Metallic prosthesis of composite porous bioceramic and method for its production

Abstract

The present application relates to the technical field of metal prosthesis, especially to a composite porous bioceramic metal prosthesis and a preparation method thereof, comprising: a metal base made of Ti6Al4V alloy, having a gradient porosity structure of 30-70%, and a pore size range of 200-600 mu m; and a bioceramic coating covering the surface of the metal base and composed of the following components by weight: hydroxyapatite HA 60-80 parts; beta-tricalcium phosphate beta-TCP 20-40 parts; the excellent mechanical properties and biocompatibility of Ti6Al4V alloy are utilized, and the structural characteristics of natural bone tissue are simulated through the design of the gradient porous structure; on the nanometer scale, the synergistic effect of HA and beta-TCP crystals creates a dynamically changing bioactive interface; the stable structure of HA provides a good attachment matrix for cells, and the moderate degradation of beta-TCP continuously releases calcium and phosphorus ions.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of metal prosthesis, in particular to a composite porous bioceramic metal prosthesis and a preparation method thereof. BACKGROUND

[0002] With the rapid development of orthopedic medicine, orthopedic implants play an increasingly important role in the treatment of bone defects, joint replacement and other fields. However, traditional metal prostheses still face many challenges in long-term clinical application, such as insufficient bioactivity, limited bone integration ability and stress shielding effect. These problems not only affect the long-term stability of the implant, but also increase the risk of secondary surgery for patients, causing additional pain and economic burden to patients.

[0003] In recent years, researchers have been committed to developing new orthopedic implant materials to improve their biocompatibility and long-term stability. Among them, porous metal materials have attracted widespread attention due to their bone-like structure and good mechanical properties. However, the pure porous metal structure still lacks sufficient bioactivity, making it difficult to effectively promote the growth and integration of bone tissue. On the other hand, bioceramic materials such as hydroxyapatite (HA) and β-tricalcium phosphate (β-TCP) are widely studied due to their excellent bioactivity and bone conductivity, but their brittleness and poor mechanical properties limit their application in load-bearing parts.

[0004] In order to overcome the above problems, researchers have tried to combine porous metal with bioceramic to obtain a composite material with both mechanical properties and bioactivity. However, existing composite technology still has some limitations. First, the design of porous structure often fails to balance mechanical properties and biocompatibility. Second, the bonding strength between bioceramic coating and metal substrate is insufficient, which is easy to fall off during use. Third, the degradation rate of bioceramic coating is difficult to control, affecting the long-term stability of the implant. Finally, the existing preparation process is difficult to form a uniform and dense bioceramic coating on the surface of the complex porous structure. SUMMARY

[0005] The present application is aimed at the above problems and proposes an innovative composite porous bioceramic metal prosthesis and a preparation method thereof. Through the careful design of gradient porous structure, the optimization of HA / β-TCP composite coating and the innovative preparation process, the present application successfully solves many problems existing in the prior art.

[0006] The purpose of the present application is to provide a composite porous bioceramic metal prosthesis, which comprises:

[0007] a metal substrate made of Ti6Al4V alloy, having a gradient porosity structure of 30-70%, and a pore size range of 200-600 μm;

[0008] A bioceramic coating, which covers the surface of the metal matrix, consists of the following components by weight:

[0009] Hydroxyapatite HA 60-80 parts;

[0010] Beta-tricalcium phosphate β-TCP 20-40 parts.

[0011] As a preference, the composition of the Ti6Al4V alloy includes, by weight percentage:

[0012] Al 5.5-6.5%, V 3.5-4.5%, Fe ≤0.25%, O ≤0.13%, C ≤0.08%, N ≤0.05%, hydrogen H ≤0.012%, the balance being Ti, totaling 100%.

[0013] As a preference, the following steps are included:

[0014] (1) A porous Ti6Al4V matrix is prepared using selective laser melting SLM 3D printing technology;

[0015] (2) The porous Ti6Al4V matrix is surface treated;

[0016] (3) A bioceramic coating is applied to the surface-treated porous Ti6Al4V matrix;

[0017] (4) The coated sample is heat treated.

[0018] As a preference, the process parameters of the SLM 3D printing in step (1) are:

[0019] Laser power 150-250 W, scanning speed 600-1000 mm / s, layer thickness 30-50 μm, spot diameter 70-100 μm, forming atmosphere high-purity argon, purity ≥99.999%, forming chamber temperature 80-120 °C, substrate preheating temperature 150-200 °C.

[0020] As a preference, the surface treatment in step (2) includes the following sub-steps:

[0021] First, acid etching treatment is performed, the acid etching solution has a formula of HF (48 wt%): HNO3 (65 wt%): H2O = 1:4:5 (volume ratio), and is treated at 20-25 °C for 8-12 min with a stirring speed of 200-300 rpm;

[0022] Second, alkali treatment is performed, the alkali solution is a 5-10 mol / L NaOH solution, and is treated at 60-80 °C for 4-6 h with a stirring speed of 100-150 rpm;

[0023] Then, ultrasonic cleaning with deionized water, cleaning time 10-15 min, ultrasonic frequency 40-60 kHz;

[0024] Finally, drying at 60-80℃ for 2-4h.

[0025] As preferred, the bioceramic coating in step (3) comprises the following sub-steps:

[0026] (a) micro-arc oxidation MAO pretreatment;

[0027] (b) electrophoretic deposition EPD.

[0028] As preferred, the process parameters of the micro-arc oxidation MAO pretreatment are:

[0029] The electrolyte formula is Ca(CH3COO)2·H2O 10-15g / L, Na2HPO4·12H2O 20-30g / L, voltage 300-400V, frequency 500-1000Hz, duty cycle 10-20%, processing time 5-10min, temperature 10-20℃.

[0030] As preferred, the process parameters of the electrophoretic deposition EPD are:

[0031] The suspension formula is HA powder 6-8g / L, β-TCP powder 2-4g / L, dispersant 0.1-0.3g / L, and the solvent is ethanol;

[0032] pH value 4.0-5.0, voltage 60-80V, deposition time 3-5min, temperature 20-25℃.

[0033] As preferred, the process parameters of the heat treatment in step (4) are:

[0034] Ramp rate 5-10℃ / min, heat treatment temperature 800-1000℃, holding time 1-2h, cooling to room temperature by furnace cooling, heat treatment atmosphere is high-purity argon with purity ≥99.999%.

[0035] As preferred, the preparation method of the HA powder and β-TCP powder comprises:

[0036] For the HA powder, 23.6-24.0g Ca(NO3)2·4H2O and 7.9-8.1g (NH4)2HPO4 are dissolved in deionized water respectively, the (NH4)2HPO4 solution is slowly added to the Ca(NO3)2 solution under continuous stirring, the pH is adjusted to 10-11 with NH4OH, the reaction is stirred at 70-80℃ for 4-6h, and after aging for 24h, filtration, washing, drying are performed, and finally calcination at 900-1000℃ for 2h;

[0037] For the β-TCP powder, 35.4-36.0 g Ca(NO3)2·4H2O and 15.8-16.2 g (NH4)2HPO4 were dissolved in deionized water respectively, the (NH4)2HPO4 solution was slowly added to the Ca(NO3)2 solution under continuous stirring, the pH was adjusted to 7-8, the reaction was stirred at 80-90℃ for 5-6 h, and after aging for 24 h, filtration, washing, drying were carried out, and finally calcination was carried out at 900-1100℃ for 3 h;

[0038] The obtained powder was treated by ball milling and then passed through a 200 mesh sieve.

[0039] The core innovation of the present application is that: first, the selective laser melting (SLM) 3D printing technology is used to prepare a Ti6Al4V alloy substrate with gradient porosity, which realizes the balance of mechanical properties and biocompatibility. Second, by combining micro-arc oxidation pretreatment and electrophoretic deposition, a HA / β-TCP composite coating with strong bonding force and uniform distribution is formed on the porous metal surface. Third, by precisely controlling the ratio of HA and β-TCP, the degradation rate of the coating is controllable. Finally, an optimized heat treatment process is used to further improve the crystallinity and mechanical properties of the coating.

[0040] From the perspective of material science, the present application ingeniously utilizes the excellent mechanical properties and biocompatibility of Ti6Al4V alloy, and at the same time, through the design of gradient porous structure, the structural characteristics of natural bone tissue are simulated. At the nanoscale, the synergistic effect of HA and β-TCP crystals creates a dynamically changing bioactive interface. The stable structure of HA provides a good attachment matrix for cells, while the moderate degradation of β-TCP continuously releases calcium and phosphorus ions, creating a microenvironment conducive to osteogenesis.

[0041] From the perspective of molecular structure and chemical mechanism, HA (Ca 10 Both HA (Ca5(PO4)6(OH)2) and β-TCP (Ca3(PO4)2) belong to calcium phosphate compounds, but their crystal structures and chemical properties differ. HA has a more stable hexagonal crystal structure, while β-TCP is orthorhombic. This structural difference leads to differences in their solubility and bioactivity in physiological environments. The hydroxyl group (OH-) of HA can interact with surrounding proteins and cells, improving biocompatibility. The higher solubility of β-TCP is beneficial for the release of calcium and phosphorus ions, promoting the bone mineralization process.

[0042] From the perspective of atomic and molecular orbital theory, titanium atoms in Ti6Al4V alloy have unfilled d orbitals, which enable them to form strong chemical bonds with oxygen atoms. During micro-arc oxidation, the TiO2 layer formed on the titanium surface not only enhances the adhesion of the coating but also further improves the bioactivity through surface hydroxylation. At the same time, the semiconductor properties of TiO2 may affect the electron transfer process to some extent, thereby regulating the adhesion and proliferation behavior of cells.

[0043] The present application achieves the following beneficial effects through the synergistic effect of multiple technical features:

[0044] 1. Optimized mechanical properties: The gradient porous structure not only reduces the overall stiffness and reduces the stress shielding effect, but also achieves uniform stress distribution through the gradual design of porosity.

[0045] 2. Enhanced bioactivity: The HA / β-TCP composite coating provides an ideal bioactive surface that promotes the adhesion, proliferation, and differentiation of bone cells. At the same time, the controlled degradation of the coating ensures continuous ion release, maintaining a microenvironment conducive to osteogenesis in the long term.

[0046] 3. Improved bone integration ability: The porous structure provides an ideal space for bone tissue ingrowth, while the bioceramic coating promotes the close integration of bone tissue and the implant.

[0047] 4. Long-term stability: Through micro-arc oxidation pretreatment and optimized heat treatment process, the bonding strength between the coating and the substrate is significantly improved, ensuring the long-term stability of the implant.

[0048] 5. Regulated degradation behavior: By precisely controlling the ratio of HA and β-TCP, the degradation rate of the coating is precisely regulated, making it better match the bone tissue reconstruction process.

[0049] 6. Uniform coating distribution: The innovative preparation process solves the problem of forming a uniform coating on the surface of a complex porous structure, ensuring that the entire implant surface has ideal bioactivity.

[0050] 7. Bionic design: The multi-scale synergistic design, from nanoscale crystal structure to macroscopic gradient porous structure, better simulates the structural and functional characteristics of natural bone tissue.

[0051] In summary, the present application successfully develops a composite porous bioceramic metal prosthesis with excellent comprehensive performance through the integration and innovation of multidisciplinary knowledge. This prosthesis not only overcomes the limitations of traditional metal prostheses and bioceramic materials, but also realizes the optimization of mechanical properties, biological activity and long-term stability through multi-scale and multi-level collaborative design. The present application provides a new idea and direction for the development of orthopedic implants, and is expected to bring significant improvement in clinical application, providing better treatment effect for patients, reducing the risk of secondary surgery and improving the quality of life. DETAILED DESCRIPTION

[0052] To make the objectives, technical solutions, and advantages of the present application clearer, the technical solutions of the present application will be described clearly and completely below in combination with specific embodiments of the present application. Obviously, the described embodiments are only some of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by a person of ordinary skill in the art without creative labor fall within the scope of protection of the present application.

[0053] Embodiment 1

[0054] The present embodiment provides a composite porous bioceramic metal prosthesis and a preparation method thereof. The metal prosthesis comprises a metal substrate made of Ti6Al4V alloy and a bioceramic coating covering the surface thereof. The metal substrate has a gradient porosity structure of 30%, and the pore size is 200 μm. The bioceramic coating is composed of the following components by weight: hydroxyapatite (HA) 80 parts and β-tricalcium phosphate (β-TCP) 20 parts.

[0055] The composition of the Ti6Al4V alloy includes, by weight percentage: aluminum (Al) 5.5%, vanadium (V) 3.5%, iron (Fe) 0.25%, oxygen (O) 0.13%, carbon (C) 0.08%, nitrogen (N) 0.05%, hydrogen (H) 0.012%, and the balance being titanium (Ti), totaling 100%.

[0056] The preparation method of the composite porous bioceramic metal prosthesis comprises the following steps:

[0057] (1) A porous Ti6Al4V substrate is prepared by selective laser melting (SLM) 3D printing technology. The process parameters of SLM 3D printing are: laser power 150 W, scanning speed 600 mm / s, layer thickness 30 μm, spot diameter 70 μm, forming atmosphere high-purity argon (purity 99.999%), forming chamber temperature 80℃, and substrate preheating temperature 150℃.

[0058] (2) The porous Ti6Al4V substrate is subjected to surface treatment. The surface treatment comprises the following sub-steps:

[0059] First, acid etching treatment was performed. The acid etching solution was prepared by mixing HF (48wt%) : HNO3 (65wt%) : H2O = 1 : 4 : 5 (volume ratio) and the treatment was performed at 20°C for 8 min with a stirring speed of 200 rpm.

[0060] Second, alkali treatment was performed. The alkali solution was 5 mol / L NaOH solution and the treatment was performed at 60°C for 4 h with a stirring speed of 100 rpm.

[0061] Then, ultrasonic cleaning was performed using deionized water for 10 min at an ultrasonic frequency of 40 kHz.

[0062] Finally, drying was performed at 60°C for 2 h.

[0063] (3) Bioceramic coating was performed on the porous Ti6Al4V substrate after surface treatment. The bioceramic coating included the following sub-steps:

[0064] (a) Micro-arc oxidation (MAO) pretreatment: the electrolyte solution was prepared by mixing Ca(CH3COO)2·H2O 10 g / L and Na2HPO4·12H2O 20 g / L, and the treatment was performed at a voltage of 300 V, a frequency of 500 Hz, a duty cycle of 10%, a temperature of 10°C, and a treatment time of 5 min.

[0065] (b) Electrophoretic deposition (EPD): the suspension solution was prepared by mixing HA powder 6 g / L, β-TCP powder 2 g / L, and dispersant 0.1 g / L with ethanol as the solvent, and the pH value was adjusted to 4.0; the voltage was 60 V, the deposition time was 3 min, and the temperature was 20°C.

[0066] (4) The coated sample was subjected to heat treatment. The heat treatment parameters were as follows: the heating rate was 5°C / min, the heat treatment temperature was 800°C, the holding time was 1 h, the cooling method was furnace cooling to room temperature, and the heat treatment atmosphere was high-purity argon (purity 99.999%).

[0067] In this embodiment, the preparation methods of HA powder and β-TCP powder were as follows:

[0068] For the HA powder, 23.6 g of Ca(NO3)2·4H2O and 7.9 g of (NH4)2HPO4 were dissolved in deionized water, respectively, and the (NH4)2HPO4 solution was slowly added to the Ca(NO3)2 solution under continuous stirring, and the pH value was adjusted to 10 with NH4OH, and the reaction was stirred at 70°C for 4 h. After aging for 24 h, filtration, washing, and drying were performed, and finally calcination was performed at 900°C for 2 h.

[0069] For β-TCP powder, 35.4 g Ca(N03)2-4H20 and 15.8 g (NH4)2HP04were dissolved in deionized water, respectively, the (NH4)2HP04solution was slowly added into the Ca(N03)2solution under continuous stirring, the pH was adjusted to 7, the reaction was stirred at 80 °C for 5 h, and after aging for 24 h, filtration, washing, drying, and finally calcination at 900 °C for 3 h were performed.

[0070] The obtained powder was sieved through a 200 mesh screen after ball milling.

[0071] Example 2: Metal prosthesis of composite porous bioceramics and method for preparing the same

[0072] This example provides a metal prosthesis of composite porous bioceramics and a method for preparing the same. The metal prosthesis comprises a metal substrate made of Ti6Al4V alloy and a bioceramic coating covering the surface thereof. The metal substrate has a gradient porosity structure of 50% with a pore size of 400 μm. The bioceramic coating is composed of the following components by weight: hydroxyapatite (HA) 70 parts and β-tricalcium phosphate (β-TCP) 30 parts.

[0073] The composition of the Ti6Al4V alloy includes, by weight percentage: aluminum (Al) 6.0%, vanadium (V) 4.0%, iron (Fe) 0.20%, oxygen (O) 0.10%, carbon (C) 0.06%, nitrogen (N) 0.03%, hydrogen (H) 0.008%, and the balance being titanium (Ti).

[0074] The method for preparing the metal prosthesis of composite porous bioceramics comprises the following steps:

[0075] (1) A porous Ti6Al4V substrate is prepared by selective laser melting (SLM) 3D printing technology. The process parameters of SLM 3D printing are: laser power 200 W, scanning speed 800 mm / s, layer thickness 40 μm, spot diameter 85 μm, forming atmosphere high-purity argon (purity 99.9995%), forming chamber temperature 100 °C, and substrate preheating temperature 175 °C.

[0076] (2) The porous Ti6Al4V substrate is subjected to surface treatment. The surface treatment comprises the following sub-steps:

[0077] Firstly, acid etching treatment is performed. The formula of the acid etching solution is HF (48 wt%): HN03(65 wt%): H20 = 1:4:5 (volume ratio), and the treatment is performed at 22.5 °C for 10 min with a stirring speed of 250 rpm.

[0078] Secondly, alkali treatment is performed. The alkali solution is a 7.5 mol / L NaOH solution, and the treatment is performed at 70 °C for 5 h with a stirring speed of 125 rpm.

[0079] Then, ultrasonic cleaning was performed using deionized water, with a cleaning time of 12.5 min and an ultrasonic frequency of 50 kHz.

[0080] Finally, drying was performed at 70 °C for 3 h.

[0081] (3) Bio-ceramic coating on the surface-treated porous Ti6Al4V substrate. The bio-ceramic coating included the following sub-steps:

[0082] (a) Micro-arc oxidation (MAO) pre-treatment: electrolyte formulation of Ca(CH3COO)2-H2O 12.5 g / L, Na2HPO4-12H2O 25 g / L, voltage 350 V, frequency 750 Hz, duty cycle 15%, treatment time 7.5 min, temperature 15 °C.

[0083] (b) Electrophoretic deposition (EPD): suspension formulation of HA powder 7 g / L, β-TCP powder 3 g / L, dispersant 0.2 g / L, solvent ethanol; pH 4.5, voltage 70 V, deposition time 4 min, temperature 22.5 °C.

[0084] (4) Heat treatment of the coated sample. The heat treatment process parameters were: heating rate 7.5 °C / min, heat treatment temperature 900 °C, holding time 1.5 h, cooling to room temperature using furnace cooling, heat treatment atmosphere high-purity argon (purity 99.9995%).

[0085] In this example, the preparation method of the HA powder and the β-TCP powder was as follows:

[0086] For the HA powder, 23.8 g of Ca(NO3)2-4H2O and 8.0 g of (NH4)2HPO4 were dissolved in deionized water, the (NH4)2HPO4 solution was slowly added to the Ca(NO3)2 solution under continuous stirring, the pH was adjusted to 10.5 using NH4OH, the reaction was stirred at 75 °C for 5 h, and after aging for 24 h, filtration, washing, drying were performed, and finally calcination was performed at 950 °C for 2 h.

[0087] For the β-TCP powder, 35.7 g of Ca(NO3)2-4H2O and 16.0 g of (NH4)2HPO4 were dissolved in deionized water, the (NH4)2HPO4 solution was slowly added to the Ca(NO3)2 solution under continuous stirring, the pH was adjusted to 7.5, the reaction was stirred at 85 °C for 5.5 h, and after aging for 24 h, filtration, washing, drying were performed, and finally calcination was performed at 1000 °C for 3 h.

[0088] The obtained powder was treated by ball milling and then sieved through a 200 mesh sieve.

[0089] Example 3

[0090] The present embodiment provides a third kind of composite porous bioceramic metal prosthesis and a preparation method thereof. The metal prosthesis comprises a metal substrate made of Ti6Al4V alloy and a bioceramic coating covering the surface of the metal substrate. The metal substrate has a gradient porosity structure of 70% and a pore size of 600 μm. The bioceramic coating is composed of the following components by weight: hydroxyapatite (HA) 60 parts and β-tricalcium phosphate (β-TCP) 40 parts.

[0091] The composition of the Ti6Al4V alloy includes, by weight percentage: aluminum (Al) 6.5%, vanadium (V) 4.5%, iron (Fe) 0.15%, oxygen (O) 0.07%, carbon (C) 0.04%, nitrogen (N) 0.02%, hydrogen (H) 0.005%, and the balance being titanium (Ti).

[0092] The preparation method of the composite porous bioceramic metal prosthesis comprises the following steps:

[0093] (1) A porous Ti6Al4V substrate is prepared by selective laser melting (SLM) 3D printing technology. The process parameters of SLM 3D printing are: laser power 250 W, scanning speed 1000 mm / s, layer thickness 50 μm, spot diameter 100 μm, forming atmosphere high-purity argon (purity 99.9999%), forming chamber temperature 120°C, substrate preheating temperature 200°C.

[0094] (2) The porous Ti6Al4V substrate is subjected to surface treatment. The surface treatment comprises the following sub-steps:

[0095] Firstly, acid etching treatment is performed. The formula of the acid etching solution is HF (48wt%): HNO3 (65wt%): H2O = 1:4:5 (volume ratio), and the treatment is carried out at 25°C for 12 min with a stirring speed of 300 rpm.

[0096] Secondly, alkali treatment is performed. The alkali solution is a 10 mol / L NaOH solution, and the treatment is carried out at 80°C for 6 h with a stirring speed of 150 rpm.

[0097] Then, ultrasonic cleaning is performed with deionized water for 15 min at an ultrasonic frequency of 60 kHz.

[0098] Finally, drying is performed at 80°C for 4 h.

[0099] (3) Bioceramic coating is performed on the porous Ti6Al4V substrate after surface treatment. The bioceramic coating comprises the following sub-steps:

[0100] (a) Micro-arc oxidation (MAO) pre-treatment: electrolyte formulation: Ca(CH3COO)2-H2O 15 g / L, Na2HPO4-12H2O 30 g / L, voltage 400 V, frequency 1000 Hz, duty cycle 20%, treatment time 10 min, temperature 20 °C.

[0101] (b) Electrophoretic deposition (EPD): suspension formulation: HA powder 8 g / L, β-TCP powder 4 g / L, dispersant 0.3 g / L, solvent: ethanol; pH 5.0, voltage 80 V, deposition time 5 min, temperature 25 °C.

[0102] (4) The coated sample was subjected to heat treatment. The process parameters of the heat treatment were: heating rate 10 °C / min, heat treatment temperature 1000 °C, holding time 2 h, cooling to room temperature by furnace cooling, heat treatment atmosphere: high-purity argon (purity 99.9999%).

[0103] In this example, the preparation method of the HA powder and the β-TCP powder was as follows:

[0104] For the HA powder, 24.0 g of Ca(NO3)2-4H2O and 8.1 g of (NH4)2HPO4 were dissolved in deionized water, respectively, the (NH4)2HPO4 solution was slowly added to the Ca(NO3)2 solution under continuous stirring, the pH was adjusted to 11 with NH4OH, the reaction was stirred at 80 °C for 6 h, and after aging for 24 h, filtration, washing, drying, and finally calcination at 1000 °C for 2 h were performed.

[0105] For the β-TCP powder, 36.0 g of Ca(NO3)2-4H2O and 16.2 g of (NH4)2HPO4 were dissolved in deionized water, respectively, the (NH4)2HPO4 solution was slowly added to the Ca(NO3)2 solution under continuous stirring, the pH was adjusted to 8, the reaction was stirred at 90 °C for 6 h, and after aging for 24 h, filtration, washing, drying, and finally calcination at 1100 °C for 3 h were performed.

[0106] The obtained powder was treated by ball milling and then sieved through a 200-mesh screen.

[0107] Example 4

[0108] This example provides a fourth kind of composite porous bioceramic metal prosthesis and a preparation method thereof. The metal prosthesis comprises a metal substrate made of Ti6Al4V alloy and a bioceramic coating covering the surface thereof. The metal substrate has a gradient porosity structure of 50%, and the pore size is 400 μm. The bioceramic coating is composed of the following components by weight: hydroxyapatite (HA) 65 parts and β-tricalcium phosphate (β-TCP) 35 parts.

[0109] The composition of the Ti6Al4V alloy includes, in terms of percentage by weight: aluminum (Al) 6.0%, vanadium (V) 4.0%, iron (Fe) 0.18%, oxygen (O) 0.09%, carbon (C) 0.05%, nitrogen (N) 0.03%, hydrogen (H) 0.007%, and the balance titanium (Ti).

[0110] The method for preparing the composite porous bioceramic metal prosthesis comprises the following steps:

[0111] (1) A porous Ti6Al4V substrate is prepared by selective laser melting (SLM) 3D printing technology. The process parameters of SLM 3D printing are: laser power 200 W, scanning speed 800 mm / s, layer thickness 40 μm, spot diameter 85 μm, forming atmosphere high-purity argon (purity 99.9997%), forming chamber temperature 100°C, and substrate preheating temperature 175°C.

[0112] (2) The porous Ti6Al4V substrate is subjected to surface treatment. The surface treatment comprises the following sub-steps:

[0113] Firstly, acid etching treatment is performed. The acid etching solution has a formula of HF (48 wt%): HNO3 (65 wt%): H2O = 1:4:5 (volume ratio), and is treated at 22.5°C for 10 min with a stirring speed of 250 rpm.

[0114] Secondly, alkali treatment is performed. The alkali solution is a 7.5 mol / L NaOH solution, and is treated at 70°C for 5 h with a stirring speed of 125 rpm.

[0115] Then, ultrasonic cleaning is performed with deionized water. The cleaning time is 12.5 min, and the ultrasonic frequency is 50 kHz.

[0116] Finally, drying is performed at 70°C for 3 h.

[0117] (3) Bioceramic coating is performed on the porous Ti6Al4V substrate subjected to surface treatment. The bioceramic coating comprises the following sub-steps:

[0118] (a) Micro-arc oxidation (MAO) pretreatment: the electrolyte formula is Ca(CH3COO)2·H2O 12.5 g / L, Na2HPO4·12H2O 25 g / L, voltage 350 V, frequency 750 Hz, duty cycle 15%, treatment time 7.5 min, and temperature 15°C.

[0119] (b) Electrophoretic deposition (EPD): the suspension formula is HA powder 7 g / L, β-TCP powder 3.5 g / L, dispersant 0.2 g / L, and solvent ethanol; the pH value is 4.5, the voltage is 70 V, the deposition time is 4 min, and the temperature is 22.5°C.

[0120] (4) The coated sample is subjected to heat treatment. The process parameters of the heat treatment are: heating rate 7.5℃ / min, heat treatment temperature 900℃, holding time 1.5h, cooling to room temperature by furnace cooling, and the heat treatment atmosphere is high-purity argon (purity 99.9997%).

[0121] In this embodiment, the preparation method of the HA powder and the β-TCP powder is as follows:

[0122] For the HA powder, 23.8g of Ca(NO3)2·4H2O and 8.0g of (NH4)2HPO4 are dissolved in deionized water respectively, the (NH4)2HPO4 solution is slowly added to the Ca(NO3)2 solution under continuous stirring, the pH is adjusted to 10.5 with NH4OH, the reaction is stirred at 75℃ for 5h, and after aging for 24h, filtration, washing, drying, and finally calcination at 950℃ for 2h are performed.

[0123] For the β-TCP powder, 35.7g of Ca(NO3)2·4H2O and 16.0g of (NH4)2HPO4 are dissolved in deionized water respectively, the (NH4)2HPO4 solution is slowly added to the Ca(NO3)2 solution under continuous stirring, the pH is adjusted to 7.5, the reaction is stirred at 85℃ for 5.5h, and after aging for 24h, filtration, washing, drying, and finally calcination at 1000℃ for 3h are performed.

[0124] The obtained powder is treated by ball milling and then sieved through a 200 mesh sieve.

[0125] As can be seen from the above four embodiments, the composite porous bioceramic metal prosthesis and the preparation method thereof have good controllability. By adjusting the gradient porosity and pore size of the Ti6Al4V alloy substrate, the balance between mechanical properties and biocompatibility can be achieved. By adjusting the ratio of HA and β-TCP in the bioceramic coating, the bioactivity and degradation rate of the coating can be controlled. At the same time, the adjustment of the parameters of each step in the preparation method, such as SLM 3D printing, surface treatment, bioceramic coating, and heat treatment, can significantly affect the performance of the final product.

[0126] It is worth noting that, by the method of micro-arc oxidation pretreatment combined with electrophoretic deposition, the present application successfully forms a uniform bioceramic coating on the surface of the porous metal substrate. This innovative coating method not only improves the bonding strength of the coating and the substrate, but also ensures the uniform distribution of the coating in the complex porous structure, thereby effectively improving the bioactivity and bone integration ability of the prosthesis.

[0127] In addition, by precisely controlling the preparation process of HA and β-TCP powders, the present application ensures the high quality and repeatability of the bioceramic coating. This strict powder preparation process lays a solid foundation for the subsequent coating process, further ensuring the performance stability of the final product.

[0128] In summary, the composite porous bioceramic metal prosthesis and its preparation method provided by the present application successfully solve the deficiencies of traditional metal prostheses in biological activity, bone integration ability and long-term stability through the synergistic effect of multiple technical features, providing a new idea and direction for the development of orthopedic implants.

[0129] Comparative Example 1: Single metal matrix prosthesis

[0130] This comparative example aims to demonstrate the importance of the composite porous bioceramic coating. The prosthesis only contains a metal matrix made of Ti6Al4V alloy without a bioceramic coating. The metal matrix has a gradient porosity structure of 50%, with a pore size of 400 μm.

[0131] The composition of the Ti6Al4V alloy is the same as in Example 2. The preparation method only includes steps (1) and (2), with the same parameters as in Example 2. Due to the lack of a bioceramic coating, although the prosthesis has good mechanical properties, its biological activity and bone integration ability are significantly lower than those of the composite prosthesis of the present application. This highlights the key role of the bioceramic coating in improving the biocompatibility of the prosthesis.

[0132] Comparative Example 2: Prosthesis with non-gradient porosity structure

[0133] This comparative example aims to demonstrate the importance of the gradient porosity structure. The prosthesis includes a Ti6Al4V alloy matrix and a bioceramic coating, but the metal matrix has a uniform 50% porosity structure with a pore size of 400 μm. The bioceramic coating composition is the same as in Example 2.

[0134] The preparation method is basically the same as in Example 2, but in step (1), the SLM 3D printing parameters are adjusted to obtain a uniform porosity structure. The results show that although the prosthesis has certain biological activity, its stress distribution is not as uniform as the gradient structure, which may lead to stress shielding effects, thereby affecting the long-term stability and bone integration effect of the prosthesis.

[0135] Comparative Example 3: Single HA coating prosthesis

[0136] This comparative example aims to demonstrate the synergistic effect of HA and β-TCP composite coating. The metal matrix of the prosthesis is the same as in Example 3, but the bioceramic coating is composed of only 100 parts of hydroxyapatite (HA).

[0137] The preparation method is basically the same as that of Example 3, but only HA powder is used in the electrophoretic deposition process of step (3). The results show that although HA has good biological activity, the degradation rate of a single HA coating is too slow to match the bone tissue reconstruction process well. This proves the advantages of the HA and β-TCP composite coating in regulating the degradation rate and promoting bone integration.

[0138] Comparative Example 4: High β-TCP Content Coated Prosthesis

[0139] This comparative example aims to verify the optimal range of the HA and β-TCP ratio. The metal substrate of this prosthesis is the same as that of Example 4, but the bioceramic coating composition is: HA 40 parts, β-TCP 60 parts.

[0140] The preparation method is basically the same as that of Example 4, but the ratio of HA and β-TCP in the electrophoretic deposition process is adjusted. The results show that although a higher β-TCP content can accelerate the degradation rate of the coating, it may also lead to a decrease in coating stability, which is not conducive to long-term bone integration. This verifies the rationality of the HA and β-TCP ratio range in the present application.

[0141] Comparative Example 5: Prosthesis without Micro-arc Oxidation Pretreatment

[0142] This comparative example aims to demonstrate the importance of micro-arc oxidation pretreatment. The basic composition of this prosthesis is the same as that of Example 1, but the micro-arc oxidation pretreatment step is omitted during preparation.

[0143] The preparation method is basically the same as that of Example 1, but the micro-arc oxidation pretreatment in step (3) is deleted, and the electrophoretic deposition is performed directly. The results show that although a bioceramic coating can still be formed, the bonding strength between the coating and the metal substrate is significantly reduced, and the coating uniformity is poor. This proves the key role of micro-arc oxidation pretreatment in improving the adhesion and uniformity of the coating.

[0144] Comparative Example 6: Low-temperature Heat Treatment Prosthesis

[0145] This comparative example aims to verify the importance of the heat treatment temperature. The basic composition of this prosthesis is the same as that of Example 4, but a lower temperature is used in the heat treatment step.

[0146] The preparation method is basically the same as that of Example 4, but in step (4), the heat treatment temperature is reduced to 700°C. The results show that although low-temperature heat treatment can improve the bonding strength between the coating and the substrate to some extent, it cannot fully activate the crystal phase transformation of the bioceramics, resulting in a coating with biological activity and mechanical properties that are not as good as the optimal range of the present application. This verifies the rationality of the heat treatment temperature range in the present application.

[0147] Through the above 6 comparative examples, the innovativeness and superiority of the present application in multiple aspects can be clearly seen:

[0148] 1. The design of the composite porous structure effectively balances the mechanical properties and biocompatibility of the prosthesis.

[0149] 2. The gradient porosity structure optimizes stress distribution and reduces stress shielding effects.

[0150] 3. The composite coating of HA and β-TCP achieves synergistic regulation of bioactivity and degradation rate.

[0151] 4. The micro-arc oxidation pretreatment significantly improves the adhesion and uniformity of the coating.

[0152] 5. The optimized heat treatment process ensures high crystallinity and good mechanical properties of the coating.

[0153] The synergistic effect of these innovations makes the composite porous bioceramic metal prosthesis of the invention have significant advantages in bioactivity, bone integration ability, and long-term stability, providing a new solution for the development of orthopedic implants.

[0154] To comprehensively evaluate the effectiveness and superiority of the composite porous bioceramic metal prosthesis and its preparation method, a series of test experiments were designed. These experiments aim to verify the core innovations of the invention from multiple angles and explore its mechanism in depth.

[0155] Firstly, in vitro bioactivity evaluation was conducted. The samples were immersed in simulated body fluid (SBF) to observe the formation of hydroxyapatite (HA) layer. The experimental conditions are as follows: the samples were immersed in SBF at 37°C, and taken out after 7 days and 14 days, respectively. The surface morphology was observed by scanning electron microscopy (SEM), and the crystallinity of the HA layer was analyzed by X-ray diffraction (XRD).

[0156] Secondly, the mechanical properties of the samples were evaluated. Compression test and interfacial shear strength test were used to test the mechanical properties of the prosthesis and the bonding strength of the coating. Compression test used a universal testing machine with a loading rate of 0.5 mm / min. Interfacial shear strength test used a special fixture with a loading rate of 0.5 mm / min.

[0157] Thirdly, in vitro cell experiments were conducted to evaluate the biocompatibility of the samples. Human bone marrow mesenchymal stem cells (hBMSCs) were selected to observe cell adhesion, proliferation, and osteogenic differentiation on the sample surface. Cell culture was carried out in a 37°C, 5% CO2 incubator. CCK-8 proliferation experiment was conducted after 3 days and 7 days, respectively, and alkaline phosphatase (ALP) activity determination was conducted after 14 days.

[0158] Finally, the degradation behavior of the coatings was evaluated through in vitro degradation experiments. The samples were immersed in phosphate buffered saline (PBS) at pH 7.4 and incubated in a constant temperature shaker at 37°C, and then taken out after 7 days, 14 days, and 28 days, respectively, to measure the calcium ion concentration in the solution and the change in pH value.

[0159] Table 1 shows the HA layer thickness and crystallinity index of all samples after immersion in SBF for 14 days:

[0160]

[0161]

[0162] Table 2 shows the compressive strength and interfacial shear strength of the samples:

[0163]

[0164] Table 3 shows the cell proliferation rate after 7 days and ALP activity after 14 days of hBMSCs cultured on the surface of the samples:

[0165]

[0166]

[0167] Table 4 shows the calcium ion release amount and pH value change of the samples after immersion in PBS for 28 days:

[0168]

[0169]

[0170] Based on the above experimental results, the following conclusions can be drawn:

[0171] 1. Biological activity: Examples 1-4 all exhibit excellent biological activity, forming a relatively thick and high-crystallinity HA layer. In particular, Example 3 exhibits the best HA layer formation ability, which can be attributed to its highest β-TCP content, providing more calcium and phosphorus ions to promote the deposition of HA.

[0172] 2. Mechanical properties: Example 2 exhibits the best overall mechanical properties, thanks to its optimized gradient porous structure and coating composition. It is worth noting that although Comparative Example 1 has the highest compressive strength, it lacks a bioceramic coating, resulting in significantly reduced biological activity.

[0173] 3. Biocompatibility: Example 3 exhibits the best cell proliferation and differentiation effect, which can be due to its optimal ratio of HA and β-TCP, providing an ideal microenvironment for cells. The cell compatibility of Comparative Example 1 is significantly poorer, again demonstrating the importance of a bioceramic coating.

[0174] 4. Degradation behavior: Example 3 exhibited the most desirable degradation behavior, releasing an appropriate amount of calcium ions and maintaining a relatively stable pH environment. Comparative Example 4 degraded too quickly due to the excessively high β-TCP content, which could affect long-term stability.

[0175] In summary, Example 3 can be considered the best embodiment of the present application. It performed the best in terms of bioactivity, cell compatibility, and degradation behavior, while maintaining good mechanical properties.

[0176] Upon further analysis of these results, the present application has the following unexpected technical effects:

[0177] 1. Synergistic effect: The combination of HA and β-TCP not only achieves the regulation of degradation rate, but also improves the overall bioactivity. This synergistic effect may be due to the unique microenvironment formed during the degradation of the two materials, which is conducive to the adhesion and proliferation of bone cells.

[0178] 2. Stress distribution optimization: The gradient porous structure not only improves the mechanical properties, but also optimizes the stress distribution. This structure may simulate the structural characteristics of natural bone tissue, helping to reduce the stress shielding effect and promote long-term reconstruction of bone tissue.

[0179] 3. Enhanced interfacial bonding: Micro-arc oxidation pretreatment not only improves the adhesion of the coating, but also may form a functional gradient transition layer between the metal substrate and the ceramic coating. This transition layer may further optimize the stress distribution and improve the overall mechanical stability.

[0180] 4. Dynamic microenvironment regulation: As the coating slowly degrades, the released ions may continuously affect the surrounding microenvironment, forming a dynamically changing bioactive interface. This dynamic process may be closer to the metabolic process of natural bone tissue, which is conducive to long-term bone integration.

[0181] 5. Multi-scale synergistic effect: From the nanoscale crystal structure to the microporous structure, and to the macroscopic gradient design, the present application optimizes performance at multiple scales. This multi-scale synergy may be the key to the superior comprehensive performance of the present application.

[0182] In summary, the present application achieves synergistic optimization of performance in multiple aspects through careful design of material combinations and preparation processes, providing new ideas and directions for the development of orthopedic implants. These unexpected technical effects not only reflect the innovation of the present application, but also provide valuable inspiration for the design of future bone tissue engineering materials.

[0183] The above merely illustrates the embodiments of the present application but should not be taken as limitations. Various changes and modifications can be made by those skilled in the art. Any modification, equivalent replacement, improvement, etc. within the spirit and principle of the present application should be included in the scope of claims of the present application.

Claims

1. A method for preparing a composite porous bioceramic metal prosthesis, characterized in that, Metal prostheses based on composite porous bioceramics include: The metal matrix is ​​made of Ti6Al4V alloy and has a gradient porosity structure of 30-70% with a pore size range of 200-600 μm; A bioceramic coating, said bioceramic coating covering the surface of the metal substrate, is composed of the following components in parts by weight: Hydroxyapatite HA 60-80 parts; 20-40 parts of β-tricalcium phosphate and β-TCP; The preparation method includes the following steps: (1) A porous Ti6Al4V matrix was prepared by selective laser melting (SLM) 3D printing technology; (2) Surface treatment of the porous Ti6Al4V substrate; (3) Bioceramic coating was performed on a surface-treated porous Ti6Al4V substrate; (4) Heat-treat the coated sample; The bioceramic coating described in step (3) includes the following sub-steps: (a) Pretreatment of MAO by micro-arc oxidation; (b) Electrophoretic deposition of EPD; The process parameters for the micro-arc oxidation MAO pretreatment are as follows: The electrolyte formulation is Ca(CH3COO)2·H2O 10-15g / L, Na2HPO4·12H2O 20-30g / L, voltage 300-400V, frequency 500-1000Hz, duty cycle 10-20%, processing time 5-10min, and temperature 10-20℃. The process parameters for the electrophoretic deposition EPD are as follows: The suspension formulation consists of 6-8 g / L HA powder, 2-4 g / L β-TCP powder, 0.1-0.3 g / L dispersant, and ethanol as the solvent. pH value 4.0-5.0, voltage 60-80V, deposition time 3-5min, temperature 20-25℃; The process parameters for the heat treatment in step (4) are as follows: Heating rate 5-10℃ / min, heat treatment temperature 800-1000℃, holding time 1-2h, furnace cooling to room temperature, heat treatment atmosphere is high-purity argon gas with purity ≥99.999%.

2. The preparation method according to claim 1, characterized in that, The composition of the Ti6Al4V alloy, by weight percentage, includes: Al 5.5-6.5%, V 3.5-4.5%, Fe ≤0.25%, O ≤0.13%, C ≤0.08%, N ≤0.05%, H ≤0.012%, balance Ti, total 100%.

3. The preparation method according to claim 1, characterized in that, The process parameters for SLM3D printing mentioned in step (1) are as follows: Laser power 150-250W, scanning speed 600-1000mm / s, layer thickness 30-50μm, spot diameter 70-100μm, forming atmosphere is high-purity argon gas with purity ≥99.999%, forming chamber temperature 80-120℃, substrate preheating temperature 150-200℃.

4. The preparation method according to claim 1, characterized in that, The surface treatment described in step (2) includes the following sub-steps: First, acid etching is performed. The acid etching solution is formulated by mixing 48wt% HF and 65wt% HNO3 and H2O in a volume ratio of 1:4:

5. The solution is treated at 20-25℃ for 8-12 minutes with a stirring speed of 200-300 rpm. Secondly, an alkaline treatment is performed, wherein the alkaline solution is a 5-10 mol / L NaOH solution, and the treatment is carried out at 60-80℃ for 4-6 hours with a stirring speed of 100-150 rpm. Then, use deionized water for ultrasonic cleaning for 10-15 minutes at an ultrasonic frequency of 40-60 kHz. Finally, dry at 60-80℃ for 2-4 hours.

5. The preparation method according to claim 1, characterized in that, The preparation methods of the HA powder and β-TCP powder include: For HA powder, 23.6-24.0g Ca(NO3)2·4H2O and 7.9-8.1g (NH4)2HPO4 were dissolved in deionized water respectively. The (NH4)2HPO4 solution was slowly added dropwise to the Ca(NO3)2 solution under continuous stirring. The pH was adjusted to 10-11 with NH4OH. The reaction was stirred at 70-80℃ for 4-6 hours. After aging for 24 hours, the mixture was filtered, washed, and dried. Finally, it was calcined at 900-1000℃ for 2 hours. For β-TCP powder, 35.4-36.0 g of Ca(NO3)2·4H2O and 15.8-16.2 g of (NH4)2HPO4 were dissolved in deionized water, and the (NH4)2HPO4 solution was slowly added dropwise to the Ca(NO3)2 solution under continuous stirring. The pH was adjusted to 7-8, and the reaction was carried out at 80-90℃ for 5-6 h. After aging for 24 h, the mixture was filtered, washed, and dried. Finally, it was calcined at 900-1100℃ for 3 h. The resulting powder was ball-milled and then passed through a 200-mesh sieve.

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