Multifunctional composite coating for medical metal materials and preparation method and application thereof

Abstract

This invention belongs to the field of surface modification technology for biomedical materials, specifically relating to a multifunctional composite coating for medical metal materials, its preparation method, and its application. The multifunctional composite coating for medical metal materials provided by this invention comprises: a rigid support layer formed on the surface of a medical metal substrate; an active intermediate layer covering at least a portion of the surface of the rigid support layer; and a lubricating functional layer grafted onto the surface of the active intermediate layer via a polymerization initiator. The multifunctional composite coating provided by this invention possesses excellent corrosion resistance, low friction and wear resistance, high-efficiency antibacterial properties, and good biocompatibility, which is of great significance for extending the lifespan of medical metal implants, improving surgical success rates, and improving patients' quality of life. It is particularly suitable for medical metal implants such as artificial joints, orthopedic implants, cardiovascular stents, and dental implants.

Description

Technical Field

[0001] This invention belongs to the field of surface modification technology for biomedical materials, specifically relating to a multifunctional composite coating for medical metal materials, its preparation method, and its application. Background Technology

[0002] Stainless steel, cobalt-chromium-molybdenum alloy (CoCrMo), titanium alloys, and other medical-grade metal materials are widely used in orthopedic implants, cardiovascular stents, dental prostheses, and other fields due to their excellent mechanical properties and fatigue resistance. However, these materials face many challenges in the complex physiological environment of the human body: First, electrolytes, proteins, and enzymes in body fluids can cause metal corrosion, weakening the material's mechanical properties and releasing metal ions that may trigger adverse reactions such as inflammation and tissue damage. Second, bacteria can adhere to the implant surface and form biofilms, leading to persistent infections and often requiring revision surgery. Furthermore, friction between moving parts of medical implants (such as artificial joints) can cause wear, shortening the implant's lifespan and causing discomfort to patients. Wear particles generated by friction can also induce osteolysis and aseptic loosening.

[0003] Surface modification is a key strategy to overcome the aforementioned application bottlenecks. Existing research on biomimetic coatings has made some progress. Currently, various surface modification techniques exist, such as physical / chemical vapor deposition, magnetron sputtering, and biomimetic coatings. A related technology discloses a method for preparing a gridded periodic structure on the surface of medical titanium using lasers to construct a silver-containing coating. This method can modulate Ag... + Release rate enables precise antibacterial performance. Another related technology uses magnetron sputtering to sequentially prepare a polytetrafluoroethylene (PTFE) coating and an iron-based coating on a magnesium alloy substrate, forming a double-layer coating. The PTFE provides chemical inertness and a hydrophobic barrier, while the iron-based coating enhances structural integrity, achieving corrosion resistance through synergistic effects. However, most existing technologies can only endow materials with a single function (such as corrosion resistance or antibacterial properties only). Designing a coating system that can simultaneously and persistently integrate multifunctional properties of corrosion resistance, lubrication, and antibacterial properties remains a significant challenge. Summary of the Invention

[0004] The purpose of this invention is to provide a multifunctional composite coating for medical metal materials, its preparation method and application. The multifunctional composite coating provided by this invention has excellent corrosion resistance, low friction and wear resistance, high efficiency antibacterial properties and good biocompatibility. It is of great significance for extending the life of medical metal implants, improving the success rate of surgery and improving the quality of life of patients. It is particularly suitable for medical metal implants such as artificial joints, orthopedic implants, cardiovascular stents and dental implants.

[0005] To achieve the above objectives, the present invention provides the following technical solution: This invention provides a multifunctional composite coating for medical metallic materials, comprising: A rigid support layer is formed on the surface of a medical metal substrate, and the rigid support layer is a diamond-like coating doped with metal elements. An active intermediate layer covers at least a portion of the surface of the rigid support layer, the active intermediate layer comprising an inorganic network framework and an antibacterial agent dispersed in the inorganic network framework; A lubricating functional layer is grafted onto the surface of the active intermediate layer via a polymerization reaction initiated by a polymerization initiator, and the lubricating functional layer is formed of a polymer having hydrophilic and / or hydration capabilities.

[0006] Preferably, the diamond-like coating doped with metal elements is a tungsten-doped diamond-like coating.

[0007] Preferably, the inorganic network framework is a silica network framework; the antibacterial agent includes one or more of bio-based surfactants, quaternary ammonium salt antibacterial agents, guanidine antibacterial agents and halogen amine antibacterial agents, and the bio-based surfactant includes one or more of rhamnolipids, sophorolipids and trehalolipids.

[0008] Preferably, the polymerization initiator is an atom transfer radical polymerization initiator; the polymer with hydrophilic and / or hydration capabilities includes one or more of sulfonate betaine-type polymers, carboxy betaine-type polymers, phosphocholine-type polymers, polyethylene glycol and its derivatives, and polyvinylpyrrolidone.

[0009] This invention provides a method for preparing the multifunctional composite coating described above, comprising the following steps: (1) Depositing a hard support layer on the surface of a medical metal substrate; (2) A mixture containing an inorganic network skeleton precursor, a polymerization initiator and an antibacterial agent is coated on at least a portion of the surface of the rigid support layer, and dried or cured to obtain a semi-finished product. An active intermediate layer is formed on at least a portion of the surface of the semi-finished product, and the polymerization initiator is dispersed in the active intermediate layer in the semi-finished product. (3) The semi-finished product is brought into contact with a reaction system containing polymerizable monomers, and a polymerization reaction is initiated by the polymerization initiator to generate a lubricating functional layer in situ on the surface of the active intermediate layer.

[0010] Preferably, in step (1), the deposition is performed by physical vapor deposition, chemical vapor deposition or magnetron sputtering; in step (2), the inorganic network skeleton precursor includes silicate compounds, and the coating is performed by one or more of dip coating, spray coating, spin coating and brush coating.

[0011] Preferably, in step (3), the polymerization reaction is at least one of atom transfer radical polymerization, reversible addition-fragmentation chain transfer polymerization, and nitric oxide stable radical polymerization; the polymerizable monomer is a vinyl unsaturated monomer, and the vinyl unsaturated monomer contains at least one of sulfonate betaine group, carboxy betaine group, phosphocholine group, ethylene glycol group, and vinylpyrrolidone group.

[0012] This invention provides the application of the multifunctional composite coating described in the above technical solution or the multifunctional composite coating prepared by the preparation method described in the above technical solution in the surface modification coating material of medical metal implants.

[0013] The present invention provides a medical metal implant device, the medical metal implant device comprising a medical metal substrate and a multifunctional composite coating as described in the above-described technical solution or a multifunctional composite coating prepared by the preparation method described in the above-described technical solution disposed on at least a portion of the surface of the medical metal substrate.

[0014] Preferably, the medical metal substrate is a titanium alloy, stainless steel, or cobalt-chromium-molybdenum alloy; the medical metal implant device includes artificial joints, orthopedic implants, cardiovascular stents, or dental implants, and the orthopedic implant includes one or more of bone fixation plates, bone screws, and spinal fixation devices.

[0015] This invention provides a multifunctional composite coating for medical metal materials, comprising: a rigid support layer formed on the surface of a medical metal substrate, wherein the rigid support layer is a diamond-like carbon coating doped with metal elements; an active intermediate layer covering at least a portion of the surface of the rigid support layer, wherein the active intermediate layer comprises an inorganic network framework and an antibacterial agent dispersed in the inorganic network framework; and a lubricating functional layer grafted onto the surface of the active intermediate layer via a polymerization initiator, wherein the lubricating functional layer is formed of a polymer having hydrophilic and / or hydration capabilities. The multifunctional composite coating for biomedical metal materials provided by this invention, from the inside out, comprises: a rigid support layer formed on the surface of a medical metal substrate, providing mechanical support for wear and corrosion resistance; and an active intermediate layer covering at least a portion of the surface of the rigid support layer, wherein the active intermediate layer serves as both a bonding layer and provides the functional component antibacterial agent. The lubricating functional layer is grafted onto the surface of the active intermediate layer through a polymerization reaction initiated by a polymerization initiator (the polymerization initiator is pre-dispersed in the inorganic network backbone of the active intermediate layer). The lubricating functional layer is formed of a polymer with hydrophilic and / or hydrating capabilities, and is used to provide an ultra-low coefficient of friction in aqueous environments. Compared with the prior art, the present invention has the following advantages: The multifunctional composite coating provided by this invention achieves multiple functions in synergy: through a multi-layer structure design, this invention enables a single coating system to simultaneously achieve excellent corrosion resistance, ultra-low and durable coefficient of friction, high-efficiency antibacterial activity, and good biocompatibility, thus solving the problem of single function in existing technologies.

[0016] The multifunctional composite coating provided by this invention possesses excellent lubricity and durability: the lubrication layer can form a stable hydration layer in an aqueous environment. Results from the embodiments show that after 50,000 reciprocating friction cycles, the coating maintains an ultra-low friction state (friction coefficient of approximately 0.0035) without failure, with a friction coefficient only 0.4% of that of traditional DLC coatings, and more than an order of magnitude lower than that of directly grafted PSPMA.

[0017] The multifunctional composite coating provided by this invention has significant corrosion resistance: electrochemical tests show that the coating of this invention can significantly increase the corrosion potential (positive shift) of medical metal substrates, while reducing the corrosion current density by 1 to 2 orders of magnitude, exhibiting good corrosion resistance.

[0018] The multifunctional composite coating provided by this invention has high antibacterial properties: the antibacterial agent in the active intermediate layer can be released for a long time through a sustained-release mechanism, and the inhibition rate of Gram-positive bacteria (such as Staphylococcus aureus) exceeds 90%, effectively preventing implant-related infections.

[0019] The multifunctional composite coating provided by this invention has good biocompatibility: the cytotoxicity test (CCK-8 method) shows that the composite coating is non-toxic to L929 fibroblasts, and does not affect the proliferation of normal cells while exerting a strong antibacterial effect, thus meeting the requirements for in vivo application of biomedical materials.

[0020] This invention provides a method for preparing the multifunctional composite coating described in the above technical solution. The preparation method provided by this invention has wide adaptability, is compatible with various medical metal substrates (titanium alloys, stainless steel, cobalt-chromium-molybdenum alloys, etc.), and can be applied using various conventional coating processes such as dip coating and spray coating, making it easy to implement in industrial applications. Attached Figure Description

[0021] Figure 1 The graphs show a comparison of the electrochemical corrosion performance of different metal substrates and their coatings in Examples 1-3. Figure 2 The friction coefficient stability of the multifunctional composite coating prepared in Example 1 during 50,000 friction cycles; Figure 3 The results show a comparison of the antibacterial properties of the coatings prepared in Example 1 and Comparative Example 1. Figure 4 Cell compatibility evaluation of the multifunctional composite coating prepared in Example 1; Figure 5 The results show a comparison of the friction coefficients of the coatings prepared in Example 1 and Comparative Example 1. Figure 6 The coefficient of friction of the coating with no active intermediate layer prepared for Comparative Example 2 during 2500 friction cycles. Detailed Implementation

[0022] This invention provides a multifunctional composite coating for medical metallic materials, comprising: A rigid support layer is formed on the surface of a medical metal substrate, and the rigid support layer is a diamond-like coating doped with metal elements. An active intermediate layer covers at least a portion of the surface of the rigid support layer, the active intermediate layer comprising an inorganic network framework and an antibacterial agent dispersed in the inorganic network framework; A lubricating functional layer is grafted onto the surface of the active intermediate layer via a polymerization reaction initiated by a polymerization initiator, and the lubricating functional layer is formed of a polymer having hydrophilic and / or hydration capabilities.

[0023] In this invention, unless otherwise specified, all raw materials / components used in the preparation are commercially available products well known to those skilled in the art.

[0024] The multifunctional composite coating for medical metal materials provided by this invention includes a rigid support layer formed on the surface of a medical metal substrate. The rigid support layer is a diamond-like carbon (DLC) coating doped with metal elements. In this invention, the DLC coating doped with metal elements is preferably a tungsten-doped DLC coating (tungsten-doped DLC coating). The tungsten-doped DLC coating further enhances its toughness and adhesion.

[0025] The multifunctional composite coating for medical metallic materials provided by this invention includes an active intermediate layer covering at least a portion of the surface of a rigid support layer. The active intermediate layer comprises an inorganic network framework and an antibacterial agent dispersed within the inorganic network framework. In this invention, the inorganic network framework is preferably a silica network framework. The silica network framework can form a stable three-dimensional porous structure, effectively anchoring and protecting the internal antibacterial agent molecules. In this invention, the antibacterial agent preferably includes one or more of bio-based surfactants, quaternary ammonium salt antibacterial agents, guanidine antibacterial agents, and halogenated amine antibacterial agents. The bio-based surfactant preferably includes one or more of rhamnolipids, sophorolipids, and trehalolipids, more preferably biocompatible rhamnolipids or sophorolipids.

[0026] In this invention, the active intermediate layer may further comprise a polymerization initiator dispersed in the inorganic network framework (the free polymerization initiator remaining after the polymerization reaction of the polymerization initiator pre-dispersed in the inorganic network framework in the active intermediate layer, i.e., the polymerization initiator that did not participate in the polymerization reaction). The polymerization initiator is an atom transfer radical polymerization initiator, and the polymerization initiator in the active intermediate layer is the remaining polymerization initiator dispersed in the inorganic network framework after participating in the polymerization reaction to form the lubricating functional layer.

[0027] The multifunctional composite coating for medical metal materials provided by this invention includes a lubricating functional layer, which is grafted onto the surface of an active intermediate layer via a polymerization reaction initiated by a polymerization initiator. The lubricating functional layer is formed of a polymer with hydrophilic and / or hydrating capabilities. In this invention, the polymerization initiator is pre-dispersed in the inorganic network framework of the active intermediate layer. Preferably, the polymerization initiator is an atom transfer radical polymerization initiator (ATRP). The polymer with hydrophilic and / or hydrating capabilities preferably includes one or more of sulfonated betaine-type polymers, carboxylated betaine-type polymers, phosphocholine-type polymers, polyethylene glycol and its derivatives, and polyvinylpyrrolidone. More preferably, the polymer with hydrophilic and / or hydrating capabilities is selected from one or more of sulfonated betaine-type polymers, carboxylated betaine-type polymers, phosphocholine-type polymers, polyethylene glycol and its derivatives, and polyvinylpyrrolidone. All of the above polymers have a strong ability to bind water molecules, and can form a dense hydrating layer on the surface. In this invention, the main body of the polymerization initiator is permanently fixed in the active intermediate layer by Si-O-Si bonds, while its end is connected to the growing lubricating molecule backbone by CC bonds.

[0028] This invention provides a method for preparing the multifunctional composite coating described above, comprising the following steps: (1) Depositing a hard support layer on the surface of a medical metal substrate; (2) A mixture containing an inorganic network skeleton precursor, a polymerization initiator and an antibacterial agent is coated on at least a portion of the surface of the rigid support layer, and dried or cured to obtain a semi-finished product. An active intermediate layer is formed on at least a portion of the surface of the semi-finished product, and the polymerization initiator is dispersed in the active intermediate layer in the semi-finished product. (3) The semi-finished product is brought into contact with a reaction system containing polymerizable monomers, and a polymerization reaction is initiated by the polymerization initiator to generate a lubricating functional layer in situ on the surface of the active intermediate layer.

[0029] This invention deposits a rigid support layer on the surface of a medical metal substrate. Prior to deposition, the medical metal substrate is preferably pretreated, which preferably includes sequential cleaning and drying. The cleaning is preferably ultrasonic cleaning. The cleaning reagents are preferably ethanol and petroleum ether, with the ultrasonic cleaning time for each reagent preferably being 10-15 minutes. This invention removes impurities from the surface of the medical metal substrate through cleaning. The drying can be achieved by nitrogen blowing.

[0030] In this invention, the deposition is preferably performed using physical vapor deposition, chemical vapor deposition, or magnetron sputtering, more preferably magnetron sputtering. The magnetron sputtering is preferably performed in the vacuum chamber of a magnetron sputtering apparatus. The sputtering target used in the magnetron sputtering is preferably a tungsten target or a carbon target. The magnetron sputtering preferably includes: at a pressure ≤ 3 × 10⁻⁶ -3 Under the condition of Pa, argon gas is introduced for plasma cleaning; then, a tungsten transition layer is deposited under the condition of argon gas introduction; and then, a tungsten-doped DLC coating is deposited under the condition of argon gas introduction. In this invention, the argon gas flow rate for plasma cleaning is preferably 60~65 sccm. The deposition conditions for the tungsten transition layer preferably include: an argon gas flow rate of preferably 40~50 sccm, a bias voltage of preferably 70~80V, a tungsten target current of 4~4.5A, and a deposition time of 10~15min. The deposition conditions for the tungsten-doped DLC coating preferably include: an argon gas flow rate of preferably 40~50 sccm, a bias voltage of preferably 70~80V, a tungsten target current of 1~1.5A, a carbon target current of 4~4.5A, and a deposition time of 10~15min.

[0031] After obtaining the rigid support layer, the present invention coats at least a portion of the surface of the rigid support layer with a mixture containing an inorganic network framework precursor, a polymerization initiator, and an antibacterial agent, and obtains a semi-finished product by drying or curing. An active intermediate layer is formed on at least a portion of the surface of the semi-finished product, and the polymerization initiator is dispersed in the active intermediate layer. In the present invention, the mixture containing the inorganic network framework precursor, polymerization initiator, and antibacterial agent can be a sol or a solution. In the present invention, the mixture containing the inorganic network framework precursor, polymerization initiator, and antibacterial agent preferably further includes a solvent, which preferably includes an organic solvent and water. The organic solvent can be anhydrous ethanol. The mixture containing the inorganic network framework precursor, polymerization initiator, and antibacterial agent preferably also includes an inorganic strong acid, which can be nitric acid, and the molar concentration of the nitric acid is preferably 0.1 mol / L. The inorganic network framework precursor preferably includes a silicate compound. The silicate compound preferably includes tetraethyl orthosilicate (TEOS) and / or methyl orthosilicate. In this invention, the polymerization initiator is preferably an atom transfer radical polymerization initiator, more preferably a halogen-containing silane coupling agent capable of initiating atom transfer radical polymerization. In the examples, it can be a Br-containing silane coupling agent capable of initiating atom transfer radical polymerization, such as a 3-aminopropyltriethoxysilane-bromoisobutyryl bromide derivative (APTES-Br). In a specific embodiment of this invention, the preparation method of the polymerization initiator (APTES-Br) preferably includes: reacting 3-aminopropyltriethoxysilane (APTES) with 2-bromoisobutyryl bromide in dry dichloromethane and triethylamine under ice bath conditions, followed by post-treatment to obtain APTES-Br. In this invention, the volume ratio of APTES to 2-bromoisobutyryl bromide is preferably 10:5.55. The volume ratio of APTES to triethylamine is preferably 10:7.8. The reaction time is preferably 12-24 h. The post-processing preferably includes: filtering the reaction product obtained from the reaction to obtain a filtrate; washing the filtrate sequentially with hydrochloric acid, sodium carbonate aqueous solution and water to obtain a washed reaction solution; and drying the washed reaction solution to remove the solvent to obtain a polymerization initiator.

[0032] In this invention, the preferred method for preparing the mixture containing the inorganic network framework precursor, polymerization initiator, and antibacterial agent includes: adding the inorganic network framework precursor and polymerization initiator to an organic solvent and stirring for 10-15 min; then adding an inorganic strong acid and stirring for 30-40 min to obtain a mixed solution; adding an aqueous solution of the antibacterial agent dropwise to the mixed solution and stirring at room temperature for 12-24 h for hydrolysis and aging to obtain the mixture containing the inorganic network framework precursor, polymerization initiator, and antibacterial agent.

[0033] In this invention, prior to coating, the rigid support layer is preferably subjected to air plasma treatment. The air plasma treatment time is preferably 1-2 minutes. This invention preferably increases surface hydrophilicity through the air plasma treatment. In this invention, the coating is preferably performed using one or more of dip coating, spray coating, spin coating, and brush coating. In a specific embodiment of this invention, the coating can be dip coating or spray coating. The dip coating is preferably performed using a dip coating machine, and the dip coating preferably includes: immersing the substrate with the rigid support layer into a mixture containing an inorganic network framework precursor, a polymerization initiator, and an antibacterial agent at a speed of 30-50 mm / min and uniformly pulling it up at a speed of 30-50 mm / min. The spray coating is performed using a spray gun, and the spraying conditions preferably include: the distance between the spray gun and the sample is preferably 15-20 cm, and the spraying pressure is preferably 0.15-0.2 MPa. In this invention, the drying or curing temperature is preferably 70-80°C, and the time is preferably 2-3 hours.

[0034] In this invention, the semi-finished product comprises an active intermediate layer formed on at least a portion of the surface of the rigid support layer, and also includes a polymerization initiator pre-dispersed in the inorganic network framework of the active intermediate layer.

[0035] After obtaining the semi-finished product, the present invention contacts the semi-finished product with a reaction system containing a polymerizable monomer, and initiates a polymerization reaction through the polymerization initiator, thereby generating a lubricating functional layer in situ on the surface of the active intermediate layer. In the present invention, the polymerization reaction is preferably at least one of atom transfer radical polymerization, reversible addition-fragmentation chain transfer polymerization, and nitrile-oxygen stabilized radical polymerization, preferably atom transfer radical polymerization. In the present invention, the polymerizable monomer is preferably a vinyl unsaturated monomer. The vinyl unsaturated monomer preferably contains at least one of sulfonate betaine group, carboxybetaine group, phosphocholine group, ethylene glycol group, and vinylpyrrolidone group. In the embodiments of the present invention, the polymerizable monomer can be potassium 3-sulfonate propyl methacrylate (SPMA) or carboxybetaine methacrylate (CBMA). The reaction system containing the polymerizable monomer preferably includes the polymerizable monomer, solvent, 2,2'-bipyridine (bipy), cuprous bromide (CuBr), and ascorbic acid. The solvent is preferably water and methanol, and the volume ratio of water to methanol is preferably 2:1. The preferred mass ratio of the polymerizable monomer to the 2,2'-bipyridine is 6:0.08. The preferred mass ratio of the 2,2'-bipyridine to the cuprous bromide is 80:35. The preferred mass ratio of the 2,2'-bipyridine to the ascorbic acid is 80:160. The contact is preferably performed by immersing the semi-finished product in the reaction system containing the polymerizable monomer for polymerization. The polymerization temperature can be room temperature. The polymerization time is preferably 1-6 hours. After the polymerization reaction, the reaction sample is taken from the reaction system and washed and dried sequentially to obtain the multifunctional composite coating. The washing reagents are preferably water and methanol. The water can be deionized water. The drying is preferably performed by nitrogen blowing.

[0036] This invention provides the application of the multifunctional composite coating described in the above technical solution or the multifunctional composite coating prepared by the preparation method described in the above technical solution in the surface modification coating material of medical metal implants.

[0037] The present invention provides a medical metal implant device, the medical metal implant device comprising a medical metal substrate and a multifunctional composite coating as described in the above-described technical solution or a multifunctional composite coating prepared by the preparation method described in the above-described technical solution disposed on at least a portion of the surface of the medical metal substrate.

[0038] In this invention, the medical metal substrate is preferably a titanium alloy, stainless steel, or a cobalt-chromium-molybdenum alloy. The stainless steel can be 316L stainless steel. The titanium alloy is preferably a Ti6Al4V alloy sheet.

[0039] In this invention, the medical metal implant device preferably includes an artificial joint, orthopedic implant, cardiovascular stent, or dental implant. The orthopedic implant preferably includes one or more of bone fixation plates, bone screws, and spinal internal fixation devices.

[0040] This invention provides a multifunctional composite coating for medical metal materials, which simultaneously possesses excellent anti-corrosion properties, ultra-low friction and high-durability lubrication properties, efficient antibacterial properties, and good biocompatibility, and is suitable for a variety of medical metal substrates.

[0041] To further illustrate the present invention, the technical solutions provided by the present invention will be described in detail below with reference to the embodiments, but they should not be construed as limiting the scope of protection of the present invention.

[0042] Example 1 (1) Substrate pretreatment: The CoCrMo alloy substrate (10 mm × 10 mm × 2 mm) was ultrasonically cleaned in ethanol and petroleum ether for 15 minutes in sequence to remove surface impurities, and then dried with nitrogen for later use.

[0043] (2) Preparation of a hard support layer (tungsten-doped DLC coating): The substrate pretreated in step (1) is placed in the vacuum chamber of a magnetron sputtering apparatus. When the chamber pressure drops to 3×10 -3 At Pa, argon gas at 65 sccm was introduced for plasma cleaning. Subsequently, a tungsten transition layer was deposited for 10 minutes under the conditions of argon gas flow rate of 40 sccm, bias voltage of 80 V, and tungsten target current of 4.5 A. While keeping the argon gas flow rate and bias voltage constant, the tungsten target current was adjusted to 1 A, and the carbon target was turned on (current of 4 A) to deposit a tungsten-doped DLC coating.

[0044] (3) Preparation of active intermediate layer (RL coating): a. Synthesis of the initiator APTES-Br: 10 mL of 3-aminopropyltriethoxysilane (APTES) and 5.55 mL of 2-bromoisobutyryl bromide were reacted in 200 mL of dry dichloromethane and 7.8 mL of triethylamine in an ice bath for 24 h. After the reaction was completed, the reaction solution was filtered to remove the white precipitate. The filtrate was then washed three times each with 1 M hydrochloric acid, 1 M Na₂CO₃ aqueous solution, and deionized water. The solution was then dried over anhydrous MgSO₄ for 4 h. Finally, the solvent was evaporated to obtain the product.

[0045] b. Preparation of a mixture containing an inorganic network backbone precursor, polymerization initiator, and antibacterial agent: Add 5 mL of tetraethyl orthosilicate (TEOS) and 0.5 mg of APTES-Br to 35 mL of anhydrous ethanol and stir for 10 minutes. Then add 0.5 mL of nitric acid (0.1 M) and continue stirring for 30 minutes. Add 2 mL of a 500 mg / L rhamnolipid aqueous solution dropwise to the above ethanol solution and continue stirring at room temperature for 24 hours to carry out hydrolysis and aging.

[0046] c. Dip-coating: The substrate with the tungsten-doped DLC coating deposited in step (2) was subjected to air plasma treatment for 2 minutes to increase surface hydrophilicity. Then, using a dip-coating machine, the substrate was dipped into the precursor sol at a speed of 50 mm / min and pulled up at a uniform speed (the uniform pulling speed was 50 mm / min). The coated substrate was placed in an 80°C oven for curing for 2 hours to obtain an active intermediate layer containing APTES-Br.

[0047] (4) Preparation of the lubricating functional layer (PSPMA coating): Prepare the ATRP reaction solution. Dissolve 6 g of SPMA monomer in 12 mL of water / methanol mixed solvent (V / V=2:1). Add 80 mg of 2,2'-bipyridine (bipy), 35 mg of cuprous bromide (CuBr), and 160 mg of ascorbic acid in sequence, and stir until a uniform dark red solution is formed to obtain a reaction system containing polymerizable monomers. Place the sample with active intermediate layer and APTES-Br obtained in step (3) into the reaction system containing polymerizable monomers and let it stand for 2 hours. After the reaction is completed, take out the sample, wash it thoroughly with deionized water and methanol in sequence, and blow it dry with nitrogen. Thus, the biomimetic multilayer composite coating provided in this embodiment is completed.

[0048] Figure 1 The results show that preparing a multifunctional composite coating on the surface of a CoCrMo alloy substrate can significantly improve corrosion resistance and effectively inhibit the erosion of the CoCrMo alloy substrate by corrosive media. The multifunctional composite coating prepared in Example 1 was subjected to 50,000 reciprocating sliding tests at a load of 5 N and a frequency of 1 Hz (e.g., ...). Figure 2 (As shown). The coefficient of friction decreased rapidly after a short run-in period and stabilized between 0.002 and 0.004, without any increase or drastic fluctuations, demonstrating excellent durability. The antibacterial properties of the multifunctional composite coating prepared in Example 1 are as follows: Figure 3 As shown, compared with the CoCrMo alloy substrate and Comparative Example 1, the bacterial colony count on the surface of the PSPMA coating in the multifunctional composite coating prepared in Example 1 was almost zero, with an antibacterial rate approaching 90%, demonstrating extremely strong antibacterial adhesion ability. The effect of the coating extract on the viability of L929 mouse fibroblasts was detected using the CCK-8 assay, and the results are as follows. Figure 4As shown, the cell survival rate of the experimental group prepared by the multifunctional composite coating in Example 1 was higher than 80%, indicating that the multifunctional composite coating prepared in Example 1 has good cell compatibility.

[0049] Example 2 Except for replacing the substrate with a medical-grade 316L stainless steel sheet (10 mm × 10 mm × 2 mm), the other steps and parameters are exactly the same as in Example 1. Figure 1 The results show that the multifunctional composite coating prepared in Example 2 can significantly improve corrosion resistance and effectively inhibit the erosion of the substrate by corrosive media.

[0050] Example 3 Except for replacing the substrate with a medical-grade Ti6Al4V alloy sheet (10 mm × 10 mm × 2 mm), the other steps and parameters are exactly the same as in Example 1. Figure 1 The results show that the multifunctional composite coating prepared in Example 3 can significantly improve corrosion resistance and effectively inhibit the erosion of the substrate by corrosive media.

[0051] Example 4 The basic steps are the same as in Example 1, except that rhamnolipid in the active intermediate layer is replaced with an equal concentration of sophorolipid. The remaining steps are the same as in Example 1. The resulting coated samples exhibited similar antibacterial properties.

[0052] Example 5 The basic steps were the same as in Example 1, except that the SPMA monomer in step three was replaced with carboxybetaine methacrylate (CBMA). The remaining steps were the same as in Example 1. The resulting coated samples also exhibited excellent hydrophilic lubricating properties.

[0053] Example 6 The basic steps are the same as in Example 1, except that in step two, a spraying method is used instead of a dip-coating method to prepare the active intermediate layer. The precursor sol is loaded into a spray gun and sprayed uniformly at a pressure of 0.2 MPa at a distance of 15-20 cm from the sample surface, followed by drying at 80°C for 2 hours. The resulting active intermediate layer has a uniform thickness and good adhesion to the subsequent lubrication functional layer.

[0054] Comparative Example 1 The CoCrMo / DLC coating was prepared according to the steps in Example 1, without depositing the RL coating and PSPMA coating.

[0055] Depend on Figure 5 As can be seen from the comparison of the friction coefficients of the coatings prepared in Comparative Example 1 and Example 1, the coating prepared in Comparative Example 1, due to the lack of RL coating and PSPMA coating, is only a single-layer tungsten-doped DLC coating and cannot achieve ultra-low friction performance.

[0056] Comparative Example 2 On the CoCrMo / DLC substrate obtained in step (2) of Example 1, an APTES-Br monolayer was prepared by chemical vapor deposition, followed by SI-ATRP polymerization of the PSPMA layer (the RL coating preparation step is omitted). The specific steps are as follows: Preparation of APTES-Br initiator monolayer: An APTES-Br initiator monolayer was prepared on the CoCrMo / DLC substrate obtained in step (2) of Example 1 by chemical vapor deposition. The CoCrMo / DLC obtained in step (2) of Example 1 was ultrasonically cleaned with acetone, ethanol and deionized water, respectively. Each ultrasonic cleaning lasted 10 min. After drying with nitrogen, the substrate was treated with oxygen plasma at a power of 75 W and a vacuum level of 0.3 Torr for 5 min. The substrate was then placed in a vacuum desiccator containing 20 μL of APTES-Br. The vacuum was evacuated for 20 min, and then baked in an oven for 30 min. The above process was repeated twice. The treated CoCrMo / DLC sample was then taken out, washed repeatedly with ethanol and deionized water, and dried with nitrogen to modify the CoCrMo / DLC with an APTES-Br monolayer.

[0057] Preparation of the lubricating functional layer (PSPMA coating): ATRP reaction solution was prepared. 6 g of SPMA monomer was dissolved in 12 mL of a water / methanol mixture (V / V = 2:1). 80 mg of 2,2'-bipyridine (bipy), 35 mg of cuprous bromide (CuBr), and 160 mg of ascorbic acid were added sequentially, and the mixture was stirred until a homogeneous dark red solution was formed, yielding a reaction system containing polymerizable monomers. The sample modified with an APTES-Br monolayer and featuring a tungsten-doped DLC coating was placed in the reaction system containing polymerizable monomers and allowed to react for 2 hours. After the reaction, the sample was removed, thoroughly washed with deionized water and methanol sequentially, and dried under nitrogen. Thus, the composite coating provided in this comparative example was prepared.

[0058] Figure 6 The friction coefficient test results for the composite coating sample prepared in Comparative Example 2 are obtained from... Figure 6 As can be seen, Comparative Example 2 suffers from significantly worse frictional stability due to the lack of an active intermediate layer. Therefore, the RL active intermediate layer is crucial for ensuring the mechanical stability and durability of the PSPMA lubricating layer and is a key structural unit for achieving ultra-low friction of 50,000 cycles.

[0059] As can be seen from the above embodiments, the present invention provides a multifunctional composite coating for medical metal materials. This composite coating includes a rigid support layer formed on the surface of a medical metal substrate, an active intermediate layer covering the rigid support layer, and a lubricating functional layer grafted onto the surface of the active intermediate layer. The active intermediate layer comprises an inorganic network framework and a polymerization initiator and an antibacterial agent dispersed therein; the lubricating functional layer is formed of a polymer with hydrophilic and / or hydrating capabilities. The coating of the present invention provides corrosion and wear resistance through the rigid support layer, achieves antibacterial effects by releasing antibacterial agents through the active intermediate layer, and forms a hydrated lubricating layer in an aqueous environment through the lubricating functional layer, thereby achieving a synergistic effect of corrosion resistance, antibacterial properties, and ultra-low friction. Experiments show that this coating can reduce the corrosion current density by 1-2 orders of magnitude on different medical metal substrates, achieve a friction coefficient as low as 0.001-0.007, and maintain a stable ultra-low friction state even after long-term friction cycles. It also exhibits an inhibition rate of over 90% against Gram-positive bacteria and good biocompatibility. The coating structure of this invention is ingenious, the preparation method is simple, and the substrate applicability is wide. It has broad application prospects in the field of surface modification of medical metal implants such as artificial joints and bone implants.

[0060] Although the above embodiments have provided a detailed description of the present invention, they are only some embodiments of the present invention, and not all embodiments. Other embodiments can be obtained based on these embodiments without creative effort, and these embodiments all fall within the protection scope of the present invention.

Claims

1. A multifunctional composite coating for medical metallic materials, characterized in that, include: A rigid support layer is formed on the surface of a medical metal substrate, and the rigid support layer is a diamond-like coating doped with metal elements. An active intermediate layer covers at least a portion of the surface of the rigid support layer, the active intermediate layer comprising an inorganic network framework and an antibacterial agent dispersed in the inorganic network framework; A lubricating functional layer is grafted onto the surface of the active intermediate layer via a polymerization reaction initiated by a polymerization initiator, and the lubricating functional layer is formed of a polymer having hydrophilic and / or hydration capabilities.

2. The multifunctional composite coating according to claim 1, characterized in that, The diamond-like coating doped with metal elements is a tungsten-doped diamond-like coating.

3. The multifunctional composite coating according to claim 1, characterized in that, The inorganic network framework is a silica network framework; the antibacterial agent includes one or more of the following: bio-based surfactants, quaternary ammonium salt antibacterial agents, guanidine antibacterial agents, and halogenated amine antibacterial agents; the bio-based surfactant includes one or more of the following: rhamnolipids, sophorolipids, and trehalolipids.

4. The multifunctional composite coating according to claim 1, characterized in that, The polymerization initiator is an atom transfer radical polymerization initiator; the polymer with hydrophilic and / or hydration capabilities includes one or more of sulfonate betaine-type polymers, carboxy betaine-type polymers, phosphocholine-type polymers, polyethylene glycol and its derivatives, and polyvinylpyrrolidone.

5. The method for preparing the multifunctional composite coating according to any one of claims 1 to 4, characterized in that, Includes the following steps: (1) Depositing a hard support layer on the surface of a medical metal substrate; (2) A mixture containing an inorganic network skeleton precursor, a polymerization initiator and an antibacterial agent is coated on at least a portion of the surface of the rigid support layer, and dried or cured to obtain a semi-finished product. An active intermediate layer is formed on at least a portion of the surface of the semi-finished product, and the polymerization initiator is dispersed in the active intermediate layer in the semi-finished product. (3) The semi-finished product is brought into contact with a reaction system containing polymerizable monomers, and a polymerization reaction is initiated by the polymerization initiator to generate a lubricating functional layer in situ on the surface of the active intermediate layer.

6. The preparation method according to claim 5, characterized in that, In step (1), the deposition is performed by physical vapor deposition, chemical vapor deposition or magnetron sputtering; in step (2), the inorganic network skeleton precursor includes silicate compounds, and the coating is performed by one or more of dip coating, spray coating, spin coating and brush coating.

7. The preparation method according to claim 5, characterized in that, In step (3), the polymerization reaction is at least one of atom transfer radical polymerization, reversible addition-fragmentation chain transfer polymerization, and nitric oxide stable radical polymerization; the polymerizable monomer is a vinyl unsaturated monomer, and the vinyl unsaturated monomer contains at least one of sulfonate betaine group, carboxy betaine group, phosphocholine group, ethylene glycol group, and vinylpyrrolidone group.

8. The application of the multifunctional composite coating according to any one of claims 1 to 4 or the multifunctional composite coating prepared by the preparation method according to any one of claims 5 to 7 in the surface modification coating material of medical metal implants.

9. A medical metal implant device, characterized in that, The medical metal implant device includes a medical metal substrate and a multifunctional composite coating as described in any one of claims 1 to 4 or a multifunctional composite coating prepared by the preparation method described in any one of claims 5 to 7, disposed on at least a portion of the surface of the medical metal substrate.

10. The medical metal implant device according to claim 9, characterized in that, The medical metal substrate is made of titanium alloy, stainless steel, or cobalt-chromium-molybdenum alloy; the medical metal implant device includes artificial joints, orthopedic implants, cardiovascular stents, or dental implants, and the orthopedic implant includes one or more of bone fixation plates, bone screws, and spinal internal fixation devices.

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