentioned vascular stent coating, comprising the following steps: Step 1: The scaffold matrix is mixed with a mixed solution containing an oxidant, albumin and a polypeptide, so that the albumin and the polypeptide containing hydrophobic amino acids co-assemble under the induction of the oxidant to obtain a porous coating containing micro-nano albumin-polypeptide particles stacked on the surface of the scaffold matrix.

[0081] When the number of layers of the porous coating is greater than or equal to 2, after obtaining the x-th layer of the porous coating, the obtained x-th layer of the porous coating is washed and placed in a new mixed solution without drying, and the next layer of the porous coating is prepared under the same co-assembly reaction conditions until the last layer of the porous coating is obtained; the number of layers of the last layer of the porous coating is defined as y, x<y.

[0082] It should be noted that the components and proportions of the mixed solutions used to prepare each porous coating layer are the same.

[0083] Taking the porous coating with two layers as an example, the preparation of the entire porous coating includes: mixing the scaffold matrix with a mixed solution a containing a mixed solution of an oxidant, albumin and a polypeptide, so that the albumin in the mixed solution a and the polypeptide containing hydrophobic amino acids undergo a co-assembly reaction under the induction of the oxidant to obtain a first layer of porous coating; washing the scaffold matrix with the first layer of porous coating, and then mixing it with a mixed solution b containing a mixed solution of an oxidant, albumin and a polypeptide, so that the albumin in the mixed solution b and the polypeptide containing hydrophobic amino acids undergo a co-assembly reaction under the induction of the oxidant, thereby obtaining a second layer of porous coating on the surface of the first layer of porous coating.

[0084] When the number of porous coating layers is 3 or more, the second porous coating layer can be obtained by referring to the above preparation method when the number of porous coating layers is 2; then, the preparation method of the second layer is referred to to prepare other porous coating layers until the final porous coating layer is obtained.

[0085] For example, the co-assembly reaction temperature can be 15°C to 60°C, such as 15°C, 20°C, 25°C, 30°C, 35°C, 40°C, 45°C, 50°C, 55°C, or 60°C, or other values within the range of 15°C to 60°C. If the co-assembly reaction temperature is lower than 15°C, the porous coating may be too thin; if the co-assembly reaction temperature is higher than 60°C, on the one hand, the porous coating may be too thick, and on the other hand, it may also adversely affect the activity of the albumin and polypeptide. In some preferred embodiments, the co-assembly reaction temperature can be 35°C to 50°C.

[0086] For example, the co-assembly reaction time can be ≥ 2 hours, such as 2 hours, 8 hours, 12 hours, 24 hours, 48 hours, 60 hours, 72 hours, 84 hours, 96 hours, or 108 hours, or other values within the range of ≥ 2 hours. In some preferred embodiments, the co-assembly reaction time is 2 hours to 72 hours; in some more preferred embodiments, the co-assembly reaction time is 4 hours to 12 hours. Under these preferred or more preferred time conditions, a porous coating with moderate thickness and high albumin and polypeptide activity can be obtained.

[0087] For example, the pH value of the co-assembly reaction can be 3 to 8, such as 3, 3.5, 4, 4.5, 5, 5.5, 6, 6.5, 7, 7.5, or 8, or other values within the range of 3 to 8. If the pH value of the co-assembly reaction is less than 3 or greater than 8, the conformational unfolding of the albumin is easily affected, making it difficult to form the coating.

[0088] For example, the pH value of the mixed solution can be 3 to 8. If the pH value of the mixed solution is less than 3, it is not conducive to the proper conformational unfolding of the albumin and the protein self-assembly, making it difficult to form a coating; if the pH value of the mixed solution is greater than 8, it is not conducive to the conformational unfolding of the albumin in the solution, making it difficult to form a coating.

[0089] For example, the mixed solution is obtained by mixing an oxidant solution, an albumin solution, and a polypeptide solution, wherein the volume ratio of the oxidant solution, the albumin solution, and the polypeptide solution can be 1:1:0.01 to 1:1:2, such as 1:1:0.01, 1:1:0.02, 1:1:0.03, 1:1:0.04, 1:1:0.05, 1:1:0.06, 1:1:0.07, 1:1:0.08, 1:1:0.09, 1:1:1, 1:1:1.5, or 1:1:12, or other values within the range of 1:1:0.01 to 1:1:2. The concentrations of the oxidant solution, the albumin solution, and the polypeptide solution can each independently be in the range of 0.01 mg / mL to 100 mg / mL, such as 0.01 mg / mL, 0.05 mg / mL, 0.1 mg / mL, 0.5 mg / mL, 1 mg / mL, 2 mg / mL, 8 mg / mL, 5 mg / mL, 10 mg / mL, 15 mg / mL, 20 mg / mL, 25 mg / mL, 30 mg / mL, 35 mg / mL, 40 mg / mL, 45 mg / mL, 50 mg / mL, 55 mg / mL, 60 mg / mL, 65 mg / mL, 70 mg / mL, 75 mg / mL, 80 mg / mL, 85 mg / mL, 90 mg / mL, 95 mg / mL, or 100 mg / mL, or other values within the range of 0.01 mg / mL to 100 mg / mL.

[0090] In some preferred embodiments, the concentration of the oxidant solution is 1 mg / mL to 10 mg / mL; in some more preferred embodiments, the concentration of the oxidant solution is 1 mg / mL to 5 mg / mL.

[0091] In some preferred embodiments, the concentration of the albumin solution is 0.5 mg / mL to 10 mg / mL; in some more preferred embodiments, the concentration of the albumin solution is 1 mg / mL to 2 mg / mL.

[0092] In some preferred embodiments, the concentration of the polypeptide solution is 0.01 mg / mL to 10 mg / mL; in some more preferred embodiments, the concentration of the polypeptide solution is 0.05 mg / mL to 2 mg / mL.

[0093] In some optional embodiments, the total concentration of albumin and polypeptide in the mixed solution can be 0.01mmol / L~10mmol / L, such as 0.01mmol / L, 0.02mmol / L, 0.05mmol / L, 0.1mmol / L, 0.2mmol / L, 0.5mmol / L, 1mmol / L, 1.5mmol / L, 2mmol / L, 2.5mmol / L, 3mmol / L, 3.5mmol / L, 4mmol / L, 4.5mmol / L, 5mmol / L, 6mmol / L, 7mmol / L, 8mmol / L, 9mmol / L or 10mmol / L, etc., and can also be other values within the range of 0.01mmol / L~10mmol / L, preferably 0.01mmol / L~5mmol / L. The molar ratio of albumin to polypeptide can be from 0.01:1 to 10:1, such as 0.01:1, 0.05:1, 0.1:1, 0.5:1, 1:1, 1.5:1, 2:1, 2.5:1, 3:1, 3.5:1, 4:1, 4.5:1, 5:1, 6:1, 7:1, 8:1, 9:1 or 10:1, etc., or other values within the range of 0.01:1 to 10:1, preferably 0.05:1 to 5:1.

[0094] Continuing from the above, if the albumin content in the mixed solution is too low, it is not conducive to the formation of a coating; if the albumin content is too high, the molecular distance is extremely small, sedimentation is likely to occur, and the formed coating is thick and unstable. If the polypeptide content in the mixed solution is too low, on the one hand, it is not conducive to the construction of a protein polypeptide coating with a micro-nano pore structure, and on the other hand, it is not conducive to ensuring that the polypeptide can exert its biological function for a long time; if the polypeptide content is too high, the constructed protein polypeptide-based coating is unstable and relatively easy to degrade. If the oxidant content in the mixed solution is too low, the albumin deformation degree will be too low, making it difficult to form a protein coating; if the oxidant content is too high, it will easily lead to excessive deformation of the albumin and polypeptide molecules, resulting in loss of activity and biological function. In addition, the above-mentioned albumin and polypeptide must also meet a specific ratio to form a protein polypeptide-based coating with a certain micro-nano pore structure for subsequent drug loading.

[0095] For example, the oxidant may include at least one of an inorganic oxidant and an organic oxidant. The inorganic oxidant may illustratively include at least one of persulfate, chlorate, perchlorate, perchlorate, dichromate, periodate, permanganate, nitrate, and an inorganic peroxide. The inorganic peroxide may illustratively, but not limitatively, include at least one of Na2O2, K2O2, MgO2, CaO2, BaO2, and H2O2. The organic oxidant may illustratively include at least one of dichlorine peroxide and peracetic acid.

[0096] For example, the isoelectric point of the polypeptide is 3 to 6.5, such as 3, 3.5, 4, 4.5, 5, 5.5, 6, or 6.5, and may also be other values or ranges within the range of 3 to 6.5. By specifically controlling the isoelectric point of the polypeptide within the range of 3 to 6.5, it coincides with the isoelectric point of albumin, which facilitates the binding and assembly of groups during the co-assembly process and avoids electrostatic repulsion.

[0097] The polypeptides may include anticoagulant polypeptides, anti-inflammatory polypeptides, and cell growth-promoting polypeptides. The anticoagulant polypeptides may include at least one of thrombomodulin-derived peptides, snake venom anticoagulant peptides, and bivalirudin. The anti-inflammatory polypeptides may include at least one of thymosin (such as thymosin β4) and antimicrobial peptides (such as defensin, cecropin, and LL-37 antimicrobial peptide). The cell growth-promoting polypeptides may include at least one of insulin, growth hormone, somatostatin, VEGF-derived peptides, EGF, bFGF, and IGF-1. Preferably, the polypeptides include those with anticoagulant function and hydrophobic amino acids.

[0098] In the present invention, the purpose of cleaning the porous coating layer is to remove substances that are not firmly adhered to the surface. For example, the cleaning solution used to clean the porous coating layer can be distilled water.

[0099] Before obtaining the last layer of porous coating, the porous coatings of other layers are cleaned and not dried. The reason is that after drying, the pore structure of the coating is exposed. When preparing the next layer, the reaction solution will more easily enter the pore structure of the coating through the capillary effect, forming nanoparticles in situ to block the pore structure and form a dense coating, which makes it impossible to achieve subsequent drug loading.

[0100] After the final porous coating layer is obtained, the entire porous coating layer is first cleaned and dried, and then reacted with an anionic solution containing drug molecules.

[0101] Illustratively, drying can be performed at 10°C to 45°C (eg, 10°C, 15°C, 20°C, 25°C, 30°C, 35°C, 40°C, or 45°C).

[0102] The drying process described above can eliminate the internal stress of the porous coating. If the internal stress of the porous coating is too great, it will be difficult to further gather the hydrophobic core of the porous coating, and the hydrophilic groups will expand in the solution, inducing the reconstruction of the protein-polypeptide pore structure. As a result, under the trend of thermodynamics driven by the minimum interfacial energy, the porous coating will reassemble from a loose porous structure into a dense and firm coating, making it difficult to obtain a dense vascular stent coating, making it difficult to achieve high drug loading and long-term sustained release.

[0103] Step 2: reacting the porous coating with an anionic solution containing drug molecules to obtain a vascular stent coating.

[0104] For example, the reaction temperature of the porous coating layer and the anionic solution containing drug molecules can be between -20°C and 50°C, such as -20°C, -15°C, -10°C, -5°C, 0°C, 5°C, 10°C, 15°C, 20°C, 25°C, 30°C, 35°C, 40°C, 45°C, or 50°C, or other values within the range of -20°C to 50°C. If the reaction temperature of the porous coating layer and the anionic solution containing drug molecules is higher than 50°C, it is not conducive to retaining the physiological activity of proteins and polypeptides.

[0105] For example, the reaction time of the porous coating layer with the anionic solution containing drug molecules can be ≥1 min, such as 1 min, 2 min, 5 min, 10 min, 15 min, 20 min, 25 min, 30 min, 40 min, 50 min, 60 min, 70 min, 80 min, 90 min or 100 min, etc., or other values within the range of ≥1 min. If the reaction time of the porous coating layer with the anionic solution containing drug molecules is shorter than 1 min, the coating layer has not yet been completely reassembled and still has some pore structure, and the loaded drug molecules are easily separated from the coating layer during cleaning. In some preferred embodiments, the reaction time of the porous coating layer with the anionic solution containing drug molecules is 5 min to 60 min. If the reaction time of the porous coating layer with the anionic solution containing drug molecules is too long, the coating layer is over-reconstructed, which is not conducive to drug retention.

[0106] For example, the pH value of the reaction between the porous coating layer and the anionic solution containing drug molecules can be 1 to 14, such as 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13 or 14, or other values within the range of 1 to 14. In some preferred embodiments, the pH value of the reaction between the porous coating layer and the anionic solution containing drug molecules is 6 to 9.

[0107] The anion solution may illustratively include at least one of a phosphoric acid solution, a phosphate solution, a hydrogen phosphate solution, and a dihydrogen phosphate solution. In some preferred embodiments, the anion solution includes a phosphate solution. The solvent in the anion solution may be, for example, water.

[0108] The present invention uses the above-mentioned substances as anionic solutions because: phosphate has a strong hydration effect, which can make the coating easier to reassemble by affecting the hydrophilic and hydrophobic groups and hydrogen bonds of the coating and the drug, thereby effectively loading drug molecules. Specifically, the above-mentioned anionic solution has a stronger hydrophilicity than albumin, and is thus easier to combine with water to form hydrogen bonds than albumin. In the process of mixing the porous coating with the anionic solution, the anionic solution has a stronger hydrophilicity than the porous coating. Therefore, the anions will preemptively bind to the water molecules in the solution system in the porous coating under the solution system, which is equivalent to further squeezing the hydrophobic nucleus, thereby causing the hydrophobic nucleus to collapse. During the collapse process, based on the effect of water and the trend of thermodynamics to drive the minimum interfacial energy, the hydrophobic nucleus will transition to the state of the lowest interfacial energy, thereby driving the entire coating to gradually become smooth and dense, and, during the above-mentioned transition process, the drug molecules can be effectively encapsulated in the micro-nano pore structure, achieving high load and long-term sustained release.

[0109] For example, the concentration of the anionic solution can be 0.1 mmol / L to 10 mmol / L, such as 0.1 mmol / L, 0.5 mmol / L, 1 mmol / L, 2 mmol / L, 3 mmol / L, 4 mmol / L, 5 mmol / L, 5.5 mmol / L, 6 mmol / L, 6.5 mmol / L, 7 mmol / L, 7.5 mmol / L, 8 mmol / L, 8.5 mmol / L, 9 mmol / L, 9.5 mmol / L, or 10 mmol / L, or other values within the range of 0.1 mmol / L to 10 mmol / L. If the concentration of the anionic solution is less than 0.1 mmol / L, it is not conducive to the complete rearrangement of the pore structure of the coating and self-encapsulation; if the concentration of the anionic solution is greater than 10 mmol / L, it is not conducive to sufficient time for the drug to be effectively loaded. In some preferred embodiments, the concentration of the anionic solution is 2 mmol / L to 6 mmol / L.

[0110] For example, the temperature of the anionic solution containing the drug molecules can be 0°C to 37°C, such as 0°C, 5°C, 10°C, 15°C, 20°C, 25°C, 30°C, 35°C, or 37°C, or other values within the range of 0°C to 37°C. If the temperature of the anionic solution is below 0°C, it is not conducive to rapid encapsulation of the coating to maintain a high drug loading; if the temperature of the anionic solution is above 37°C, it is not conducive to maintaining the functional activity of the drug and polypeptide. In some preferred embodiments, the temperature of the anionic solution containing the drug molecules is 4°C to 25°C.

[0111] For example, the concentration of the drug molecule in the anionic solution can be 0.1 mmol / L to 10 mmol / L, such as 0.1 mmol / L, 0.2 mmol / L, 0.5 mmol / L, 0.8 mmol / L, 1 mmol / L, 1.2 mmol / L, 1.5 mmol / L, 2 mmol / L, 2.5 mmol / L, 3 mmol / L, 3.5 mmol / L, 4 mmol / L, 5 mmol / L, 8 mmol / L, or 10 mmol / L, or other values within the range of 0.1 mmol / L to 10 mmol / L. In some preferred embodiments, the concentration of the drug molecule in the anionic solution can be 1 mmol / L to 5 mmol / L, such as 1 mmol / L, 1.5 mmol / L, 2 mmol / L, 2.5 mmol / L, 3 mmol / L, 3.5 mmol / L, 4 mmol / L, 4.5 mmol / L, or 5 mmol / L. If the concentration of drug molecules in the anionic solution is too high, it will no longer effectively increase the drug loading capacity, resulting in reagent waste. At the same time, excessive solution ionic strength may also affect the self-encapsulation process of the anion.

[0112] In some optional embodiments, the anion solution containing the drug molecules is obtained by mixing a drug solution with an anion solution.

[0113] The drug solution is obtained by dissolving the drug molecules in a solvent. The concentration of the drug solution can be 0.01 mg / mL to 100 mg / mL, such as 0.01 mg / mL, 0.05 mg / mL, 0.1 mg / mL, 0.5 mg / mL, 1 mg / mL, 5 mg / mL, 10 mg / mL, 20 mg / mL, 30 mg / mL, 40 mg / mL, 50 mg / mL, 60 mg / mL, 70 mg / mL, 80 mg / mL, 90 mg / mL or 100 mg / mL, or other values within the range of 0.01 mg / mL to 100 mg / mL.

[0114] In some preferred embodiments, the concentration of the drug solution is 0.01 mg / mL to 10 mg / mL; in some more preferred embodiments, the concentration of the drug solution is 1 mg / mL to 5 mg / mL.

[0115] The solvent in the drug solution may illustratively include at least one of ultrapure water, physiological saline, alcohol, anhydrous ethanol, phosphate buffered saline, and dimethyl sulfoxide.

[0116] The drug molecules may illustratively include at least one of chemically synthesized drugs, biomass drugs, gene therapy drugs, antibodies, Chinese herbal medicines, and plant extracts.

[0117] The chemically synthesized drugs may exemplarily include at least one of anti-inflammatory drugs, statins, antibiotics, and anti-tumor drugs. The anti-tumor drugs may exemplarily include at least one of rapamycin, paclitaxel, and targeted drugs.

[0118] The biomass medicine may illustratively include at least one of monoclonal antibodies, vaccines, cytokines, and exosomes.

[0119] Gene therapy drugs may illustratively include at least one of drugs for targeting gene expression (such as at least one of RNA drugs and siRNA drugs) and drugs for gene repair (such as CRISPR drugs).

[0120] The Chinese herbal medicine and plant extracts may illustratively include at least one of artemisinin and its derivatives, colchicine and its derivatives, oregano and its derivatives, and allicin and its derivatives.

[0121] After the porous coating reacts with the anionic solution containing drug molecules, it is further dried. For example, the drying process can be carried out in a constant temperature drying oven at 37° C. for 12 hours.

[0122] For example, the scaffold matrix may include at least one of a metal material, an inorganic material, a polymer material, a natural biological material, and an artificially synthesized polypeptide hydrogel material.

[0123] The metal material may illustratively include at least one of cobalt-based alloys, titanium and its alloys, nickel-titanium alloys, platinum and its alloys, magnesium and its alloys, iron and its alloys, and zinc and its alloys.

[0124] The inorganic material may illustratively include at least one of titanium oxide and its nanotubes, carbon materials, silicon, silicon dioxide, calcium phosphate, silicon nitride, silicon carbide, aluminosilicate, calcium aluminum system, bioglass, titanium nitride and biomedical micro-nanoparticles.

[0125] The biomedical micro-nanoparticles may illustratively include at least one of ferroferric oxide nanoparticles, silicon dioxide nanoparticles, titanium oxide nanoparticles, and zinc oxide nanoparticles.

[0126] The polymer material may illustratively include at least one of polyester, polyethylene, polyvinyl chloride, polytetrafluoroethylene, polyurethane, polystyrene, polyvinyl alcohol, polypropylene, polyoxymethylene, polycarbonate, carbon copolymer, polyglycolic acid, polymethyl methacrylate, polyvinyl acetate, polylactic acid, glycolide-lactide copolymer, polytrimethylene carbonate, polycaprolactone, polyhydroxyalkanoate, polybutylene succinate, polyamide, polydioxanone, epoxy resin, silicone rubber, silicone gel, polyacrylic acid and its derivatives, polyethylene glycol and its derivatives.

[0127] The natural biomaterial may illustratively include at least one of animal-derived decellularized tissues and organs, gelatin, collagen, fibrin, silk protein, keratin, and polysaccharides. The animal-derived decellularized tissues and organs may illustratively include at least one of blood vessels, valves, heart, bone, lungs, ligaments, bladder, mucosa, and cornea. The polysaccharide may illustratively include at least one of sodium hyaluronate, sodium alginate, agarose, plastic starch materials, cellulose, hemicellulose, lignin, chitin, and derivatives thereof.

[0128] The artificially synthesized polypeptide hydrogel material may illustratively include at least one of L-lysine and poly-L-glutamic acid.

[0129] In addition, the present invention also provides a vascular stent, which comprises a stent matrix and the vascular stent coating.

[0130] The stent coating imparts long-lasting anticoagulant properties to the stent surface, modulates inflammatory responses, and regulates smooth muscle cell growth, thereby regulating the regeneration and repair of diseased blood vessels. The stent can effectively reduce the incidence of in-stent restenosis, prolong the stent's therapeutic effect, and reduce the rate of unplanned reoperations.

[0131] Taking the drug molecule colchicine as an example, the corresponding vascular stent can achieve long-term, controlled sustained release of the peptide and colchicine, thereby endowing the stent surface with long-lasting anticoagulant effects, scavenging oxygen free radicals in lesions, regulating inflammatory responses, and modulating the growth of smooth muscle and endothelial cells, thereby promoting the regeneration and repair of diseased blood vessels. This coating has enormous application prospects and value in the construction of new drug-loaded coatings for vascular stents.

[0132] The features and performance of the present invention are further described in detail below with reference to the embodiments.

[0133] Example 1 This embodiment provides a vascular stent coating, the preparation process of which is as follows: Step 1: Immerse the vascular stent in a mixed solution containing an oxidant, albumin, and a polypeptide, so that the albumin and the polypeptide containing hydrophobic amino acids co-assemble under the induction of the oxidant. After the co-assembly reaction is completed, remove the vascular stent, wash it with distilled water (temperature of 20°C) to remove the material that is not firmly adhered to the surface, and then dry it at 37°C for 12 hours to obtain a porous coating (layer number 1) containing micro-nano albumin-polypeptide particles stacked on the surface of the stent matrix.

[0134] The temperature of the co-assembly reaction was 37° C., the reaction time was 12 h, and the pH value was 6.

[0135] A mixed solution was prepared by mixing an oxidant solution, an albumin solution, and a peptide solution. The volume ratio of the oxidant solution, albumin solution, and peptide solution was 1:1:0.2. The solvent used to prepare the oxidant solution, albumin solution, and peptide solution was ultrapure water with a pH of 6 (pH adjusted with HCl). The concentrations of the oxidant solution were 4 mg / mL, the albumin solution was 1 mg / mL, and the peptide solution was 1 mg / mL. The oxidant was sodium sulfate (SPS), the albumin was serum albumin (SA) with an isoelectric point of 4.7, and the peptide was bivalirudin (BIV) with an isoelectric point of 3.99. A porous coating was obtained.

[0136] In other words, in the mixed solution, the total concentration of albumin and polypeptide is 0.15 mmol / L, and the molar ratio of albumin to polypeptide is 0.16:1.

[0137] Step 2: Immerse the porous coating in an anionic solution containing drug molecules and react. After the reaction is completed, place the porous coating in a constant temperature drying oven at 37° C. and dry it for 12 hours to obtain a vascular stent coating.

[0138] The porous coating layer reacts with the anionic solution containing drug molecules at a temperature of 25° C., a time of 10 minutes, and a pH value of 8.5.

[0139] An anionic solution containing drug molecules (temperature 25°C) was prepared by mixing a 2 mg / mL colchicine solution (solvent: distilled water) with an anionic solution (solution: 6 mmol / L sodium dihydrogen phosphate solution). This mixture resulted in a colchicine concentration of 3 mmol / L in the anionic solution.

[0140] The stent coating provided in this embodiment maximizes the anticoagulant activity of bivalirudin and provides long-term sustained release of bivalirudin, imparting long-term anticoagulant properties to the stent surface. Combined with the high loading and sustained release of colchicine, the coating imparts long-lasting anti-inflammatory properties and lesion microenvironment regulation to the stent, potentially enabling regenerative repair of diseased vessels.

[0141] Example 2 This embodiment provides a vascular stent coating, which differs from Example 1 in that the polypeptide is replaced by thrombomodulin-derived peptide (TMDP), and the rest is the same as Example 1.

[0142] The stent coating provided in this example maximizes the activity of thrombomodulin-derived peptides and provides long-term sustained release of thrombomodulin-derived peptides, imparting long-term anti-inflammatory properties to the stent surface. Combined with the high loading and sustained release of colchicine, the coating imparts long-lasting anti-inflammatory properties and regulates the lesion microenvironment, thereby enabling regenerative repair of diseased vessels.

[0143] Example 3 This embodiment provides a vascular stent coating, which differs from Example 1 in that the polypeptide is replaced by a VEGF-derived peptide, and the rest is the same as Example 1.

[0144] The stent coating provided in this example maximizes the activity of VEGF-derived peptides and provides long-term sustained release of VEGF-derived peptides, endowing the stent surface with the ability to promote endothelial cell adhesion and growth. Combined with the high loading and sustained release of colchicine, the stent possesses long-lasting anti-inflammatory and lesion microenvironmental regulation, thereby enabling regeneration and repair of diseased blood vessels.

[0145] Example 4 This embodiment provides a vascular stent coating, which differs from embodiment 1 in that the polypeptide is replaced by a snake venom anticoagulant peptide, and the rest is the same as embodiment 1.

[0146] Example 5 This embodiment provides a vascular stent coating, which differs from embodiment 1 in that the polypeptide is replaced by thymosin β4, and the rest is the same as embodiment 1.

[0147] Example 6 This embodiment provides a vascular stent coating, which differs from Example 1 in that the polypeptide is replaced by defensin, and the rest is the same as Example 1.

[0148] Example 7 This embodiment provides a vascular stent coating, which differs from Example 1 in that the polypeptide is replaced by cecropin, and the rest is the same as Example 1.

[0149] Example 8 This embodiment provides a vascular stent coating, which differs from Example 1 in that the polypeptide is replaced by LL-37 antimicrobial peptide, and the rest is the same as Example 1.

[0150] Example 9 This embodiment provides a vascular stent coating, which differs from Example 1 in that the polypeptide is replaced by insulin, and the rest is the same as Example 1.

[0151] Example 10 This embodiment provides a vascular stent coating, which differs from Example 1 in that the polypeptide is replaced by growth hormone, and the rest is the same as Example 1.

[0152] Example 11 This embodiment provides a vascular stent coating, which differs from embodiment 1 in that the polypeptide is replaced by somatostatin, and the rest is the same as embodiment 1.

[0153] Example 12 This embodiment provides a vascular stent coating, which differs from Example 1 in that the polypeptide is replaced by EGF, and the rest is the same as Example 1.

[0154] Example 13 This embodiment provides a vascular stent coating, which differs from embodiment 1 in that the polypeptide is replaced with bFGF, and the rest is the same as embodiment 1.

[0155] Example 14 This embodiment provides a vascular stent coating, which differs from embodiment 1 in that the polypeptide is replaced by IGF-1, and the rest is the same as embodiment 1.

[0156] Example 15 This embodiment provides a vascular stent coating, which differs from Example 1 in that the drug molecule is replaced with paclitaxel, and the rest is the same as Example 1.

[0157] Example 16 This embodiment provides a vascular stent coating, which differs from Example 1 in that the drug molecule is replaced with rapamycin, and the rest is the same as Example 1.

[0158] Example 17 This embodiment provides a vascular stent coating, which differs from Example 1 in that the drug molecule is replaced with artemisinin, and the rest is the same as Example 1.

[0159] Example 18 This embodiment provides a vascular stent coating, which differs from Example 1 in that the drug molecule is replaced with oregano phenol, and the rest is the same as Example 1.

[0160] Example 19 This embodiment provides a vascular stent coating, which differs from Example 1 in that the drug molecule is replaced with an RNA drug, and the rest is the same as Example 1.

[0161] Example 20 This embodiment provides a vascular stent coating, which differs from Example 1 in that the drug molecule is replaced with a CRISPR drug, and the rest is the same as Example 1.

[0162] Example 21 This embodiment provides a vascular stent coating, which differs from Example 1 in that the anion solution is replaced by a phosphoric acid aqueous solution, and the rest is the same as Example 1.

[0163] Example 22 This embodiment provides a vascular stent coating, which differs from Example 1 in that the anion solution is replaced by a sodium dihydrogen phosphate aqueous solution, and the rest is the same as Example 1.

[0164] Test Example 1 ①, the porous coating obtained in step 1 of Example 1 and the vascular stent coating obtained in step 2 were observed by scanning electron microscopy, and the results are as follows: Figure 1 shown.

[0165] Figure 1 (a) is a SEM image of the surface of the porous coating in Example 1, (b) is a SEM image of the cross section of the porous coating in Example 1, and (c) and (d) are SEM images of different positions on the surface of the vascular stent coating in Example 1, respectively.

[0166] Depend on Figure 1 It can be seen that before loading drug molecules, the corresponding porous coating presents a loose porous structure; after loading drug molecules, the obtained vascular stent coating presents a dense structure, and the vascular stent coating is smoother than the porous coating.

[0167] ②, taking Example 1 as an example, a control group was set up. The difference between the control group and Example 1 was that the porous coating did not contain polypeptide. The porous coating obtained in step 1 of the control group and the vascular stent coating obtained in step 2 were observed by scanning electron microscopy. The results were as follows: Figure 2 shown.

[0168] Figure 2 (a) is the SEM image of the porous coating surface in the control group, and (b) is the enlarged image of the local area in (a); (c) is the SEM image of the vascular stent coating surface in the control group, (d) is the enlarged image of the left box in (c), and (e) is the enlarged image of the right box in (c).

[0169] And by Figure 1 and Figure 2 Comparison shows that the coating prepared in step 1 of the control group has fewer pores, which is not conducive to loading drugs; due to the complex structure of the vascular stent, the surface of the vascular stent coating obtained in step 2 is relatively flat, with almost no suitable pores for loading drugs.

[0170] ③. The vascular stent with a porous coating obtained in step 1 of Example 1 and the stent with a vascular stent coating obtained in step 2 were observed under a scanning electron microscope. The results are as follows: Figure 3 shown.

[0171] Figure 3(a) is the result of the vascular stent obtained in step 1 of Example 1 under a scanning electron microscope, (b) is an enlarged view of the left box of (a), and (c) is an enlarged view of the right box of (a); (d) is the result of the vascular stent obtained in step 2 of Example 1 under a scanning electron microscope, (e) is an enlarged view of the left box of (d), and (f) is an enlarged view of the right box of (e).

[0172] Depend on Figure 3 It can be seen that no matter before or after loading the drug, there is almost no damage to the coating after the vascular stent is expanded.

[0173] Test Example 2 Taking Example 1 as an example, a vascular stent with a vascular stent coating was used as a sample for an immersion experiment. The experimental method and conditions are as follows: a portion of the vascular stent sample prepared in step S1 of Example 1 and the vascular stent sample prepared in step S2 were taken out at different immersion time points and the immersion liquid. The control group was a bare substrate and a simulated body fluid used for the immersion experiment. Equal amounts of platelet-poor plasma (PPP) were added to the sample surface and the immersion liquid, respectively. The mixture was incubated in a 37°C incubator for 30 minutes. The PPP was taken out and mixed with an equal amount of thrombin reagent. The time when the mixed reaction liquid began to coagulate was observed and recorded. The thrombin time test results of the sample and the immersion liquid in the experiment are shown as follows: Figure 4 and Figure 5 shown.

[0174] Figure 4 and Figure 5 In the figure, the three bar graphs corresponding to the same time correspond to the results of the blank control, Example 1 and step S1 from left to right.

[0175] Depend on Figure 4 and Figure 5 It can be seen that the vascular stent samples obtained in step S1 and step S2 can both achieve the release of bivalirudin for up to 30 days, and the vascular stent sample obtained in step S2 has a better anticoagulant effect than the vascular stent sample obtained in step S1.

[0176] Test Example 3 ①. This test case studies the effects of different types of anion solutions or anion solution concentrations on the release of colchicine.

[0177] This test example includes samples 3-1 to 3-6, where: The only difference between Sample 3-1 and Example 1 is that the anion solution is replaced with ultrapure water.

[0178] The only difference between Sample 3-2 and Example 1 is that the anion solution is replaced with a sodium sulfate solution with a concentration of 3 mmol / L.

[0179] The only difference between Sample 3-3 and Example 1 is that the anion solution is a disodium hydrogen phosphate solution with a concentration of 0.01 mmol / L.

[0180] The only difference between Sample 3-4 and Example 1 is that the anion solution is a disodium hydrogen phosphate solution with a concentration of 2 mmol / L.

[0181] The only difference between Sample 3-5 and Example 1 is that the anion solution is a disodium hydrogen phosphate solution with a concentration of 10 mmol / L.

[0182] The only difference between Sample 3-6 and Example 1 is that the anion solution is a disodium hydrogen phosphate solution with a concentration of 12 mmol / L.

[0183] The vascular stents of Example 1 and each sample were subjected to an immersion experiment. The experimental method and conditions were the same as those of Experimental Example 2. The release of colchicine after immersion of each vascular stent for 12 hours, 1 day, 3 days, 5 days, 7 days, 10 days, 15 days, 20 days, 25 days and 30 days was tested. The results are shown in FIG. Figure 6 shown.

[0184] Depend on Figure 6 It can be seen that the vascular stent prepared in Example 1 has the best effect in terms of long-term sustained release of colchicine.

[0185] ② This test example studies the effect of the reaction time between the porous coating and anionic solution containing drug molecules on the drug release. The method is the same as that described in ① above.

[0186] This test example includes samples 3-8 to 3-10, among which: The only difference between Sample 3-8 and Example 1 is that the mixing time is 1 min.

[0187] The only difference between Sample 3-9 and Example 1 is that the mixing time is 5 minutes.

[0188] The only difference between Sample 3-10 and Example 1 is that the mixing time is 10 minutes.

[0189] After the reaction is completed, each sample is taken out and cleaned with distilled water to remove unstable substances adsorbed on the surface. After drying, the coating is completely eluted with 0.1wt% sodium dodecyl sulfate (SDS) solution. The eluate is taken and the absorption peak of the solution at 350nm is detected by UV spectrophotometer. A colchicine standard solution is prepared and detected by UV spectrophotometer to draw a colchicine standard curve. The standard curve is converted into colchicine release amount. The results are shown as follows: Figure 7 shown.

[0190] Depend on Figure 7It can be seen that the colchicine loading capacity is positively correlated with the degree of self-encapsulation of the coating. After the coating is completely self-encapsulated, the colchicine loading capacity will not increase with the extension of the anion treatment time.

[0191] Test Example 4 This experimental example studies the effect of the reaction conditions between the porous coating and an anionic solution containing drug molecules on the drug release from the stent coating. The method is the same as ① in Experiment 3.

[0192] This test example includes samples 4-1 to 4-5, where: The difference between Sample 4-1 and Example 1 is that the reaction temperature of the porous coating layer and the anionic solution containing drug molecules is -30°C.

[0193] The difference between Sample 4-2 and Example 1 is that the reaction temperature of the porous coating and the anionic solution containing drug molecules is -20°C.

[0194] The difference between Sample 4-3 and Example 1 is that the reaction temperature of the porous coating layer and the anionic solution containing drug molecules is 50°C.

[0195] The difference between Sample 4-4 and Example 1 is that the reaction temperature of the porous coating layer and the anionic solution containing drug molecules is 60°C.

[0196] The difference between Sample 4-5 and Example 1 is that the pH value of the reaction between the porous coating and the anion solution containing drug molecules is 0.5.

[0197] The performance test method refers to Test Example 3, and the results are as follows Figure 8 shown.

[0198] Depend on Figure 8 It can be seen that within the same reaction time, if the anion solution treatment temperature is too low, the drug loading amount will be reduced; if the anion solution treatment temperature is too high and the pH value is too low, the stability of the coating may be affected, thereby causing a sharp decrease in drug loading amount.

[0199] Test Example 5 This experiment studies the effect of co-assembly reaction conditions on the drug release from vascular stent coatings.

[0200] This test example includes samples 5-1 to 5-13, among which: The difference between sample 5-1 and Example 1 is that the temperature of the co-assembly reaction is 10°C.

[0201] The difference between sample 5-2 and Example 1 is that the temperature of the co-assembly reaction is 15°C.

[0202] The difference between Sample 5-3 and Example 1 is that the temperature of the co-assembly reaction is 50°C.

[0203] The difference between sample 5-4 and Example 1 is that the temperature of the co-assembly reaction is 60°C.

[0204] The difference between sample 5-5 and Example 1 is that the temperature of the co-assembly reaction is 70°C.

[0205] The difference between Sample 5-6 and Example 1 is that the co-assembly reaction time is 1 hour.

[0206] The difference between sample 5-7 and Example 1 is that the co-assembly reaction time is 2 hours.

[0207] The difference between Sample 5-8 and Example 1 is that the co-assembly reaction time is 4 hours.

[0208] The difference between sample 5-9 and Example 1 is that the co-assembly reaction time is 72 hours.

[0209] The difference between Sample 5-10 and Example 1 is that the pH value of the co-assembly reaction is 2.

[0210] The difference between sample 5-11 and Example 1 is that the pH value of the co-assembly reaction is 3.

[0211] The difference between Sample 5-12 and Example 1 is that the pH value of the co-assembly reaction is 8.

[0212] The difference between sample 5-13 and Example 1 is that the pH value of the co-assembly reaction is 10.

[0213] The performance test method refers to Test Example 3, and the results are as follows Figure 9 shown.

[0214] Depend on Figure 9 It can be seen that the co-assembly reaction conditions of the protein and polypeptide coating have a great influence on the drug release in the vascular stent coating.

[0215] Test Example 6 This experiment studies the effect of mixed solution on the drug release from vascular stent coating.

[0216] This test example includes samples 6-1 to 6-8, where: The difference between Sample 6-1 and Example 1 is that the volume ratio of the oxidant solution, the albumin solution and the polypeptide solution is 1:1:0.005.

[0217] The difference between Sample 6-2 and Example 1 is that the volume ratio of the oxidant solution, the albumin solution and the polypeptide solution is 1:1:2.

[0218] The difference between Sample 6-3 and Example 1 is that the concentration of the oxidant solution in the mixed solution is 0.005 mg / mL.

[0219] The difference between Sample 6-4 and Example 1 is that the concentration of the oxidant solution in the mixed solution is 120 mg / mL.

[0220] The difference between Sample 6-5 and Example 1 is that the concentration of the albumin solution in the mixed solution is 0.005 mg / mL.

[0221] The difference between Sample 6-6 and Example 1 is that the concentration of the albumin solution in the mixed solution is 120 mg / mL.

[0222] The difference between Sample 6-7 and Example 1 is that the concentration of the polypeptide solution in the mixed solution is 0.005 mg / mL.

[0223] The difference between Sample 6-8 and Example 1 is that the concentration of the polypeptide solution in the mixed solution is 120 mg / mL.

[0224] The performance test method refers to Test Example 3, and the results are as follows Figure 10 shown.

[0225] Depend on Figure 10 It can be seen that Example 1 is the most optimized process, which can not only ensure the stability of the coating, but also maximize the pores of the coating for drug loading sites, thereby ensuring the maximum drug loading capacity.

[0226] Test Example 7 This experiment studies the effect of the isoelectric point of the polypeptide on the performance of the vascular stent coating.

[0227] This test example includes sample 7-1 and sample 7-2, where: The difference between sample 7-1 and Example 1 is that the polypeptide is gastrin with an isoelectric point of less than 3.

[0228] The difference between sample 7-2 and Example 1 is that the polypeptide is a defensin with an isoelectric point > 6.5.

[0229] The performance test method refers to Test Example 3, and the results are as follows Figure 11 shown.

[0230] Depend on Figure 11 It can be seen that peptides with a pH value of 3-6.5 are most suitable for constructing protein-peptide coatings with self-encapsulated pore structures that can be used for drug loading. This may be because in the reaction solution, the isoelectric points of proteins and peptides are similar, and the binding force between the two to form a coating is mainly hydrophobic force, which is more easily induced by anions to self-encapsulate.

[0231] In summary, the porous coating provided by the present invention has excellent biocompatibility, and the degradation products have little impact on the microenvironment of the lesion. In addition, the coating can release polypeptides with specific physiological functions in a long-term manner, giving the stent surface multiple biological functions. Moreover, the coating has a porous structure. In a specific drug-anion solution, the pore structure of the coating undergoes reconstruction and self-encapsulation, thereby achieving high drug loading. As the vascular stent coating degrades, the polypeptides and drug molecules are released to exert their physiological functions, and it has the potential value of developing into a new drug-eluting stent coating.

[0232] The foregoing description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Those skilled in the art will readily appreciate that various modifications and variations of the present invention are possible. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present invention shall be included within the scope of protection of the present invention.

Claims

1. A vascular stent coating, characterized in that: The stent coating is obtained by reacting a porous coating with an anionic solution containing drug molecules. The porous coating contains micro-nano albumin-polypeptide particles stacked on the surface of the stent matrix. The micro-nano albumin-polypeptide particles are formed by co-assembly of albumin and a polypeptide containing hydrophobic amino acids under the induction of an oxidant. The porosity of the stent coating is smaller than that of the porous coating.

2. The vascular stent coating according to claim 1, characterized in that: The particle size of the micro-nano albumin-polypeptide particles is 800nm~2000nm.

3. The vascular stent coating according to claim 1, characterized in that: The number of layers of the porous coating layer is 1 to 10.

4. The vascular stent coating according to claim 3, characterized in that: The number of layers of the porous coating layer is 2 to 3.

5. A method for preparing a vascular stent coating according to any one of claims 1 to 4, characterized in that: The method comprises the following steps: mixing a stent matrix with a mixed solution containing an oxidant, albumin and a polypeptide, so that the albumin and the polypeptide containing hydrophobic amino acids undergo a co-assembly reaction under the induction of the oxidant, thereby obtaining the porous coating containing micro-nano albumin-polypeptide particles stacked on the surface of the stent matrix; and reacting the porous coating with an anion solution containing drug molecules to obtain the vascular stent coating.

6. The preparation method according to claim 5, characterized in that When the number of layers of the porous coating is greater than or equal to 2, after obtaining the x-th layer of porous coating, the obtained x-th layer of porous coating is washed and continuously placed in a new mixed solution without drying, and the next layer of porous coating is prepared under the same co-assembly reaction conditions until the last layer of porous coating is obtained; the number of layers of the last layer of porous coating is defined as y, x<y.

7. The preparation method according to claim 5 or 6, characterized in that: The co-assembly reaction has at least one of the following characteristics: Feature 1: The temperature of the co-assembly reaction is 15°C~60°C; Feature 2: The co-assembly reaction time is ≥ 2 h; Feature 3: The pH value of the co-assembly reaction is 3~8.

8. The preparation method according to claim 7, characterized in that The temperature of the co-assembly reaction is 35°C~50°C.

9. The preparation method according to claim 7, characterized in that The total assembly reaction time is 2h~72h.

10. The preparation method according to claim 9, characterized in that The total assembly reaction time is 4h~12h.

11. The preparation method according to claim 5 or 6, characterized in that: The pH value of the mixed solution is 3-8.

12. The preparation method according to claim 5 or 6, characterized in that: The mixed solution is obtained by mixing an oxidant solution, an albumin solution and a polypeptide solution; The volume ratio of the oxidant solution, the albumin solution, and the polypeptide solution is 1:1:0.01 to 1:1:2; the concentration of the oxidant solution is 0.01 mg / mL to 100 mg / mL, the concentration of the albumin solution is 0.01 mg / mL to 100 mg / mL, and the concentration of the polypeptide solution is 0.01 mg / mL to 100 mg / mL.

13. The preparation method according to claim 5 or 6, characterized in that: The total concentration of the albumin and the polypeptide in the mixed solution is 0.01 mmol / L to 10 mmol / L, and the molar ratio of the albumin to the polypeptide is 0.01:1 to 10:

1.

14. The preparation method according to claim 13, characterized in that The total concentration of the albumin and the polypeptide in the mixed solution is 0.01 mmol / L to 5 mmol / L.

15. The preparation method according to claim 13, characterized in that The molar ratio of the albumin to the polypeptide is 0.05:1 to 5:

1.

16. The preparation method according to claim 5 or 6, characterized in that: The oxidant includes at least one of an inorganic oxidant and an organic oxidant.

17. The preparation method according to claim 16, characterized in that The inorganic oxidant includes at least one of persulfate, chlorate, perchlorate, perchlorate, dichromate, periodate, permanganate, nitrate and inorganic peroxide.

18. The preparation method according to claim 16, characterized in that The organic oxidant includes at least one of dichlorine peroxide and peracetic acid.

19. The preparation method according to claim 5 or 6, characterized in that: The isoelectric point of the polypeptide is 3-6.

5.

20. The preparation method according to claim 19, characterized in that The polypeptides include anticoagulant functional polypeptides, anti-inflammatory functional polypeptides and cell growth promoting polypeptides.

21. The preparation method according to claim 20, characterized in that The polypeptide includes a polypeptide having anticoagulant function and hydrophobic amino acids.

22. The preparation method according to claim 21, characterized in that The anticoagulant functional polypeptide comprises at least one of a thrombomodulin-derived peptide, a snake venom anticoagulant peptide, and bivalirudin; And / or, the anti-inflammatory functional polypeptide includes at least one of thymosin and antimicrobial peptide; And / or the cell growth promoting polypeptide includes at least one of insulin, growth hormone, somatostatin, VEGF-derived peptide, EGF, bFGF and IGF-1.

23. The preparation method according to claim 6, characterized in that The cleaning solution used is distilled water.

24. The preparation method according to claim 6, characterized in that After the final porous coating layer is obtained, the entire porous coating layer is first cleaned and dried, and then reacted with an anionic solution containing drug molecules.

25. The preparation method according to claim 24, characterized in that Drying is carried out at 10℃~45℃.

26. The preparation method according to claim 5, characterized in that The reaction of the porous coating with the anionic solution containing drug molecules includes at least one of the following features: Feature 4: The reaction temperature of the porous coating and the anionic solution containing drug molecules is -20°C to 50°C; Feature 5: The reaction time between the porous coating and the anionic solution containing drug molecules is ≥ 1 min; Feature 6: The pH value of the reaction between the porous coating and the anionic solution containing drug molecules is 1-14.

27. The preparation method according to claim 26, characterized in that The reaction time of the porous coating and the anion solution containing drug molecules is 5 min to 60 min.

28. The preparation method according to claim 5, characterized in that The concentration of the anion solution is 0.1 mmol / L to 10 mmol / L.

29. The preparation method according to claim 5, characterized in that The concentration of the anion solution is 2 mmol / L to 6 mmol / L.

30. The preparation method according to claim 5, characterized in that The anion solution includes at least one of a phosphoric acid solution, a phosphate solution, a hydrogen phosphate solution and a dihydrogen phosphate solution.

31. The preparation method according to claim 30, characterized in that The anion solution includes a phosphate solution.

32. The preparation method according to claim 26, characterized in that The temperature of the anion solution containing drug molecules is 0°C to 37°C.

33. The preparation method according to claim 32, characterized in that The temperature of the anion solution containing drug molecules is 4°C to 25°C.

34. The preparation method according to claim 26, characterized in that The concentration of the drug molecules in the anion solution is 0.1 mmol / L to 10 mol / L.

35. The preparation method according to claim 34, characterized in that The concentration of the drug molecules in the anion solution is 1 mmol / L to 5 mmol / L.

36. The preparation method according to claim 26, characterized in that The anion solution containing drug molecules is obtained by mixing a drug solution with an anion solution; Wherein, the drug solution is obtained by dissolving drug molecules in a solvent.

37. The preparation method according to claim 36, characterized in that The concentration of the drug solution is 0.01 mg / mL to 100 mg / mL.

38. The preparation method according to claim 36, characterized in that The solvent in the drug solution includes at least one of ultrapure water, physiological saline, alcohol, anhydrous ethanol, phosphate buffered saline solution and dimethyl sulfoxide.

39. The preparation method according to claim 5, characterized in that The drug molecules include at least one of chemically synthesized drugs, biomass drugs, gene therapy drugs, antibodies, Chinese herbal medicines and plant extracts.

40. The preparation method according to claim 39, characterized in that The chemically synthesized drugs include at least one of anti-inflammatory drugs, statins, antibiotics and anti-tumor drugs.

41. The preparation method according to claim 40, characterized in that The anti-tumor drug includes at least one of rapamycin, paclitaxel and targeted drugs.

42. The preparation method according to claim 39, characterized in that The biomass medicine includes at least one of monoclonal antibodies, vaccines, cytokines and exosomes.

43. The preparation method according to claim 39, characterized in that The gene therapy drug includes at least one of a drug for targeting gene expression and a drug for gene repair.

44. The preparation method according to claim 39, characterized in that The Chinese herbal medicine and plant extracts include at least one of artemisinin and its derivatives, colchicine and its derivatives, oregano and its derivatives, and allicin and its derivatives.

45. The preparation method according to claim 5, characterized in that The support matrix includes at least one of metal materials, inorganic materials, polymer materials, natural biological materials and artificially synthesized polypeptide hydrogel materials.

46. The preparation method according to claim 45, characterized in that The metal material includes at least one of cobalt-based alloys, titanium and its alloys, nickel-titanium alloys, platinum and its alloys, magnesium and its alloys, iron and its alloys, and zinc and its alloys.

47. The preparation method according to claim 45, characterized in that The inorganic material includes at least one of titanium oxide and its nanotubes, carbon materials, silicon, silicon dioxide, calcium phosphate, silicon nitride, silicon carbide, aluminosilicate, calcium aluminum series, bioglass, titanium nitride and biomedical micro-nano particles.

48. The preparation method according to claim 47, characterized in that The biomedical micro-nanoparticles include at least one of ferroferric oxide nanoparticles, silicon dioxide nanoparticles, titanium oxide nanoparticles and zinc oxide nanoparticles.

49. The preparation method according to claim 45, characterized in that The polymer material includes at least one of polyester, polyethylene, polyvinyl chloride, polytetrafluoroethylene, polyurethane, polystyrene, polyvinyl alcohol, polypropylene, polyoxymethylene, polycarbonate, carbon copolymer, polyglycolic acid, polymethyl methacrylate, polyvinyl acetate, polylactic acid, glycolide-lactide copolymer, polytrimethylene carbonate, polycaprolactone, polyhydroxyalkanoate, polybutylene succinate, polyamide, polydioxanone, epoxy resin, silicone rubber, silicone gel, polyacrylic acid and its derivatives, polyethylene glycol and its derivatives.

50. The preparation method according to claim 45, characterized in that The natural biological material includes at least one of decellularized tissues and organs of animal origin, gelatin, collagen, fibrin, silk protein, keratin and polysaccharide.

51. The preparation method according to claim 50, characterized in that The animal-derived decellularized tissues and organs include at least one of blood vessels, valves, hearts, bones, lungs, ligaments, bladders, mucosa, and corneas.

52. The preparation method according to claim 50, characterized in that The polysaccharide includes at least one of sodium hyaluronate, sodium alginate, agarose, plastic starch material, cellulose, hemicellulose, lignin, chitin and derivatives thereof.

53. The preparation method according to claim 45, characterized in that The artificially synthesized polypeptide hydrogel material includes at least one of L-lysine and poly-L-glutamic acid.

54. A vascular stent, characterized in that: The vascular stent comprises a stent matrix and the vascular stent coating according to any one of claims 1 to 4.

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