Preparation method of graphene-based composite antibacterial coating for titanium tantalum alloy surface

Abstract

The present invention discloses a preparation method of a graphene-based composite antibacterial coating for the surface of a titanium tantalum alloy. The method includes: First, synthesizing a hyperbranched polysiloxane by reacting a dibasic acid or a diol with triethoxysilane or trimethoxysilane; Second, grafting the hyperbranched polysiloxane onto the surface of graphene and its derivatives to obtain a hyperbranched polysilane-grafted graphene-based composite; Third, formulating the hyperbranched polysilane-grafted graphene-based composite into an aqueous solution and then coating it on the surface of the titanium tantalum alloy to form a graphene-based composite antibacterial coating. By grafting the hyperbranched polysiloxane onto the surface of graphene and its derivatives and then coating to prepare the graphene-based composite antibacterial coating, the present invention improves the dispersibility of graphene and its derivatives on the surface of the titanium tantalum alloy substrate and the bonding strength between the coating and the substrate, enhances the antibacterial effect of the graphene-based composite antibacterial coating, and is conducive to the further clinical promotion and application of the titanium tantalum alloy.

Description

Technical Field

[0001] The present invention belongs to the technical field of antibacterial coatings, and particularly relates to a preparation method of a graphene-based composite antibacterial coating for the surface of a titanium tantalum alloy. Background Art

[0002] Due to reasons such as the aging population, frequent traffic accidents, and sports injuries, the number of cases of hard tissue replacement has shown an increasing trend year by year, and the core is the design and manufacture of hard tissue implants. Among them, titanium and its alloys, as the main matrix materials for the repair and replacement of hard tissues such as bones and teeth, are widely used clinically. Considering that medical titanium alloys need to have better biomechanical adaptability, better corrosion resistance, and better biocompatibility, titanium tantalum alloys have become the best choice due to their lower elastic modulus, higher strength and corrosion resistance, and more excellent biocompatibility. However, poor bone integration and infection are still the main reasons for the failure of implant surgery. Research shows that the occurrence of early infection will exacerbate the increase in the rate of poor bone integration. Therefore, endowing the surface of titanium tantalum alloy implants with antibacterial functions through effective surface modification means has become a hot issue that needs to be studied and solved urgently.

[0003] In recent years, many methods for solving bacterial infections have emerged, such as antibiotics, antimicrobial peptides, and gold nanoparticles, etc., but there are still disadvantages such as poor drug resistance, short lifespan, and cytotoxicity. Photothermal therapy (PTT) and photodynamic therapy (PDT) are both non-invasive, clinically approved, and safe treatment strategies. Graphene (Gr) and its derivatives (graphene oxide (GO), reduced graphene oxide (RGO)) are ideal high-performance sources for PTT and PDT due to their photothermal effects under near-infrared light illumination and easy functionalization. In addition, GO has good dispersibility, enhanced substrate effect, and excellent biocompatibility.

[0004] To obtain a high-performance graphene-based antibacterial composite coating, the most prominent problem is how to achieve the uniform dispersion of graphene and its derivatives in the polymer matrix and the high-strength interfacial bonding between them and the titanium tantalum alloy matrix. Hyperbranched polymers have a unique macromolecular structure, with characteristics such as low viscosity, good organic compatibility, and many end functional groups with strong modification ability. Using hyperbranched polysilane to modify graphene and its derivatives can improve their dispersibility in the substrate. On the other hand, using the characteristics of hyperbranched polysilane to build a connecting bridge between graphene and its derivatives and the surface of the titanium tantalum alloy matrix can overcome the defect of low interfacial bonding strength.

[0005] Therefore, constructing a composite antibacterial coating with excellent antibacterial performance and firm bonding to the substrate on the surface of titanium tantalum alloy plays an important role in the promotion of titanium tantalum alloy in the medical implant market. Summary of the Invention

[0006] The technical problem to be solved by the present invention is to provide a preparation method of a graphene-based composite antibacterial coating for the surface of a titanium-tantalum alloy in view of the deficiencies of the above-mentioned prior art. This method prepares a graphene-based composite antibacterial coating by grafting hyperbranched polysiloxane onto the surface of graphene and its derivatives and then coating it, which improves the dispersibility of graphene and its derivatives on the surface of the titanium-tantalum alloy. At the same time, the bonding strength between the graphene-based composite antibacterial coating and the titanium-tantalum alloy substrate is improved. At the same time, the dual antibacterial effect is achieved by combining the photodynamic characteristics of hyperbranched polysiloxane and the photothermal characteristics of graphene and its derivatives, which improves the antibacterial effect of the graphene-based composite antibacterial coating and solves the problems of poor dispersion of graphene and its derivatives on the surface of the titanium-tantalum alloy substrate and high-strength interfacial bonding between the graphene and its derivatives and the titanium-tantalum alloy substrate.

[0007] To solve the above technical problems, the technical solution adopted by the present invention is: a preparation method of a graphene-based composite antibacterial coating for the surface of a titanium-tantalum alloy, characterized in that the method comprises the following steps:

[0008] Step 1, synthesize hyperbranched polysiloxane by transesterification polycondensation of a dibasic acid or a diol with triethoxysilane or trimethoxysilane;

[0009] Step 2, graft the hyperbranched polysiloxane obtained in Step 1 onto the surface of graphene and its derivatives by transesterification polycondensation to obtain a hyperbranched polysilane-grafted graphene-based composite;

[0010] Step 3, after formulating the hyperbranched polysilane-grafted graphene-based composite obtained in Step 2 into an aqueous solution, coat it on the surface of the cleaned titanium-tantalum alloy and dry it to form a graphene-based composite antibacterial coating on the surface of the titanium-tantalum alloy.

[0011] The above-mentioned preparation method of a graphene-based composite antibacterial coating for the surface of a titanium-tantalum alloy is characterized in that the dibasic acid in Step 1 is malonic acid, succinic acid, 3,3′-dithiobispropionic acid, 2,2′-dithiobispropionic acid or dithioglycolic acid.

[0012] The above-mentioned preparation method of a graphene-based composite antibacterial coating for the surface of a titanium-tantalum alloy is characterized in that the diol in Step 1 is 1,2-propanediol, propylene glycol, butanediol or 2,2′-dithiodiethanol.

[0013] The above-mentioned preparation method of a graphene-based composite antibacterial coating for the surface of a titanium-tantalum alloy is characterized in that the triethoxysilane in Step 1 is (3-glycidoxy)methyldiethoxysilane, 3-aminopropylmethyldiethoxysilane, vinylmethyldiethoxysilane, 3-glycidoxy triethoxysilane, 3-aminopropyltriethoxysilane or vinyltriethoxysilane.

[0014] By selecting raw materials, the present invention is conducive to obtaining hyperbranched polysiloxanes with excellent photophysical and photothermal properties. At the same time, by selecting raw materials, hyperbranched polysiloxanes with amino groups at the ends are obtained, which facilitates further grafting of graphene.

[0015] The above-mentioned method for preparing a graphene-based composite antibacterial coating for the surface of a titanium-tantalum alloy is characterized in that the process of synthesizing the hyperbranched polysiloxane in Step 1 is as follows:

[0016] Step 101: React a dibasic acid or a diol with triethoxysilane or trimethoxysilane in a molar ratio of 0.5-1:0.7-1.2 at 60°C-150°C under the protection of nitrogen or argon for 8h-24h until no more distillate is produced;

[0017] Step 102: Add the product obtained in Step 101 into a dialysis bag with a molecular weight of 1000D-5000D and dialyze for 24h-48h, and then perform rotary evaporation to obtain the hyperbranched polysiloxane.

[0018] The above-mentioned method for preparing a graphene-based composite antibacterial coating for the surface of a titanium-tantalum alloy is characterized in that the graphene and its derivatives in Step 2 are graphene, graphene oxide or reduced graphene oxide.

[0019] The above-mentioned method for preparing a graphene-based composite antibacterial coating for the surface of a titanium-tantalum alloy is characterized in that the process of obtaining the graphene-based composite grafted with hyperbranched polysilane in Step 2 is as follows: Mix the hyperbranched polysiloxane and the graphene and its derivatives in a mass ratio of 10:1, disperse them ultrasonically in water for 0.5h-2h, then place them in an oil bath at 60°C-80°C and react for 6h-24h with condensation reflux. After taking out the remaining solid, wash it 3 times with distilled water and dry it in vacuum to obtain the graphene-based composite grafted with hyperbranched polysilane.

[0020] The above-mentioned method for preparing a graphene-based composite antibacterial coating for the surface of a titanium-tantalum alloy is characterized in that the coating process in Step 3 is as follows: Spin-coat 10 μL of an aqueous solution of the graphene-based composite with a mass concentration of 1% on the surface of a cleaned titanium-tantalum alloy with a length×width of 10mm×10mm and dry it. After repeatedly spin-coating and drying 3 times, a graphene-based composite antibacterial coating is formed on the surface of the titanium-tantalum alloy.

[0021] The above-mentioned method for preparing a graphene-based composite antibacterial coating for the surface of a titanium-tantalum alloy is characterized in that the thickness of the graphene-based composite antibacterial coating in Step 3 is 200nm-1400nm.

[0022] The present invention has the following advantages compared with the prior art:

[0023] 1. The present invention uses the transesterification polycondensation method to graft hyperbranched polysiloxane onto the surface of graphene and its derivatives to obtain a graphene-based composite grafted with hyperbranched polysilane, and formulates it into a solution and coats it on the surface of a titanium-tantalum alloy to prepare a graphene-based composite antibacterial coating. The grafting of hyperbranched polysiloxane effectively disperses graphene and its derivatives, improves the dispersibility of graphene and its derivatives in the solution, thereby improving the dispersibility of graphene and its derivatives on the surface of the titanium-tantalum alloy, and effectively solving the problem of poor thermal stability of the antibacterial coating caused by agglomeration.

[0024] 2. By grafting hyperbranched polysiloxane onto the surface of graphene and its derivatives, the present invention uses the abundant functional groups on the surface of the hyperbranched polysiloxane macromolecular polymer structure to effectively connect graphene and its derivatives with the surface of the titanium-tantalum alloy matrix, improving the bonding strength between the graphene-based composite antibacterial coating and the titanium-tantalum alloy matrix, overcoming the defect of low interfacial bonding strength, and avoiding the loss of implant function caused by coating shedding and serious damage to patients.

[0025] 3. The molecular weight of the hyperbranched polysiloxane prepared in the present invention is 2000D - 20000D, which conforms to the molecular weight distribution of typical polymer materials. This hyperbranched polysiloxane has the property of photoluminescence, that is, it has the potential of photodynamic sterilization, while graphene and its derivatives have the property of photothermal effect. Therefore, the antibacterial coating prepared in the present invention has photodynamic and photothermal properties, and uses the active oxygen generated by the photoluminescence of polysiloxane to combine with the photothermal effect of graphene and its derivatives under near-infrared light irradiation to kill bacteria, exerting a dual antibacterial effect and strengthening the antibacterial properties of the graphene-based composite antibacterial coating material.

[0026] 4. The graphene-based composite antibacterial coating constructed on the surface of the titanium-tantalum alloy in the present invention is firmly combined with the substrate, has photodynamic and photothermal antibacterial properties, can effectively prevent the adhesion of Escherichia coli and Staphylococcus aureus, and sterilizes through the dual action of photodynamic and photothermal, laying a foundation for the further clinical promotion of the titanium-tantalum alloy.

[0027] 5. The present invention uses the transesterification polycondensation method without organic solvents and catalysts, so the preparation process is green, environmentally friendly, economical and efficient, and has broad application prospects.

[0028] The technical solution of the present invention will be further described in detail below with reference to the drawings and embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 It is the synthesis schematic diagram of hyperbranched polysiloxane in Example 1 of the present invention.

[0030] Figure 2 It is the preparation schematic diagram of the graphene-based composite grafted with hyperbranched polysilane in Example 1 of the present invention.

[0031] Figure 3 This is a comparative graph of the photothermal effect between the titanium tantalum alloy in Example 1 of the present invention and the graphene-based composite antibacterial coating formed on the surface of the titanium tantalum alloy.

[0032] Figure 4 This is a comparative graph of the morphological characteristics of bacteria after co-culturing the titanium tantalum alloy in Example 1 of the present invention and the graphene-based composite antibacterial coating formed on the surface of the titanium tantalum alloy with bacteria. Detailed implementation manners

[0033] Example 1

[0034] This example includes the following steps:

[0035] Step 1. As shown in Figure 1 , hyperbranched polysiloxane is synthesized by the transesterification polycondensation method using malonic acid and 3-glycidoxy triethoxysilane. The specific process is as follows:

[0036] Step 101. At room temperature, add 33.4 g of 3-glycidoxy triethoxysilane and 10.4 g of malonic acid into a 100 mL three-necked flask. At the same time, install a thermometer, a stirring paddle and a distillation device, pass argon gas, then turn on the magnetic stirring of the oil bath, heat the reaction system to 70 °C, and maintain this temperature until the materials are dissolved. Then gradually raise the temperature of the reactants to 140 °C within 7 h, maintain this temperature for 2 h until the distillation temperature drops below 45 °C, stop heating, then take out the reaction product and let it cool to room temperature, and then evacuate for 30 min to remove the residual by-products in the three-necked flask, obtaining a polymer that is light yellow viscous at room temperature;

[0037] Step 102. Transfer the polymer obtained in Step 101 to a 250 mL beaker, pour in 100 mL of distilled water and stir with a glass rod until the polymer is completely dissolved. Then transfer it to a dialysis bag with a molecular weight of 3000 D and add distilled water for dialysis for 24 h to remove the low molecular weight products. Then rotate and evaporate the dialyzed solution at 45 °C and vacuum dry it at 62 °C for 4 h to obtain hyperbranched polysiloxane HEP;

[0038] Step 2. As shown in Figure 2 , graft the hyperbranched polysiloxane obtained in Step 1 onto the surface of graphene oxide by the transesterification polycondensation method to obtain a hyperbranched polysilane-grafted graphene-based composite. The specific process is as follows: Add 2 g of hyperbranched polysiloxane and 0.2 g of graphene oxide to 10 mL of water and perform ultrasonic dispersion for 1 h, then place it in an oil bath at 70 °C for constant temperature reaction for 6 h with condensation reflux. After the reaction is completed, filter to obtain the remaining solid, wash away the unreacted HEP with ethanol, wash it 3 times with distilled water, and then place it in a 60 °C oven for vacuum drying for 6 h to obtain a hyperbranched polysilane-grafted graphene-based composite HEP-GO;

[0039] Step 3: After preparing the HEP-GO obtained in Step 2 into an aqueous solution of graphene-based composite with a mass concentration of 1%, take 10 μL and coat it on the surface of a cleaned titanium tantalum alloy (TiTa) with a length × width of 10 mm × 10 mm and dry it. After repeatedly spin-coating and drying 3 times, a graphene-based composite antibacterial coating (TiTa / HEP-GO) with a thickness of 400 nm is formed on the surface of the titanium tantalum alloy.

[0040] Figure 3 This is a comparison diagram of the photothermal effects of the titanium tantalum alloy and the graphene-based composite antibacterial coating formed on its surface in this embodiment. The titanium tantalum alloy and the sample of the graphene-based composite antibacterial coating formed on its surface are irradiated with near-infrared light of 1.5 W for 10 min, and a photo is taken every 2 min to obtain an infrared thermal imaging diagram, that is Figure 3 , from Figure 3 it can be seen that the graphene-based composite antibacterial coating (TiTa / HEP-GO) prepared on the surface of the titanium tantalum alloy in this embodiment absorbs near-infrared light (NIR), and then generates a large amount of heat, and the temperature can reach up to 56.9 °C at most as time increases, indicating that TiTa / HEP-GO has excellent photodynamic and photothermal properties.

[0041] Figure 4 This is a comparison diagram of the morphological characteristics of bacteria after co-culturing the titanium tantalum alloy and the graphene-based composite antibacterial coating formed on its surface with bacteria in this embodiment. Among them, Figure (a) is the morphological characteristic diagram of bacteria after co-culturing the titanium tantalum alloy with bacteria, and Figure (b) is the morphological characteristic diagram of bacteria after co-culturing the graphene-based composite antibacterial coating formed on the surface of the titanium tantalum alloy with bacteria. From Figure 4 it can be seen that the bacteria on the surface of the titanium tantalum alloy in Figure (a) have a complete morphology, while the bacteria on the surface of the graphene-based composite antibacterial coating formed on the surface of the titanium tantalum alloy show obvious damage and the outflow of contents, indicating that the graphene-based composite antibacterial coating has excellent bactericidal properties.

[0042] The dibasic acid in Step 1 of the present invention can also be replaced by succinic acid, 3,3'-dithiobispropionic acid, 2,2'-dithiobispropionic acid or dithioglycolic acid, or replaced by 1,2-propanediol, propylene glycol, butanediol or 2,2'-dithiodiethanol; the triethoxysilane can also be replaced by (3-glycidyloxy)methyldiethoxysilane, 3-aminopropylmethyldiethoxysilane, vinylmethyldiethoxysilane, 3-aminopropyltriethoxysilane or vinyltriethoxysilane; the graphene oxide in Step 2 can also be replaced by graphene or reduced graphene oxide.

[0043] Example 2

[0044] This embodiment includes the following steps:

[0045] Step 1: As Figure 1As shown, hyperbranched polysiloxane was synthesized by transesterification polycondensation of malonic acid and 3-glycidoxy triethoxysilane. The specific process is as follows:

[0046] Step 101: At room temperature, add 19.48 g of 3-glycidoxy triethoxysilane and 5.2 g of malonic acid into a 100 mL three-necked flask. At the same time, install a thermometer, a stirring paddle and a distillation device, pass nitrogen, then turn on the magnetic stirring of the oil bath, heat the reaction system to 70 °C, and maintain this temperature until the materials are dissolved. Then gradually raise the temperature of the reactants to 60 °C within 6 h, maintain this temperature for 18 h until the distillation temperature drops below 45 °C, stop heating, then take out the reaction product and let it cool to room temperature. Then evacuate for 30 min to remove the residual by-products in the three-necked flask, and obtain a polymer that is light yellow and viscous at room temperature;

[0047] Step 102: Transfer the polymer obtained in Step 101 to a 250 mL beaker, pour in 100 mL of distilled water and stir with a glass rod until the polymer is completely dissolved. Then transfer it to a dialysis bag with a molecular weight of 1000 D and dialyze with distilled water for 48 h to remove low molecular weight products. Then rotate and evaporate the dialyzed solution at 45 °C and vacuum dry it at 62 °C for 4 h to obtain hyperbranched polysiloxane HEP;

[0048] Step Two: As Figure 2 shown, the hyperbranched polysiloxane obtained in Step One was grafted onto the surface of graphene oxide by transesterification polycondensation to obtain a graphene-based composite grafted with hyperbranched polysilane. The specific process is as follows: Add 2 g of hyperbranched polysiloxane and 0.2 g of graphene oxide into 10 mL of water and disperse ultrasonically for 0.5 h, then place it in an oil bath at 60 °C for constant temperature reaction for 12 h with condensation reflux. After the reaction is completed, filter by suction to obtain the remaining solid, wash away the unreacted HEP with ethanol, then wash with distilled water 3 times, and then place it in a 60 °C oven for vacuum drying for 6 h to obtain a graphene-based composite grafted with hyperbranched polysilane HEP-GO;

[0049] Step Three: After preparing the HEP-GO obtained in Step Two into an aqueous solution of graphene-based composite with a mass concentration of 1%, take 10 μL and coat it on the surface of a cleaned titanium tantalum alloy (TiTa) with a length × width of 10 mm × 10 mm and dry it. Spin coat-dry repeatedly 3 times, and a graphene-based composite antibacterial coating (TiTa / HEP-GO) with a thickness of 200 nm is formed on the surface of the titanium tantalum alloy.

[0050] In step one of the present invention, the dibasic acid can also be replaced with succinic acid, 3,3'-dithiobispropionic acid, 2,2'-dithiobispropionic acid or dithioglycolic acid, or replaced with 1,2-propanediol, propylene glycol, butanediol or 2,2'-dithiodiethanol; the triethoxysilane can also be replaced with (3-glycidyloxy)methyldiethoxysilane, 3-aminopropylmethyldiethoxysilane, vinylmethyldiethoxysilane, 3-aminopropyltriethoxysilane or vinyltriethoxysilane; in step two, the graphene oxide can also be replaced with graphene or reduced graphene oxide.

[0051] Example 3

[0052] This example includes the following steps:

[0053] Step one, as Figure 1 shown, synthesize hyperbranched polysiloxane by transesterification polycondensation of malonic acid and (3-glycidyloxy)triethoxysilane. The specific process is as follows:

[0054] Step 101: At room temperature, add 27.83 g of (3-glycidyloxy)triethoxysilane and 7.28 g of malonic acid into a 100 mL three-necked flask. At the same time, install a thermometer, a stirring paddle and a distillation device, pass argon gas, then turn on the magnetic stirring of the oil bath, heat the reaction system to 70 °C, and maintain this temperature until the materials are dissolved. Then gradually raise the temperature of the reactants to 150 °C within 7 h, maintain this temperature for 2 h until the distillation temperature drops below 45 °C, stop heating, then take out the reaction product and let it cool to room temperature, and then evacuate for 30 min to remove the residual by-products in the three-necked flask, obtaining a polymer that is light yellow and viscous at room temperature;

[0055] Step 102: Transfer the polymer obtained in step 101 to a 250 mL beaker, pour in 100 mL of distilled water and stir with a glass rod until the polymer is completely dissolved. Then transfer it to a dialysis bag with a molecular weight of 5000 D and add distilled water for dialysis for 36 h to remove low molecular weight products. Then rotate and evaporate the dialyzed solution at 45 °C and vacuum dry it at 62 °C for 4 h to obtain hyperbranched polysiloxane HEP;

[0056] Step two, as Figure 2As shown in the figure, the hyperbranched polysiloxane obtained in Step 1 is grafted onto the surface of graphene oxide by transesterification polycondensation method to obtain a graphene-based composite grafted with hyperbranched polysilane. The specific process is as follows: 2 g of hyperbranched polysiloxane and 0.2 g of graphene oxide are added to 10 mL of water and ultrasonically dispersed for 2 h, then placed in an oil bath at 80 °C for constant temperature reaction for 24 h with condensation reflux. After the reaction is completed, the remaining solid is obtained by suction filtration, the unreacted HEP is washed away with ethanol, then washed 3 times with distilled water, and then placed in an oven at 60 °C for vacuum drying for 6 h to obtain a graphene-based composite grafted with hyperbranched polysilane HEP-GO;

[0057] Step 3: After preparing the HEP-GO obtained in Step 2 into an aqueous solution of graphene-based composite with a mass concentration of 1%, take 10 μL and coat it on the surface of a cleaned titanium tantalum alloy (TiTa) with a length × width of 10 mm × 10 mm and dry it. After repeated spin coating - drying 3 times, a graphene-based composite antibacterial coating (TiTa / HEP-GO) with a thickness of 1400 nm is formed on the surface of the titanium tantalum alloy.

[0058] In Step 1 of the present invention, the dibasic acid can also be replaced by succinic acid, 3,3'-dithiobispropionic acid, 2,2'-dithiobispropionic acid or dithioglycolic acid, or replaced by 1,2-propanediol, propylene glycol, butanediol or 2,2'-dithiodiethanol; the triethoxysilane can also be replaced by (3-glycidoxy)methyldiethoxysilane, 3-aminopropylmethyldiethoxysilane, vinylmethyldiethoxysilane, 3-aminopropyltriethoxysilane or vinyltriethoxysilane; the graphene oxide in Step 2 can also be replaced by graphene or reduced graphene oxide.

[0059] As mentioned above, it is only a preferred embodiment of the present invention and does not impose any limitation on the present invention. Any simple modification, change and equivalent change made to the above embodiments according to the technical essence of the invention still fall within the protection scope of the technical solution of the present invention.

Claims

1. A preparation method of a graphene-based composite antibacterial coating for the surface of a titanium tantalum alloy, characterized in that, The method comprises the following steps: Step 1: Synthesize hyperbranched polysiloxane by transesterification polycondensation of a dibasic acid or a diol with triethoxysilane or trimethoxysilane; Step 2: Graft the hyperbranched polysiloxane obtained in Step 1 onto the surface of graphene oxide by transesterification polycondensation to obtain a graphene-based composite grafted with hyperbranched polysilane; the process of obtaining the graphene-based composite grafted with hyperbranched polysilane is as follows: Mix the hyperbranched polysiloxane and graphene oxide according to a mass ratio of 10:1, perform ultrasonic dispersion in water for 0.5 h to 2 h, then place it in an oil bath at 60 °C to 80 °C for reaction for 6 h to 24 h with condensation reflux, take out the remaining solid, wash it 3 times with distilled water and dry it under vacuum to obtain the graphene-based composite grafted with hyperbranched polysilane; Step 3: After formulating the graphene-based composite grafted with hyperbranched polysilane obtained in Step 2 into an aqueous solution, coat it on the surface of a cleaned titanium tantalum alloy and dry it to form a graphene-based composite antibacterial coating on the surface of the titanium tantalum alloy.

2. The preparation method of a graphene-based composite antibacterial coating for the surface of a titanium tantalum alloy according to claim 1, wherein, The dibasic acid in Step 1 is malonic acid, succinic acid, 3,3′-dithiobispropionic acid, 2,2′-dithiobispropionic acid or dithioglycolic acid.

3. The preparation method of a graphene-based composite antibacterial coating for a titanium tantalum alloy surface according to claim 1, characterized in that, The diol in Step 1 is 1,2-propanediol, propylene glycol, butanediol or 2,2′-dithiodiethanol.

4. The preparation method of a graphene-based composite antibacterial coating for the surface of a titanium tantalum alloy according to claim 1, characterized in that, The triethoxysilane in Step 1 is (3-glycidyloxy)methyldiethoxysilane, 3-aminopropylmethyldiethoxysilane, vinylmethyldiethoxysilane, 3-glycidyloxytriethoxysilane, 3-aminopropyltriethoxysilane or vinyltriethoxysilane.

5. The preparation method of a graphene-based composite antibacterial coating for the surface of a titanium tantalum alloy according to claim 1, characterized in that, The process of synthesizing the hyperbranched polysiloxane in Step 1 is as follows: Step 101: React the dibasic acid or diol with triethoxysilane or trimethoxysilane according to a molar ratio of 0.5 to 1:0.7 to 1.2 under the protection of nitrogen or argon at 60 °C to 150 °C for 8 h to 24 h until no more distillate is produced; Step 102: Add the product after the reaction in Step 101 into a dialysis bag with a molecular weight of 1000D to 5000D for dialysis for 24 h to 48 h, and then perform rotary evaporation to obtain hyperbranched polysiloxane.

6. The preparation method of a graphene-based composite antibacterial coating for the surface of a titanium tantalum alloy according to claim 1, characterized in that, The coating process in Step 3 is as follows: Spin-coat 10 μL of an aqueous solution of the graphene-based composite with a mass concentration of 1% on the surface of a cleaned titanium tantalum alloy with a length × width of 10 mm × 10 mm and dry it. After repeatedly spin-coating and drying 3 times, a graphene-based composite antibacterial coating is formed on the surface of the titanium tantalum alloy.

7. The preparation method of a graphene-based composite antibacterial coating for the surface of a titanium tantalum alloy according to claim 1, characterized in that, The thickness of the graphene-based composite antibacterial coating in Step 3 is 200 nm to 1400 nm.

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