Coating for medical material surfaces and method for its production, use and medical material

Abstract

This application provides a coating for the surface of medical materials, its preparation method, application, and the medical materials themselves. The preparation method includes the following steps: co-depositing dopamine and a polyamino compound on the surface of the medical material to form an amino-containing adhesive layer; mixing heparin and hyaluronic acid and activating the carboxyl groups of the heparin and hyaluronic acid; contacting the amination-treated medical material with the carboxyl-activated heparin and hyaluronic acid to allow the amino groups on the surface of the medical material to undergo a covalent grafting reaction with the activated carboxyl groups of the heparin and hyaluronic acid, thereby obtaining the coating for the surface of the medical material. This coating possesses both highly efficient anticoagulant and anti-inflammatory biological activities and exhibits excellent stability.

Description

Technical Field

[0001] This application relates to the field of surface modification technology for medical materials, and in particular to coatings for the surface of medical materials, their preparation methods, applications, and medical materials. Background Technology

[0002] When blood or tissue fluid comes into contact with the surface of implanted medical devices (such as vascular stents, heart valves, artificial blood vessels, indwelling catheters, hemodialysis membranes, and artificial organs), a cascade of biological reactions is rapidly triggered. On the one hand, the non-specific adsorption of plasma proteins (such as fibrinogen and von Willebrand factor) on the material surface promotes platelet adhesion, activation, and aggregation, activating the coagulation cascade and ultimately leading to thrombosis. On the other hand, the material, as a "foreign body," also activates the complement system, induces immune cells (such as neutrophils and monocytes / macrophages) to be recruited to and adhere to the implantation site, releases inflammatory factors (such as IL-1β and TNF-α), triggers acute and chronic inflammatory responses, and may even lead to tissue fibrosis or implantation failure. Thrombosis and inflammation mutually promote each other, forming a vicious cycle, which constitutes a major challenge in the clinical application of medical devices (especially blood-contact devices and implants). Therefore, improving the blood compatibility (anticoagulant properties) and biocompatibility (anti-inflammatory properties) of medical materials is a core objective in the field of surface engineering.

[0003] Surface modification techniques have been extensively studied to improve the surface properties of materials; in particular, coatings are widely used to modify the surface of medical materials. The stability of the coating has a significant impact on the efficacy and service life of medical materials.

[0004] Therefore, there is an urgent need to provide a coating for the surface of medical materials that has both highly efficient anticoagulant and anti-inflammatory dual biological activities and excellent stability. Summary of the Invention

[0005] Based on this, this application provides a coating for the surface of medical materials that has both highly efficient anticoagulant and anti-inflammatory dual biological activities and excellent stability, as well as its preparation method, application, and medical materials.

[0006] The first aspect of this application provides a method for preparing a coating for the surface of medical materials, comprising the following steps:

[0007] Dopamine and a polyamino compound are co-deposited on the surface of a medical material to form an amino-containing adhesion layer on the surface of the medical material.

[0008] Heparin and hyaluronic acid are mixed, and the carboxyl groups of the heparin and hyaluronic acid are activated.

[0009] The amino-containing adhesive layer is brought into contact with the carboxyl-activated heparin and hyaluronic acid to allow the amino groups to undergo a covalent grafting reaction with the carboxyl groups of the heparin and hyaluronic acid to obtain a coating for use on the surface of medical materials.

[0010] In some embodiments, the mass ratio of the dopamine to the polyamino compound is (1-2):1.

[0011] In some embodiments, the polyamino compound includes one or more of polylysine, polyethyleneimine, and lysozyme.

[0012] In some embodiments, the step of co-depositing dopamine and a polyamine compound on the surface of the medical material to perform amination treatment on the surface of the medical material includes:

[0013] The dopamine and the polyamino compound are dissolved in a weakly alkaline buffer solution with a pH of 8-9 to obtain a first mixed solution. The medical material is then immersed in the first mixed solution to allow the dopamine and the polyamino compound to co-deposit on the surface of the medical material.

[0014] In some embodiments, the combined mass percentage of the dopamine and the polyamino compound in the first mixed solution is 1%-5%.

[0015] In some embodiments, the co-deposition time is 2 hours to 24 hours.

[0016] In some embodiments, the mass ratio of heparin to hyaluronic acid is (1-16):4.

[0017] In some embodiments, the step of mixing heparin and hyaluronic acid and activating the carboxyl groups of the heparin and hyaluronic acid includes:

[0018] The heparin and hyaluronic acid are dissolved in a weakly acidic buffer solution with a pH of 5-6 to obtain a second mixed solution. Then, a carboxyl activator and a catalyst are added to the second mixed solution to activate the carboxyl groups of the heparin and hyaluronic acid.

[0019] In some embodiments, the combined mass percentage of heparin and hyaluronic acid in the second mixed solution is 0.5%-3%.

[0020] In some embodiments, the carboxyl activator includes one or more of 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride, N,N'-dicyclohexylcarbodiimide, and N,N'-diisopropylcarbodiimide.

[0021] In some embodiments, the molar concentration of the carboxyl activator in the second mixed solution after the addition of the carboxyl activator and the catalyst is 2 mM-20 mM.

[0022] In some embodiments, the catalyst comprises one or more of 1-hydroxy-2,5-pyrrolidone, 1-hydroxy-7-azabenzotriazole, and 1,1'-carbonyldiimidazole.

[0023] In some embodiments, the molar concentration of the catalyst in the second mixed solution after the addition of the carboxyl activator and the catalyst is 2 mM-20 mM.

[0024] In some embodiments, the activation treatment is performed at a temperature of 20°C-25°C for a time of 30-120 minutes.

[0025] In some embodiments, the covalent grafting reaction is carried out at a temperature of 35°C-40°C for 8-12 hours.

[0026] A second aspect of this application provides a coating for the surface of a medical material, comprising an adhesive layer and heparin and hyaluronic acid fixed to the surface of the adhesive layer, the adhesive layer comprising a polymer of dopamine and a polyamino compound, the heparin and hyaluronic acid being fixed to the surface of the adhesive layer via amide bonds.

[0027] In some embodiments, the mass ratio of heparin to hyaluronic acid is (1-16):4.

[0028] In some embodiments, there are protrusions on the surface of the coating, the height of which is 20nm-30nm.

[0029] In some embodiments, the surface roughness of the coating is 12nm-80nm.

[0030] In some embodiments, the water contact angle of the coating surface is 30°-45°.

[0031] The third aspect of this application provides the application of a coating prepared by the preparation method of the first aspect of this application or a coating of the second aspect of this application in the preparation of medical materials with dual anticoagulant and anti-inflammatory effects.

[0032] The fourth aspect of this application provides a medical material whose surface has a coating prepared by the preparation method of the first aspect of this application or a coating of the second aspect of this application.

[0033] In some embodiments, the medical material includes one or more of blood contact medical devices and implants.

[0034] In some embodiments, the medical material includes one or more of the following: vascular stents, heart valves, artificial blood vessels, indwelling catheters, hemodialysis membranes, and extracorporeal membrane oxygenation (ECMO) devices.

[0035] The above-described method for preparing a coating for the surface of medical materials has at least the following beneficial effects:

[0036] (1) This preparation method innovatively achieves chemical co-immobilization of heparin and hyaluronic acid in the same coating, endowing the surface of medical materials with synchronous and long-lasting dual bioactivity of anticoagulation and anti-inflammation. At the same time, heparin and hyaluronic acid can produce synergistic effects in the coating (for example, the steric hindrance of hyaluronic acid enhances the accessibility of heparin's anticoagulant activity, and the binding of heparin to antithrombin III also indirectly regulates the inflammatory pathway).

[0037] (2) This preparation method, through covalent amide bonds between the aminated surface and the pre-activated carboxyl groups (heparin / hyaluronic acid), exhibits significantly improved chemical and mechanical stability compared to traditional methods such as physical adsorption, ion bonding, or single-component modification. The coating is difficult to detach in bodily fluids and can maintain its biological activity for a long period (weeks to months), making it particularly suitable for medical devices that require long-term implantation.

[0038] (3) This preparation method utilizes the co-deposition of dopamine and polyamine compounds. On the one hand, the self-polymerization / copolymerization of dopamine forms an adhesion layer; on the other hand, the introduction of high-density polyamine compounds significantly enhances the surface primary amino group density and stability, providing sufficient active sites for subsequent covalent fixation. The preparation steps of this method are clear and controllable, the conditions are mild, and it is applicable to a wide range of substrates, such as metals, polymers, inorganic materials, and other commonly used materials in medical devices.

[0039] (4) The hydrophilic hyaluronic acid molecules provide a large hydration layer spatial barrier, which, combined with the negative charge effect of heparin, effectively resists the non-specific adsorption of blood cells and inflammatory cells on the material surface, forming a key starting point for inhibiting subsequent thrombosis and inflammatory response. This coating can effectively solve two major complications commonly seen after the implantation or use of medical materials (such as vascular stents, catheters, heart valves, extracorporeal circulation tubing, etc.)—thrombosis and inflammatory response, and is expected to significantly improve the biocompatibility and clinical safety / effectiveness of medical devices. Attached Figure Description

[0040] To more clearly illustrate the technical solutions in the embodiments of this application and to more completely understand this application and its beneficial effects, the drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0041] Figure 1 The image shows the microstructure of the surface coating of the medical material prepared in Example 1.

[0042] Figure 2 This is a microscopic morphology diagram of the medical polyurethane material used in Comparative Example 1.

[0043] Figure 3 The surface water contact angle diagram of the medical material surface coating prepared in Example 1 is shown.

[0044] Figure 4 The diagram shows the surface water contact angle of the medical polyurethane material used in Comparative Example 1.

[0045] Figure 5 Blood cell adhesion diagram of the surface coating of the medical material prepared in Example 1.

[0046] Figure 6 This is a blood cell adhesion diagram of the medical polyurethane material used in Comparative Example 1.

[0047] Figure 7 This is an image showing the inflammatory cell adhesion of the surface coating of the medical material prepared in Example 1.

[0048] Figure 8 This is an inflammatory cell adhesion diagram of the medical polyurethane material used in Comparative Example 1.

[0049] Figure 9 The data on the secretion of inflammatory factors are obtained after the surface coating of the medical material prepared in Example 1 and the medical polyurethane material used in Comparative Example 1 are co-cultured with inflammatory material after they are fully saturated. Detailed Implementation

[0050] To facilitate understanding of this application, a more complete description of the application will be provided below with reference to relevant embodiments. Preferred embodiments of the application are given below. However, the application can be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided to provide a thorough and complete understanding of the disclosure of this application.

[0051] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the application.

[0052] As used herein, the terms "and / or," "or / and," and "and / or" encompass any one of two or more of the related listed items, as well as any and all combinations of the related listed items. These arbitrary and all combinations include any two related listed items, any more related listed items, or a combination of all related listed items. It should be noted that when at least three items are connected using at least two conjunctions selected from "and / or," "or / and," and "and / or," it should be understood that, in this application, the technical solution undoubtedly includes solutions connected by "logical AND," and also undoubtedly includes solutions connected by "logical OR."

[0053] In this application, the technical features described in an open-ended manner include both closed technical solutions consisting of the listed features and open technical solutions that include the listed features.

[0054] In this application, numerical ranges are referred to as continuous unless otherwise specified, and include the minimum and maximum values ​​of the range, as well as every value between the minimum and maximum values. Furthermore, when the range refers to integers, it includes every integer between the minimum and maximum values ​​of the range. Additionally, when multiple ranges are provided to describe a feature or characteristic, the ranges may be merged. In other words, unless otherwise specified, all ranges disclosed herein should be understood to include any and all subranges to which they are incorporated.

[0055] This document only specifically discloses some numerical ranges. However, any lower limit can be combined with any upper limit to form an unspecified range; and any lower limit can be combined with other lower limits to form an unspecified range, just as any upper limit can be combined with any other upper limit to form an unspecified range. Furthermore, each individually disclosed point or single value can itself serve as a lower or upper limit and be combined with any other point or single value or with other lower or upper limits to form an unspecified range.

[0056] Unless otherwise specified, the temperature parameters in this application may be either constant temperature processing or processing within a certain temperature range. The constant temperature processing allows temperature fluctuations within the precision range controlled by the instrument, such as ±5°C, ±4°C, ±3°C, ±2°C, or ±1°C.

[0057] In this document, the term "suitable" as used in phrases such as "suitable combination," "suitable method," and "any suitable method" refers to the ability to implement the technical solution of this application, solve the technical problem of this application, and achieve the expected technical effect of this application.

[0058] In this application, terms such as "further," "even further," and "particularly" are used to describe purposes and indicate differences in content, but should not be construed as limiting the scope of protection of this application.

[0059] In this application, "optionally," "optionally," and "optional" mean that something is optional, that is, it means that it is selected from either "with" or "without." If there are multiple "optional" entries in a technical solution, unless otherwise specified, and there are no contradictions or mutual constraints, each "optional" entry shall be independent.

[0060] In the description of the application, "multiple" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0061] Unless otherwise specified, all embodiments and optional embodiments of this application can be combined to form new technical solutions. Unless otherwise specified, all technical features and optional technical features of this application can be combined to form new technical solutions.

[0062] Unless otherwise specified, all steps of this application may be performed sequentially or randomly, but sequentially is preferred.

[0063] Surface modification techniques have been extensively studied to improve the surface properties of materials. Among these, heparin is the oldest and most widely accepted anticoagulant due to its excellent anticoagulant effect. Heparin binds to antithrombin III (ATIII) with high affinity through its specific pentasaccharide sequence, accelerating the inactivation of thrombin and coagulation factor Xa by ATIII, thereby effectively blocking the coagulation pathway. Physical adsorption, ionic bonding, or covalent immobilization of heparin are common strategies for improving the anticoagulant properties of materials. However, existing heparin coatings have significant limitations. For example, patent applications with publication numbers CN113384758A and CN106730051A adsorb heparin and other positively charged compounds onto the surface of medical materials using electrostatic and van der Waals forces. The resulting heparin anticoagulant coatings have the following limitations:

[0064] 1. Limited Function: Heparin mainly targets the coagulation pathway and lacks the ability to directly regulate the inflammatory response, making it difficult to meet the complex needs of multiple concurrent biological responses after device implantation.

[0065] 2. Stability defects: Heparin that is physically adsorbed or ion-bound is easily desorbed and lost under the action of body fluids, mechanical friction or biological enzymes (such as heparinase), resulting in a significant decrease in anticoagulant activity over time.

[0066] 3. Potential inflammatory risks: While heparin coating prevents blood clotting, it does not adequately suppress the inflammatory cascade response (such as complement activation and leukocyte infiltration) in the early stages of implantation. Some studies have even found that improper heparin immobilization may trigger adverse reactions through the contact activation pathway.

[0067] To compensate for the shortcomings of heparin coatings in terms of biocompatibility and anti-inflammation, a natural glycosaminoglycan hyaluronic acid (HA) has attracted attention due to its unique properties: HA possesses excellent biocompatibility, high hydrophilicity, lubricity, and non-immunogenicity, and can exert an active anti-inflammatory effect by regulating macrophage phenotypes (such as promoting anti-inflammatory M2 polarization). Its dense hydration layer formed by its highly hydrophilic long-chain molecules can effectively shield protein adsorption (“non-thrombogenic surface”), thereby indirectly inhibiting cell adhesion. However, hyaluronic acid alone has significant shortcomings as a coating. For example, patent applications with publication numbers CN107976472A and CN109825835A, which prepare hyaluronic acid coatings on the surface of medical materials, have the following shortcomings: weak anticoagulant capacity: HA lacks a direct and efficient targeted anticoagulant mechanism similar to heparin (such as activating ATIII), and cannot provide sufficient antithrombotic protection, especially in high-thrombotic-risk environments (such as arterial blood flow, low shear stress areas), making it difficult to meet requirements alone.

[0068] Given the natural functional complementarity between heparin and hyaluronic acid (heparin's potent anticoagulation + hyaluronic acid's active anti-inflammatory / passive antifouling properties), researchers have recently begun exploring the combined use of the two. However, key bottlenecks remain in related technologies (such as simple physical mixing and alternating layer-by-layer self-assembly).

[0069] Poor functional synergy: Components with unoptimized ratios or unstable binding are prone to non-synergistic release in the in vivo environment, making it impossible to guarantee the formation of a durable, uniform and functionally coordinated dual-active interface on the material surface.

[0070] Low stability: The coating, bound by physical forces (such as electrostatics and van der Waals forces), has weak resistance to rinsing and poor mechanical stability. Long-term use leads to component decomposition and separation, resulting in uncontrollable efficacy.

[0071] Uncontrollable structure: Key parameters affecting the function, such as molecular density, orientation, and spatial distribution, are difficult to control precisely, resulting in uneven bioactivity and poor reproducibility of the coating.

[0072] Therefore, developing a composite coating technology that can stably, densely, and controllably co-immobilize heparin and hyaluronic acid on the surface of medical materials, fully leveraging their dual synergistic effects of "anticoagulation and anti-inflammation," and possessing excellent stability and biosafety, is of great significance for overcoming the bottleneck of thrombosis and inflammatory complications in high-end medical devices (especially long-term / permanent implantable devices) and improving overall clinical safety and efficacy.

[0073] To address the aforementioned issues, this application first modifies the surface of medical materials by amylation to construct a high-density primary amine interface, and then activates the carboxyl groups of heparin and hyaluronic acid. Subsequently, heparin and hyaluronic acid are covalently grafted onto the surface of the medical materials through an amidation reaction between the amino groups on the surface of the medical materials and the activated carboxyl groups of heparin and hyaluronic acid. This coating combines the potent anticoagulant properties of heparin with the active anti-inflammatory / spatial shielding functions of hyaluronic acid. The high hydrophilicity of hyaluronic acid synergistically reduces blood cell adhesion with heparin, significantly inhibiting inflammatory cell adhesion and the release of inflammatory factors. Covalent bonding ensures long-term stability and can be widely used for surface functionalization of cardiovascular implantable devices and extracorporeal circulation tubing.

[0074] One or more embodiments of this application provide a method for preparing a coating for the surface of a medical material, comprising the following steps: co-depositing dopamine and a polyamino compound on the surface of the medical material to form an amino-containing adhesive layer on the surface of the medical material; mixing heparin and hyaluronic acid and activating the carboxyl groups of heparin and hyaluronic acid; contacting the amino-containing adhesive layer with the carboxyl-activated heparin and hyaluronic acid to cause a covalent grafting reaction between the amino groups and the carboxyl groups of the activated heparin and hyaluronic acid, thereby obtaining a coating for the surface of the medical material.

[0075] It should be noted that when dopamine and polyamine compounds are co-deposited on the surface of medical materials, polymerization reactions occur, including the self-polymerization of dopamine and the copolymerization of dopamine and polyamine compounds.

[0076] After the amino group undergoes a covalent grafting reaction with the carboxyl group of heparin and hyaluronic acid after activation treatment, heparin and hyaluronic acid are fixed on the surface of the adhesion layer through amide bonds.

[0077] Understandably, the method for preparing a coating for the surface of medical materials according to this application has at least the following beneficial effects:

[0078] (1) This preparation method innovatively achieves chemical co-immobilization of heparin and hyaluronic acid in the same coating, endowing the surface of medical materials with synchronous and long-lasting dual bioactivity of anticoagulation and anti-inflammation. At the same time, heparin and hyaluronic acid can produce synergistic effects in the coating (for example, the steric hindrance of hyaluronic acid enhances the accessibility of heparin's anticoagulant activity, and the binding of heparin to antithrombin III also indirectly regulates the inflammatory pathway).

[0079] (2) This preparation method, through covalent amide bonds between the aminated surface and the pre-activated carboxyl groups (heparin / hyaluronic acid), exhibits significantly improved chemical and mechanical stability compared to traditional methods such as physical adsorption, ion bonding, or single-component modification. The coating is difficult to detach in bodily fluids and can maintain its biological activity for a long period (weeks to months), making it particularly suitable for medical devices that require long-term implantation.

[0080] (3) This preparation method utilizes the co-deposition of dopamine and polyamine compounds. On the one hand, the self-polymerization / copolymerization of dopamine forms an adhesion layer; on the other hand, the introduction of high-density polyamine compounds significantly enhances the surface primary amino group density and stability, providing sufficient active sites for subsequent covalent fixation. The preparation steps of this method are clear and controllable, the conditions are mild, and it is applicable to a wide range of substrates, such as metals, polymers, inorganic materials, and other commonly used materials in medical devices.

[0081] (4) The hydrophilic hyaluronic acid molecules provide a large hydration layer spatial barrier, which, combined with the negative charge effect of heparin, effectively resists the non-specific adsorption of blood cells and inflammatory cells on the material surface, forming a key starting point for inhibiting subsequent thrombosis and inflammatory response. This coating can effectively solve two major complications commonly seen after the implantation or use of medical materials (such as vascular stents, catheters, heart valves, extracorporeal circulation tubing, etc.)—thrombosis and inflammatory response, and is expected to significantly improve the biocompatibility and clinical safety / effectiveness of medical devices.

[0082] As one possible implementation, the mass ratio of dopamine to the polyamine compound is (1-2):1; for example, it can be, but is not limited to, 1:1, 1.1:1, 1.2:1, 1.3:1, 1.4:1, 1.5:1, 1.6:1, 1.7:1, 1.8:1, 1.9:1, 2:1, or any range between two of the above mass ratios. This is beneficial for improving the efficiency of the co-deposition reaction of dopamine and the polyamine compound on the surface of medical materials, thereby enhancing the amino activity of the medical material surface.

[0083] In some embodiments, the polyamino compound includes one or more of polylysine, polyethyleneimine, and lysozyme.

[0084] In some alternative embodiments, the step of co-depositing dopamine and a polyamine compound on the surface of a medical material to amination the surface of the medical material includes: dissolving dopamine and a polyamine compound in a weakly alkaline buffer solution with a pH of 8-9 to obtain a first mixed solution, and immersing the medical material in the first mixed solution to co-deposit dopamine and the polyamine compound on the surface of the medical material.

[0085] It should be noted that the terms "first mixed solution," "second mixed solution," etc., mentioned in the context are for descriptive purposes only and should not be construed as indicating or implying relative importance or quantity, nor should they be interpreted as implicitly indicating the importance or quantity of the indicated technical features. Moreover, "first," "second," etc., serve only as a non-exhaustive enumeration and should be understood as not constituting a closed limitation on quantity.

[0086] As an example, the pH value of the weakly alkaline buffer can be, but is not limited to, 8, 8.1, 8.2, 8.3, 8.4, 8.5, 8.6, 8.7, 8.8, 8.9, 9, or any range between two of the above pH values. Optionally, the weakly alkaline buffer can be Tris-HCl with a pH of 8.5.

[0087] In some exemplary embodiments, the combined mass percentage of dopamine and the polyamine compound in the first mixed solution is 1%-5%. For example, it can be, but is not limited to, 1%, 1.5%, 2%, 2.5%, 3%, 3.5%, 4%, 4.5%, 5%, or any range between two of the above values. Thus, dopamine self-polymerizes on the surface of the medical material to form a highly adhesive polydopamine, and dopamine copolymerizes with the polyamine compound, achieving co-deposition of both on the surface of the medical material to form a stable composite film.

[0088] In some alternative embodiments, the co-deposition time is 2 hours to 24 hours; for example, it can be, but is not limited to, 2 hours, 4 hours, 6 hours, 8 hours, 10 hours, 12 hours, 14 hours, 16 hours, 18 hours, 20 hours, 22 hours, 24 hours, or any range between two of the above times. When the co-deposition time is within the above range, the thickness, uniformity, hydrophilicity, chemical composition, and functionality of the resulting coating are best suited for subsequent applications.

[0089] As one possible implementation, the mass ratio of heparin to hyaluronic acid is (1-16):4; for example, it can be, but is not limited to, 1:4, 2:4, 3:4, 4:4, 5:4, 6:4, 7:4, 8:4, 9:4, 10:4, 11:4, 12:4, 13:4, 14:4, 15:4, 16:4, or any range between two of the above mass ratios. When the mass ratio of heparin to hyaluronic acid is within the above range, it is beneficial to balance the strong anticoagulant activity of heparin with the anti-inflammatory, hydrophilic, and steric barrier effects of hyaluronic acid.

[0090] In some embodiments, the step of mixing heparin and hyaluronic acid and activating the carboxyl groups of heparin and hyaluronic acid includes: dissolving heparin and hyaluronic acid in a weakly acidic buffer solution with a pH of 5-6 to obtain a second mixed solution; and then adding a carboxyl activator and a catalyst to the second mixed solution to activate the carboxyl groups of heparin and hyaluronic acid. This efficiently converts the free carboxyl groups on the molecular chains of heparin and hyaluronic acid into highly reactive esters.

[0091] As an example, the pH value of the weakly acidic buffer can be, but is not limited to, 5, 5.1, 5.2, 5.3, 5.4, 5.5, 5.6, 5.7, 5.8, 5.9, 6, or any range between two of the above pH values. Optionally, the weakly acidic buffer is a 2-(N-morpholino)ethanesulfonic acid buffer with a pH of 6.

[0092] In some optional embodiments, the combined mass percentage of heparin and hyaluronic acid in the second mixed solution is 0.5%-3%. For example, it can be, but is not limited to, 0.5%, 1%, 1.5%, 2%, 2.5%, 3%, or any range between two of the above values. Therefore, heparin and hyaluronic acid have a better solubility in the second mixed solution, resulting in a lower solution viscosity range, which is beneficial for subsequent reactions.

[0093] As one possible implementation, the carboxyl activator includes one or more of 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride, N,N'-dicyclohexylcarbodiimide, and N,N'-diisopropylcarbodiimide.

[0094] In some embodiments, the molar concentration of the carboxyl activator in the second mixed solution after the addition of the carboxyl activator and the catalyst is 2 mM-20 mM; for example, it can be, but is not limited to, 2 mM, 4 mM, 6 mM, 8 mM, 10 mM, 12 mM, 14 mM, 16 mM, 18 mM, 20 mM, or any range between two of the above molar concentrations. Thus, the carboxyl activator is in a suitable concentration range, which helps to activate the carboxyl functional groups on the heparin and hyaluronic acid molecules.

[0095] It should be noted that "mM" in the context refers to millimoles per liter.

[0096] As one possible implementation, the catalyst includes one or more of 1-hydroxy-2,5-pyrrolidone, 1-hydroxy-7-azabenzotriazole, and 1,1'-carbonyldiimidazole.

[0097] In some optional embodiments, the molar concentration of the catalyst in the second mixed solution after the addition of the carboxyl activator and the catalyst is 2 mM-20 mM; for example, it can be, but is not limited to, 2 mM, 4 mM, 6 mM, 8 mM, 10 mM, 12 mM, 14 mM, 16 mM, 18 mM, 20 mM, or any range between two of the above molar concentrations. Thus, the catalyst and the carboxyl activator work together to catalyze the reaction between the carboxyl functional groups on heparin and hyaluronic acid and the amino groups on the surface of the medical material.

[0098] In some alternative embodiments, the activation treatment temperature is 20°C-25°C; for example, it can be, but is not limited to, 20°C, 21°C, 22°C, 23°C, 24°C, 25°C, or any range between two of the above temperatures.

[0099] In some embodiments, the activation treatment time is 30 to 120 minutes. For example, it can be, but is not limited to, 30 minutes, 40 minutes, 50 minutes, 60 minutes, 70 minutes, 80 minutes, 90 minutes, 100 minutes, 110 minutes, 120 minutes, or any range between two of the above times.

[0100] In some embodiments, the temperature of the covalent grafting reaction is 35°C-40°C; for example, it can be, but is not limited to, 35°C, 36°C, 37°C, 38°C, 39°C, 40°C, or any range between two of the above temperatures.

[0101] As one possible implementation, the covalent grafting reaction time is 8 to 12 hours; for example, it can be, but is not limited to, 8 hours, 9 hours, 10 hours, 11 hours, 12 hours or any range between the above two times.

[0102] When the temperature and time of the covalent grafting reaction are within the above ranges, it is beneficial for the activated carboxyl groups to undergo an efficient amidation reaction with the primary amino groups on the surface of the medical material, forming a stable covalent amide bond, thereby firmly covalently grafting heparin and hyaluronic acid onto the material surface.

[0103] As a non-limiting example, after the covalent grafting reaction is complete, the applied material is removed and the surface is thoroughly rinsed with deionized water (3-5 times) to completely remove physically adsorbed or unreacted components.

[0104] One or more embodiments of this application provide a coating for the surface of a medical material, including an adhesive layer and heparin and hyaluronic acid fixed to the surface of the adhesive layer. The adhesive layer comprises a polymer of dopamine and a polyamino compound, and the heparin and hyaluronic acid are fixed to the surface of the adhesive layer via amide bonds.

[0105] It should be noted that the polymer of dopamine and polyamine compounds is formed by copolymerization of dopamine and polyamine compounds. Furthermore, the adhesive layer may also contain polymers obtained by the self-polymerization of dopamine.

[0106] Understandably, the coating on the surface of the medical material of this application stably fixes heparin and hyaluronic acid to the surface of the adhesion layer via amide bonds, forming a coating with simultaneous and durable anticoagulant and anti-inflammatory dual bioactivities. The hydrophilic hyaluronic acid molecules in the coating provide a large hydration layer spatial barrier, which, combined with the negative charge effect of heparin, effectively resists the non-specific adsorption of blood cells and inflammatory cells on the material surface, forming a key starting point for inhibiting subsequent thrombosis and inflammatory responses. This coating can effectively address two major complications commonly encountered after the implantation or use of medical materials (such as vascular stents, catheters, heart valves, and extracorporeal circulation tubing)—thrombosis and inflammatory responses—and is expected to significantly improve the biocompatibility and clinical safety / effectiveness of medical devices.

[0107] The coating of this application, when applied to the surface of medical materials, has at least the following beneficial effects: 1. Significantly reduces blood cell adhesion: particularly effectively reduces the adhesion and activation of blood cells such as platelets on the material surface; 2. Enhances coagulation: significantly prolongs the coagulation time on the material surface and inhibits thrombus formation; 3. Effectively reduces inflammatory cell adhesion: significantly reduces the adhesion of inflammatory cells such as neutrophils and macrophages on the material surface; 4. Enhances anti-inflammatory effect: reduces the inflammatory response of the tissue surrounding the material after implantation or use.

[0108] In some embodiments, the mass ratio of heparin to hyaluronic acid is (1-16):4; for example, it can be, but is not limited to, 1:4, 2:4, 3:4, 4:4, 5:4, 6:4, 7:4, 8:4, 9:4, 10:4, 11:4, 12:4, 13:4, 14:4, 15:4, 16:4, or any range between two of the above mass ratios. When the mass ratio of heparin to hyaluronic acid is within the above range, it is beneficial to balance the strong anticoagulant activity of heparin with the anti-inflammatory, hydrophilic, and steric barrier effects of hyaluronic acid.

[0109] As one possible implementation, in the coating, heparin and hyaluronic acid are in the form of raised bumps with a height of 20nm-30nm; for example, but not limited to 20nm, 21nm, 22nm, 23nm, 24nm, 25nm, 26nm, 27nm, 28nm, 29nm, 30nm or any range between two of the above heights.

[0110] It should be noted that the "height of the protrusion" mentioned in the context refers to the maximum vertical distance from the protrusion to the adhesive layer in the direction perpendicular to the adhesive layer.

[0111] In some embodiments, the surface roughness of the coating is 12nm-80nm. For example, it can be, but is not limited to, 12nm, 15nm, 20nm, 25nm, 30nm, 35nm, 40nm, 45nm, 50nm, 55nm, 60nm, 65nm, 70nm, 75nm, 80nm, or any range between two of the above values.

[0112] As one possible implementation, the water contact angle of the coating surface is 30°-45°. For example, it can be, but is not limited to, 30°, 32°, 34°, 36°, 38°, 40°, 42°, 44°, 45°, or any range between two of the above water contact angles.

[0113] One or more embodiments of this application provide a coating prepared by the above-described preparation method or the application of the above-described coating in the preparation of medical materials with dual anticoagulant and anti-inflammatory effects.

[0114] It should be noted that the anticoagulant function mentioned in the context includes inhibiting platelet adhesion and activation, prolonging clotting time, and inhibiting thrombus formation. The anti-inflammatory function includes inhibiting inflammatory cell adhesion and reducing tissue inflammatory response.

[0115] One or more embodiments of this application provide a medical material whose surface has a coating prepared by the above-described preparation method or the coating described above.

[0116] In some embodiments, medical materials include one or more of blood-contact medical devices and implants.

[0117] In some alternative implementations, the medical material includes one or more of the following: vascular stents, heart valves, artificial blood vessels, indwelling catheters, hemodialysis membranes, and extracorporeal membrane oxygenation (ECMO) devices.

[0118] The technical solutions of this application will be described in detail below with reference to specific embodiments. It should be understood that these embodiments are only for illustrating this application and are not intended to limit the scope of this application. For experimental methods in the following embodiments where specific conditions are not specified, please refer to the guidelines given in this application first, or follow experimental manuals or conventional conditions in the field, or follow the conditions recommended by the manufacturer, or refer to experimental methods known in the field.

[0119] In the specific embodiments described below, the measurement parameters involving raw material components may have slight deviations within the weighing accuracy range unless otherwise specified. Temperature and time parameters are subject to acceptable deviations due to instrument testing accuracy or operational precision.

[0120] Unless otherwise specified, all raw materials in the following examples and comparative examples are commercially available or prepared using conventional methods.

[0121] The coatings obtained in the following embodiments and comparative examples were evaluated, mainly including surface microstructure, water contact angle test, surface blood cell adhesion test, surface inflammatory cell adhesion test, and surface inflammatory factor secretion test. The test methods are as follows:

[0122] (1) Surface micromorphology testing: The surface micromorphology of the material was analyzed and tested using a Burker Dimension Icon atomic force microscope (BFM). The tapping mode was selected for the test. The material was fixed on a glass slide and placed in the instrument test position. The surface of the material was scanned according to the instrument test method. The scanning range was 20×20μm, and three different regions were scanned for each sample. The micro-roughness of the surface was analyzed, and the average value was taken.

[0123] (2) Water contact angle test of material surface: The hydrophilicity and hydrophobicity of the obtained material surface were analyzed and tested using an OCA25 optical contact angle meter from Dataphysics, Germany. The material was fixed on a glass slide and placed on the test platform. The contact time between the droplet and the material surface was set to 30s. After stabilization, each sample was tested 5 times and the average value was taken.

[0124] (3) Blood cell adhesion test on material surface: After the medical material comes into contact with blood, blood cells will adhere to the material surface and activate the coagulation function. To verify the adhesion characteristics of blood cells on the material surface, the material was incubated with rat blood and then co-cultured. The surface of the material after co-culture with blood was analyzed by SEM. The material was incubated with fresh rat anticoagulated whole blood (1:9 sodium citrate anticoagulation) at 37°C for 2 hours, fixed with 2.5% glutaraldehyde, dehydrated, sputter-coated with gold, and observed in 3 fields of view by SEM and the blood cell adhesion density was counted.

[0125] (4) Adhesion test of inflammatory cells on the surface of the material: After the surface of the medical material comes into contact with blood, inflammatory cells in the blood will adhere to the surface of the material, causing further inflammatory response. To verify the adhesion characteristics of the material surface to inflammatory cells, the material was co-cultured with rat inflammatory macrophages. The material was cut into 1×1cm pieces and placed in a culture dish. The inflammatory macrophages were cultured on the material for 2 days. Then, the cells were washed once with PBS, fixed and stained, and then the cell state was observed using a laser scanning confocal microscope. Three fields of view were photographed and the density of inflammatory cell adhesion was counted.

[0126] (5) Surface Inflammatory Factor Test: When medical materials come into contact with blood, they stimulate inflammatory cells in the blood to release inflammatory cytokines, triggering an inflammatory response. To verify the anti-inflammatory properties of the material surface, the content of inflammatory factors in the blood was tested after co-culturing the material with blood. After co-culturing the material with inflammatory cells for 24 hours, the supernatant was collected by centrifugation and the inflammatory factors were tested by enzyme-linked immunosorbent assay (ELISA).

[0127] Example 1

[0128] Step S1: Modify the surface of the polyurethane material to construct a reactive platform rich in primary amines (-NH2): Select medical polyurethane (PU) material as the substrate. Clean the medical polyurethane material sequentially with ethanol and deionized water using ultrasonic cleaning for 15 minutes each, then dry it with nitrogen. Mix dopamine and polylysine in a weakly alkaline buffer solution (Tris-HCl, pH≈8.5). After complete dissolution, obtain the first mixed solution. The mass percentage of dopamine in the first mixed solution is 2%, and the mass percentage of polylysine in the first mixed solution is 1%. Immerse the medical polyurethane material in the first mixed solution and react it under constant temperature and light conditions (25℃, 120 rpm) for 8 hours. Remove the material, ultrasonically rinse it three times with deionized water to remove physical adsorbates, and dry it with nitrogen to obtain the aminated polyurethane material.

[0129] Step S2, Mixing and Carboxyl Activation of Heparin and Hyaluronic Acid: Heparin and hyaluronic acid are mixed and dissolved in a buffer solution (2-(N-morpholino)ethanesulfonic acid buffer, MES, pH≈6.0) to obtain a second mixed solution; the mass percentage of heparin in the second mixed solution is 0.8%, and the mass percentage of hyaluronic acid in the second mixed solution is 0.2%. A carboxyl activator, 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride (EDC), and a catalyst, 1-hydroxy-2,5-pyrrolidone (NHS), are added to the second mixed solution to obtain a third mixed solution; the molar concentration of the carboxyl activator in the third mixed solution is 2 mM, and the molar concentration of the catalyst is 10 mM. The third mixed solution is placed at room temperature (25°C) for a carboxyl activation reaction for approximately 30 minutes, efficiently converting the free carboxyl groups (-COOH) on the heparin and hyaluronic acid molecular chains into highly reactive esters (such as NHS esters).

[0130] Step S3, Covalent Grafting of Heparin and Hyaluronic Acid: The amination-treated medical material prepared in Step S1 is transferred into the third mixed solution containing carboxyl-activated heparin and hyaluronic acid described in Step S2. The reaction is carried out at 37°C with constant-temperature shaking (120 rpm) in the dark for 8 hours. After the reaction, the material is removed and ultrasonically rinsed three times each with NaCl solution and deionized water to thoroughly remove physically adsorbed or unreacted components. After drying, a polyurethane material with a covalently modified heparin and hyaluronic acid composite coating is obtained.

[0131] After testing, as shown in the attached document Figure 1 The coating surface exhibits strip-shaped protrusions with a height of 20-30 nm, corresponding to covalently fixed heparin and hyaluronic acid molecules, with a surface roughness of 15.8 ± 2.1 nm. The water contact angle of the coating surface is shown in the attached figure. Figure 3 The surface water contact angle is 38±6°, and the coating surface exhibits high hydrophilicity. Blood cells adhere to the coating surface as shown in the image. Figure 5 The number of blood cells adhering to the surface is relatively small, with a blood cell adhesion density ≤200 cells / mm². 2 Inflammatory cell adhesion on the coating surface, as shown in the attached image. Figure 7 The number of inflammatory cells adhering to the surface is relatively small. (See attached image) Figure 9 The amount of inflammatory factors released from the coating surface was 1050±180 pg / mL.

[0132] Example 2

[0133] Step S1: Modify the surface of the polyurethane material to construct a reactive platform rich in primary amines (-NH2): Select medical polyurethane (PU) material as the substrate. Clean the medical polyurethane material sequentially with ethanol and deionized water using ultrasonic cleaning for 15 minutes each, then dry it with nitrogen. Mix dopamine and polyethyleneimine in a weakly alkaline buffer solution (Tris-HCl, pH≈8.5). After complete dissolution, obtain the first mixed solution. The mass percentage of dopamine in the first mixed solution is 2%, and the mass percentage of polyethyleneimine is 1%. Immerse the medical polyurethane material in the first mixed solution and react it under constant temperature and light conditions (25℃, 120 rpm) for 8 hours. Remove the material, ultrasonically rinse it three times with deionized water to remove physical adsorbates, and dry it with nitrogen to obtain the aminated polyurethane material.

[0134] Step S2, Mixing and Carboxyl Activation of Heparin and Hyaluronic Acid: Heparin and hyaluronic acid are mixed and dissolved in a buffer solution (2-(N-morpholino)ethanesulfonic acid buffer, MES, pH≈6.0) to obtain a second mixed solution; the mass percentage of heparin in the second mixed solution is 0.5%, and the mass percentage of hyaluronic acid in the second mixed solution is 0.5%. A carboxyl activator, 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride (EDC), and a catalyst, 1-hydroxy-2,5-pyrrolidone (NHS), are added to the second mixed solution to obtain a third mixed solution; the molar concentration of the carboxyl activator in the third mixed solution is 20 mM, and the molar concentration of the catalyst is 10 mM. The third mixed solution is placed at room temperature (25°C) for a carboxyl activation reaction for approximately 30 minutes, efficiently converting the free carboxyl groups (-COOH) on the heparin and hyaluronic acid molecular chains into highly reactive esters (such as NHS esters).

[0135] Step S3, Covalent Grafting of Heparin and Hyaluronic Acid: The amination-treated medical material prepared in Step S1 is transferred into the third mixed solution containing carboxyl-activated heparin and hyaluronic acid described in Step S2. The reaction is carried out at 37°C with constant-temperature shaking (120 rpm) in the dark for 8 hours. After the reaction, the material is removed and ultrasonically rinsed three times each with NaCl solution and deionized water to thoroughly remove physically adsorbed or unreacted components. After drying, a polyurethane material with a covalently modified heparin and hyaluronic acid composite coating is obtained.

[0136] Testing revealed strip-shaped protrusions with a height of 20-30 nm on the coating surface, corresponding to covalently fixed heparin and hyaluronic acid molecules, with a surface roughness of 13.2 ± 1.9 nm. The water contact angle of the coating surface was 32 ± 4°, indicating high hydrophilicity. The number of blood cells adhering to the coating surface was low, with a blood cell adhesion density ≤ 280 cells / mm². 2 The number of inflammatory cells adhering to the coating surface was low, and the release of inflammatory factors from the surface was 980±210 pg / mL.

[0137] Example 3

[0138] Step S1: Modify the surface of the polyurethane material to construct a reactive platform rich in primary amines (-NH2): Select medical polyurethane (PU) material as the substrate. Clean the medical polyurethane material sequentially with ethanol and deionized water using ultrasonic cleaning for 15 minutes each, then dry it with nitrogen. Mix dopamine and lysozyme in a weakly alkaline buffer solution (Tris-HCl, pH≈8.5). After complete dissolution, obtain the first mixed solution. The mass percentage of dopamine in the first mixed solution is 2%, and the mass percentage of lysozyme in the first mixed solution is 1%. Immerse the medical polyurethane material in the first mixed solution and react it under constant temperature and light conditions (25℃, 120rpm) for 8 hours. Remove the material, ultrasonically rinse it three times with deionized water to remove physical adsorbates, and dry it with nitrogen to obtain the aminated polyurethane material.

[0139] Step S2, Mixing and Carboxyl Activation of Heparin and Hyaluronic Acid: Heparin and hyaluronic acid are mixed and dissolved in a buffer solution (2-(N-morpholino)ethanesulfonic acid buffer, MES, pH≈6.0) to obtain a second mixed solution; the mass percentage of heparin in the second mixed solution is 0.2%, and the mass percentage of hyaluronic acid in the second mixed solution is 0.8%. A carboxyl activator, 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride (EDC), and a catalyst, 1-hydroxy-2,5-pyrrolidone (NHS), are added to the second mixed solution to obtain a third mixed solution; the molar concentration of the carboxyl activator in the third mixed solution is 20 mM, and the molar concentration of the catalyst is 10 mM. The third mixed solution is placed at room temperature (25°C) for a carboxyl activation reaction for approximately 30 minutes, efficiently converting the free carboxyl groups (-COOH) on the heparin and hyaluronic acid molecular chains into highly reactive esters (such as NHS esters).

[0140] Step S3, Covalent Grafting of Heparin and Hyaluronic Acid: The amination-treated medical material prepared in Step S1 is transferred into the third mixed solution containing carboxyl-activated heparin and hyaluronic acid described in Step S2. The reaction is carried out at 37°C with constant-temperature shaking (120 rpm) in the dark for 8 hours. After the reaction, the material is removed and ultrasonically rinsed three times each with NaCl solution and deionized water to thoroughly remove physically adsorbed or unreacted components. After drying, a polyurethane material with a covalently modified heparin and hyaluronic acid composite coating is obtained.

[0141] Testing revealed strip-shaped protrusions with a height of 20-30 nm on the coating surface, corresponding to covalently fixed heparin and hyaluronic acid molecules, with a surface roughness of 25.3 ± 3.1 nm. The water contact angle of the coating surface was 31 ± 6°, indicating high hydrophilicity. The number of blood cells adhering to the coating surface was low, with a blood cell adhesion density ≤ 310 cells / mm². 2The number of inflammatory cells adhering to the coating surface was low, and the release of inflammatory factors from the surface was 890±175 pg / mL.

[0142] Example 4

[0143] The preparation method of Example 4 is similar to that of Example 1, except that: in step S1 of Example 4, the mass percentage of dopamine in the first mixed solution is 1.8%, and the mass percentage of polylysine in the first mixed solution is 1.2%; all other aspects are the same.

[0144] Testing revealed strip-shaped protrusions with a height of 20-30 nm on the coating surface, corresponding to covalently fixed heparin and hyaluronic acid molecules, with a surface roughness of 28.2 ± 5.3 nm. The water contact angle of the coating surface was 34 ± 2°, indicating high hydrophilicity. The number of blood cells adhering to the coating surface was low, with a blood cell adhesion density ≤ 390 cells / mm². 2 The number of inflammatory cells adhering to the coating surface was low, and the release of inflammatory factors from the surface was 910±162 pg / mL.

[0145] Example 5

[0146] The preparation method of Example 5 is similar to that of Example 1, except that: in step S1 of Example 5, the mass percentage of dopamine in the first mixed solution is 1.5%, and the mass percentage of polylysine in the first mixed solution is 1.5%; all other aspects are the same.

[0147] Testing revealed strip-shaped protrusions with a height of 20-30 nm on the coating surface, corresponding to covalently fixed heparin and hyaluronic acid molecules, with a surface roughness of 32.1 ± 4.3 nm. The water contact angle of the coating surface was 36 ± 4°, indicating high hydrophilicity. The number of blood cells adhering to the coating surface was low, with a blood cell adhesion density ≤ 410 cells / mm². 2 The number of inflammatory cells adhering to the coating surface was low, and the release of inflammatory factors from the surface was 1020±131 pg / mL.

[0148] Comparative Example 1

[0149] Medical polyurethane (PU) material was ultrasonically cleaned with ethanol and deionized water for 15 minutes in sequence, and then dried with nitrogen gas. This was used as Comparative Example 1. That is, unmodified polyurethane material was used as Comparative Example 1.

[0150] After testing, as shown in the attached document Figure 2 The polyurethane material has a smooth, flat surface with no obvious features, and a surface roughness of 3.2 ± 0.5 nm. The water contact angle of the polyurethane surface is shown in the attached figure. Figure 4 The surface has a water contact angle of 102±3°, exhibiting high hydrophobicity. Blood cells adhere to the polyurethane surface as shown in the image. Figure 6The surface is covered with a large number of blood cells, with a blood cell adhesion density >1200 cells / mm². 2 Inflammatory cell adhesion on polyurethane surface, as shown in the image. Figure 8 The surface is covered with a large number of inflammatory cells. (Attached) Figure 9 The amount of inflammatory factors released from the surface of the polyurethane material was 3410±290 pg / mL.

[0151] Comparative Example 2

[0152] The preparation method of Comparative Example 2 is similar to that of Example 1, except that only heparin is used in step S2 of Comparative Example 2, and in step S3, the prepared amination-treated medical material is transferred into the mixed solution containing heparin with carboxyl activation described in step S2 to react, thereby obtaining a polyurethane material with only a heparin coating covalently modified on the surface.

[0153] Tests showed that only polyurethane materials with covalently modified heparin coatings could effectively inhibit blood cell adhesion, but had no significant inhibitory effect on inflammatory cell adhesion. The coating only had an anticoagulant effect, but its anti-inflammatory effect was poor.

[0154] Comparative Example 3

[0155] The preparation method of Comparative Example 3 is similar to that of Example 1, except that: in step S2 of Comparative Example 3, only hyaluronic acid is used, and in step S3, the prepared amination-treated medical material is transferred into the mixed solution containing carboxyl-activated hyaluronic acid described in step S2 to react, thereby obtaining a polyurethane material with a surface only covalently modified with a hyaluronic acid coating.

[0156] Tests showed that the polyurethane material surface with only covalently modified hyaluronic acid coating had a generally poor effect on inhibiting blood cell adhesion, and the coating had a poor anticoagulant effect.

[0157] Comparative Example 4

[0158] The preparation method of Comparative Example 4 is similar to that of Example 1, except that in step S1 of Comparative Example 4, only dopamine is used to modify the surface of the polyurethane material, and the mass percentage of dopamine in the first mixed solution is 3%; all other steps are the same. Step S1 of Comparative Example 4 is as follows:

[0159] Step S1: Modify the surface of the polyurethane material to construct a reactive platform containing primary amines (-NH2): Select medical polyurethane (PU) material as the substrate. Clean the medical polyurethane material sequentially with ethanol and deionized water using ultrasonic cleaning for 15 minutes each, then dry it with nitrogen. Mix dopamine in a weakly alkaline buffer solution (Tris-HCl, pH≈8.5) until fully dissolved to obtain a first mixed solution. The mass percentage of dopamine in the first mixed solution is 3%. Immerse the medical polyurethane material in the first mixed solution and react it under constant temperature and light conditions (25℃, 120 rpm) for 8 hours. Remove the material, ultrasonically rinse it three times with deionized water to remove physical adsorbates, and dry it with nitrogen to obtain the aminated polyurethane material.

[0160] Testing revealed a small number of strip-shaped protrusions with a height of 20-30 nm on the coating surface, indicating a low concentration of covalently fixed heparin and hyaluronic acid molecules. The surface roughness was 28.1 ± 2.3 nm. The water contact angle of the coating surface was 54 ± 4°, indicating reduced hydrophilicity. A high number of blood cells adhered to the coating surface, with a blood cell adhesion density ≥ 620 cells / mm². 2 The coating surface showed a high number of inflammatory cells adhering to it, with a surface inflammatory factor release level of 1420±139 pg / mL. The adhesion intermediate layer containing only dopamine deposited on the material surface had relatively few active amino groups, thus affecting the subsequent surface modification amounts of heparin and hyaluronic acid.

[0161] Comparative Example 5

[0162] The preparation method of Comparative Example 5 is similar to that of Example 1, except that in step S1 of Comparative Example 5, only polylysine is used to modify the surface of the polyurethane material, and the mass percentage of polylysine in the first mixed solution is 3%; all other steps are the same. Step S1 of Comparative Example 5 is as follows:

[0163] Step S1: Modify the surface of the polyurethane material to construct a reactive platform containing primary amines (-NH2): Select medical polyurethane (PU) material as the substrate. Clean the medical polyurethane material sequentially with ethanol and deionized water using ultrasonic cleaning for 15 minutes each, then dry it with nitrogen. Mix polylysine in a weakly alkaline buffer solution (Tris-HCl, pH≈8.5) until fully dissolved to obtain a first mixed solution. The mass percentage of polylysine in the first mixed solution is 3%. Immerse the medical polyurethane material in the first mixed solution and react it under constant temperature and light conditions (25℃, 120 rpm) for 8 hours. Remove the material, ultrasonically rinse it three times with deionized water to remove physical adsorbates, and dry it with nitrogen to obtain the aminated polyurethane material.

[0164] Testing revealed no significant strip-like protrusions on the coating surface, indicating a low concentration of covalently fixed heparin and hyaluronic acid molecules. The surface roughness was 12.2 ± 1.9 nm. The water contact angle of the coating surface was 61 ± 5°, indicating reduced hydrophilicity. A high number of blood cells adhered to the coating surface, with a blood cell adhesion density ≥ 820 cells / mm². 2 A large number of inflammatory cells adhered to the coating surface, and the release of inflammatory factors was 1730±146 pg / mL. A stable modified layer could not be formed on the surface solely through electrostatic adsorption of polylysine.

[0165] Comparative Example 6

[0166] In Comparative Example 6, only heparin and hyaluronic acid were used for surface modification of the polyurethane material via electrostatic adsorption. Comparative Example 6 is detailed below:

[0167] Step S1: Modify the surface of the polyurethane material. Select medical polyurethane (PU) material as the substrate. Clean the medical polyurethane material with ethanol and deionized water in sequence for 15 minutes by ultrasonic cleaning, and then dry it with nitrogen.

[0168] Step S2: Mix heparin and hyaluronic acid, and dissolve the mixture in a buffer solution of (2-(N-morpholino)ethanesulfonic acid buffer, MES, pH≈6.0) to obtain a mixed solution; the mass percentage of heparin in the mixed solution is 0.8%, and the mass percentage of hyaluronic acid in the mixed solution is 0.2%.

[0169] Step S3: Place the polyurethane material in the mixed solution and react for 8 hours in the dark at a constant temperature (37℃, 120 rpm). Remove the material, ultrasonically rinse it three times with deionized water to remove physical adsorbates, and dry it with nitrogen to obtain a polyurethane material with heparin and hyaluronic acid electrostatically adsorbed on its surface.

[0170] The main differences between the above embodiments and comparative examples are shown in Table 1.

[0171] Table 1

[0172]

[0173] In Table 1, mass ratio 1 refers to the mass ratio of dopamine to polyamino compounds; mass ratio 2 refers to the mass ratio of heparin to hyaluronic acid.

[0174] Examples 1-5 all exhibited high hydrophilicity, low adhesion of blood cells and inflammatory cells, and low levels of inflammatory factor release, indicating that the coating of this application possesses both good anticoagulant and anti-inflammatory properties. In Comparative Example 1, the unmodified polyurethane material showed poor surface biocompatibility; in Comparative Example 2, the single heparin coating showed good anticoagulant effect but insufficient anti-inflammatory activity; in Comparative Example 3, the single hyaluronic acid coating showed acceptable anti-inflammatory properties but poor anticoagulant performance. As shown in Table 1, the results of Examples 1-5 and Comparative Examples 1-3 indicate that heparin and hyaluronic acid exert a synergistic effect, jointly endowing the material surface with excellent blood compatibility and anti-inflammatory function, demonstrating promising clinical application prospects.

[0175] The results of Example 1 and Comparative Examples 4-6 show that by using dopamine and polyamine compounds to co-deposit the surface of medical materials, the surface primary amino density and stability of medical materials can be significantly enhanced. Then, heparin and hyaluronic acid are covalently fixed on the surface of the aminated medical materials through an amidation reaction, which effectively improves the stability of the coating and significantly improves the biocompatibility and service life of the material surface.

[0176] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0177] The embodiments described above are merely illustrative of several implementation methods of this application, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the patent application. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this patent application should be determined by the appended claims.

Claims

1. A method for the production of a coating for the surface of a medical material, characterized in that, Includes the following steps: A dopamine and a polyamino compound are co-deposited on the surface of a medical material to form an amino-containing adhesion layer on the surface of the medical material; the polyamino compound includes one or more of polylysine, polyethyleneimine, and lysozyme. Heparin and hyaluronic acid are dissolved in a weakly acidic buffer solution with a pH of 5-6 to obtain a second mixed solution. Then, a carboxyl activator and a catalyst are added to the second mixed solution to activate the carboxyl groups of the heparin and hyaluronic acid. The carboxyl activator includes one or more of 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride, N,N'-dicyclohexylcarbodiimide, and N,N'-diisopropylcarbodiimide. The catalyst includes one or more of 1-hydroxy-2,5-pyrrolidone, 1-hydroxy-7-azabenzotriazole, and 1,1'-carbonyldiimidazole. The amino-containing adhesive layer is brought into contact with the carboxyl-activated heparin and hyaluronic acid to allow the amino groups to undergo a covalent grafting reaction with the carboxyl groups of the heparin and hyaluronic acid to obtain a coating for use on the surface of medical materials.

2. The method for producing a coating for a medical material surface according to claim 1, wherein The mass ratio of the dopamine to the polyamino compound is (1-2):

1.

3. The method for producing a coating for a medical material surface according to claim 1, wherein The step of co-depositing dopamine and a polyamine compound on the surface of the medical material to perform amination treatment on the surface of the medical material includes: The dopamine and the polyamino compound are dissolved in a weakly alkaline buffer solution with a pH of 8-9 to obtain a first mixed solution. The medical material is then immersed in the first mixed solution to allow the dopamine and the polyamino compound to co-deposit on the surface of the medical material.

4. The method for preparing a coating for the surface of medical materials as described in claim 3, characterized in that, The combined mass percentage of the dopamine and the polyamino compound in the first mixed solution is 1%-5%.

5. The method for preparing a coating for the surface of medical materials as described in claim 3, characterized in that, The co-deposition time is 2 hours to 24 hours.

6. The method for preparing a coating for the surface of medical materials as described in claim 1, characterized in that, The mass ratio of heparin to hyaluronic acid is (1-16):

4.

7. The method for preparing a coating for the surface of medical materials as described in claim 1, characterized in that, The combined mass percentage of heparin and hyaluronic acid in the second mixed solution is 0.5%-3%.

8. The method for preparing a coating for the surface of medical materials as described in claim 1, characterized in that, The molar concentration of the carboxyl activator in the second mixed solution after the addition of the carboxyl activator and the catalyst is 2 mM-20 mM.

9. The method for preparing a coating for the surface of medical materials as described in claim 1, characterized in that, The molar concentration of the catalyst in the second mixed solution after the addition of the carboxyl activator and the catalyst is 2 mM-20 mM.

10. The method for preparing a coating for the surface of medical materials as described in claim 1, characterized in that, The activation treatment temperature is 20℃-25℃, and the time is 30 minutes-120 minutes.

11. The method for preparing a coating for the surface of medical materials according to any one of claims 1 to 10, characterized in that, The temperature for the covalent grafting reaction is 35℃-40℃, and the time is 8-12 hours.

12. A coating for the surface of medical materials, characterized in that, The coating for the surface of medical materials is prepared by any one of the preparation methods described in claims 1 to 11, and includes an adhesive layer and heparin and hyaluronic acid fixed on the surface of the adhesive layer. The adhesive layer contains a polymer of dopamine and a polyamino compound, and the heparin and hyaluronic acid are fixed on the surface of the adhesive layer by amide bonds.

13. The coating for the surface of medical materials as described in claim 12, characterized in that, The mass ratio of heparin to hyaluronic acid is (1-16):4; and / or, The surface of the coating has protrusions with a height of 20 nm-30 nm; and / or, The surface roughness of the coating is 12nm-80nm; and / or, The water contact angle of the coating surface is 30°-45°.

14. The application of the coating prepared by the preparation method according to any one of claims 1 to 11 or the coating according to any one of claims 12 to 13 in the preparation of medical materials with dual anticoagulant and anti-inflammatory effects.

15. A medical material, characterized in that, The surface of the medical material has a coating prepared by any one of the preparation methods according to claims 1 to 11 or a coating according to any one of claims 12 to 13.

16. The medical material as described in claim 15, characterized in that, The medical materials include one or more of blood contact medical devices and implants.

17. The medical material as described in claim 16, wherein the medical material comprises one or more of the following: vascular stents, heart valves, artificial blood vessels, indwelling catheters, hemodialysis membranes, and extracorporeal membrane oxygenation (ECMO) devices.

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