A piezoelectric composite coating functionalized titanium-based implant material and its preparation and application

Abstract

This invention discloses a titanium-based implant material functionalized with a piezoelectric composite coating, as well as its preparation and application. This invention constructs piezoelectric barium titanate nanopillars on the surface of an inert titanium implant through hydrothermal and alkaline heat treatment, imparting piezoelectric responsiveness to the material. A hydrogel coating is then applied in situ to the surface of the piezoelectric nanopillars through physical intercalation, creating a titanium-based implant material functionalized with a piezoelectric hydrogel coating. This material achieves mechanoelectric coupling signal regulation of vascularization and osseointegration, meeting clinical requirements.

Description

Technical Field

[0001] The present invention belongs to the field of medical devices, and in particular relates to a piezoelectric composite coating functionalized titanium-based implant material and its preparation and application. Background Art

[0002] In recent years, the demand for orthopedic implants has increased dramatically due to the frequent occurrence of traffic accidents, an aging population, and the increasing number of patients suffering from high-energy trauma and tumors. Bone regeneration and repair are divided into four stages: the first stage: hematoma formation, fibrous callus formation, bony callus formation, and bone remodeling; the second stage: the hematoma organizes, the proliferating tissue heals, and fibrosis occurs, forming a fibrous callus. This stage primarily involves vascularization; the third stage: osteoblasts produce new bone, gradually replacing the fibrous callus, beginning the formation of osteoid tissue. Calcium salts are deposited, forming a bony callus. This stage primarily involves osseointegration. Clinical orthopedic implants such as titanium and its alloys are commonly used in load-bearing bone replacement, spinal fusion, and bone fixation devices due to their excellent mechanical properties and biocompatibility. However, the bioinertness of traditional titanium implants severely limits vascularization and osseointegration.

[0003] Bioelectricity is an essential component of the regenerative microenvironment and a fundamental mechanism for tissue response to external stimuli and regulation of cell fate. Endogenous piezoelectricity is widely believed to be closely related to the growth and remodeling of skeletal tissue, and intrinsic piezoelectric properties play a key role in bone remodeling and repair. Furthermore, the viscoelastic matrix is ​​an important biophysical cue that regulates the biological behavior of human bone marrow mesenchymal stem cells through mechanotransduction consistent with cell-matrix interactions. Mechanical signal transduction influences vascular migration during bone healing and the regeneration and repair of bone tissue through multiple mechanisms.

[0004] Therefore, there is an urgent need to develop an implant material that can promote vascularization and bone integration through electromechanical coupling signals to meet clinical use. Summary of the Invention

[0005] In order to solve the shortcomings and deficiencies of the prior art, the primary purpose of the present invention is to provide a method for preparing a piezoelectric composite coating functionalized titanium-based implant material.

[0006] In order to achieve piezoelectric properties to regulate bone integration, the present invention constructs piezoelectric barium titanate nanocolumns on the surface of inert titanium implants through hydrothermal and alkali heat treatment to give the material piezoelectric responsiveness; in order to achieve mechanoelectric coupling signals to regulate vascularization and bone integration, a hydrogel coating is in situ coated on the surface of the piezoelectric nanocolumns through physical intercalation to construct a piezoelectric composite coating functionalized titanium-based implant material.

[0007] Another object of the present invention is to provide a piezoelectric composite coating-functionalized titanium-based implant material produced by the aforementioned preparation method. Natural bone is a composite material similar to polymer ceramics, consisting of approximately 65% ​​inorganic components and 25-30% organic components. From a biomimetic bone perspective, the piezoelectric composite coating-functionalized titanium-based implant material constructed in the present invention promotes vascularization and osteogenesis through electromechanical coupling.

[0008] Another object of the present invention is to provide an application of the above-mentioned piezoelectric composite coating functionalized titanium-based implant material.

[0009] The purpose of the present invention is achieved through the following technical solutions:

[0010] A method for preparing a piezoelectric composite coating functionalized titanium-based implant material comprises the following steps:

[0011] (1) placing the titanium implant in an alkaline solution for alkaline thermal reaction, and then placing it in a barium hydroxide solution for hydrothermal reaction to obtain a barium titanate nanostructured implant;

[0012] (2) adding methacrylic anhydride dropwise to a phosphate buffer solution containing gelatin to react, centrifuging, dialysis, and freeze-drying to obtain a GelMA hydrogel;

[0013] (3) GelMA hydrogel was dissolved in a phosphate buffer solution containing a photoinitiator, and the resulting mixed solution was spin-coated onto the surface of the barium titanate nanostructured implant and photocured to obtain a piezoelectric hydrogel coating functionalized titanium-based implant material.

[0014] Preferably, the titanium implant in step (1) needs to be pretreated, and the pretreatment comprises: ultrasonic cleaning, pickling, and drying the titanium implant to obtain a pretreated titanium-based substrate.

[0015] More preferably, the ultrasonic cleaning refers to immersing the titanium implant in acetone, anhydrous ethanol, and deionized water in sequence and performing ultrasonic cleaning for 10 to 20 minutes respectively.

[0016] More preferably, the pickling is to first add nitric acid and hydrofluoric acid to deionized water in sequence to prepare an acid solution, stir it evenly, and then add it to the titanium implant for pickling.

[0017] More preferably, the drying temperature is 40-80° C. and the drying time is 0.5-2 h.

[0018] Preferably, the alkaline solution in step (1) is a sodium hydroxide solution; the concentration of the alkaline solution is 6 to 10 mol / L; more preferably 8 mol / L.

[0019] Preferably, the temperature of the alkali thermal reaction in step (1) is 90-120° C., and the time is 18-24 h; more preferably, the temperature of the alkali thermal reaction is 100° C., and the time is 24 h.

[0020] Preferably, the concentration of the barium hydroxide solution in step (1) is 0.03 to 0.08 mol / L; more preferably 0.05 mol / L.

[0021] Preferably, the temperature of the hydrothermal reaction in step (1) is 180-210° C., and the time is 6-10 h; more preferably, the temperature of the hydrothermal reaction is 210° C., and the time is 8 h.

[0022] Preferably, the mass ratio of the gelatin in step (2) to the volume ratio of the phosphate buffer is 0.05-0.2 g:1 ml; more preferably 0.1 g:1 ml; the mass ratio of the methacrylic anhydride to the gelatin is 0.3-1.0:1; more preferably 0.94:1.

[0023] Preferably, the pH of the phosphate buffer in steps (2) and (3) is 6 to 8; more preferably 7.4.

[0024] Preferably, the reaction temperature in step (2) is 50-60°C and the reaction time is 2-4 hours; more preferably, the reaction temperature is 50°C and the reaction time is 3 hours.

[0025] Preferably, in step (2), the reaction is terminated by adding phosphate buffer to the reaction system.

[0026] Preferably, the centrifugal speed in step (2) is 5000-10000 rpm, and the time is 3-5 min.

[0027] Preferably, the dialysis time in step (2) is 3 to 7 days.

[0028] Preferably, in the phosphate buffer containing the photoinitiator in step (3), the mass concentration of the photoinitiator is 0.2-0.3%, more preferably 0.25%.

[0029] Preferably, the photoinitiator in step (3) is at least one of LAP and photoinitiator 2959.

[0030] Preferably, the volume ratio of the mass of the GelMA hydrogel in step (3) to the phosphate buffer containing the photoinitiator is 0.5-2 g:10 ml; more preferably 1 g:10 ml.

[0031] Preferably, the spin coating speed in step (3) is 500 to 3000 r / min, and the time is 10 to 60 s.

[0032] Preferably, the ratio of the volume of the mixed solution in step (3) to the area of ​​the barium titanate nanostructure implant is 30-130 μL: 1 cm 2 More preferably, 38 μL: 1 cm 2 .

[0033] Preferably, the light curing time in step (3) is 30 to 300 seconds, and the curing light source is ultraviolet light.

[0034] The piezoelectric composite coating functionalized titanium-based implant material is prepared by the preparation method.

[0035] The application of the above-mentioned piezoelectric composite coating functionalized titanium-based implant material in the preparation of medical devices.

[0036] Preferably, the invention is used in the preparation of electromechanical coupling hydrogel modified titanium implant material.

[0037] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0038] (1) The piezoelectric hydrogel coating functionalized titanium-based implant material prepared by the present invention can mimic the organic-inorganic composite structure of bones and promote vascularization and osteogenesis through mechanical-electrical biophysical signals.

[0039] (2) The hydrogel coating prepared by the present invention effectively reduces the mechanical modulus of the titanium implant and facilitates the migration and spreading of blood vessels.

[0040] (3) The hydrogel prepared by the present invention and the piezoelectric nanocolumn titanium-based implant material are physically interlocked through a spin coating process, showing excellent coating stability, which is beneficial for practical clinical applications.

[0041] (4) The present invention proposes a method for preparing an organic-inorganic coating implant material with a mechanoelectric coupling signal, which has a simple process, low cost, short cycle, and is suitable for industrial production.

[0042] (5) The spin coating process of the present invention facilitates the formation of a uniform microstructure with no apparent particle aggregation, and the electromechanical signals of the thin film material are stable, demonstrating the reliability of the film-forming process. Furthermore, the films prepared by the spin coating process exhibit a smooth surface and high bonding strength, which is crucial for improving the durability and performance of the coating. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] Figure 1 These are scanning electron microscope (SEM) images of the materials of Example 1, where (A) is GelMA hydrogel (BTO), (B) is barium titanate (BTO) array, and (C) is GelMA / BTO.

[0044] Figure 2These are the subjective morphology images of Example 1 and Comparative Example 1, where A is a Ti sheet, B is a flat Ti-BTO, C is an array Ti-BTO, D is Ti-GelMA, E is a flat Ti-BTO-GelMA, and F is an array Ti-BTO-GelMA. The microscopic morphology proves that only the array BTO surface can grow a uniform hydrogel coating.

[0045] Figure 3 These are scanning electron microscope (SEM) images of Example 1 and Comparative Example 2, where A is Ti-GelMA, B is Ti-BTO-GelMA prepared by dipping, and C is Ti-BTO-GelMA prepared by spin coating. SEM shows that only the surface of the arrayed BTO can form a hydrogel coating with uniform thickness.

[0046] Figure 4 This is the NMR spectrum of GelMA in Example 1.

[0047] Figure 5 This is the XRD pattern of the barium titanate array in Example 1.

[0048] Figure 6 Infrared spectra of GelMA, Ti-BTO, and Ti-BTO-GelMA.

[0049] Figure 7 is the elastic modulus of Ti, Ti-BTO, and Ti-BTO-GelMA.

[0050] Figure 8 This is the electrical signal generated by the electromechanical coupling of the hydrogel coating in Example 1.

[0051] Figure 9 The live-dead staining of Example 1 proves the excellent biocompatibility of the material.

[0052] Figure 10 The staining of the cytoskeleton and the quantitative characterization of the skeleton spreading area in Example 1 prove that the material is conducive to the growth and spreading of cells. DETAILED DESCRIPTION

[0053] The present invention will be described in further detail below with reference to examples and drawings, but the embodiments of the present invention are not limited thereto.

[0054] In the examples of the present invention, if the specific conditions are not specified, the experiments were carried out according to conventional conditions or the conditions recommended by the manufacturer. All raw materials and reagents used without specifying the manufacturer are conventional products that can be purchased from the market.

[0055] Example 1

[0056] A method for preparing a piezoelectric composite coating functionalized titanium-based implant material comprises the following steps:

[0057] (1) Pretreatment of titanium substrate: The titanium implant was immersed in acetone, anhydrous ethanol, and deionized water for ultrasonic cleaning for 15 minutes respectively, and then 2.61 ml of nitric acid and 1.831 ml of hydrofluoric acid were added dropwise to 400 ml of deionized water. The titanium implant was immersed in the water and stirred for 15 minutes. The titanium implant was taken out and immersed in deionized water for ultrasonic cleaning for 5 minutes. The implant was placed in a thermostat set at 60°C and dried for 1 hour to obtain the pretreated titanium implant.

[0058] (2) Preparation of inorganic piezoelectric barium titanate nanocolumn materials on titanium surfaces: The pretreated titanium implant was placed in 60 mL of 8 mol / L sodium hydroxide solution for alkaline thermal reaction. The temperature was set at 100°C and the reaction time was 24 hours. After the reaction, a sodium titanate nanostructured implant was obtained. The sodium titanate nanostructured implant was placed in 60 mL of 0.05 mol / L barium hydroxide solution for hydrothermal reaction. The temperature was set at 210°C and the reaction time was 8 hours. After the reaction, a barium titanate nanostructured implant was obtained.

[0059] (3) Preparation of methacrylated gelatin: 10 g of gelatin was placed in 100 ml of PBS solution (pH = 7.4) and stirred at 60°C for 30 min. 9 ml of methacrylic anhydride was added dropwise using a syringe and stirred at 50°C for 3 h. 400 ml of PBS solution (pH = 7.4) was added and the reaction was terminated for 30 min. The solution was poured into a centrifuge tube and centrifuged at 5000 rpm for 3-5 min. The supernatant was collected and placed in a dialysis bag. After dialysis for 5 days, the supernatant was freeze-dried in a freeze dryer at -60°C for 3 days to obtain GelMA hydrogel.

[0060] (4) Preparation of piezoelectric hydrogel coating functionalized titanium-based implant material: Take 0.0025g of photoinitiator LAP and dissolve it in 1ml of PBS solution with pH=7.4, take 0.1g of GelMA hydrogel and dissolve it in the above solution to obtain GelMA prepolymer solution. Place a 1cm diameter circular sheet of barium titanate nanostructure implant on a gelator, set the speed to 1000r / min, and the time to 30s. Use a pipette to transfer 30μL of GelMA prepolymer solution for spin coating. After the spin coating is completed, irradiate with UV light for 60s to obtain a piezoelectric hydrogel coating functionalized titanium-based implant material.

[0061] Relevant characterization of the piezoelectric hydrogel coating functionalized titanium-based implant material prepared in Example 1:

[0062] like Figure 1 As shown in the figure, the barium titanate nanostructures are evenly distributed on the surface, while the hydrogel coating is evenly dispersed on the surface of the piezoelectric array, so the hydrogel coating and the piezoelectric nanopillars are observed on the surface of the titanium implant. Figure 2 、 Figure 3As shown, compared with Example 1, Comparative Examples 1 and 2, it is proved that Comparative Examples 1 and 2 cannot prepare uniform hydrogel coatings. Figure 4 As shown in Figure 5, the characteristic peak of GelMA was observed at ppm = 5.7, proving the successful preparation of the hydrogel. Figure 5 As shown in Figure 2, Ti, O, and Bi elements can be observed in titanium implants. Figure 6 As shown in Figure 2, infrared spectroscopy confirmed the successful preparation of Ti-BTO-GelMA. Figure 7 As shown in Figure 2, the viscoelastic hydrogel coating effectively reduces the mechanical strength of the titanium implant. The electrical signal generated by the electromechanical coupling of the hydrogel coating is shown in Figure 2. Figure 8 As shown. Figure 9 As shown in Figure 2, live-dead staining demonstrates the excellent biocompatibility of the material. Figure 10 As shown, piezoelectric hydrogel-coated titanium-based implants facilitate the expansion of the skeleton.

[0063] Comparative Example 1

[0064] (1) Pretreatment of titanium substrate: The titanium implant was immersed in acetone, anhydrous ethanol, and deionized water for ultrasonic cleaning for 15 minutes respectively, and then 2.61 ml of nitric acid and 1.831 ml of hydrofluoric acid were added dropwise to 400 ml of deionized water. The titanium implant was immersed in the water and stirred for 15 minutes. The titanium implant was taken out and immersed in deionized water for ultrasonic cleaning for 5 minutes. The implant was placed in a thermostat set at 60°C and dried for 1 hour to obtain the pretreated titanium implant.

[0065] (2) Preparation of inorganic piezoelectric barium titanate nanocolumn materials on titanium surfaces: The pretreated titanium implant was placed in 60 mL of 8 mol / L sodium hydroxide solution for alkaline thermal reaction. The temperature was set at 100°C and the reaction time was 24 hours. After the reaction, a sodium titanate nanostructured implant was obtained. The sodium titanate nanostructured implant was placed in 60 mL of 0.05 mol / L barium hydroxide solution for hydrothermal reaction. The temperature was set at 210°C and the reaction time was 8 hours. After the reaction, a barium titanate nanostructured implant was obtained.

[0066] (3) Preparation of methacrylated gelatin: 10 g of gelatin was placed in 100 ml of PBS solution (pH 7.4) and stirred at 60°C for 30 min. 9 ml of methacrylic anhydride was added dropwise using a syringe and stirred at 50°C for 3 h. 400 ml of PBS solution (pH 7.4) was added and the reaction was terminated for 30 min. The solution was poured into a centrifuge tube and centrifuged at 5000 rpm for 3-5 min. The supernatant was collected and placed in a dialysis bag. After dialysis for 5 days, it was freeze-dried in a freeze dryer for 3 days to obtain GelMA hydrogel.

[0067] (4) Preparation of piezoelectric hydrogel-coated titanium-based implants: 0.0025 g of photoinitiator LAP was dissolved in 1 ml of PBS (pH 7.4), and 0.1 g of GelMA hydrogel was dissolved in the above solution to obtain a GelMA prepolymer solution. A 1 cm diameter circular barium titanate nanostructured implant was immersed in 30 μL of the GelMA prepolymer solution for 30 seconds and then irradiated with a UV lamp for 60 seconds.

[0068] Comparative Example 2

[0069] (1) Pretreatment of titanium substrate: The titanium implant was immersed in acetone, anhydrous ethanol, and deionized water for ultrasonic cleaning for 15 minutes respectively, and then 2.61 ml of nitric acid and 1.831 ml of hydrofluoric acid were added dropwise to 400 ml of deionized water. The titanium implant was immersed in the water and stirred for 15 minutes. The titanium implant was taken out and immersed in deionized water for ultrasonic cleaning for 5 minutes. The implant was placed in a thermostat set at 60°C and dried for 1 hour to obtain the pretreated titanium implant.

[0070] (2) Preparation of titanium-based barium titanate material with flat surface: The pretreated titanium implant was placed in a 60 mL, 0.1 mol / L mixed solution of barium hydroxide and 0.1 mol / L KOH for alkaline thermal reaction. The temperature was set to 180 ° C and the reaction time was 8 h. After the reaction was completed, a flat barium titanate implant was obtained.

[0071] (3) Preparation of methacrylated gelatin: 10 g of gelatin was placed in 100 ml of PBS solution (pH = 7.4) and stirred at 60°C for 30 min. 9 ml of methacrylic anhydride was added dropwise using a syringe and stirred at 50°C for 3 h. 400 ml of PBS solution (pH = 7.4) was added and the reaction was terminated for 30 min. The solution was poured into a centrifuge tube and centrifuged at 5000 rpm for 3-5 min. The supernatant was collected and placed in a dialysis bag. After dialysis for 5 days, the supernatant was freeze-dried in a freeze dryer at -60°C for 3 days to obtain GelMA hydrogel.

[0072] (4) Preparation of piezoelectric hydrogel-coated functionalized titanium-based implant material: Dissolve 0.0025 g of photoinitiator LAP in 1 ml of PBS solution (pH = 7.4) and dissolve 0.1 g of GelMA hydrogel in the above solution to obtain a GelMA prepolymer solution. Place a 1 cm diameter circular flat barium titanate implant on a gelator and set the speed to 1000 r / min for 30 s. Use a pipette to transfer 30 μL of the GelMA prepolymer solution for spin coating. After the spin coating is completed, irradiate with UV light for 60 s.

[0073] The above embodiments are preferred implementation modes of the present invention, but the implementation modes of the present invention are not limited to the above embodiments. Any other changes, modifications, substitutions, combinations, and simplifications that do not deviate from the spirit and principles of the present invention should be considered as equivalent replacement methods and are included in the scope of protection of the present invention.

Claims

1. A method for preparing a piezoelectric composite coating functionalized titanium-based implant material, characterized in that: The following steps are involved: (1) placing the titanium implant in an alkaline solution for alkaline thermal reaction, and then placing it in a barium hydroxide solution for hydrothermal reaction to obtain a barium titanate nanostructured implant; (2) Methacrylic anhydride was added dropwise to a phosphate buffer solution containing gelatin to react. After the reaction was completed, the mixture was centrifuged, dialyzed, and freeze-dried to obtain a GelMA hydrogel. (3) GelMA hydrogel was dissolved in a phosphate buffer solution containing a photoinitiator, and the resulting mixed solution was spin-coated onto the surface of the barium titanate nanostructured implant and photocured to obtain a piezoelectric composite coating functionalized titanium-based implant material; The alkaline solution in step (1) is a sodium hydroxide solution; the concentration of the alkaline solution is 6 to 10 mol / L; The temperature of the alkaline thermal reaction in step (1) is 90-120°C and the time is 18-24 hours; The concentration of the barium hydroxide solution in step (1) is 0.03 to 0.08 mol / L; The temperature of the hydrothermal reaction in step (1) is 180-210°C and the time is 6-10 hours; In step (3), the volume ratio of the GelMA hydrogel mass to the phosphate buffer solution containing the photoinitiator is 0.5-2 g:10 ml; The spin coating speed in step (3) is 500-3000 r / min, and the time is 10-60 s; The ratio of the volume of the mixed solution in step (3) to the area of ​​the barium titanate nanostructure implant is 30-130 μL:1 cm 2 .

2. The method for preparing a piezoelectric composite coating functionalized titanium-based implant material according to claim 1, characterized in that: In the phosphate buffer containing the photoinitiator in step (3), the mass concentration of the photoinitiator is 0.2-0.3%; The photoinitiator in step (3) is at least one of LAP and photoinitiator 2959; The light curing time in step (3) is 30 to 300 seconds, and the curing light source is ultraviolet light.

3. The method for preparing a piezoelectric composite coating functionalized titanium-based implant material according to claim 1, characterized in that: In step (2), the mass ratio of the gelatin to the phosphate buffer is 0.05-0.2 g:1 ml; the mass ratio of the methacrylic anhydride to the gelatin is 0.3-1.0:1; The reaction temperature in step (2) is 50-60°C and the reaction time is 2-4 hours; The pH of the phosphate buffer in steps (2) and (3) is 6-8.

4. The method for preparing a piezoelectric composite coating functionalized titanium-based implant material according to claim 1, characterized in that: In step (3), the volume ratio of the GelMA hydrogel to the phosphate buffer solution containing the photoinitiator is 1 g:10 ml; The ratio of the volume of the mixed solution in step (3) to the area of ​​the barium titanate nanostructure implant is 38 μL: 1 cm 2 ; The spin coating speed in step (3) is 1000 r / min and the time is 30 s.

5. The method for preparing a piezoelectric composite coating functionalized titanium-based implant material according to claim 1, characterized in that: The concentration of the alkaline solution in step (1) is 8 mol / L; The temperature of the alkaline thermal reaction in step (1) is 100°C and the time is 24 hours; The concentration of the barium hydroxide solution in step (1) is 0.05 mol / L; The temperature of the hydrothermal reaction in step (1) is 210°C and the time is 8 hours; In step (2), the mass ratio of the gelatin to the volume of the phosphate buffer solution is 0.1 g:1 ml; the mass ratio of the methacrylic anhydride to the gelatin is 0.94:1; The pH of the phosphate buffer in steps (2) and (3) is 7.4; The reaction temperature in step (2) is 50° C. and the reaction time is 3 h.

6. The method for preparing a piezoelectric composite coating functionalized titanium-based implant material according to claim 1, characterized in that: The titanium implant in step (1) needs to be pretreated, and the pretreatment includes: ultrasonic cleaning, pickling, and drying the titanium implant to obtain a pretreated titanium-based substrate; The ultrasonic cleaning refers to immersing the titanium implant in acetone, anhydrous ethanol, and deionized water in sequence and ultrasonically cleaning each for 10 to 20 minutes; The pickling process involves first adding nitric acid and hydrofluoric acid dropwise to deionized water to prepare an acid solution, stirring the solution evenly, and then adding the solution to the titanium implant for pickling.

7. A piezoelectric composite coating functionalized titanium-based implant material prepared by the preparation method according to any one of claims 1 to 6.

8. Use of the piezoelectric composite coating functionalized titanium-based implant material according to claim 7 in the preparation of medical devices.

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