A bionic coating on titanium alloy implant surface and preparation method thereof

Abstract

This invention belongs to the field of biomimetic materials technology and discloses a biomimetic coating for titanium alloy implant surfaces and its preparation method. The biomimetic coating comprises: a porous titanium scaffold layer, prepared by plasma spraying a micron-sized porous titanium layer, then doped with nanohydroxyapatite to enhance osteoinductivity; a modified graphene reinforcement layer, comprising an electrochemically deposited graphene oxide film, covalently bonded to the titanium substrate via a silane coupling agent, and loaded with strontium ions to promote osteogenic differentiation; and an antibacterial active layer, comprising an in-situ reduced graphene oxide layer forming a three-dimensional mesh-like conductive structure, ultrasonically dispersed and loaded with tantalum-doped carbon nitride quantum dots embedded between the graphene layers to form an antibacterial phase, followed by hydrothermal growth of magnesium silicate nanowires to form a bioactive phase. Through the triple biomimetic design of porous titanium, ion release / photothermal response, and PDA adhesion, the coating improves bone bonding strength, antibacterial properties, wear resistance, and corrosion resistance at the interface.

Description

Technical Field

[0001] The present invention belongs to the technical field of bionic materials, and in particular relates to a bionic coating on the surface of a titanium alloy implant and a preparation method thereof. Background Art

[0002] Natural bone tissue possesses a multi-level micro / nanostructure, and numerous studies have demonstrated that artificial biomimetic micro / nanostructures can better promote osseointegration than single structures. Furthermore, given the complex nature of implant function, appropriate surface modification to impart antimicrobial, angiogenic, osteogenesis-promoting, and immunomodulatory properties is crucial. Therefore, developing implants with micro / nano-inspired multifunctional composite coatings is considered a potential approach to improving implant success rates.

[0003] Titanium and titanium alloys (such as Ti-6Al-4V) are the preferred materials for implants due to their unique biocompatibility. Hydroxyapatite (HA) coatings, as bioactive ceramic coatings, interact with bone tissue after implantation, forming a osseointegrated bond. HA coatings are a primary material for orthopedic implants due to their similar composition to human bone, excellent bioactivity, and non-toxic, harmless, and non-carcinogenic properties. They also have a strong bone growth-inducing effect.

[0004] Currently, hydroxyapatite (HA) coatings are primarily prepared directly on medical nickel-titanium alloys through micro-arc oxidation and hydrothermal treatment. However, since the calcium and phosphorus used to synthesize HA during hydrothermal treatment all come from the micro-arc oxidation film, the sources of calcium and phosphorus are limited, and the thickness of the HA layer formed is very limited. Furthermore, the growth efficiency of HA under hydrothermal treatment is low, and the overall bonding strength of the coating is not high. Therefore, there is an urgent need for an excellent biomimetic coating to improve the overall performance of implants. Summary of the Invention

[0005] In order to solve the deficiencies mentioned in the above-mentioned background technology, the purpose of the present invention is to provide a bionic coating on the surface of a titanium alloy implant and a preparation method thereof. The bionic coating includes an interface strengthening layer, a porous titanium support layer, a modified graphene reinforcement layer and an antibacterial active layer. Through the triple bionic design of porous titanium, ion release / photothermal response and PDA adhesion, the bone bonding strength, antibacterial property, wear resistance and corrosion resistance of the coating interface are improved, and the comprehensive performance exceeds the existing HA coating.

[0006] The purpose of the present invention can be achieved through the following technical solutions:

[0007] A bionic coating on the surface of a titanium alloy implant, comprising:

[0008] The porous titanium scaffold layer is prepared by plasma spraying, and then doped with nano-hydroxyapatite to enhance osteoinductivity;

[0009] Modified graphene reinforcement layer, electrochemically deposited graphene oxide film, covalently bonded to the titanium substrate via silane coupling agent, and loaded with strontium ions to promote osteogenic differentiation;

[0010] The antibacterial active layer is formed by in-situ reduction of graphene oxide to form a three-dimensional network conductive structure, and tantalum-doped carbon nitride quantum dots are embedded in the graphene layers through ultrasonic dispersion to form an antibacterial phase. Then, magnesium silicate nanowires are hydrothermally grown to form a bioactive phase.

[0011] The porous titanium scaffold layer, the modified graphene reinforcement layer and the antibacterial active layer are sequentially arranged on the surface of the titanium alloy implant.

[0012] Preferably, an interface strengthening layer is further included, which is arranged between the titanium alloy implant and the porous titanium support layer. The interface bonding force is enhanced by pre-depositing a 450-550 nm polydopamine film on the surface of the titanium alloy implant, while providing active sites to anchor graphene.

[0013] Preferably, the porous titanium layer has a porosity of 40-50%, a pore diameter of 100-300 μm, and a doping rate of nano-hydroxyapatite of 8-10 wt%.

[0014] Preferably, the thickness of the graphene oxide film of the modified graphene reinforcement layer is 2-3 μm, and the loading rate of strontium ions is 8.5-8.8 wt%.

[0015] Preferably, the particle size of the tantalum-doped carbon nitride quantum dots in the antibacterial active layer is less than 10 nm, and the diameter of the magnesium silicate nanowires is 45-55 nm and the length is 1-2 μm.

[0016] A method for preparing a bionic coating on the surface of a titanium alloy implant comprises the following steps:

[0017] S1. Pre-treat the titanium alloy implant, then dissolve dopamine hydrochloride in a Tris buffer solution. Finally, immerse the pre-treated titanium alloy implant in the dopamine hydrochloride solution, shake at a constant temperature of 50°C for 3-5 hours, purge with nitrogen, and then vacuum dry to form an interface strengthening layer on the surface of the titanium alloy implant.

[0018] S2. Titanium powder and nano-hydroxyapatite were mixed in a mass ratio of 9:1 and ball-milled for 2-4 h. The powders were fed at a rate of 25 g / min using argon and hydrogen as carrier gases. The titanium alloy implant obtained in step S1 was plasma sprayed to a thickness of 140-160 μm to form a porous titanium scaffold layer.

[0019] S3, adding graphene oxide and γ-aminopropyltriethoxysilane to an ethanol solution, ultrasonically treating for 3-5 hours to obtain a stable dispersion, then immersing the titanium alloy implant obtained in step S2 in the dispersion, and depositing a graphene oxide film on the surface of the titanium alloy implant by electrophoretic deposition;

[0020] S4, immersing the titanium alloy implant obtained in step S3 in a mixed solution of strontium chloride and ascorbic acid, reacting at 60° C. for 4-6 hours, taking out and vacuum drying to form a modified graphene reinforcement layer;

[0021] S5. Disperse the tantalum-doped carbon nitride quantum dots with deionized water, and then evenly apply the dispersion to the surface of the titanium alloy implant obtained in step S4, and perform vacuum-assisted infiltration at -0.08 MPa for 20 to 40 minutes.

[0022] S6. Dissolve magnesium nitrate, sodium silicate and urea in deionized water to prepare a precursor solution, then immerse the titanium alloy implant obtained in step S5 in the precursor solution, react at 180°C for 8-12 hours, and simultaneously apply a 10mT static magnetic field to induce the vertical growth of nanowires to form an antibacterial active layer, thereby completing the preparation of the bionic coating on the surface of the titanium alloy implant.

[0023] Preferably, the pretreatment in step S1 includes sandblasting, acid activation and anodizing, and specifically includes the following steps:

[0024] A. Sandblasting: Use Al2O3 particles with a particle size of 150-200 μm to spray the titanium alloy implant surface at a pressure of 0.5 MPa for 20-40 seconds, and the surface roughness Sa of the titanium alloy implant is reduced to 3.1-3.3 μm;

[0025] B. Acid etching activation: Immerse the sandblasted titanium alloy implant in a mixed acid solution at 60°C for 8-10 minutes to obtain a pit structure with a depth of 5-8 μm and increase the specific surface area;

[0026] C. Anodic oxidation: Immerse the titanium alloy implant after acid etching and activation in electrolyte and perform anodization at 25°C and 20V DC voltage for 20-40 minutes to form a regular titanium dioxide nanotube array on the surface of the titanium alloy implant.

[0027] Preferably, the mixed acid solution is an aqueous solution of sulfuric acid and hydrogen peroxide, the mass concentration of sulfuric acid is 18wt%, and the mass concentration of hydrogen peroxide is 5wt%; the electrolyte is an ethylene glycol solution of ammonium fluoride and water, the mass concentration of ammonium fluoride is 0.5wt%, and the mass concentration of water is 3wt%.

[0028] Preferably, the method for preparing tantalum-doped carbon nitride quantum dots comprises the following steps:

[0029] (1) Melamine, tantalum pentachloride and sodium citrate were mixed and ball-milled for 1-3 h, and then added to ethanol for ultrasonic dispersion to form a uniform slurry;

[0030] (2) The slurry was placed in a muffle furnace and heated to 350°C at a rate of 5°C / min and maintained for 1-3 h to generate a light yellow intermediate. The slurry was then placed in a nitrogen atmosphere and heated to 550°C at a rate of 2°C / min and calcined for 3-5 h to obtain a dark yellow tantalum-doped carbon nitride block.

[0031] (3) The tantalum-doped carbon nitride bulk material was placed in concentrated sulfuric acid, stirred at 80°C for 8-12 hours, and centrifuged to remove undissociated large particles. The supernatant was filtered through a nylon membrane and dialyzed to remove free Ta ions. After pre-freezing at -80°C, the material was vacuum freeze-dried to obtain a light green tantalum-doped carbon nitride quantum dot powder.

[0032] Preferably, melamine, tantalum pentachloride and sodium citrate are mixed in a mass ratio of 20:3:1.

[0033] Beneficial effects of the present invention:

[0034] The bionic coating on the titanium alloy implant surface of the present invention includes an interface strengthening layer, a porous titanium scaffold layer, a modified graphene reinforcement layer and an antibacterial active layer, and forms a multi-level bionic structure through micron pores (osseointegration) + nanotubes / nanowires (cell adhesion) + graphene network (mechanical conduction). 2+ / Mg 2+ Ion gradient release regulates osteogenesis, photothermal triggering of Ta-g-C3N4 QDs achieves on-demand antibacterial properties, and interface durability is ensured through PDA chemical adhesion + graphene mechanical interlocking. Through the triple design of structural bionics (porous titanium), functional bionics (ion release / photothermal response) and interface bionics (PDA adhesion), the comprehensive performance surpasses existing HA coatings. DETAILED DESCRIPTION

[0035] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making any creative efforts shall fall within the scope of protection of the present invention.

[0036] A bionic coating on the surface of a titanium alloy implant, comprising:

[0037] The porous titanium scaffold layer is prepared by plasma spraying, and then doped with nano-hydroxyapatite to enhance osteoinductivity. The porous titanium layer has a porosity of 40-50%, a pore size of 100-300 μm, and a nano-hydroxyapatite doping rate of 8-10 wt%.

[0038] The modified graphene reinforcement layer is electrochemically deposited with a graphene oxide film, which is covalently bonded to the titanium substrate via a silane coupling agent and loaded with strontium ions to promote osteogenic differentiation. The graphene oxide film in the modified graphene reinforcement layer has a thickness of 2-5 nm and a strontium ion loading rate of 8.5-8.8 wt%.

[0039] The antibacterial active layer is formed by in-situ reduction of graphene oxide to form a three-dimensional mesh conductive structure. Tantalum-doped carbon nitride quantum dots are embedded in the graphene layers through ultrasonic dispersion to form an antibacterial phase. Magnesium silicate nanowires are then hydrothermally grown to form a bioactive phase. The particle size of the tantalum-doped carbon nitride quantum dots in the antibacterial active layer is less than 10nm, and the diameter of the magnesium silicate nanowires is 45-55nm and the length is 1-2μm.

[0040] The porous titanium scaffold layer, the modified graphene reinforcement layer and the antibacterial active layer are sequentially arranged on the surface of the titanium alloy implant.

[0041] In some embodiments, an interface strengthening layer is further included, which is arranged between the titanium alloy implant and the porous titanium support layer. The interface bonding force is enhanced by pre-depositing a 450-550 nm polydopamine film on the surface of the titanium alloy implant, while providing active sites to anchor graphene.

[0042] Example 1: A titanium alloy implant surface pretreatment method, including sandblasting, acid etching activation and anodizing, specifically comprising the following steps:

[0043] A. Sandblasting: Use Al2O3 particles with a particle size of 150-200 μm to spray the titanium alloy implant surface at a pressure of 0.5 MPa for 30 seconds, and the surface roughness Sa of the titanium alloy implant is reduced to 3.2 μm;

[0044] B. Acid etching activation: The sandblasted titanium alloy implants were immersed in a mixed acid solution containing 18wt% sulfuric acid and 5wt% hydrogen peroxide at 60°C for 10 minutes to obtain a pit structure with a depth of 5-8μm and increase the specific surface area.

[0045] C. Anodic oxidation: The titanium alloy implant after acid etching activation is immersed in an electrolyte, which is an ethylene glycol solution of ammonium fluoride and water. The mass concentration of ammonium fluoride is 0.5wt% and the mass concentration of water is 3wt%. Anodization is carried out at 25°C and 20V DC voltage for 30 minutes to form a regular titanium dioxide nanotube array on the surface of the titanium alloy implant.

[0046] Example 2: A method for preparing tantalum-doped carbon nitride quantum dots comprises the following steps:

[0047] (1) Melamine, tantalum pentachloride and sodium citrate were mixed in a mass ratio of 20:3:1 and ball-milled for 2 h. The mixture was then added to ethanol and ultrasonically dispersed to form a uniform slurry.

[0048] (2) The slurry was placed in a muffle furnace and heated to 350°C at a rate of 5°C / min and maintained for 2 h to generate a light yellow intermediate. The slurry was then placed in a nitrogen atmosphere and heated to 550°C at a rate of 2°C / min and calcined for 4 h to obtain a dark yellow tantalum-doped carbon nitride block.

[0049] (3) The tantalum-doped carbon nitride bulk material was placed in concentrated sulfuric acid, stirred at 80°C for 10 h, and centrifuged to remove undissociated large particles. The supernatant was filtered through a nylon membrane and dialyzed to remove free tantalum ions. After pre-freezing at -80°C, vacuum freeze-drying was performed to obtain a light green tantalum-doped carbon nitride quantum dot powder.

[0050] Example 3: A biomimetic coating on the surface of a titanium alloy implant, comprising a porous titanium scaffold layer, a modified graphene reinforcement layer, and an antibacterial active layer sequentially disposed on the surface of the implant titanium alloy, wherein the preparation method comprises the following steps:

[0051] S1. Pretreating the titanium alloy implant as described in Example 1, then mixing titanium powder and nano-hydroxyapatite in a mass ratio of 9:1 and ball milling for 3 h, using argon and hydrogen as carrier gases at a rate of 25 g / min, and plasma spraying the titanium alloy implant obtained in step S1 to a spray layer thickness of 150 μm to form a porous titanium scaffold layer;

[0052] S2. adding graphene oxide and γ-aminopropyltriethoxysilane to an ethanol solution, ultrasonically treating for 4 hours to obtain a stable dispersion, then immersing the titanium alloy implant obtained in step S1 in the dispersion, and depositing a 2.5 μm graphene oxide film on the surface of the titanium alloy implant by electrophoretic deposition;

[0053] S3, immersing the titanium alloy implant obtained in step S2 in a mixed solution of strontium chloride and ascorbic acid, reacting at 60° C. for 5 hours, taking out and vacuum drying to form a modified graphene reinforcement layer;

[0054] S4, dispersing the tantalum-doped carbon nitride quantum dots with deionized water, and then evenly applying the dispersion to the surface of the titanium alloy implant obtained in step S3, and performing vacuum-assisted infiltration at -0.08 MPa for 30 minutes;

[0055] S5. Dissolve magnesium nitrate, sodium silicate and urea in deionized water to prepare a precursor solution, then immerse the titanium alloy implant obtained in step S4 in the precursor solution, react at 180°C for 10 hours, and simultaneously apply a 10mT static magnetic field to induce the vertical growth of nanowires to form an antibacterial active layer, thereby completing the preparation of the bionic coating on the surface of the titanium alloy implant.

[0056] Example 4: A biomimetic coating on the surface of a titanium alloy implant comprises an interface strengthening layer, a porous titanium scaffold layer, a modified graphene reinforcement layer, and an antibacterial active layer sequentially disposed on the surface of the implant titanium alloy. The preparation method comprises the following steps:

[0057] S1. Pre-treating the titanium alloy implant, dissolving dopamine hydrochloride in a Tris buffer solution, and finally immersing the pre-treated titanium alloy implant in the dopamine hydrochloride solution, shaking at a constant temperature of 50° C. for 3 hours, purging with nitrogen, and then vacuum drying to form an interface strengthening layer on the surface of the titanium alloy implant;

[0058] S2. Titanium powder and nano-hydroxyapatite were mixed in a mass ratio of 9:1 and ball-milled for 4 h. The powders were fed at a rate of 25 g / min using argon and hydrogen as carrier gases. The titanium alloy implant obtained in step S1 was plasma sprayed to a thickness of 140 μm to form a porous titanium scaffold layer.

[0059] S3, adding graphene oxide and γ-aminopropyltriethoxysilane to an ethanol solution, ultrasonically treating for 5 hours to obtain a stable dispersion, then immersing the titanium alloy implant obtained in step S2 in the dispersion, and depositing a 2.2 μm graphene oxide film on the surface of the titanium alloy implant by electrophoretic deposition;

[0060] S4, immersing the titanium alloy implant obtained in step S3 in a mixed solution of strontium chloride and ascorbic acid, reacting at 60° C. for 6 hours, taking out and vacuum drying to form a modified graphene reinforcement layer;

[0061] S5, dispersing the tantalum-doped carbon nitride quantum dots with deionized water, and then evenly applying the dispersion to the surface of the titanium alloy implant obtained in step S4, and performing vacuum-assisted infiltration at -0.08 MPa for 20 minutes;

[0062] S6. Dissolve magnesium nitrate, sodium silicate and urea in deionized water to prepare a precursor solution, then immerse the titanium alloy implant obtained in step S5 in the precursor solution, react at 180°C for 12 hours, and simultaneously apply a 10mT static magnetic field to induce the vertical growth of nanowires to form an antibacterial active layer, thereby completing the preparation of the bionic coating on the surface of the titanium alloy implant.

[0063] Example 5: A biomimetic coating on the surface of a titanium alloy implant comprises an interface strengthening layer, a porous titanium scaffold layer, a modified graphene reinforcement layer, and an antibacterial active layer sequentially disposed on the surface of the implant titanium alloy. The preparation method comprises the following steps:

[0064] S1. Pre-treat the titanium alloy implant, then dissolve dopamine hydrochloride in a Tris buffer solution, and finally immerse the pre-treated titanium alloy implant in the dopamine hydrochloride solution, shake at a constant temperature of 50°C for 5 hours, purge with nitrogen, and then vacuum dry to form an interface strengthening layer on the surface of the titanium alloy implant;

[0065] S2. Titanium powder and nano-hydroxyapatite were mixed in a mass ratio of 9:1 and ball-milled for 2 h. The powders were fed at a rate of 25 g / min using argon and hydrogen as carrier gases. The titanium alloy implant obtained in step S1 was plasma sprayed to a thickness of 160 μm to form a porous titanium scaffold layer.

[0066] S3, adding graphene oxide and γ-aminopropyltriethoxysilane to an ethanol solution, ultrasonically treating for 3 hours to obtain a stable dispersion, then immersing the titanium alloy implant obtained in step S2 in the dispersion, and depositing a 2.8 μm graphene oxide film on the surface of the titanium alloy implant by electrophoretic deposition;

[0067] S4, immersing the titanium alloy implant obtained in step S3 in a mixed solution of strontium chloride and ascorbic acid, reacting at 60° C. for 4 hours, taking out and vacuum drying to form a modified graphene reinforcement layer;

[0068] S5, dispersing the tantalum-doped carbon nitride quantum dots with deionized water, and then evenly applying the dispersion to the surface of the titanium alloy implant obtained in step S4, and performing vacuum-assisted infiltration at -0.08 MPa for 40 minutes;

[0069] S6. Dissolve magnesium nitrate, sodium silicate and urea in deionized water to prepare a precursor solution, then immerse the titanium alloy implant obtained in step S5 in the precursor solution, react at 180°C for 8 hours, and simultaneously apply a 10mT static magnetic field to induce the vertical growth of nanowires to form an antibacterial active layer, thereby completing the preparation of the bionic coating on the surface of the titanium alloy implant.

[0070] Example 6: A biomimetic coating on the surface of a titanium alloy implant, comprising an interface strengthening layer, a porous titanium scaffold layer, a modified graphene reinforcement layer, and an antibacterial active layer sequentially disposed on the surface of the implant titanium alloy, wherein the preparation method comprises the following steps:

[0071] S1. Pre-treating the titanium alloy implant, dissolving dopamine hydrochloride in a Tris buffer solution, and finally immersing the pre-treated titanium alloy implant in the dopamine hydrochloride solution, shaking at a constant temperature of 50° C. for 4 hours, purging with nitrogen, and then vacuum drying to form an interface strengthening layer on the surface of the titanium alloy implant;

[0072] S2. Titanium powder and nano-hydroxyapatite were mixed in a mass ratio of 9:1 and ball-milled for 3 h. The powders were fed at a rate of 25 g / min using argon and hydrogen as carrier gases. The titanium alloy implant obtained in step S1 was plasma sprayed to a thickness of 150 μm to form a porous titanium scaffold layer.

[0073] S3, adding graphene oxide and γ-aminopropyltriethoxysilane to an ethanol solution, ultrasonically treating for 4 hours to obtain a stable dispersion, then immersing the titanium alloy implant obtained in step S2 in the dispersion, and depositing a 2.5 μm graphene oxide film on the surface of the titanium alloy implant by electrophoretic deposition;

[0074] S4, immersing the titanium alloy implant obtained in step S3 in a mixed solution of strontium chloride and ascorbic acid, reacting at 60° C. for 5 hours, taking out and vacuum drying to form a modified graphene reinforcement layer;

[0075] S5, dispersing the tantalum-doped carbon nitride quantum dots with deionized water, and then evenly applying the dispersion to the surface of the titanium alloy implant obtained in step S4, and performing vacuum-assisted infiltration at -0.08 MPa for 30 minutes;

[0076] S6. Dissolve magnesium nitrate, sodium silicate and urea in deionized water to prepare a precursor solution, then immerse the titanium alloy implant obtained in step S5 in the precursor solution, react at 180°C for 10 hours, and simultaneously apply a 10mT static magnetic field to induce the vertical growth of nanowires to form an antibacterial active layer, thereby completing the preparation of the bionic coating on the surface of the titanium alloy implant.

[0077] Comparative Example 1: A bionic coating on the surface of a titanium alloy implant, comprising an interface strengthening layer, a modified graphene reinforcement layer, and an antibacterial active layer sequentially arranged on the surface of the implant titanium alloy, wherein the preparation method thereof comprises the following steps:

[0078] S1. Pre-treating the titanium alloy implant, dissolving dopamine hydrochloride in a Tris buffer solution, and finally immersing the pre-treated titanium alloy implant in the dopamine hydrochloride solution, shaking at a constant temperature of 50° C. for 4 hours, purging with nitrogen, and then vacuum drying to form an interface strengthening layer on the surface of the titanium alloy implant;

[0079] S2. adding graphene oxide and γ-aminopropyltriethoxysilane to an ethanol solution, ultrasonically treating for 4 hours to obtain a stable dispersion, then immersing the titanium alloy implant obtained in step S1 in the dispersion, and depositing a 2.5 μm graphene oxide film on the surface of the titanium alloy implant by electrophoretic deposition;

[0080] S3, immersing the titanium alloy implant obtained in step S2 in a mixed solution of strontium chloride and ascorbic acid, reacting at 60° C. for 5 hours, taking out and vacuum drying to form a modified graphene reinforcement layer;

[0081] S4, dispersing the tantalum-doped carbon nitride quantum dots with deionized water, and then evenly applying the dispersion to the surface of the titanium alloy implant obtained in step S3, and performing vacuum-assisted infiltration at -0.08 MPa for 30 minutes;

[0082] S5. Dissolve magnesium nitrate, sodium silicate and urea in deionized water to prepare a precursor solution, then immerse the titanium alloy implant obtained in step S4 in the precursor solution, react at 180°C for 10 hours, and simultaneously apply a 10mT static magnetic field to induce the vertical growth of nanowires to form an antibacterial active layer, thereby completing the preparation of the bionic coating on the surface of the titanium alloy implant.

[0083] Comparative Example 2: A bionic coating on the surface of a titanium alloy implant, comprising an interface strengthening layer, a porous titanium scaffold layer, and an antibacterial active layer sequentially arranged on the surface of the implant titanium alloy, wherein the preparation method thereof comprises the following steps:

[0084] S1. Pre-treating the titanium alloy implant, dissolving dopamine hydrochloride in a Tris buffer solution, and finally immersing the pre-treated titanium alloy implant in the dopamine hydrochloride solution, shaking at a constant temperature of 50° C. for 4 hours, purging with nitrogen, and then vacuum drying to form an interface strengthening layer on the surface of the titanium alloy implant;

[0085] S2. Titanium powder and nano-hydroxyapatite were mixed in a mass ratio of 9:1 and ball-milled for 3 h. The powders were fed at a rate of 25 g / min using argon and hydrogen as carrier gases. The titanium alloy implant obtained in step S1 was plasma sprayed to a thickness of 150 μm to form a porous titanium scaffold layer.

[0086] S3, dispersing the tantalum-doped carbon nitride quantum dots with deionized water, and then evenly applying the dispersion to the surface of the titanium alloy implant obtained in step S2, and performing vacuum-assisted infiltration at -0.08 MPa for 30 minutes;

[0087] S4. Dissolve magnesium nitrate, sodium silicate and urea in deionized water to prepare a precursor solution, then immerse the titanium alloy implant obtained in step S3 in the precursor solution, react at 180°C for 10 hours, and simultaneously apply a 10mT static magnetic field to induce the vertical growth of nanowires to form an antibacterial active layer, thereby completing the preparation of the bionic coating on the surface of the titanium alloy implant.

[0088] Comparative Example 3: A bionic coating on the surface of a titanium alloy implant, comprising an interface strengthening layer, a porous titanium scaffold layer, and a modified graphene reinforcement layer sequentially arranged on the surface of the implant titanium alloy, wherein the preparation method comprises the following steps:

[0089] S1. Pre-treating the titanium alloy implant, dissolving dopamine hydrochloride in a Tris buffer solution, and finally immersing the pre-treated titanium alloy implant in the dopamine hydrochloride solution, shaking at a constant temperature of 50° C. for 4 hours, purging with nitrogen, and then vacuum drying to form an interface strengthening layer on the surface of the titanium alloy implant;

[0090] S2. Titanium powder and nano-hydroxyapatite were mixed in a mass ratio of 9:1 and ball-milled for 3 h. The powders were fed at a rate of 25 g / min using argon and hydrogen as carrier gases. The titanium alloy implant obtained in step S1 was plasma sprayed to a thickness of 150 μm to form a porous titanium scaffold layer.

[0091] S3, adding graphene oxide and γ-aminopropyltriethoxysilane to an ethanol solution, ultrasonically treating for 4 hours to obtain a stable dispersion, then immersing the titanium alloy implant obtained in step S2 in the dispersion, and depositing a 2.5 μm graphene oxide film on the surface of the titanium alloy implant by electrophoretic deposition;

[0092] S4. Immerse the titanium alloy implant obtained in step S3 in a mixed solution of strontium chloride and ascorbic acid, react at 60° C. for 5 hours, take out and vacuum dry to form a modified graphene reinforcement layer, thereby completing the preparation of the bionic coating on the surface of the titanium alloy implant.

[0093] Performance testing

[0094] 1. Bone bonding strength test

[0095] The titanium alloy implant material was made into a cylinder with a size of 4 mm in diameter and 10 mm in length. A bionic coating was then prepared on the surface of the titanium alloy implant material according to the methods of Examples 3, 6 and Comparative Examples 1 to 3. The implant was then implanted into the femoral condyle of a New Zealand white rabbit (with a 4.2 mm diameter drill hole). The material was harvested 8 weeks after surgery, and the bone-implant interface was kept moist with physiological saline. The bone bonding strength test was performed according to the method in ISO-13779-2 standard. The test was performed using a universal material testing machine with a loading rate of 1 mm / min, and the maximum shear force F was recorded. max Repeat 3-5 times and calculate the bone bonding strength. The calculation formula is C=F max / π*d*h, C is the bone bonding strength (MPa), d is the diameter (mm), and h is the implant length (mm). The obtained data are shown in Table 1 below.

[0096] Table 1 Test results of titanium alloy implant-bone graft bonding strength

[0097]

[0098] It can be seen from the data in Table 1 that the absence of the porous titanium scaffold layer in Comparative Example 1 has the greatest impact on the bone bonding strength of the titanium alloy implant material. The porous titanium scaffold layer of the present invention is prepared by plasma spraying a micron-sized porous titanium layer, which imitates the trabecular structure, promotes osteoblast migration and vascularization, and is doped with nano-hydroxyapatite to enhance bone inductivity, which can effectively improve the bone bonding strength of the titanium alloy implant.

[0099] 2. Antibacterial rate test

[0100] The titanium alloy implant material was made into a 10mm*10mm*1mm square piece, and then a bionic coating was prepared on the surface of the titanium alloy implant material according to the method in Examples 3, 6 and Comparative Examples 1 to 3, and then 10 5 CFU / mL Staphylococcus aureus (ATCC 6538) bacterial solution, one group at an intensity of 1W / cm 2 The cells were irradiated with 808 nm NIR (near-infrared light) for 10 min, while the other group was not irradiated with NIR (near-infrared light). Then, they were covered with polyethylene film and cultured at 37°C for 24 h. After rinsing with PBS, the bacterial solution was collected by ultrasonic vibration (40 kHz, 5 min). The number of surviving bacteria was determined by the plate dilution coating method. The number of colonies before and after treatment was compared. The antibacterial rate was calculated after repeating 3 to 5 times. The data are shown in Table 2 below.

[0101] Table 2 Antibacterial test results of bionic coating on titanium alloy implant surface

[0102]

[0103] From the data in Table 2, it can be seen that the antibacterial active layer is missing in Comparative Example 3, and the antibacterial property of the coating decreases significantly. In the antibacterial active layer of the present invention, the near-infrared responsive photothermal effect of Ta-QDs triggers instant sterilization, and the Mg2SiO4 nanowires continuously release Mg 2+ , which can upregulate the gene expression of a series of cytokines that are beneficial to osteogenesis, such as CCL5, IL-1ra, IL-8, TGF-β1, BMP2, VEGFA, and IL-10. In addition, the antibacterial activity of the coating in Comparative Example 2 was slightly reduced. This is because the broadband light absorption of rGO in the modified graphene reinforcement layer enhances the photothermal conversion efficiency of Ta-QDs, which can improve its antibacterial effect.

[0104] 3. Wear resistance test

[0105] Titanium alloy implant material was formed into circular pieces with a diameter of 10 mm and a thickness of 3 mm. A biomimetic coating was then applied to the titanium alloy implant surface according to the methods described in Examples 3 and 6 and Comparative Examples 1-3. The coating wear resistance was tested according to ASTM F1978-18. The wear piece was lubricated with a 6 mm diameter Al2O3 ball and SBF (simulated body fluid) lubrication at 25°C, a load of 5 N, a rotation speed of 60 rpm, and a total of 1 million cycles. The wear scar volume was measured using a white light interferometer, and the coefficient of friction was recorded. The data are shown in Table 3 below. The SBF (simulated body fluid) formulation was: NaCl 8.035 g / L, NaHCO3 0.355 g / L, KCl 0.225 g / L, CaCl2·2H2O 0.292 g / L, MgCl2·6H2O 0.311 g / L, with the balance being deionized water.

[0106] Table 3 Wear resistance test results of bionic coating on titanium alloy implant surface

[0107]

[0108] It can be seen from the data in Table 3 that the missing porous titanium support layer in Comparative Example 1 and the missing interface strengthening layer in Example 3 significantly affect the wear resistance. The porous structure of the porous titanium support layer absorbs friction energy through plastic deformation, reducing coating peeling, while the catechol group of the PDA in the interface strengthening layer forms a chelate bond with the titanium substrate and anchors the graphene through π-π stacking, thereby improving the bonding strength of the coating.

[0109] 4. Corrosion resistance test

[0110] A titanium alloy implant material was made into a cylinder with a diameter of 10 mm and a length of 15 mm. A biomimetic coating was then prepared on the surface of the titanium alloy implant material according to the methods of Examples 3, 6 and Comparative Examples 1 to 3. The biomimetic coating was ultrasonically cleaned with ethanol / acetone and dried with nitrogen. The material was used as the electrode to be tested, and a saturated calomel electrode (SCE) was used as the reference electrode. SBF (simulated body fluid) was used as the electrolyte. The temperature was maintained at 37°C. The stable potential of the electrolyte when it reached dynamic equilibrium, i.e., the self-corrosion potential E of the material, was measured. corr Polarization curves were scanned using a Gamry Reference 3000 electrochemical workstation with a scan range of -0.5 V to +1.5 V (vs OCP) and a scan rate of 1 mV / s. Current values were recorded every 0.1 mV. Data were processed using Gamry Echem Analyst software. The ±250 mV linear region was selected, and the cathode slope ( β a ) / anode slope ( β c ) fitting, calculate the corrosion current density i corr = β a β c / 2.303( β a + β c )·( di / dE ) E＝Ecorr , and the data are shown in Table 4 below.

[0111] Table 4 Corrosion resistance test results of bionic coating on titanium alloy implant surface

[0112]

[0113] It can be seen from the data in Table 4 that the modified graphene reinforcement layer and the interface strengthening layer contribute significantly to corrosion protection. The dense lamellar structure of rGO in the modified graphene reinforcement layer blocks the Cl⁻ permeation path, the high electron mobility of graphene promotes the repair of the passivation film, and the interface strengthening layer PDA fills the microcracks in the coating and can inhibit the penetration of the electrolyte.

[0114] Throughout this specification, references to terms such as "one embodiment," "example," or "specific example" indicate that the specific features, structures, materials, or characteristics described in conjunction with that embodiment or example are included in at least one embodiment or example of the present invention. In this specification, schematic representations of these terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

[0115] The basic principles, main features, and advantages of the present invention are shown and described above. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The above embodiments and descriptions are merely illustrative of the principles of the present invention. Various changes and modifications may be made to the present invention without departing from the spirit and scope of the present invention, and such changes and modifications fall within the scope of the invention as claimed.

Claims

1. A bionic coating on the surface of a titanium alloy implant, characterized in that: include: The porous titanium scaffold layer is prepared by plasma spraying with a micron-sized porous titanium layer, which is doped with nano-hydroxyapatite to enhance osteoinductivity; The preparation method of the porous titanium scaffold layer is as follows: S2. Titanium powder and nano-hydroxyapatite were mixed in a mass ratio of 9:1 and ball-milled for 2-4 h. The powders were fed at a rate of 25 g / min using argon and hydrogen as carrier gases. The titanium alloy implant obtained in step S1 was plasma sprayed to a thickness of 140-160 μm to form a porous titanium scaffold layer. Modified graphene reinforcement layer, electrochemically deposited graphene oxide film, covalently bonded to the titanium substrate via silane coupling agent, and loaded with strontium ions to promote osteogenic differentiation; The antibacterial active layer is formed by in-situ reduction of graphene oxide to form a three-dimensional network conductive structure, and tantalum-doped carbon nitride quantum dots are embedded in the graphene layers through ultrasonic dispersion to form an antibacterial phase. Then, magnesium silicate nanowires are hydrothermally grown to form a bioactive phase. The porous titanium scaffold layer, the modified graphene reinforcement layer and the antibacterial active layer are sequentially arranged on the surface of the titanium alloy implant.

2. The bionic coating on the titanium alloy implant surface according to claim 1, characterized in that: The invention also includes an interface strengthening layer, which is arranged between the titanium alloy implant and the porous titanium support layer. The interface strengthening layer enhances the interface bonding force by pre-depositing a 450-550nm polydopamine film on the surface of the titanium alloy implant and provides active sites for anchoring graphene.

3. The bionic coating on the titanium alloy implant surface according to claim 1, characterized in that: The porous titanium layer has a porosity of 40-50%, a pore diameter of 100-300 μm, and a nano-hydroxyapatite doping rate of 8-10 wt %.

4. The bionic coating on the titanium alloy implant surface according to claim 1, characterized in that: The modified graphene enhancement layer has a graphene oxide film thickness of 2-3 μm and a strontium ion loading rate of 8.5-8.8 wt %.

5. The bionic coating on the titanium alloy implant surface according to claim 1, characterized in that: The antibacterial active layer has a tantalum-doped carbon nitride quantum dot particle size of less than 10 nm, and a magnesium silicate nanowire diameter of 45-55 nm and a length of 1-2 μm.

6. The method for preparing a bionic coating on the surface of a titanium alloy implant according to any one of claims 1 to 5, characterized in that: The following steps are involved: S1. Pre-treat the titanium alloy implant, then dissolve dopamine hydrochloride in a Tris buffer solution. Finally, immerse the pre-treated titanium alloy implant in the dopamine hydrochloride solution, shake at a constant temperature of 50°C for 3-5 hours, purge with nitrogen, and then vacuum dry to form an interface strengthening layer on the surface of the titanium alloy implant. S2. Titanium powder and nano-hydroxyapatite were mixed in a mass ratio of 9:1 and ball-milled for 2-4 h. The powders were fed at a rate of 25 g / min using argon and hydrogen as carrier gases. The titanium alloy implant obtained in step S1 was plasma sprayed to a thickness of 140-160 μm to form a porous titanium scaffold layer. S3, adding graphene oxide and γ-aminopropyltriethoxysilane to an ethanol solution, ultrasonically treating for 3-5 hours to obtain a stable dispersion, then immersing the titanium alloy implant obtained in step S2 in the dispersion, and depositing a graphene oxide film on the surface of the titanium alloy implant by electrophoretic deposition; S4, immersing the titanium alloy implant obtained in step S3 in a mixed solution of strontium chloride and ascorbic acid, reacting at 60° C. for 4-6 hours, taking out and vacuum drying to form a modified graphene reinforcement layer; S5. Disperse the tantalum-doped carbon nitride quantum dots with deionized water, and then evenly apply the dispersion to the surface of the titanium alloy implant obtained in step S4, and perform vacuum-assisted infiltration at -0.08 MPa for 20 to 40 minutes. S6. Dissolve magnesium nitrate, sodium silicate and urea in deionized water to prepare a precursor solution, then immerse the titanium alloy implant obtained in step S5 in the precursor solution, react at 180°C for 8-12 hours, and simultaneously apply a 10mT static magnetic field to induce the vertical growth of nanowires to form an antibacterial active layer, thereby completing the preparation of the bionic coating on the surface of the titanium alloy implant.

7. The method for preparing a bionic coating on a titanium alloy implant surface according to claim 6, characterized in that: The pretreatment in step S1 includes sandblasting, acid activation and anodizing, and specifically includes the following steps: A. Sandblasting: Use Al2O3 particles with a particle size of 150-200 μm to spray the titanium alloy implant surface at a pressure of 0.5 MPa for 20-40 seconds, and the surface roughness Sa of the titanium alloy implant is reduced to 3.1-3.3 μm; B. Acid etching activation: Immerse the sandblasted titanium alloy implant in a mixed acid solution at 60°C for 8-10 minutes to obtain a pit structure with a depth of 5-8 μm and increase the specific surface area; C. Anodic oxidation: Immerse the titanium alloy implant after acid etching and activation in electrolyte and perform anodization at 25°C and 20V DC voltage for 20-40 minutes to form a regular titanium dioxide nanotube array on the surface of the titanium alloy implant.

8. The method for preparing a bionic coating on the surface of a titanium alloy implant according to claim 7, characterized in that: The mixed acid solution is an aqueous solution of sulfuric acid and hydrogen peroxide, with the mass concentration of sulfuric acid being 18wt% and the mass concentration of hydrogen peroxide being 5wt%; the electrolyte is an ethylene glycol solution of ammonium fluoride and water, with the mass concentration of ammonium fluoride being 0.5wt% and the mass concentration of water being 3wt%.

9. The method for preparing a bionic coating on a titanium alloy implant surface according to claim 6, characterized in that: The preparation method of the tantalum-doped carbon nitride quantum dots comprises the following steps: (1) Melamine, tantalum pentachloride and sodium citrate were mixed and ball-milled for 1-3 h, and then added to ethanol for ultrasonic dispersion to form a uniform slurry; (2) The slurry was placed in a muffle furnace and heated to 350°C at a rate of 5°C / min and maintained for 1-3 h to generate a light yellow intermediate. The slurry was then placed in a nitrogen atmosphere and heated to 550°C at a rate of 2°C / min and calcined for 3-5 h to obtain a dark yellow tantalum-doped carbon nitride block. (3) The tantalum-doped carbon nitride bulk material was placed in concentrated sulfuric acid, stirred at 80°C for 8-12 hours, and centrifuged to remove undissociated large particles. The supernatant was filtered through a nylon membrane and dialyzed to remove free Ta ions. After pre-freezing at -80°C, the material was vacuum freeze-dried to obtain a light green tantalum-doped carbon nitride quantum dot powder.

10. The method for preparing a bionic coating on the surface of a titanium alloy implant according to claim 9, characterized in that: The melamine, tantalum pentachloride and sodium citrate are mixed in a mass ratio of 20:3:1.

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