Self-lubricating hydrogel titanium alloy bionic joint bearing interface and preparation method thereof

Abstract

The invention discloses a self-lubricating hydrogel titanium alloy bionic joint bearing interface and a preparation method thereof. The self-lubricating hydrogel titanium alloy bionic joint bearing interface is composed of a porous titanium alloy matrix, a functional interface layer, an electronegative hydrogel layer and a self-lubricating adsorption layer. Laser drilling is conducted on the surface of the Ti6Al4V substrate through a laser drilling method, and a porous structure is formed; the surface of a Ti6Al4V sample is coated with the hydrogel precursor solution, ultraviolet radiation curing is carried out, and an electronegative hydrogel titanium alloy composite sample is obtained; and performing freezing-unfreezing circulation treatment on the electronegative hydrogel titanium alloy composite sample, and immersing the electronegative hydrogel titanium alloy composite sample into a zwitter-ion or cation solution for adsorption to obtain the hydrogel titanium alloy bionic joint bearing interface with the self-lubricating property. According to the hydrogel titanium alloy bionic joint bearing interface, the lubricating performance of a titanium alloy material for an artificial joint is remarkably improved, bionic design of a natural joint is achieved from the tissue structure and the lubricating function, and the hydrogel titanium alloy bionic joint bearing interface is suitable for the field of injured articular cartilage repair and replacement.

Description

Technical Field

[0001] The present invention belongs to the technical field of bionic joint material structures and preparation technologies, and particularly relates to a self-lubricating hydrogel titanium alloy bionic joint bearing interface and a preparation method thereof. Background Art

[0002] Titanium alloy has high specific strength, hardness and elasticity similar to human bones, excellent corrosion resistance and outstanding biocompatibility, and is currently the most widely used artificial joint material. Generally, the acetabular cup, femoral stem of artificial hip joint prosthesis and tibial plateau in artificial knee joint are made of titanium alloy. Clinical trials have also proved that pure titanium can be used in parts of the human body with low bearing capacity, and Ti6Al4V alloy can be used in parts of the human body with high bearing capacity. However, the relatively high friction coefficient and poor wear resistance of the titanium alloy surface limit its application in the bearing interface of artificial joints.

[0003] Patent CN117379593A and patent CN11950679A only achieved the bionics of the hydrogel / titanium alloy composite structure, focused on improving the bonding strength between the hydrogel layer and the substrate, and ignored the important lubrication characteristics of artificial joints. In addition, the use of magnetron sputtering to deposit tantalum has the disadvantages of cumbersome process and high cost. Patent CN109137036A discloses a composite coating of a ceramic layer grafted with hydrogel on the surface of titanium alloy and a preparation method thereof, which achieves the bionics of the natural joint hydrogel / titanium alloy composite structure. However, the micro-arc oxidation technology used has disadvantages such as complex process and high energy consumption, and the friction coefficient of the hydrogel / titanium alloy composite specimen is about 0.3, which is still far from the excellent lubrication characteristics of natural joints (0.0005 - 0.04). Therefore, in order to meet the actual application, it is necessary to further optimize and improve the lubrication performance of the hydrogel / titanium alloy bionic joint bearing interface.

[0004] The excellent load-bearing / shear-resistant / lubrication ability of natural joints is closely related to the articular cartilage covering its surface. The proteoglycans (rich in carboxylic acid and sulfonic acid groups) interspersed in the superficial layer of cartilage make the cartilage surface hydrophilic and negatively charged. Aggrecan and hyaluronic acid form large aggregates, which are trapped in the collagen network and generate an osmotic pressure to resist compressive loads. This property plays a positive role in the efficient lubrication of natural joints. On the other hand, biological macromolecules in articular cartilage or synovial fluid can tightly absorb water molecules to form a tough hydrated lubricating layer, jointly maintaining long-term superlubrication performance. Summary of the Invention

[0005] Objective of the Invention: In order to overcome the deficiencies in the prior art, the present invention provides a self-lubricating hydrogel titanium alloy bionic joint bearing interface and its preparation method. By bionic design, a self-lubricating hydrogel titanium alloy joint bearing interface is constructed. The dynamic hydration lubricating film is used to reduce the friction coefficient to a level close to that of natural joints, and the wear resistance is improved by combining interface strengthening processes to extend the lifespan of artificial joints.

[0006] Technical Solution: To achieve the above objective, a self-lubricating hydrogel titanium alloy bionic joint bearing interface of the present invention, a self-lubricating hydrogel titanium alloy bionic joint bearing interface, includes:

[0007] Porous titanium alloy substrate: Made of Ti6Al4V alloy, with regularly distributed pit structures on the surface. The pit diameter is 100 - 300 μm, the pit spacing is 50 - 200 μm, and an oxide layer is formed by thermal oxidation treatment;

[0008] Functionalized interface layer: The surface of the porous titanium alloy substrate is hydroxylated and modified with a silane coupling agent. The silane coupling agent is γ-propyltrimethoxysilane with a carbon-carbon double bond;

[0009] Negatively charged hydrogel layer: Covering the functionalized interface layer, composed of acrylamide, 2-acrylamido-2-methyl-1-propanesulfonic acid, a crosslinking agent, a photoinitiator, and polyvinyl alcohol;

[0010] Wherein, the mass ratio of acrylamide, 2-acrylamido-2-methyl-1-propanesulfonic acid, the crosslinking agent, the photoinitiator, and polyvinyl alcohol is 1.0 - 2.0:0.3 - 1.0:0.005 - 0.02:0.005 - 0.02:0.1 - 1.0;

[0011] Self-lubricating adsorption layer: Bound to the surface of the negatively charged hydrogel layer by electrostatic adsorption, composed of zwitterionic or cationic monomers, with an adsorption concentration of 5 - 25 mg / ml;

[0012] Wherein, the friction coefficient of the self-lubricating hydrogel titanium alloy bionic joint bearing interface under a load of 2 - 3 N is 0.02 - 0.08.

[0013] Further, the pit diameter is 200 μm, and the pit spacing is 100 μm.

[0014] Further, the crosslinking agent is N,N'-methylenebisacrylamide, and the photoinitiator is α-ketoglutaric acid.

[0015] Further, the zwitterionic monomer is betaine N,N-dimethylammonium propanesulfonate inner salt.

[0016] Further, the thickness of the negatively charged hydrogel layer is 50 - 200 μm.

[0017] A preparation method for a self-lubricating hydrogel titanium alloy bionic joint bearing interface, comprising the following steps:

[0018] Step 1: Pretreat the surface of the Ti6Al4V substrate, including sandpaper grinding, mechanical polishing, ultrasonic cleaning and nitrogen drying. Subsequently, use the laser drilling method to perform laser drilling on the surface of the Ti6Al4V substrate to form a porous structure with a pit diameter of 100 - 300 μm and a spacing of 50 - 200 μm, and perform secondary grinding and polishing on the edges of the micropores to eliminate the heat affected zone at the micropore edges;

[0019] Step 2: Heat-oxidize the porous Ti6Al4V sample prepared in Step 1 at 700 - 800 °C for 5 - 30 hours and cool it in the furnace;

[0020] Step 3: Perform surface hydroxylation treatment and silane coupling agent modification on the sample after heat oxidation in Step 2;

[0021] Step 4: Construct a surface soft hydrogel layer on the sample in Step 3. Dissolve acrylamide, 2-acrylamido-2-methyl-1-propanesulfonic acid, crosslinking agent, photoinitiator and polyvinyl alcohol in deionized water to obtain a hydrogel precursor solution;

[0022] Step 5: Coat the hydrogel precursor solution on the surface of the Ti6Al4V sample obtained in Step 3 and cure it by ultraviolet irradiation to obtain a negatively charged hydrogel titanium alloy composite sample;

[0023] Step 6: Perform freeze-thaw cycle treatment on the negatively charged hydrogel titanium alloy composite sample obtained in Step 5 and immerse it in a zwitterionic or cationic solution for adsorption to obtain a self-lubricating hydrogel titanium alloy bionic joint bearing interface.

[0024] Further, in Step 2, heat up to 700 °C at a heating rate of 10 °C / min, maintain the heat oxidation temperature of 700 °C for insulation for 10 hours, and then cool to room temperature.

[0025] Further, in Step 4, the composition of the hydrogel precursor solution is: 1.6324 g of acrylamide, 0.5 g of 2-acrylamido-2-methyl-1-propanesulfonic acid, 0.01 g of N,N'-methylenebisacrylamide, 0.01 g of α-ketoglutaric acid, and 0.4 g of polyvinyl alcohol.

[0026] Further, in Step 5, the ultraviolet irradiation is under an ultraviolet lamp and the ultraviolet irradiation time is 30 min.

[0027] Further, in the step 6, the number of freeze-thaw cycles is 3 - 5 times, the concentration of the adsorption solution is 5 - 25 mg / ml, and the adsorption time is 12 - 48 hours.

[0028] Beneficial effects: 1) By using the two-phase treatment method combining laser drilling and thermal oxidation, a porous titanium alloy substrate with high wear resistance is constructed, which has the advantages of simpler preparation process, good repeatability, high speed, and environmental protection;

[0029] 2) By introducing a silane coupling agent containing carbon-carbon double bonds, under ultraviolet irradiation, it can covalently crosslink with the carbon-carbon double bond monomers in the hydrogel precursor solution, further improving the bonding performance between the hydrogel layer and the substrate;

[0030] 3) By using the electrostatic adsorption technology to dynamically adsorb SBMA zwitterions onto the surface of the negatively charged hydrogel layer, the simulation of the natural cartilage's adsorption of biomacromolecules in synovial fluid during movement is realized, further improving the hydration boundary lubrication ability of the composite bearing interface. Description of the Drawings

[0031] Figure 1 It is a schematic diagram of the construction mechanism of the self-lubricating hydrogel titanium alloy bionic joint bearing interface;

[0032] Figure 2 It is a schematic diagram of the interface SEM morphology of the self-lubricating hydrogel titanium alloy bionic joint bearing interface;

[0033] Figure 3 It is a schematic diagram of the average friction coefficient measured for the self-lubricating hydrogel titanium alloy bionic joint bearing interface under 2N and 3N loads. Detailed Embodiments

[0034] The present invention will be further described below with reference to the drawings.

[0035] As Figure 1 、 Figure 2 and Figure 3 shown, a self-lubricating hydrogel titanium alloy bionic joint bearing interface is characterized by comprising:

[0036] Porous titanium alloy matrix: It is made of Ti6Al4V alloy, with regularly distributed pit structures on the surface, the pit diameter is 100 - 300 μm, the pit spacing is 50 - 200 μm, and an oxide layer is formed by thermal oxidation treatment;

[0037] Functionalized interface layer: The surface of the porous titanium alloy matrix is hydroxylated and modified with a silane coupling agent, and the silane coupling agent is γ-(methacryloyloxy)propyltrimethoxysilane (KH570) with carbon-carbon double bonds;

[0038] Negative charge hydrogel layer: covering the functionalized interface layer, composed of acrylamide (AM), 2-acrylamido-2-methylpropane sulfonic acid (AMPS), crosslinking agent, photoinitiator and polyvinyl alcohol (PVA); wherein, the mass ratio of acrylamide (AM), 2-acrylamido-2-methylpropane sulfonic acid (AMPS), crosslinking agent, photoinitiator to polyvinyl alcohol (PVA) is 1.0-2.0:0.3-1.0:0.005-0.02:0.005-0.02:0.1-1.0;

[0039] Self-lubricating adsorption layer: electrostatically adsorbed on the surface of the negative charge hydrogel layer, composed of zwitterionic or cationic monomers, and the adsorption concentration is 5-25 mg / ml; wherein, the friction coefficient of the self-lubricating hydrogel titanium alloy bionic joint bearing interface under a load of 2-3 N is 0.02-0.08.

[0040] The diameter of the pit is 200 μm, and the pit spacing is 100 μm.

[0041] The crosslinking agent is N,N'-methylenebisacrylamide (MBAA), and the photoinitiator is α-ketoglutaric acid (KA).

[0042] The zwitterionic monomer is betaine N,N-dimethyl(methacryloyloxyethyl) ammonium propanesulfonate inner salt (SBMA).

[0043] The thickness of the negative charge hydrogel layer is 50-200 μm.

[0044] A preparation method of a self-lubricating hydrogel titanium alloy bionic joint bearing interface, comprising the following steps:

[0045] Step 1: Pretreat the surface of the Ti6Al4V substrate, including sandpaper grinding, mechanical polishing, ultrasonic cleaning and nitrogen drying, and then use the laser drilling method to drill holes on the surface of the Ti6Al4V substrate to form a porous structure with a pit diameter of 100-300 μm and a spacing of 50-200 μm, and perform secondary grinding and polishing on the edges of the micropores to eliminate the heat affected zone at the micropore edges.

[0046] Step 2: Heat-oxidize the porous Ti6Al4V sample prepared in Step 1 at 700-800 °C for 5-30 hours and cool it with the furnace;

[0047] In Step 2, heat up to 700 °C at a heating rate of 10 °C / min, maintain the heat oxidation temperature of 700 °C for insulation for 10 hours, and then cool to room temperature.

[0048] Step 3: Perform surface hydroxylation treatment and silane coupling agent modification on the sample heat-oxidized in Step 2.

[0049] Step 4: Construct a surface soft hydrogel layer on the specimen in Step 3. Dissolve acrylamide, 2-acrylamido-2-methyl-1-propanesulfonic acid, crosslinking agent, photoinitiator and polyvinyl alcohol in deionized water to obtain a hydrogel precursor solution;

[0050] In the said Step 4, the composition of the hydrogel precursor solution is: acrylamide (AM) 1.6324 g, 2-acrylamido-2-methyl-1-propanesulfonic acid (AMPS) 0.5 g, N,N'-methylenebisacrylamide (MBAA) 0.01 g, α-ketoglutaric acid (KA) 0.01 g, polyvinyl alcohol (PVA) 0.4 g.

[0051] Step 5: Coat the hydrogel precursor solution on the surface of the Ti6Al4V specimen obtained in Step 3, and cure it by ultraviolet irradiation to obtain a negatively charged hydrogel-titanium alloy composite specimen;

[0052] In the said Step 5, the ultraviolet irradiation is carried out under an ultraviolet lamp, and the ultraviolet irradiation time is 30 min.

[0053] Step 6: Carry out freeze-thaw cycle treatment on the negatively charged hydrogel-titanium alloy composite specimen obtained in Step 5, and immerse it in zwitterionic or cationic solution for adsorption to obtain a hydrogel-titanium alloy bionic joint bearing interface with self-lubricating characteristics.

[0054] In the said Step 6, the number of freeze-thaw cycles is 3 - 5 times, the concentration of the adsorption solution is 5 - 25 mg / ml, and the adsorption time is 12 - 48 hours.

[0055] To better understand the lubrication advantages of the self-lubricating hydrogel-titanium alloy bionic joint bearing interface of the present invention, in combination with Figure 2 and Figure 3 Analysis is as follows from the microscopic physical and chemical and biological perspectives:

[0056] 1. Structure and function of the porous titanium alloy matrix

[0057] 1.1) Microscopic morphology design: The regular pit structure (diameter 100 - 300 μm, spacing 50 - 200 μm) formed by laser drilling enhances lubrication in the following ways:

[0058] Liquid storage effect: The pits act as "micro liquid storage pools" that can adsorb and slowly release lubricants (such as zwitterionic solutions, calf serum, phosphate buffered saline solution) to continuously replenish the lubricating interface;

[0059] Stress dispersion: The porous structure disperses the contact stress, reduces the local pressure, and avoids the rupture of the lubricating film.

[0060] 1.2) Thermal oxidation layer strengthening:

[0061] The oxide layer (such as TiO2) formed by thermal oxidation at 700 - 800 °C significantly improves the hardness and wear resistance of the substrate, reducing the generation of microcracks and abrasive particles during the friction process.

[0062] 2. Covalent bonding of the functionalized interface layer

[0063] Hydroxylation and modification with silane coupling agent:

[0064] 2.1) Hydroxylation treatment makes the surface of the titanium alloy rich in hydroxyl groups (-OH), which form Si - O - Ti covalent bonds after the hydrolysis of the methoxy groups (-OCH3) of the silane coupling agent (KH570).

[0065] 2.2) The terminal carbon - carbon double bond (C=C) of KH570 undergoes free - radical copolymerization with acrylamide - type monomers in the hydrogel precursor to form strong interfacial covalent bonds, preventing the hydrogel layer from peeling off during the friction process.

[0066] 3. Bionic lubrication mechanism of the negatively charged hydrogel layer

[0067] 3.1) Chemical composition:

[0068] The hydrogel is composed of acrylamide (AM), 2 - acrylamido - 2 - methyl - 1 - propane sulfonic acid (AMPS), etc. The sulfonic acid group (-SO3H) of AMPS endows the hydrogel with negative charge.

[0069] 3.2) Electrostatic adsorption and formation of the lubricating layer:

[0070] The negatively charged hydrogel adsorbs cations or zwitterions (such as SBMA) through electrostatic interaction to form a dynamic hydrated lubricating layer;

[0071] The zwitterionic structure of SBMA (containing quaternary ammonium cations and sulfonic acid anions) adsorbs a large number of water molecules through strong hydration to form a hydrated film with a thickness of about 1 - 10 nm, achieving boundary lubrication and significantly reducing the friction coefficient (which can be as low as 0.02).

[0072] 4. Dynamic response characteristics of the self - lubricating adsorption layer

[0073] 4.1) Lubrication enhancement mechanism of zwitterions:

[0074] SBMA molecules form an orderly arranged hydrophilic layer on the surface of the hydrogel, and its hydration produces a "super - lubrication effect" under the frictional shear force;

[0075] Under the action of load, the zwitterionic layer can dynamically adjust its orientation, reducing the direct contact area through the "molecular brush" effect and further reducing the frictional resistance.

[0076] 4.2) Microscopic regulation of freeze - thaw cycles:

[0077] The cyclic treatment induces the formation of a denser physical cross - linked network inside the hydrogel, enhancing its mechanical strength and lubricant retention ability, and avoiding the extrusion failure of the lubricating layer under high pressure.

[0078] 5. Bionic synergistic effect of the composite interface

[0079] 5.1) Bionic simulation of natural articular cartilage:

[0080] Soft / hard gradient structure: titanium alloy (hard) → hydrogel (soft) → zwitterionic lubricating layer (ultra - soft), simulating the hierarchical mechanical properties of cartilage - subchondral bone and achieving gradient transfer of load;

[0081] Bionic lubrication mechanism: Through negative - charge adsorption and hydration lubrication, the function of the proteoglycan - hyaluronic acid lubricating layer in natural joints is reproduced.

[0082] 5.2) Dynamic self - repair ability:

[0083] During the friction process, when the local lubricant is lost, the porous matrix can release the stored lubricant, and the zwitterionic molecules can re - cover the surface through diffusion to achieve the dynamic repair of the lubricating layer.

[0084] In summary, the core logic for optimizing the lubrication performance of the self - lubricating hydrogel - titanium alloy bionic joint bearing interface of the present invention is as follows:

[0085] a. Structure for storing liquid (porous matrix) → strong interface bonding (covalent bond) → molecular lubrication (zwitterionic hydration layer) → dynamic response (load adaptation and self - repair);

[0086] b. Through the synergistic effect of micro - structure design and chemical components, the friction coefficient is reduced from 0.3 - 0.5 of titanium alloy to 0.02 - 0.08, approaching the level of natural joints (0.0005 - 0.04), and at the same time having high wear resistance and long - term stability.

[0087] It should be noted that, Figure 3 as can be seen from the test histogram in, the friction coefficient of the zwitterionic adsorption solution is the lowest at 10 mg / ml under 2N and 3N loads, while the friction coefficient of the zwitterionic adsorption solution at 15 mg / ml under 2N and 3N loads has a tendency to be roughly balanced. Based on this, it is concluded that the preferred range of the friction coefficient of the self - lubricating hydrogel - titanium alloy bionic joint bearing interface of the present invention under 2 - 3N loads is 0.02 - 0.08.

[0088] The advantages of the present invention are as follows:

[0089] 1) By means of the two - phase treatment method combining laser drilling and thermal oxidation, a highly wear - resistant porous titanium alloy substrate is constructed, which has the advantages of simpler preparation process, good repeatability, high speed and environmental protection;

[0090] 2) By introducing a silane coupling agent containing a carbon-carbon double bond, under ultraviolet light irradiation, it generates covalent cross-linking with the carbon-carbon double bond monomer in the hydrogel precursor solution, further improving the bonding performance between the hydrogel layer and the substrate;

[0091] 3) By using the electrostatic adsorption technology to dynamically adsorb SBMA zwitterions onto the surface of the negatively charged hydrogel layer, the simulation of the natural cartilage's adsorption of biomacromolecules in synovial fluid during movement is realized, and the hydration boundary lubrication ability of the composite bearing interface is further improved.

[0092] The above are only the preferred embodiments of the present invention. It should be pointed out that for those of ordinary skill in the art, without departing from the principle of the present invention, several improvements and modifications can be made, and these improvements and modifications should also be regarded as the protection scope of the present invention.

Claims

1. A self-lubricating hydrogel titanium alloy bionic joint bearing interface, characterized in that: Comprising: Porous titanium alloy substrate: Made of Ti6Al4V alloy, with regularly distributed pit structures on the surface, the pit diameter is 100 - 300 μm, the pit spacing is 50 - 200 μm, and an oxide layer is formed by thermal oxidation treatment; Functionalized interface layer: The surface of the porous titanium alloy substrate is hydroxylated and modified with a silane coupling agent, and the silane coupling agent is γ - propyltrimethoxysilane with a carbon - carbon double bond; Negatively charged hydrogel layer: Covering the functionalized interface layer, composed of acrylamide, 2 - acrylamido - 2 - methyl - 1 - propane sulfonic acid, cross - linker, photo - initiator, and polyvinyl alcohol; Among them, the mass ratio of acrylamide, 2 - acrylamido - 2 - methyl - 1 - propane sulfonic acid, cross - linker, photo - initiator to polyvinyl alcohol is 1.0 - 2.0:0.3 - 1.0:0.005 - 0.02:0.005 - 0.02:0.1 - 1.0; Self - lubricating adsorption layer: Bound to the surface of the negatively charged hydrogel layer by electrostatic adsorption, composed of zwitterionic or cationic monomers, with an adsorption concentration of 5 - 25 mg / ml; Among them, the friction coefficient of the self - lubricating hydrogel titanium alloy bionic joint bearing interface under a load of 2 - 3 N is 0.02 - 0.

08.

2. The self-lubricating hydrogel titanium alloy bionic joint bearing interface according to claim 1, wherein: The pit diameter is 200 μm, and the pit spacing is 100 μm.

3. A self-lubricating hydrogel titanium alloy bionic joint bearing interface according to claim 1, characterized in that: The cross - linker is N,N'-methylenebisacrylamide, and the photo - initiator is α - ketoglutaric acid.

4. A self-lubricating hydrogel titanium alloy bionic joint bearing interface according to claim 1, characterized in that: The zwitterionic monomer is betaine - type N,N - dimethylammonium propanesulfonate inner salt.

5. A self-lubricating hydrogel titanium alloy bionic joint bearing interface according to claim 1, characterized in that: The thickness of the negatively charged hydrogel layer is 50 - 200 μm.

6. The preparation method of a self-lubricating hydrogel titanium alloy bionic joint bearing interface according to claim 1, wherein: Including the following steps: Step 1: Pretreat the surface of the Ti6Al4V substrate, including sandpaper grinding, mechanical polishing, ultrasonic cleaning, and nitrogen drying. Subsequently, use the laser drilling method to drill holes on the surface of the Ti6Al4V substrate to form a porous structure with a pit diameter of 100 - 300 μm and a spacing of 50 - 200 μm, and perform secondary grinding and polishing on the edges of the micropores to eliminate the heat - affected zone at the micropore edges; Step 2: Heat - oxidize the porous Ti6Al4V sample prepared in Step 1 at 700 - 800 °C for 5 - 30 hours and cool it in the furnace; Step 3: Perform surface hydroxylation treatment and silane coupling agent modification on the sample heat - oxidized in Step 2; Step 4: Construct a surface soft hydrogel layer on the sample in Step 3. Dissolve acrylamide, 2 - acrylamido - 2 - methyl - 1 - propane sulfonic acid, cross - linker, photo - initiator, and polyvinyl alcohol in deionized water to obtain a hydrogel precursor solution; Step 5: Coat the hydrogel precursor solution on the surface of the Ti6Al4V sample obtained in Step 3 and cure it by ultraviolet irradiation to obtain a negatively charged hydrogel - titanium alloy composite sample; Step 6: Perform freeze - thaw cycle treatment on the negatively charged hydrogel - titanium alloy composite sample obtained in Step 5 and immerse it in a zwitterionic or cationic solution for adsorption to obtain a hydrogel - titanium alloy bionic joint bearing interface with self - lubricating properties.

7. The preparation method of a self-lubricating hydrogel titanium alloy bionic joint bearing interface according to claim 6, wherein: In step 2, the temperature is raised to 700 °C at a heating rate of 10 °C / min, the thermal oxidation temperature of 700 °C is maintained for 10 hours, and then it is cooled to room temperature.

8. The preparation method of a self-lubricating hydrogel titanium alloy bionic joint bearing interface according to claim 6, characterized in that: In step 4, the composition of the hydrogel precursor solution is as follows: 1.6324 g of acrylamide, 0.5 g of 2-acrylamido-2-methyl-1-propanesulfonic acid, 0.01 g of N,N'-methylenebisacrylamide, 0.01 g of α-ketoglutaric acid, and 0.4 g of polyvinyl alcohol.

9. The preparation method of a self-lubricating hydrogel titanium alloy bionic joint bearing interface according to claim 6, characterized in that: In step 5, the ultraviolet irradiation is carried out under an ultraviolet lamp, and the ultraviolet irradiation time is 30 min.

10. The preparation method of a self-lubricating hydrogel titanium alloy bionic joint bearing interface according to claim 6, characterized in that: In step 6, the number of freeze-thaw cycles is 3 - 5 times, the concentration of the adsorption solution is 5 - 25 mg / ml, and the adsorption time is 12 - 48 hours.

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