A biomimetic hydrophilic bioactive ceramic coating material for bone formation and a preparation method thereof

Abstract

The application discloses a kind of biomimetic biological mineralization osteogenesis hydrophilic bioactive ceramic coating material, which includes HA / BaTiO3 composite layer in the material.The application also discloses its preparation method, which is prepared by using wideband laser cladding method.The application introduces BaTiO3 into traditional bioactive ceramic coating material to form HA / BaTiO3 composite layer, in-situ constructs bioelectric microenvironment to make hydrophilic bioactive ceramic coating, realizes the effective combination of electric stimulation and artificial joint coating, uses the electrostatic interaction between piezoelectric charge and inorganic salt ions in body fluid to adsorb calcium and phosphorus inorganic salt to coating surface, creates osteogenesis environment for life body osteogenesis, improves the hydrophilic performance of coating surface, promotes the inorganic salt and water molecules in body fluid environment to infiltrate on material surface, enhances bioactivity and accelerates bone integration, so as to be beneficial to promote the rapid establishment of joint prosthesis and host bone interface bone integration.

Description

Technical Field

[0001] This invention relates to the field of bioactive ceramic materials technology, and in particular to a hydrophilic bioactive ceramic coating material that mimics biomineralization and osteogenic formation, and its preparation method. Background Technology

[0002] With the aging population and the increase in accidents such as traffic accidents, joint diseases and injuries seriously threaten the health and quality of life of the Chinese people. Artificial joint replacement has become the most effective method for restoring joint function, but poor osseointegration at the joint prosthesis-host bone interface, leading to joint loosening, remains a very challenging problem. Providing electrical stimulation signals to enhance the activity of artificial joints during their service life is a key condition for promoting rapid and long-term stable osseointegration at the joint prosthesis-host bone interface.

[0003] The bioactive ceramic coating materials disclosed in patent documents CN113088958A and CN 113730654A all consist of an Ag barrier layer, a hydroxyapatite / Ag composite transition layer, and a hydroxyapatite bioceramic layer. These coatings exhibit good bioactivity but lack electrical stimulation signals. Furthermore, the bioactivity expression of these coatings primarily occurs through the release of calcium and phosphorus ions from the coating itself, inducing an inorganic precipitation reaction on the coating surface to form apatite that mineralizes and forms bone on the coating surface, thereby promoting bone integration. Clearly, this bioactivity expression is a non-living process, thus its stimulation of osteoblast proliferation and differentiation is limited. It is also difficult to induce the adsorption of calcium and phosphorus ions from host body fluids onto the coating surface. Its activity and osteogenic capacity gradually decline with the release of calcium and phosphorus ions from the coating itself, leading to slow or even failed interfacial bone integration, making it impossible to achieve controllable mineralization and osteogenic processes during life processes.

[0004] The surface coating of the joint stem, acting as a carrier, needs to provide the necessary biological microenvironment for osteoblasts. Osteogenesis in living organisms involves osteoblasts enriching themselves with calcium and phosphate ions from the body fluid, producing apatite through their life processes. This apatite is then transported to the coating surface, where the bioactive coating material, similar to and compatible with the apatite produced by the cells, facilitates osteogenic integration. Therefore, it is crucial to provide continuous and effective osteogenic stimulation to osteoblasts, inducing new bone formation. This allows for rapid and excellent osseointegration during the postoperative recovery period after joint replacement surgery and maintains a stable interfacial osseointegration during long-term service, enabling continuous proliferation and formation of new bone tissue. Thus, establishing a suitable biological microenvironment for osteoblast proliferation in the titanium alloy joint stem surface coating, continuously stimulating and promoting new bone formation, has become a bottleneck issue in the preparation of high-quality osseointegration-promoting bioactive coatings.

[0005] However, when the surface of hydroxyapatite (HA) biomaterials comes into contact with the physiological environment, inorganic salts of calcium and phosphorus and water molecules from the environment first reach the surface of the material, followed by proteins from body fluids and blood adsorbing onto the surface, and finally cells coming into contact with the material surface. Therefore, cell-material adhesion occurs through protein mediation. Hydrophilic biomaterials are beneficial for the expression of biological activities, facilitate the adsorption of inorganic salts of calcium and phosphorus to the joint prosthesis-host bone interface to create an osteogenic environment for osteogenic formation, and promote the rapid establishment of osteointegration at the joint prosthesis-host bone interface. Although HA has good hydrophilic properties, coating materials made under high temperatures will cause HA to decompose, thereby losing its hydrophilic groups (hydroxyl (-OH) and phosphate (PO4) groups). 3- Therefore, improving the hydrophilicity of HA biomaterials when used as coating materials has become a key challenge in preparing high-quality bioactive coatings. Summary of the Invention

[0006] The technical problem to be solved by the present invention is to overcome the shortcomings of the prior art and provide a hydrophilic bioactive ceramic coating material for biomimetic biomineralization and osteogenic formation and its preparation method.

[0007] To solve the above-mentioned technical problems, the technical solution proposed by this invention is as follows:

[0008] A biomimetic biomineralized osteogenic hydrophilic bioactive ceramic coating material includes a titanium substrate and a hydrophilic bioactive ceramic coating covering the surface of the titanium substrate. The hydrophilic bioactive ceramic coating includes, from the inside to the outside, an Ag barrier layer, an HA / Ag composite transition layer and an HA / BaTiO3 composite layer.

[0009] Preferably, the thickness of the HA / BaTiO3 composite layer in the above-mentioned hydrophilic bioactive ceramic coating material is 150μm-250μm.

[0010] In the above-mentioned hydrophilic bioactive ceramic coating material, preferably, the mass ratio of HA to BaTiO3 in HA / BaTiO3 is (70-90):(10-30).

[0011] Preferably, the piezoelectric coefficient of the HA / BaTiO3 composite layer in the above-mentioned hydrophilic bioactive ceramic coating material is 50 pm / V-750 pm / V.

[0012] Preferably, in the above-mentioned hydrophilic bioactive ceramic coating material, the thickness of the Ag barrier layer is 100μm-200μm; the thickness of the HA / Ag composite transition layer is 100μm-200μm; and the mass content of Ag in the HA / Ag composite transition layer is 10%-40%.

[0013] As a general inventive concept, the present invention also provides a method for preparing the above-mentioned hydrophilic bioactive ceramic coating material, comprising the following steps:

[0014] (1) The surface-pretreated pure titanium sample block is placed on a constant temperature heating table and heated. Pure silver paste is coated on the surface of the pure titanium sample block, vacuum dried, and then broadband laser cladding is performed to form an Ag barrier layer on the surface of the pure titanium sample block.

[0015] (2) The sample block obtained in step (1) is pretreated on the surface and then placed on a constant temperature heating table for heating. The slurry containing HA and Ag is coated on the surface of the Ag barrier layer, vacuum dried, and then broadband laser cladding is performed to form an HA / Ag composite transition layer on the surface of the Ag barrier layer.

[0016] (3) The sample block obtained in step (2) is pretreated on the surface and then placed on a constant temperature heating table for heating. The slurry containing BaTiO3 and HA is coated on the surface of the HA / Ag composite transition layer, vacuum dried, and then broadband laser cladding is performed to form an HA / BaTiO3 composite layer on the surface of the HA / Ag composite transition layer, thus completing the preparation of the hydrophilic bioactive ceramic coating material.

[0017] In the above preparation method, preferably, in step (3), the process conditions for broadband laser cladding are: laser power of 1100W-1300W, laser scanning speed of 160mm / min-220mm / min, spot size of 15mm-20mm in length and 1mm-3mm in width, and argon flow rate of protective gas of 10L / min-20L / min.

[0018] In the broadband laser cladding process, BaTiO3 is added to the slurry of the hydroxyapatite bioceramic layer. Taking advantage of the rapid melting / solidification characteristics of the powder by laser cladding and the good biocompatibility and piezoelectric properties of BaTiO3, and the fact that the melting point of barium titanate (approximately 1600℃) is higher than that of nano-hydroxyapatite (approximately 1200℃), the barium titanate added to the powder is embedded in the coating during the laser cladding process. This provides a mechanoelectric conversion function on the surface of the HA / BaTiO3 composite layer, constructing a micro-region piezoelectric response on the coating surface. This mimics the piezoelectric properties of natural bone tissue, giving the surface of the coating material both piezoelectric stimulation and bioactivity functions.

[0019] In the above preparation method, preferably, in step (3), the slurry containing BaTiO3 and HA is prepared by mixing HA powder with an average particle size of 20 nm and a purity greater than 99.5% and BaTiO3 powder with an average particle size of 1 μm without ball milling, then adding it to a polyvinyl alcohol aqueous solution with a concentration of 2 wt.%-3 wt.% and stirring for 10 min-15 min, and then ultrasonically dispersing for 5 min-10 min.

[0020] In the above preparation method, preferably, in step (1), the pure silver paste is obtained by adding Ag powder with an average particle size of 1 μm and a purity greater than 99.5% to a polyvinyl alcohol aqueous solution with a concentration of 2wt.%-3wt.% and stirring for 10min-15min, and then ultrasonically dispersing for 5min-10min.

[0021] In the above preparation method, preferably, in step (1), the process conditions for broadband laser cladding are: laser power of 1800-2400W, laser scanning speed of 210-400mm / min, spot size of 18-20mm in length and 2-4mm in width, and argon flow rate of protective gas of 15-20L / min.

[0022] In the above preparation method, preferably, in step (2), the average particle size of Ag particles in the slurry containing HA and Ag is 1 μm and the purity is greater than 99.5%, and the average particle size of HA is 20 nm and the purity is greater than 99.5%. The slurry containing HA and Ag is obtained by mixing Ag powder and HA powder without ball milling, then adding them to a polyvinyl alcohol aqueous solution with a concentration of 2wt.%-3wt.% and stirring for 10 min-15 min, and then ultrasonically dispersing for 5 min-10 min.

[0023] In the above preparation method, preferably, the process conditions for broadband laser cladding in step (2) are: laser power of 1400-1650W, laser scanning speed of 210-300mm / min, spot size of 18-20mm in length and 2-4mm in width, and argon flow rate of protective gas of 15-20L / min.

[0024] In the above preparation method, preferably, in steps (1), (2) and (3), the surface pretreatment of the specimen block is to place the specimen block in a mixture of deionized water and ethanol, clean it with an ultrasonic cleaner for 15 min-30 min, and then place it in a vacuum dryer at 60°C for 8 h-10 h.

[0025] In the above preparation method, preferably, in steps (1), (2) and (3), the heating temperature of the constant temperature heating stage is 80℃-90℃; the vacuum drying temperature is 60℃-70℃; and the vacuum drying time is 24h-48h.

[0026] Compared with the prior art, the advantages of the present invention are as follows:

[0027] (1) In this invention, BaTiO3 is introduced into the traditional hydrophilic bioactive ceramic coating material to form a HA / BaTiO3 composite layer, which improves the hydrophilicity of the hydrophilic bioactive ceramic coating material. This facilitates the wetting of inorganic salts and water molecules in the body fluid environment on the material surface, promotes a larger nucleation area of ​​the apatite phase on the material surface when immersed in simulated body fluid, and improves the bioactivity. This is conducive to promoting the rapid establishment of bone integration between the joint prosthesis and the host bone interface.

[0028] (2) The BaTiO3 particles introduced in this invention can also be used as a source of electromechanical conversion to prepare a composite active ceramic coating with both piezoelectric stimulation and bioactivity functions. It mimics the piezoelectric properties of human bone tissue, constructs a bioelectric microenvironment in situ, and achieves an effective combination of electrical stimulation and artificial joint coating. Under ultrasonic stimulation, it helps the coating to adsorb calcium ions and calcium phosphate ions in the body fluid environment, enhances the bioactivity of the coating, and accelerates bone integration.

[0029] (3) The hydrophilic bioactive ceramic coating material of the present invention contains an HA / BaTiO3 composite layer. The HA / BaTiO3 composite layer has a mechanoelectric conversion function, which makes the coating very similar to the host bone tissue in terms of mechanoelectric conversion function and has better biological performance. It can convert the stress it receives into a weak bioelectric signal on the bone surface, forming a bioelectric microenvironment in the bone tissue, which plays an important role in regulating bone growth and maintaining bone tissue metabolism. Furthermore, the electrical signal on the surface of the HA / BaTiO3 composite layer also helps the exchange, degradation and HA deposition of inorganic salt ions in the body fluid environment, which promotes the formation of new bone and good bone integration.

[0030] (4) This invention adds BaTiO3 to the slurry of HA, taking advantage of the high plasticity of its biocompatible metal Ti, the good osteoconductivity of HA bioactive ceramics which promotes bone mineralization and deposition, and the ability of BaTiO3 piezoelectric ceramics to stimulate osteoblasts to enhance their activity and continuously promote bone regeneration and reconstruction. The three are combined on the surface of pure titanium to construct a piezoelectric active coating that combines biomechanical properties, bioactivity and piezoelectric stimulation. By utilizing the osteoconductivity of the bioactive ceramic phase and the electrical stimulation of the piezoelectric ceramic phase, a suitable biological microenvironment for osteoblast proliferation is established, which continuously stimulates and promotes new bone formation. This can solve the mechanical problems of the coating and improve its biological properties, thereby providing conditions for the rapid establishment and long-term stability of bone integration after artificial joint replacement surgery.

[0031] (5) This invention utilizes the characteristics of rapid melting / solidification of powder layers by laser cladding and the excellent biocompatibility and piezoelectric properties of BaTiO3. Without the need for an external power source, the piezoelectric effect can be induced under the physiological force load of daily activities. By constructing a micro-region piezoelectric response on the surface of the piezoelectric active coating, the piezoelectric properties of natural bone tissue are biomimetic. The electrostatic interaction between the piezoelectric charge and inorganic salt ions in the body fluid is utilized to facilitate the adsorption of inorganic salts such as calcium and phosphorus to the interface between the joint prosthesis and the host bone, creating an osteogenic environment for the body to form osteogenic tissue. This improves the hydrophilicity and bioactivity of the coating surface, which is conducive to promoting the rapid establishment of bone integration between the joint prosthesis and the host bone interface, thereby promoting bone integration between the artificial joint and the host bone interface. Attached Figure Description

[0032] Figure 1 This is a schematic diagram of the structure of the hydrophilic bioactive ceramic coating material of the present invention.

[0033] Figure 2 The microscopic cross-sectional morphology of the hydrophilic bioactive ceramic coating materials prepared in Examples 1-3 and the comparative examples of the present invention is shown.

[0034] Figure 3 The results of energy dispersive spectroscopy (EDS) analysis of the hydrophilic bioactive ceramic coating material prepared in Example 1 of this invention are shown.

[0035] Figure 4 The high-magnification microscopic cross-sectional morphology of the hydrophilic bioactive ceramic coating materials prepared in Examples 1-3 and the comparative examples of the present invention is shown.

[0036] Figure 5 The images show the XRD patterns of the hydrophilic bioactive ceramic coating materials prepared in Examples 1-3 and the comparative examples of this invention.

[0037] Figure 6 The micro-region piezoelectric properties of the hydrophilic bioactive ceramic coating materials prepared in Examples 1-3 and the comparative examples of this invention are shown.

[0038] Figure 7 The butterfly loop and hysteresis loop are those of the hydrophilic bioactive ceramic coating materials prepared in Examples 1-3 and the comparative examples of this invention.

[0039] Figure 8 The piezoelectric response of the hydrophilic bioactive ceramic coating materials prepared in Examples 1-3 and the comparative examples of the present invention is shown.

[0040] Figure 9 The surface morphology of the hydrophilic bioactive ceramic coating materials prepared in Examples 1-3 and the comparative examples of the present invention after immersion in simulated body fluid (SBF) for 14 days, without ultrasonic stimulation and with ultrasonic stimulation.

[0041] Figure 10The hydrophilic bioactive ceramic coating materials prepared in Examples 1-3 and the comparative examples of this invention were subjected to immersion in simulated body fluid (SBF) for 6 h, 12 h, 24 h, and 48 h, respectively, to obtain Ca. 2+ Concentration changes and PO4 3- Concentration changes.

[0042] Figure 11 The hydrophilic properties of the hydrophilic bioactive ceramic coating materials prepared in Examples 1-3 and the comparative examples of this invention are shown.

[0043] Legend:

[0044] 1. Titanium matrix; 2. Ag barrier layer; 3. HA / Ag composite transition layer; 4. HA / BaTiO3 composite layer. Detailed Implementation

[0045] To facilitate understanding of the present invention, the present invention will be described more fully and in detail below with reference to the accompanying drawings and preferred embodiments, but the scope of protection of the present invention is not limited to the following specific embodiments.

[0046] Unless otherwise defined, all technical terms used herein have the same meaning as commonly understood by those skilled in the art. The technical terms used herein are for the purpose of describing particular embodiments only and are not intended to limit the scope of the invention.

[0047] Unless otherwise specified, all reagents and raw materials used in this invention are commercially available products or products that can be prepared by known methods.

[0048] Example 1:

[0049] The biomimetic biomineralized osteogenic hydrophilic bioactive ceramic coating material in this embodiment has the following structural schematic diagram: Figure 1 As shown, the structure includes a titanium substrate 1 and a hydrophilic bioactive ceramic coating clad on the surface of the titanium substrate 1. From the inside out, the hydrophilic bioactive ceramic coating comprises, in sequence, an Ag barrier layer 2, an HA / Ag composite transition layer 3, and an HA / BaTiO3 composite layer 4. The HA / BaTiO3 composite layer 4 has a thickness of approximately 170 μm and a piezoelectric coefficient of 712.6 pm / V. The mass fraction of BaTiO3 in the HA / BaTiO3 composite layer 4 is 20 wt.%, and the mass fraction of HA is 80 wt.%. The thickness of the HA / Ag composite transition layer 3 is approximately 170 μm, and the mass fraction of Ag in the HA / Ag composite transition layer 3 is 25 wt.%, and the mass fraction of HA is 75 wt.%. The thickness of the Ag barrier layer 2 is approximately 120 μm.

[0050] The preparation method of the biomimetic biomineralized osteogenic hydrophilic bioactive ceramic coating material in this embodiment includes the following steps:

[0051] (1) Weigh 0.2g of Ag powder (purity ≥99.5%, average particle size 1μm) using an electronic analytical balance, add it to 1mL of polyvinyl alcohol aqueous solution with a mass concentration of 3wt.%, stir for 10min, and then place it on an ultrasonic dispersion table for ultrasonic dispersion for 5min to prepare slurry A (Ag slurry).

[0052] Hydroxyapatite powder (purity ≥99.5%, average particle size 20 nm) and Ag powder (purity ≥99.5%, average particle size 1 μm) were mixed in a horizontal planetary ball mill at a mass ratio of 75 wt.% : 25 wt.% to prepare a mixed powder. 0.2 g of this mixed powder was weighed using an electronic analytical balance and added to 1 mL of a 3 wt.% polyvinyl alcohol aqueous solution. After stirring for 10 min, the solution was ultrasonically dispersed for 5 min to prepare slurry B (Ag+HA mixed slurry).

[0053] Hydroxyapatite powder (purity ≥99.5%, average particle size 20 nm) and BaTiO3 powder (purity ≥95%, average particle size 1 μm) were mixed in a horizontal planetary ball mill at a mass ratio of 80 wt.%:20 wt.% to prepare a mixed powder. 0.4 g of this mixed powder was weighed using an electronic analytical balance and added to 1 mL of a 3 wt.% polyvinyl alcohol aqueous solution. After stirring for 10 min, the mixture was ultrasonically dispersed for 5 min to prepare slurry C (HA+BaTiO3 mixed slurry).

[0054] Pure titanium plates were cut into sample blocks with dimensions of 20mm×30mm×4mm using a wire cutting machine. The blocks were then polished with 80-mesh SiC sandpaper to remove the surface oxide film. The polished pure titanium sample blocks were then placed in deionized water and ethanol and cleaned with an ultrasonic cleaner for 30 minutes. After cleaning, they were placed in a vacuum dryer at 60℃ for 8 hours for later use.

[0055] (2) Place the sample block prepared in step (1) on an 80°C constant temperature heating table, spread the slurry A evenly on the surface of the sample block substrate, and then put it into a 60°C vacuum dryer to dry for 24 hours.

[0056] A broadband laser cladding process was used to clad Ag onto the surface of a pure titanium substrate to form an Ag barrier layer. The broadband laser cladding process parameters were as follows: laser power of 2000W, laser scanning speed of 240mm / min, spot size of 18mm×2mm, and argon flow rate of 15L / min.

[0057] (3) Place the sample block with Ag barrier layer on the surface prepared in step (2) in deionized water and ethanol, clean it with an ultrasonic cleaner for 30 min, and then place the cleaned sample block in a vacuum dryer at 60℃ for 8 h.

[0058] The dried sample block with the Ag barrier layer was placed on an 80℃ constant temperature heating table and heated. Slurry B was evenly spread on the surface of the Ag barrier layer and then dried in a 60℃ vacuum dryer for 24 hours.

[0059] A broadband laser process was used to clad Ag and HA onto the surface of the Ag barrier layer to form an HA / Ag composite transition layer. The broadband laser cladding process parameters were as follows: laser power of 1550W, laser scanning speed of 280mm / min, spot size of 18mm×2mm, and argon flow rate of 15L / min.

[0060] (4) Place the sample block coated with HA / Ag composite transition layer in step (3) in deionized water and ethanol, clean it with an ultrasonic cleaner for 30 minutes, and then place the cleaned sample block in a vacuum dryer at 60°C for 8 hours for later use.

[0061] The sample block was placed on an 80℃ constant temperature heating table and heated. Slurry C was evenly spread on the surface of the HA / Ag composite transition layer of the sample block, and then placed in a 60℃ vacuum dryer to dry for 24 hours.

[0062] Broadband laser technology was used to clad HA+BaTiO3 onto the surface of the HA / Ag composite transition layer. The cladding process parameters were: laser power of 1250W, laser scanning speed of 200mm / min, spot size of 18mm×2mm, and argon flow rate of 15L / min, thus completing the preparation of the hydrophilic bioactive ceramic coating material.

[0063] Example 2, Example 3 and Comparative Example 1:

[0064] The only difference between Examples 2, 3 and Comparative Example 1 and Example 1 is the preparation of slurry C in step (1) (see Table 1). The other preparation processes are exactly the same as those in Example 1.

[0065] Table 1. Slurry C used in Examples 1, 2, 3 and Comparative Example 1

[0066]

[0067] The cross-sectional morphologies of the hydrophilic bioactive ceramic coating materials prepared in Examples 1-3 and Comparative Example 1 are shown in the figure. Figure 2As shown in the figure, 2M, 2N, 2O, and 2P are all titanium substrates; 2I, 2J, 2K, and 2L are barrier layers; 2E, 2F, 2G, and 2H are transition layers; and 2A, 2B, 2C, and 2D are HA / BaTiO3 composite layers. From the cross-sectional morphology, it can be seen that, within the scope of protection of this invention, hydrophilic bioactive ceramic coatings with good metallurgical bonding to the titanium substrate can be prepared under different BaTiO3 powder addition conditions.

[0068] Figure 3 The results are based on the energy dispersive spectroscopy analysis of 3A in the hydrophilic bioactive ceramic coating prepared in Example 1. The results show that it contains a high relative atomic percentage of Ba, which is 22.62 at.%. Therefore, the spherical particles 3A embedded in the coating are BaTiO3.

[0069] The high-magnification microstructures of the hydrophilic bioactive ceramic coatings prepared in Examples 1-3 and Comparative Example 1 are shown in Figure 1. Figure 4 As shown, 3A, 3B, and 3C are spherical BaTiO3 particles embedded in the coating, while the hydrophilic bioactive ceramic coating of Comparative Example 1 does not contain spherical BaTiO3 particles embedded in the coating. From the cross-sectional morphology, it can be seen that, within the scope of protection of this invention, under different addition ratios of BaTiO3 powder, BaTiO3 powder particles can be embedded in the hydrophilic bioactive ceramic coating, providing the hydrophilic bioactive ceramic coating with electromechanical conversion function, and having the potential to construct a micro-region piezoelectric response on the surface of the hydrophilic bioactive ceramic coating.

[0070] The XRD patterns of the hydrophilic bioactive ceramic coatings prepared in Examples 1-3 and Comparative Example 1 are as follows: Figure 5 As shown in the XRD pattern, it can be seen from the phase composition that, within the scope of protection of this invention, under different ratios of BaTiO3 powder addition conditions, HA (hydroxyapatite), TCP (tricalcium phosphate), TTCP (tetracalcium phosphate), BaTiO3 (barium titanate), etc. can be detected in the hydrophilic bioactive ceramic coating.

[0071] The changes in the micro-region piezoelectric properties of the hydrophilic bioactive ceramic coatings prepared in Examples 1-3 and Comparative Example 1 are shown in the figure. Figure 6 As shown, the piezoelectric properties of the hydrophilic bioactive ceramic coating surface were tested using piezoelectric microscopy (PFM).

[0072] As can be seen from the amplitude diagram of the hydrophilic bioactive ceramic coating surface, the hydrophilic bioactive ceramic coating surfaces prepared in Examples 1-3 all have large area amplitude response, and the maximum amplitude in Example 1 is about 15mV, while the hydrophilic bioactive ceramic coating surface prepared in Comparative Example 1 without the addition of BaTiO3 has no obvious amplitude response.

[0073] As can be seen from the surface phase diagram of the hydrophilic bioactive ceramic coating, the hydrophilic bioactive ceramic coating prepared by adding BaTiO3 in Examples 1-3 has a large area of ​​phase reversal on the surface, while the hydrophilic bioactive ceramic coating prepared by not adding BaTiO3 in Comparative Example 1 has no phase reversal on the surface.

[0074] As can be seen from the surface potential of the hydrophilic bioactive ceramic coatings, the bioactive ceramics prepared by adding BaTiO3 in Examples 1-3 all have a large area of ​​high potential. Specifically, the maximum potential of the hydrophilic bioactive ceramic coating surface in Example 1 is about 229.8 mV, the maximum potential of the hydrophilic bioactive ceramic coating surface in Example 2 is about 108.6 mV, and the maximum potential of the hydrophilic bioactive ceramic coating surface in Example 3 is about 128.2 mV. However, the bioactive ceramic surface prepared in Comparative Example 1 without adding BaTiO3 does not have a large area of ​​potential.

[0075] Figure 7 The butterfly loop and hysteresis loop of the hydrophilic bioactive ceramic coatings prepared in Examples 1-3 and the comparative example are shown. The results indicate that the butterfly loop and hysteresis loop of the hydrophilic bioactive ceramic coating prepared in Example 1 with BaTiO3 are both closed loops when a needle tip bias voltage of ±10V is applied, indicating the presence of a high coercive field. In Example 1, the positive saturation bias voltage is approximately 2V, and the negative saturation bias voltage is approximately -1.8V. From the hysteresis loops of Examples 2 and 3, it can be seen that the positive saturation bias voltages are 0.4V and 1.1V, and the negative saturation bias voltages are -0.1V and -0.9V, respectively. This indicates that the hydrophilic bioactive ceramic coatings in Examples 1-3 all possess an asymmetric coercive field, which is closely related to the BaTiO3 particles embedded in the hydrophilic bioactive ceramic coatings in Examples 1-3. In contrast, the hydrophilic bioactive ceramic coating prepared in Comparative Example 1 without BaTiO3 does not exhibit butterfly loops or hysteresis loops and does not possess piezoelectric properties. It is evident that the hydrophilic bioactive ceramic coating prepared with the addition of BaTiO3 can successfully construct a micro-region piezoelectric response on the coating surface, while the coating surface prepared without the addition of BaTiO3 does not have a micro-region piezoelectric response.

[0076] Figure 8To directly characterize the piezoelectric response of the hydrophilic bioactive ceramic coatings in Examples 1-3 and Comparative Example 1, the piezoelectric coefficient of the hydrophilic bioactive ceramic coatings was calculated by calculating the response slope. The amplitude of the surface of the hydrophilic bioactive ceramic coating in Comparative Example 1 hardly changed with the applied voltage, indicating that the surface of the hydrophilic bioactive ceramic coating prepared without BaTiO3 does not have a piezoelectric response. The piezoelectric coefficient in Example 1 was 712.6 pm / V, while the piezoelectric coefficients of the hydrophilic bioactive ceramic coatings prepared in Examples 2 and 3 were 87.9 pm / V and 283.3 pm / V, respectively, both less than the piezoelectric coefficient of 712.6 pm / V in Example 1. This indicates that the piezoelectric coefficient of the hydrophilic bioactive ceramic coating first increases and then decreases with the addition of BaTiO3.

[0077] The surface morphologies of the hydrophilic bioactive ceramic coatings prepared in Examples 1-3 and Comparative Example 1 after immersion in simulated body fluid (SBF) for 14 days, with and without ultrasonic stimulation, are as follows: Figure 9 As shown, 9A, 9B, 9C, and 9D represent small spherical stacks and layers formed without ultrasound stimulation, while 9E, 9F, 9G, and 9H represent small spherical stacks and layers formed with ultrasound stimulation. From... Figure 9 It can be observed that small spherical deposits and layers formed on the surface of all hydrophilic bioactive ceramic coatings, consistent with the characteristic structure of induced apatite formation, indicating that the hydrophilic bioactive ceramic coatings possess good bioactivity. In Comparative Example 1, there was no difference in the extent of induced apatite deposits and layers on the surface of the hydrophilic bioactive ceramic coatings with and without ultrasonic stimulation. However, in Examples 1-3, the induced apatite deposits and layers formed under ultrasonic stimulation were larger, demonstrating the excellent bioactivity of the hydrophilic bioactive ceramic coatings. These results indicate that apatite-like substances can be induced on the surface of each coating. Adding BaTiO3 particles to the bioactive layer prepared on the pure titanium surface not only imparts piezoelectric properties to the coating but also helps to improve its bioactivity.

[0078] The hydrophilic bioactive ceramic coatings prepared in Examples 1-3 and Comparative Example 1 were immersed in SBF for 6 h, 12 h, 24 h, and 48 h in Ca. 2+ and PO4 3- Concentration change test results as follows Figure 10 As shown, where Figure 10 (a) and Figure 10 (b) Ca2+ with and without ultrasonic stimulation during soaking for 6h, 12h, 24h, and 48h. 2+ Concentration change, Figure 10 (c) and Figure 10 (d) PO42-H2O with and without ultrasonic stimulation during immersion for 6h, 12h, 24h, and 48h. 3- Concentration change. From Figure 10 (a) Immersion without ultrasonic stimulation shows that Ca in SBF... 2+ The concentration gradually decreased during the immersion period, indicating that the coating surface adsorbed Ca from the simulated body fluid. 2+ In Examples 1-3 and Comparative Example 1, the Ca in simulated body fluids was measured at the 48th hour of immersion. 2+ With no significant difference in concentration and without ultrasonic stimulation on the surface, Examples 1-3 and Comparative Example 1 showed differences in Ca concentration in simulated body fluids. 2+ Adsorption was indistinguishable. From Figure 10 (b) As can be seen from ultrasonic immersion, the Ca in SBF 2+ The concentration gradually decreased during the immersion period, indicating that the coating surface could also adsorb Ca from simulated body fluids under ultrasonic stimulation. 2+ Furthermore, in Examples 1-3 and Comparative Example 1, at the 48th hour of immersion, the Ca in the simulated body fluid of Examples 1-3 was... 2+ The concentrations were all significantly lower than those in Comparative Example 1, indicating that under ultrasonic stimulation, the electromechanical conversion function of the coatings in Examples 1-3 was activated, promoting the coatings' response to Ca in simulated body fluids. 2+ Adsorption.

[0079] from Figure 10 (c) Immersion without ultrasonic stimulation indicates that PO4 in SBF 3- The concentration gradually decreased during the immersion period, indicating that the coating surface adsorbed PO4 from the simulated body fluid. 3- In Examples 1-3 and Comparative Example 1, the PO4 content in simulated body fluids was measured at the 48th hour of immersion. 3- With no significant difference in concentration and without ultrasonic stimulation on the surface, Examples 1-3 and Comparative Example 1 showed differences in PO4 in simulated body fluids. 3- Adsorption was indistinguishable. From Figure 10 (d) As can be seen from ultrasonic immersion, PO4 in SBF... 3- The concentration gradually decreased during the immersion period, indicating that the coating surface could also adsorb PO4 from simulated body fluids under ultrasonic stimulation. 3- Furthermore, in Examples 1-3 and Comparative Example 1, at the 48th hour of immersion, the PO4 in the simulated body fluid of Examples 1-3 was... 3- The concentrations were all significantly lower than those in Comparative Example 1, indicating that under ultrasonic stimulation, the electromechanical conversion function of the coatings in Examples 1-3 was activated, promoting the coatings' response to PO4 in simulated body fluids. 3- Adsorption.

[0080] The hydrophilic properties of the hydrophilic bioactive ceramic coatings prepared in Examples 1-3 and Comparative Example 1 are as follows: Figure 11 As shown, from Figure 11It can be seen that the contact angle between Example 1 and SBF is 54°, which is smaller than that of Comparative Example 1; the contact angles between Examples 2 and 3 and SBF are also smaller than those of Comparative Example 1. This indicates that the HA / BaTiO3 composite layer in the embodiments of the present invention improves the hydrophilicity of the hydrophilic bioactive ceramic coating to SBF. This is partly due to the presence of hydroxyl groups (-OH) and phosphate groups (PO4) in the coatings of Examples 1-3. 3- Polar groups such as ) have an affinity for SBF; on the other hand, the micro-area electrical environment on the surface of the hydrophilic bioactive ceramic coating in Examples 1-3 also improves the affinity of the coating surface for SBF. The improved hydrophilicity of the hydrophilic bioactive ceramic coating is conducive to the wetting of inorganic salts and water molecules in SBF on the coating surface, promoting a larger HA nucleation area on the coating surface during SBF immersion, thereby further promoting bone integration at the interface between the artificial joint and the host bone.

[0081] In summary, the technical solution of this invention, by adding BaTiO3 powder to the slurry of the hydroxyapatite bioceramic layer and using a broadband laser cladding process, prepares a hydrophilic bioactive ceramic coating that forms a good metallurgical bond with the titanium-based material. On the one hand, this ensures the bioactivity of the ceramic coating, and on the other hand, it constructs a micro-region piezoelectric response on the surface of the hydrophilic bioactive ceramic coating. By utilizing the electrostatic interaction between the piezoelectric charge and inorganic salt ions in the body fluid, inorganic salts of calcium and phosphorus are adsorbed onto the coating surface, creating an osteogenic environment for osteogenic formation in living organisms, improving the hydrophilicity and bioactivity of the coating surface, and promoting the rapid establishment of osseointegration between the joint prosthesis and the host bone interface, thereby promoting osseointegration between the artificial joint and the host bone interface.

Claims

1. A hydrophilic bioactive ceramic coating material for biomimetic biomineralization and osteogenic formation, characterized in that, The invention comprises a titanium substrate and a hydrophilic bioactive ceramic coating covering the surface of the titanium substrate. The hydrophilic bioactive ceramic coating, from the inside out, comprises an Ag barrier layer, an HA / Ag composite transition layer, and an HA / BaTiO3 composite layer. The mass ratio of HA to BaTiO3 in the HA / BaTiO3 layer is 80:

20. The piezoelectric coefficient of the HA / BaTiO3 composite layer is 712.6 pm / V. The thickness of the Ag barrier layer is 120 μm. The thickness of the HA / Ag composite transition layer is 170 μm, and the mass content of Ag in the HA / Ag composite transition layer is 25%. The thickness of the HA / BaTiO3 composite layer is 170 μm.

2. A method for preparing the hydrophilic bioactive ceramic coating material as described in claim 1, characterized in that, Includes the following steps: (1) The surface-pretreated pure titanium sample block was placed on a constant temperature heating table and heated. Pure silver paste was coated on the surface of the pure titanium sample block, vacuum dried, and then broadband laser cladding was performed to form an Ag barrier layer on the surface of the pure titanium sample block. (2) The sample block obtained in step (1) is pretreated on the surface and then placed on a constant temperature heating table for heating. The slurry containing HA and Ag is coated on the surface of the Ag barrier layer, vacuum dried, and then broadband laser cladding is performed to form an HA / Ag composite transition layer on the surface of the Ag barrier layer. (3) The sample block obtained in step (2) is pretreated on the surface and then placed on a constant temperature heating table for heating. The slurry containing BaTiO3 and HA is coated on the surface of the HA / Ag composite transition layer, vacuum dried, and then broadband laser cladding is performed to form an HA / BaTiO3 composite layer on the surface of the HA / Ag composite transition layer, thus completing the preparation of the hydrophilic bioactive ceramic coating material.

3. The preparation method according to claim 2, characterized in that, In step (3), the process conditions for broadband laser cladding are as follows: laser power is 1100 W-1300 W, laser scanning speed is 160 mm / min-220 mm / min, the length of the spot is 15 mm-20 mm, the width is 1 mm-3 mm, and the flow rate of the protective argon gas is 10 L / min-20 L / min.

4. The preparation method according to claim 2, characterized in that, In step (3), the slurry containing BaTiO3 and HA is obtained by mixing HA powder with an average particle size of 20 nm and a purity of greater than 99.5% and BaTiO3 powder with an average particle size of 1 μm without ball milling, then adding it to a polyvinyl alcohol aqueous solution with a concentration of 2 wt.%-3 wt.% and stirring for 10 min-15 min, and then ultrasonically dispersing for 5 min-10 min.

5. The preparation method according to claim 2, characterized in that, In step (1), the process conditions for broadband laser cladding are: laser power of 1800-2400 W, laser scanning speed of 210-400 mm / min, spot size of 18-20 mm in length and 2-4 mm in width, and argon flow rate of protective gas of 15-20 L / min.

6. The preparation method according to claim 2, characterized in that, In step (2), the slurry containing HA and Ag is obtained by mixing Ag powder with an average particle size of 1 μm and a purity greater than 99.5% and HA powder with an average particle size of 20 nm and a purity greater than 99.5% without ball milling, then adding it to a polyvinyl alcohol aqueous solution with a concentration of 2 wt.%-3 wt.% and stirring for 10 min-15 min, and then ultrasonically dispersing for 5 min-10 min. The process conditions for broadband laser cladding are as follows: laser power of 1400-1650 W, laser scanning speed of 210-300 mm / min, spot size of 18-20 mm in length and 2-4 mm in width, and argon flow rate of protective gas of 15-20 L / min.

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