A piezoelectric coating on a medical metal surface and a preparation method thereof

Abstract

This invention discloses a piezoelectric coating for a medical metal surface and its preparation method, belonging to the technical field of medical biomaterial implants. The piezoelectric coating preparation method comprises: performing laser ablation on the metal surface to obtain an oxidized nanocoating; then hydrothermally reacting an alkaline solution with the oxidized nanocoating under high temperature and high pressure conditions to obtain the piezoelectric coating. The metal is tantalum, titanium, or niobium, and the high temperature and high pressure conditions are 100-300°C and 1-30 MPa. This method aims to address the problems of poor bone-to-bone bonding, low mechanical strength, and poor biocompatibility of existing implant piezoelectric coatings.

Description

Technical Field

[0001] The present invention belongs to the technical field of medical biomaterial implants, and in particular relates to a medical metal surface piezoelectric coating and a preparation method thereof. Background Art

[0002] The information disclosed in this background technology section is only intended to enhance understanding of the overall background of the invention and should not necessarily be regarded as an admission or any form of suggestion that the information constitutes the prior art already known to those skilled in the art.

[0003] In the medical field, implant-related infection remains a challenging clinical problem. Traditional treatments rely on the use of antibiotics or physical surgery to remove the implant and infected tissue. How to effectively improve the osteogenic properties and antibacterial ability of implants has become a research hotspot. Although traditional orthopedic implants such as titanium alloys, ceramics and polymer materials have good mechanical properties and biocompatibility, they have the risk of bacterial infection during the bone integration process, which not only affects the function of the implant, but may also lead to serious complications such as osteomyelitis and implant failure.

[0004] In clinical practice, some exogenous physical inducers have been greatly developed and applied. Piezodynamic therapy (SDT) has attracted widespread attention in antibacterial treatment due to its unique therapeutic advantages such as non-invasiveness, flexibility, repeatability, and controllability. The mechanism of SDT is that the sonosensitizer absorbs ultrasound (US) energy, triggering the separation of electron-hole pairs, leading to redox reactions and the generation of reactive oxygen species. Reactive oxygen species exert a powerful antibacterial effect by causing bacterial lipid peroxidation, biofilm destruction, and ultimately bacterial death.

[0005] Piezoelectric materials have the property of generating an electric charge when subjected to mechanical stress, which can stimulate the growth and differentiation of bone cells. The osteogenesis mechanism of piezoelectric coatings relies mainly on the electric field formed by the coating around bone cells. This electric field can mimic the electrical signals in natural bone tissue, activating the biological programs of osteoblasts (such as osteoblasts and mesenchymal stem cells), thereby promoting the formation of new bone.

[0006] Currently, the most effective piezoelectric catalytic materials are inorganic metal oxides or sulfides, including BaTiO3, SrTiO3, LiTaO3, KNbO3, and MoS2. Studies have shown that ultrasound-triggered piezoelectric materials can effectively treat bacterial-induced osteomyelitis. Therefore, piezoelectric materials hold great promise for the treatment of peri-implantitis and implant-induced osteomyelitis.

[0007] However, although piezoelectric coating technology has shown great potential in research, it still faces many challenges in practical applications. For example, most bio-related applications of piezoelectric materials are usually in the form of nanoparticles, which may involve invasiveness, and nanoparticles are easily cleared and excreted by the body, and their limited scope of use hinders their practical application in dentistry. How to ensure the stability and durability of the coating on the surface of the implant, and how to optimize the piezoelectric properties of the coating to meet the needs of different types of bone damage are problems that need to be solved. At the same time, the existing technical means of preparing piezoelectric coatings on the surface of implants not only have problems such as weak adhesion and poor uniformity, but also use mechanical cutting, which can easily cause deformation or damage to the material, affecting the accuracy of the implant. Summary of the Invention

[0008] In order to address the deficiencies of the prior art, the present invention aims to provide a piezoelectric coating for a medical metal surface and a preparation method thereof, so as to solve the problems of poor bonding between the existing implant bone and the piezoelectric coating and low mechanical strength.

[0009] In order to achieve the above objectives, the first aspect of the present invention discloses a method for preparing a piezoelectric coating on a medical metal surface, comprising:

[0010] Laser ablation of metal surfaces to obtain oxidized nano-coatings;

[0011] The alkaline solution and the oxidized nano-coating are subjected to a hydrothermal reaction under high temperature and high pressure conditions to obtain a piezoelectric coating;

[0012] Wherein, the metal is tantalum, titanium or niobium; and the high temperature and high pressure conditions are 100-300°C and 1-5MPa.

[0013] In some embodiments, the metal is pretreated before laser ablation; preferably, the metal is polished with sandpaper, then cleaned with an organic solvent and pure water in sequence, and finally dried at 20-40°C; further preferably, the medical metal is polished with 400 mesh, 600 mesh, 1000 mesh and 1200 mesh sandpaper in sequence, then ultrasonically cleaned with acetone, anhydrous ethanol and pure water for 30 minutes, and dried at 25-35°C for 12-24 hours.

[0014] In some embodiments, laser ablation is performed in air.

[0015] In some embodiments, the laser ablation is laser surface direct writing ablation; preferably, it is performed using a pulsed laser; further preferably, the wavelength of the pulsed laser is 532-1064 nm, the pulse width is 0.5-15 ns, and the power density is 0.5-15.0 J / cm 2 , frequency is 50-500Hz.

[0016] In some embodiments, the metal after laser ablation is cleaned and dried before undergoing a hydrothermal reaction; preferably, the metal after laser ablation is cleaned and dried, and the preferred method is: rinse with pure water and anhydrous ethanol respectively and ultrasonicate for 10-30 minutes, and finally dry at 30-50°C for 12-24 hours.

[0017] In some embodiments, the alkaline solution is one or both of strontium hydroxide and strontium carbonate; preferably, it is a mixed solution of strontium hydroxide and strontium carbonate. Further preferably, the concentration of strontium hydroxide in the alkaline solution is 0.01-1 mol / L; the concentration of strontium carbonate is 0.01-1 mol / L.

[0018] In some embodiments, the alkaline solution is one or both of barium hydroxide and barium carbonate; preferably, it is a mixed solution of barium hydroxide and barium carbonate. Further preferably, the concentration of barium hydroxide in the alkaline solution is 0.01-1 mol / L; the concentration of barium carbonate is 0.01-1 mol / L.

[0019] In some embodiments, the alkaline solution is one or both of lithium hydroxide and lithium carbonate; preferably, it is a mixed solution of lithium hydroxide and lithium carbonate. Further preferably, the concentration of lithium hydroxide in the alkaline solution is 0.01-1 mol / L; the concentration of lithium carbonate is 0.01-1 mol / L.

[0020] In some embodiments, after the hydrothermal reaction, the metal is cleaned and dried; a preferred method is to rinse with pure water and anhydrous ethanol respectively and ultrasonicate for 10-20 minutes, and finally dry at 30-50° C. for 12-24 hours.

[0021] The second aspect of the present invention discloses a medical metal surface piezoelectric coating, which is obtained by the above-mentioned preparation method.

[0022] In some embodiments, the particle size of the piezoelectric coating on the metal surface is 10-100 nm.

[0023] The beneficial effects of the present invention are:

[0024] 1. The present invention utilizes a hydrothermal synthesis method to in-situ grow a layer of piezoelectric particles on the metal surface after laser ablation, thereby obtaining a uniform and highly adherent piezoelectric nanocoating on the metal surface. By laser ablation of the metal, laser ablation is used instead of mechanical cutting, which not only prevents deformation or damage of the material and improves the precision of the metal implant, but also enables rapid acquisition of complex and precise surface geometries. The metal surface after laser ablation is uniform and has strong mechanical strength. A metal oxide nanocoating is formed on the metal surface after laser ablation, so that a subsequent hydrothermal reaction can be performed. The hydrothermal reaction is performed using an alkaline solution, which has low reaction energy consumption, mild conditions, and high purity of the synthesized material. The present invention can control the crystal morphology and particle size of the final piezoelectric coating by adjusting temperature, time, solution pH, etc., and is suitable for the preparation of various forms of nanostructures (such as nanowires, nanorods, and nanosheets).

[0025] 2. The use of laser surface direct writing technology can achieve nanometer-level processing accuracy, which is very suitable for micro-nano processing that requires fine structures. This process can generate complex and precise surface geometries with high resolution in a clean and fast manner, which is superior to other surface modification technologies. At the same time, compared with machined surface implants, laser surface direct writing technology implants induce significantly more bone-implant contact. Laser processing is non-contact and does not apply mechanical pressure to the material, avoiding material deformation or damage that may be caused by traditional mechanical processing. In addition, laser processing is fast and is particularly suitable for large-area and highly repeatable micro-nano structure processing, which improves production efficiency. Moreover, the metal surface after laser ablation is uniform and has strong mechanical strength, laying the foundation for the preparation of uniform and firm piezoelectric coatings.

[0026] 3. Hydrothermal synthesis is used to prepare piezoelectric coatings. Water allows the reactants to fully dissolve and mix, reducing the introduction of impurities, resulting in a high-purity synthesized material. Furthermore, by adjusting the reaction conditions, the crystal morphology and particle size of the final product can be controlled, making the hydrothermal reaction suitable for the preparation of various nanostructures. Therefore, we utilize hydrothermal synthesis to in-situ grow a layer of piezoelectric particles on a laser-ablated metal surface, resulting in a uniform and highly adherent piezoelectric nanocoating on the metal surface. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] The accompanying drawings, which constitute a part of the present invention, are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute improper limitations on the present invention.

[0028] Figure 1 This is a SEM image of the titanium plate after laser ablation in Example 1 of the present invention.

[0029] Figure 2 This is an SEM image of the tantalum plate after laser ablation in Example 4 of the present invention.

[0030] Figure 3 This is a SEM image of the strontium titanate coating obtained after hydrothermal synthesis of the titanium plate in Example 1 of the present invention.

[0031] Figure 4 This is a SEM image of the strontium titanate coating obtained after hydrothermal synthesis of the titanium plate in Example 2 of the present invention.

[0032] Figure 5 This is a SEM image of the strontium titanate coating obtained after hydrothermal synthesis of the titanium plate in Example 3 of the present invention.

[0033] Figure 6 This is an SEM image of the barium titanate coating obtained after hydrothermal synthesis of the titanium plate in Example 4 of the present invention.

[0034] Figure 7 This is an SEM image of the barium titanate coating obtained after hydrothermal synthesis of the titanium plate in Example 5 of the present invention.

[0035] Figure 8 This is an SEM image of the barium titanate coating obtained after hydrothermal synthesis of the titanium plate in Example 6 of the present invention.

[0036] Figure 9 This is an SEM image of the lithium tantalate coating obtained after hydrothermal synthesis of the tantalum plate in Example 7 of the present invention.

[0037] Figure 10 This is an SEM image of the lithium tantalate coating obtained after hydrothermal synthesis of the tantalum plate in Example 8 of the present invention.

[0038] Figure 11 This is an SEM image of the lithium tantalate coating obtained after hydrothermal synthesis of the tantalum plate in Example 9 of the present invention.

[0039] Figure 12 This is the XRD image of the strontium titanate coating obtained after hydrothermal synthesis of the titanium plate in Example 1 of the present invention.

[0040] Figure 13 This is the XRD image of the strontium titanate coating obtained after hydrothermal synthesis of the titanium plate in Example 2 of the present invention.

[0041] Figure 14 This is the XRD image of the strontium titanate coating obtained after hydrothermal synthesis of the titanium plate in Example 3 of the present invention.

[0042] Figure 15 This is the XRD image of the barium titanate coating obtained after hydrothermal synthesis of the titanium plate in Example 4 of the present invention.

[0043] Figure 16This is the XRD image of the barium titanate coating obtained after hydrothermal synthesis of the titanium plate in Example 5 of the present invention.

[0044] Figure 17 This is the XRD image of the barium titanate coating obtained after hydrothermal synthesis of the titanium plate in Example 6 of the present invention.

[0045] Figure 18 This is the XRD image of the lithium tantalate coating obtained after hydrothermal synthesis of the tantalum plate in Example 7 of the present invention.

[0046] Figure 19 This is the XRD image of the lithium tantalate coating obtained after hydrothermal synthesis of the tantalum plate in Example 8 of the present invention.

[0047] Figure 20 This is the XRD image of the lithium tantalate coating obtained after hydrothermal synthesis of the tantalum plate in Example 9 of the present invention.

[0048] Figure 21 This is the phase amplitude diagram and surface roughness image of the piezoelectric coating obtained in Example 8 of the present invention.

[0049] Figure 22 3 is an image of the piezoelectric response phase and amplitude curves of the piezoelectric coating obtained in Example 8 of the present invention.

[0050] Figure 23 This is a nano scratch test image of the tantalum substrate of the present invention.

[0051] Figure 24 This is a nano scratch test image of the tantalum oxide nanocoating according to Example 8 of the present invention.

[0052] Figure 25 This is a nano scratch test image of the lithium tantalate coating of Example 8 of the present invention.

[0053] Figure 26 This is a bar graph showing the activity of cells cultured with different treatments according to the present invention.

[0054] Figure 27 The SEM image of cells adhering to the tantalum substrate of the present invention.

[0055] Figure 28 This is an SEM image of cell adhesion on the lithium tantalate coating of Example 8 of the present invention.

[0056] Figure 29 This is an SEM image of cell adhesion of the lithium tantalate coating under ultrasonic stimulation of the lithium tantalate coating of Example 8 of the present invention. DETAILED DESCRIPTION

[0057] In response to the problems of poor bonding between existing implant bones and piezoelectric coatings and low mechanical strength, the present invention proposes a medical metal surface piezoelectric coating and its preparation method. This technology can improve the biocompatibility and mechanical properties of the implant, and utilize the piezoelectric properties of the metal surface piezoelectric coating to promote bone integration between the implant and surrounding tissues, and achieve antibacterial effects by generating active oxygen through the piezoelectric effect.

[0058] In order to enable those skilled in the art to more clearly understand the technical solution of the present invention, the technical solution of the present invention will be described in detail below with reference to specific embodiments. It should be noted that the materials used in the present invention are all commonly available on the market.

[0059] Example 1

[0060] This embodiment provides a method for preparing a piezoelectric coating on a medical metal surface, and the specific steps are as follows:

[0061] (1) The titanium plate was polished with 400-mesh, 600-mesh, 1000-mesh, and 1200-mesh sandpaper in sequence, and then ultrasonically cleaned with acetone, anhydrous ethanol, and pure water for 30 min, respectively. Finally, the plate was dried at 30°C for 24 h.

[0062] (2) Laser ablation of the pre-treated titanium plate was performed using a nanosecond pulse laser with a wavelength of 532 nm, a pulse width of 10 ns, and a power density of 0.9 J / cm 2 , frequency is 400Hz, processing area is 6cm 2 , processing time is 100min;

[0063] (3) The titanium plate after laser ablation was rinsed with pure water and anhydrous ethanol in turn and ultrasonicated for 20 minutes, and finally dried at 30°C for 24 hours.

[0064] (4) A 0.1 mol / L strontium hydroxide solution and a strontium carbonate solution were mixed in a ratio of 1:1 to obtain a mixed solution, and the mixed solution was reacted with the titanium plate after laser ablation at 200°C and 1 MPa for 24 hours.

[0065] (5) The titanium plate after hydrothermal synthesis is rinsed with pure water and anhydrous ethanol in turn and ultrasonicated for 20 minutes, and finally dried at 30°C for 24 hours to obtain a piezoelectric coating on the surface of the titanium plate.

[0066] Example 2

[0067] This embodiment provides a method for preparing a piezoelectric coating on a medical metal surface, and the specific steps are as follows:

[0068] (1) The titanium plate was polished with 400-mesh, 600-mesh, 1000-mesh, and 1200-mesh sandpaper in sequence, and then ultrasonically cleaned with acetone, anhydrous ethanol, and pure water for 30 min, respectively. Finally, the plate was dried at 40°C for 12 h.

[0069] (2) Laser ablation of the pre-treated titanium plate was performed using a nanosecond pulse laser with a wavelength of 1064 nm, a pulse width of 0.5 ns, and a power density of 0.5 J / cm 2 , frequency is 50Hz, processing area is 6cm 2 , processing time is 150min;

[0070] (3) The titanium plate after laser ablation was rinsed with pure water and anhydrous ethanol in turn and ultrasonicated for 10 minutes, and finally dried at 50°C for 12 hours.

[0071] (4) A 1 mol / L strontium hydroxide solution was reacted with the laser-ablated titanium plate at 100°C and 5 MPa for 24 hours.

[0072] (5) The titanium plate after hydrothermal synthesis is rinsed with pure water and anhydrous ethanol in turn and ultrasonicated for 20 minutes, and finally dried at 30°C for 24 hours to obtain a piezoelectric coating on the surface of the titanium plate.

[0073] Example 3

[0074] This embodiment provides a method for preparing a piezoelectric coating on a medical metal surface, and the specific steps are as follows:

[0075] (1) The titanium plate was polished with 400-mesh, 600-mesh, 1000-mesh, and 1200-mesh sandpaper in sequence, and then ultrasonically cleaned with acetone, anhydrous ethanol, and pure water for 20 min, respectively. Finally, the plate was dried at 20°C for 24 h.

[0076] (2) Laser ablation of the pre-treated titanium plate was performed using a nanosecond pulse laser with a wavelength of 532 nm, a pulse width of 15 ns, and a power density of 15 J / cm 2 , frequency is 500Hz, processing area is 6cm 2 , processing time is 60min;

[0077] (3) The titanium plate after laser ablation was rinsed with pure water and anhydrous ethanol in turn and ultrasonicated for 20 minutes, and finally dried at 30°C for 24 hours.

[0078] (4) A 0.01 mol / L strontium carbonate solution was reacted with the laser-ablated titanium plate at 300°C and 2 MPa for 24 hours.

[0079] (5) The titanium plate after hydrothermal synthesis is rinsed with pure water and anhydrous ethanol in turn and ultrasonicated for 20 minutes, and finally dried at 30°C for 24 hours to obtain a piezoelectric coating on the surface of the titanium plate.

[0080] Example 4

[0081] This embodiment provides a method for preparing a piezoelectric coating on a medical metal surface, and the specific steps are as follows:

[0082] (1) The titanium plate was polished with 400-mesh, 600-mesh, 1000-mesh and 1200-mesh sandpaper in sequence, and then ultrasonically cleaned with acetone, anhydrous ethanol and pure water for 30 min respectively, and finally dried at 30 °C for 24 h;

[0083] (2) Laser ablation of the pre-treated titanium plate was performed using a nanosecond pulse laser with a wavelength of 532 nm, a pulse width of 10 ns, and a power density of 0.9 J / cm 2 , frequency is 400Hz, processing area is 6cm 2 , processing time is 100min;

[0084] (3) The titanium plate after laser ablation was rinsed with pure water and anhydrous ethanol in turn and ultrasonicated for 20 minutes, and finally dried at 30°C for 24 hours.

[0085] (4) A 0.1 mol / L barium hydroxide solution and a barium carbonate solution were mixed in a ratio of 1:1 to obtain a mixed solution, and the mixed solution was reacted with the laser ablated titanium plate at 200°C and 3 MPa for 24 hours.

[0086] (5) The titanium plate after hydrothermal synthesis is rinsed with pure water and anhydrous ethanol in turn and ultrasonicated for 20 minutes, and finally dried at 30°C for 24 hours to obtain a piezoelectric coating on the surface of the titanium plate.

[0087] Example 5

[0088] This embodiment provides a method for preparing a piezoelectric coating on a medical metal surface, and the specific steps are as follows:

[0089] (1) The titanium plate was polished with 400-mesh, 600-mesh, 1000-mesh, and 1200-mesh sandpaper in sequence, and then ultrasonically cleaned with acetone, anhydrous ethanol, and pure water for 30 min, respectively. Finally, the plate was dried at 40°C for 12 h.

[0090] (2) Laser ablation of the pre-treated titanium plate was performed using a nanosecond pulse laser with a wavelength of 1064 nm, a pulse width of 0.5 ns, and a power density of 0.5 J / cm 2 , frequency is 50Hz, processing area is 6cm 2, processing time is 150min;

[0091] (3) The titanium plate after laser ablation was rinsed with pure water and anhydrous ethanol in turn and ultrasonicated for 10 minutes, and finally dried at 50°C for 12 hours.

[0092] (4) A 1 mol / L barium hydroxide solution was reacted with the laser-ablated titanium plate at 100°C and 5 MPa for 24 h.

[0093] (5) The titanium plate after hydrothermal synthesis is rinsed with pure water and anhydrous ethanol in turn and ultrasonicated for 20 minutes, and finally dried at 30°C for 24 hours to obtain a piezoelectric coating on the surface of the titanium plate.

[0094] Example 6

[0095] This embodiment provides a method for preparing a piezoelectric coating on a medical metal surface, and the specific steps are as follows:

[0096] (1) The titanium plate was polished with 400-mesh, 600-mesh, 1000-mesh, and 1200-mesh sandpaper in sequence, and then ultrasonically cleaned with acetone, anhydrous ethanol, and pure water for 20 min, respectively. Finally, the plate was dried at 20°C for 24 h.

[0097] (2) Laser ablation of the pre-treated titanium plate was performed using a nanosecond pulse laser with a wavelength of 532 nm, a pulse width of 15 ns, and a power density of 15 J / cm 2 , frequency is 500Hz, processing area is 6cm 2 , processing time is 60min;

[0098] (3) The titanium plate after laser ablation was rinsed with pure water and anhydrous ethanol in turn and ultrasonicated for 20 minutes, and finally dried at 30°C for 24 hours.

[0099] (4) A 0.01 mol / L barium carbonate solution was reacted with the laser-ablated titanium plate at 300°C and 1 MPa for 24 hours.

[0100] (5) The titanium plate after hydrothermal synthesis is rinsed with pure water and anhydrous ethanol in turn and ultrasonicated for 20 minutes, and finally dried at 30°C for 24 hours to obtain a piezoelectric coating on the surface of the titanium plate.

[0101] Example 7

[0102] This embodiment provides a method for preparing a piezoelectric coating on a medical metal surface, and the specific steps are as follows:

[0103] (1) The tantalum plate was polished with 400-mesh, 600-mesh, 1000-mesh and 1200-mesh sandpaper in sequence, and then ultrasonically cleaned with acetone, anhydrous ethanol and pure water for 30 minutes respectively, and finally dried at 30°C for 24 hours;

[0104] (2) Laser ablation of the pre-treated tantalum plate was performed using a nanosecond pulse laser with a wavelength of 532 nm, a pulse width of 10 ns, and a power density of 0.9 J / cm 2 , frequency is 400Hz, processing area is 6cm 2 , processing time is 100min;

[0105] (3) The tantalum plate after laser ablation was rinsed with pure water and anhydrous ethanol in turn and ultrasonicated for 20 minutes, and finally dried at 30°C for 24 hours.

[0106] (4) A lithium hydroxide solution with a concentration of 0.1 mol / L and a lithium carbonate solution were mixed in a ratio of 1:1 to obtain a mixed solution, and the mixed solution was reacted with the laser ablated tantalum plate at 200° C. and 4 MPa for 24 hours.

[0107] (5) The tantalum plate after hydrothermal synthesis is rinsed with pure water and anhydrous ethanol in turn and ultrasonicated for 20 minutes, and finally dried at 30°C for 24 hours to obtain a piezoelectric coating on the surface of the tantalum plate.

[0108] Example 8

[0109] This embodiment provides a method for preparing a piezoelectric coating on a medical metal surface, and the specific steps are as follows:

[0110] (1) The tantalum plate was polished with 400-mesh, 600-mesh, 1000-mesh, and 1200-mesh sandpaper in sequence, and then ultrasonically cleaned with acetone, anhydrous ethanol, and pure water for 30 minutes, respectively. Finally, the plate was dried at 40°C for 12 hours.

[0111] (2) The pre-treated tantalum plate was laser ablated using a nanosecond pulse laser with a wavelength of 1064 nm, a pulse width of 0.5 ns, and a power density of 0.5 J / cm 2 , frequency is 50Hz, processing area is 6cm 2 , processing time is 150min;

[0112] (3) The tantalum plate after laser ablation was rinsed with pure water and anhydrous ethanol in turn and ultrasonicated for 10 minutes, and finally dried at 50°C for 12 hours.

[0113] (4) A lithium hydroxide solution with a concentration of 1 mol / L was reacted with the laser-ablated tantalum plate at 100°C and 5 MPa for 24 hours.

[0114] (5) The tantalum plate after hydrothermal synthesis is rinsed with pure water and anhydrous ethanol in turn and ultrasonicated for 20 minutes, and finally dried at 30°C for 24 hours to obtain a piezoelectric coating on the surface of the tantalum plate.

[0115] Example 9

[0116] This embodiment provides a method for preparing a piezoelectric coating on a medical metal surface, and the specific steps are as follows:

[0117] (1) The tantalum plate was polished with 400-mesh, 600-mesh, 1000-mesh, and 1200-mesh sandpaper in sequence, and then ultrasonically cleaned with acetone, anhydrous ethanol, and pure water for 20 minutes, respectively. Finally, the plate was dried at 20°C for 24 hours.

[0118] (2) Laser ablation of the pre-treated tantalum plate was performed using a nanosecond pulse laser with a wavelength of 532 nm, a pulse width of 15 ns, and a power density of 15 J / cm 2 , frequency is 500Hz, processing area is 6cm 2 , processing time is 60min;

[0119] (3) The tantalum plate after laser ablation was rinsed with pure water and anhydrous ethanol in turn and ultrasonicated for 20 minutes, and finally dried at 30°C for 24 hours.

[0120] (4) A lithium carbonate solution with a concentration of 0.01 mol / L was reacted with the laser-ablated tantalum plate at 300°C and 1 MPa for 24 hours.

[0121] (5) The tantalum plate after hydrothermal synthesis is rinsed with pure water and anhydrous ethanol in turn and ultrasonicated for 20 minutes, and finally dried at 30°C for 24 hours to obtain a piezoelectric coating on the surface of the tantalum plate.

[0122] Characterization and performance testing of piezoelectric coatings

[0123] The performance and characterization results of the piezoelectric coatings obtained in the above examples were tested, and the CCK-8 test and cell adhesion test were performed on the piezoelectric coatings obtained in the examples.

[0124] The surface morphology of the coating was observed using a scanning electron microscope (SEM, Regulus8100), the physical phase of the surface piezoelectric coating was detected using an X-ray diffractometer (XRD, Smartlab SE), the piezoelectric properties of the coating were determined using a piezoresistive force microscope (PFM, DimensionIcon, Bruker), and the bonding degree and hardness of the surface oxide nanolayer and the piezoelectric coating were determined using a nanoscratch tester (Hysitron TI 950).

[0125] The cytotoxicity of the surface nanocoating was determined using the CCK-8 method. The specific steps are as follows:

[0126] Rat bone marrow mesenchymal stem cells (BMSCs) were processed into a cell suspension. The cell suspension and the sample were added to the cell culture medium and cultured at 37°C and 5% CO2 for 1 day, 3 days, and 5 days. The co-cultured samples were taken out at the corresponding time points. The experiment was divided into three treatments: the control group: the sample was set as a tantalum substrate and no ultrasound was performed during the culture period; the treatment group 1: the sample was set as the piezoelectric coating obtained in Example 8 and no ultrasound was performed during the culture period; the treatment group 2: the sample was set as the piezoelectric coating obtained in Example 8 and ultrasound was performed during the culture period. The ultrasound treatment was performed at 3W / cm 2 Ultrasound at low intensity for 5 minutes, and ultrasonicate once every two days. Take the cell proliferation fluid and prepare CCK-8 solution according to the ratio of low sugar culture medium: cell proliferation fluid = 9:1. Then move the tantalum substrate and the piezoelectric coating sample material obtained in Example 8 to the blank wells of the 96-well plate, and add 400 microliters of CCK-8 solution to each well. Incubate at 37°C in the dark for 2 hours. After reaching the time point, aspirate 100 microliters of reaction solution and add it to the 96-well plate. Aspirate each well three times as three replicates, and then use a microplate reader to detect the optical density value (OD) at 450nm.

[0127] The adhesion of cells on the sample surface was observed using a scanning electron microscope (SEM, Regulus 8100). The cells and materials were cultured at 37°C and 5% CO2 for 3 days, during which the ultrasound group was irradiated at 3W / cm 2 Ultrasound was performed at 500 nm for 5 minutes at the lowest intensity, and once every two days. The samples were washed three times with PBS and fixed with 4% paraformaldehyde. After being placed at 4°C for 12 hours overnight, the samples were washed again with PBS three times and subjected to gradient dehydration (using 30%, 50%, 70%, 90%, 95% and 100% anhydrous ethanol, respectively, with each gradient reaction lasting 10 minutes). Finally, the samples were dried in a vacuum drying oven at 40°C for half an hour.

[0128] in, Figure 1 and Figure 2 The SEM images of the titanium plate in Example 1 and the tantalum plate in Example 7 after laser ablation are respectively described. As can be seen from the images, the particle size of the nanoparticles on the metal surface is in the range of 10-50nm, and the particles are evenly distributed.

[0129] Figure 3 、 Figure 4 and Figure 5 The SEM images of the strontium titanate coatings obtained after hydrothermal synthesis of titanium plates in Examples 1 to 3 are respectively described. As can be seen from the images, the particle size of the strontium titanate piezoelectric coatings is in the range of 30-100 nm, and the particles are evenly distributed.

[0130] Figure 6 、 Figure 7 and Figure 8 The SEM images of the barium titanate coatings obtained after hydrothermal synthesis of titanium plates in Examples 4 to 6 are respectively shown. As can be seen from the images, the particle size of the barium titanate piezoelectric coatings is in the range of 10-100 nm, and the particles are evenly distributed.

[0131] Figure 9 、 Figure 10 and Figure 11 3 and 4 respectively depict SEM images of the lithium tantalate coating obtained after hydrothermal synthesis of the tantalum plates in Examples 7 to 9. As can be seen from the figures, the particle size of the lithium tantalate piezoelectric coating is in the range of 20-100 nm, and the particles are evenly distributed.

[0132] Figure 12 、 Figure 13 and Figure 14 The XRD patterns of the strontium titanate coatings obtained after hydrothermal synthesis of titanium plates in Examples 1-3 are shown. As can be seen from the figures, the compositions of the strontium titanate piezoelectric coatings obtained in Examples 1, 2, and 3 respectively conform to the physical phase of strontium titanate and are consistent with the target composition. Furthermore, the prepared strontium titanate piezoelectric coatings exhibit good crystallinity.

[0133] Figure 15 、 Figure 16 and Figure 17 The XRD patterns of the barium titanate coatings obtained after hydrothermal synthesis of titanium plates in Examples 4-6 are shown. As can be seen from the figures, the composition of the barium titanate piezoelectric coatings obtained in Examples 4, 5, and 6 is consistent with the physical phase of barium titanate, and the prepared barium titanate piezoelectric coatings have good crystallinity.

[0134] Figure 18 、 Figure 19 and Figure 20 The XRD patterns of the lithium tantalate coatings obtained from the hydrothermal synthesis of tantalum sheets in Examples 7-9 are depicted. As can be seen from the figures, the compositions of the lithium tantalate piezoelectric coatings obtained in Examples 7, 8, and 9 are consistent with the physical phase of lithium tantalate, and the prepared lithium tantalate piezoelectric coatings exhibit good crystallinity.

[0135] Figure 21 The phase amplitude diagram and surface roughness image of the piezoelectric coating obtained in Example 8 are described. As can be seen from the figure, the lithium tantalate piezoelectric coating obtained in Example 8 has piezoelectric properties and further confirms that the surface particle size is 20-60nm.

[0136] Figure 22 The graph depicts the piezoelectric response phase and amplitude curves of the piezoelectric coating obtained in Example 8. The graph further confirms that the lithium tantalate piezoelectric coating obtained in Example 8 has piezoelectric properties.

[0137] Figure 23 、 Figure 24 、 Figure 25 The nano scratch test images of tantalum, tantalum oxide nanocoating and lithium tantalate coating obtained from Example 8 are described respectively. As can be seen from the figure, the critical load of tantalum surface is about 4571.4μN (as shown in Figure 1). Figure 1 After laser ablation, the critical load of the generated oxide nanocoating was increased to 9204.9 μN (e.g. Figure 22 ), significantly improving the mechanical strength of the material surface and indicating that the oxidized nano-coating has a high degree of bonding. The critical load of the lithium tantalate coating generated in situ on the material surface by hydrothermal reaction is about 7664.0μN (such as Figure 23 ), although the bonding degree is reduced compared with the oxide nano coating, the coating still has high bonding degree and mechanical strength compared with the tantalum surface.

[0138] Figure 26 A bar graph depicts cell activity in CCK-8 experiments using different materials. As shown, both the ultrasonically treated and untreated lithium tantalate coating groups exhibited good cell activity on days 1, 3, and 5, similar to that of the tantalum substrate-treated group. Cell activity in the ultrasonically treated lithium tantalate coating group increased significantly on day 5, demonstrating the piezoelectric coating's lack of cytotoxicity and good cytocompatibility. Furthermore, the piezoelectric coating's ultrasonic stimulation was more conducive to cell growth.

[0139] Figure 27 、 28 Figures 29 and 29 respectively depict SEM images of tantalum, the lithium tantalate coating obtained in Example 8, and cell adhesion to the lithium tantalate coating under ultrasound stimulation. As can be seen from the figures, cells on the lithium tantalate coating have better spreading and more pseudopodia than those on the tantalum coating, and the cells spread even more under ultrasound stimulation.

[0140] As can be seen from the foregoing, the embodiments of the present invention achieve high precision and no deformation or damage to the metal material after laser ablation. The piezoelectric coating on the metal surface after laser ablation exhibits uniformity and strong mechanical strength, and the piezoelectric coating adheres evenly to the metal surface with strong adhesion. Furthermore, the piezoelectric coating exhibits good biocompatibility, and the surface nanostructure facilitates cell attachment. Ultrasonic stimulation also enhances biocompatibility and surface spreading.

[0141] The foregoing description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Those skilled in the art will readily appreciate that various modifications and variations of the present invention are possible. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present invention are intended to be within the scope of protection of the present invention.

Claims

1. A method for preparing a piezoelectric coating on a medical metal surface, characterized in that: include: Laser ablation of metal surfaces to obtain oxidized nano-coatings; After laser ablation, the particle size of the nanoparticles on the metal surface is 10-50 nm; The alkaline solution and the oxidized nano-coating are subjected to a hydrothermal reaction under high temperature and high pressure conditions to obtain a piezoelectric coating; the particle size of the piezoelectric coating is 10-100 nm; Wherein, the metal is tantalum, titanium or niobium; the high temperature and high pressure conditions are 100-300°C and 1-5 MPa; The laser ablation is performed using a pulsed laser; The pulse laser has a wavelength of 532-1064 nm, a pulse width of 0.5-15 ns, and a power density of 0.5-15.0 J / cm 2 , frequency is 50-500 Hz; The alkaline solution is one or both of strontium hydroxide and strontium carbonate; Alternatively, the alkaline solution is one or both of barium hydroxide and barium carbonate; Alternatively, the alkaline solution is one or both of lithium hydroxide and lithium carbonate.

2. The method for preparing a piezoelectric coating on a medical metal surface according to claim 1, wherein: Pre-treat the metal before laser ablation.

3. The method for preparing a piezoelectric coating on a medical metal surface according to claim 2, wherein: The metal is polished with sandpaper, then cleaned with organic solvent and pure water in sequence, and finally dried at 20-40°C.

4. The method for preparing a piezoelectric coating on a medical metal surface according to claim 3, wherein: The medical metal was polished with 400-mesh, 600-mesh, 1000-mesh and 1200-mesh sandpaper in sequence, and then ultrasonically cleaned with acetone, anhydrous ethanol and pure water for 30 minutes in sequence, and dried at 25-35°C for 12-24 hours.

5. The method for preparing a piezoelectric coating on a medical metal surface according to claim 1, wherein: Laser ablation is performed in air.

6. The method for preparing a piezoelectric coating on a medical metal surface according to claim 1, wherein: The laser-ablated metal is cleaned and dried before undergoing a hydrothermal reaction.

7. The method for preparing a piezoelectric coating on a medical metal surface according to claim 1, wherein: The method for cleaning and drying the metal after laser ablation is: rinse with pure water and anhydrous ethanol respectively and ultrasonicate for 10-30 minutes, and finally dry at 30-50°C for 12-24 hours.

8. The method for preparing a piezoelectric coating on a medical metal surface according to claim 1, wherein: The alkaline solution is a mixed solution of strontium hydroxide and strontium carbonate.

9. The method for preparing a piezoelectric coating on a medical metal surface according to claim 1, wherein: The concentration of strontium hydroxide in the alkaline solution is 0.01-1 mol / L; the concentration of strontium carbonate is 0.01-1 mol / L.

10. The method for preparing a piezoelectric coating on a medical metal surface according to claim 1, wherein: The alkaline solution is a mixed solution of barium hydroxide and barium carbonate.

11. The method for preparing a piezoelectric coating on a medical metal surface according to claim 1, wherein: The concentration of barium hydroxide in the alkaline solution is 0.01-1 mol / L; the concentration of barium carbonate is 0.01-1 mol / L.

12. The method for preparing a piezoelectric coating on a medical metal surface according to claim 1, wherein: The alkaline solution is a mixed solution of lithium hydroxide and lithium carbonate.

13. The method for preparing a piezoelectric coating on a medical metal surface according to claim 1, wherein: The concentration of lithium hydroxide in the alkaline solution is 0.01-1 mol / L; the concentration of lithium carbonate is 0.01-1 mol / L.

14. The method for preparing a piezoelectric coating on a medical metal surface according to claim 1, wherein: After the hydrothermal reaction, the metal is cleaned and dried.

15. The method for preparing a piezoelectric coating on a medical metal surface according to claim 14, wherein: The method for cleaning and drying the metal is to rinse with pure water and anhydrous ethanol respectively and ultrasonicate for 10-20 minutes, and finally dry at 30-50 °C for 12-24 hours.

16. A piezoelectric coating on a medical metal surface, characterized in that: The method is as described in any one of claims 1 to 15.

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