Implant piezoelectric nano-coating, preparation method and application thereof

Abstract

The application discloses a kind of implant piezoelectric nano coating and its preparation method and application.The nano coating is composed of nano-flower-shaped barium titanate and gold nanoparticles loaded on its surface.In this application, gold nanoparticles are deposited on nano-barium titanate at high temperature by using the method of sodium citrate reducing tetrachloroauric acid. The nBTO@Au prepared by this method has obvious osteogenesis and antibacterial properties. The application provides a high reactivity, catalytic and non-invasive immediate treatment mode for peri-implantitis, which has wide application potential in implant post-disinfection, peri-implantitis treatment and improving implant survival rate.

Description

Technical Field

[0001] This invention belongs to the field of biomedical technology, specifically relating to a piezoelectric nanocoating for implants, its preparation method, and its application. Background Technology

[0002] Plaque buildup around infected implants can replicate continuously, leading to inflammation of the peri-implant soft tissue and destruction of the alveolar bone. This condition, known as peri-implantitis, is an unresolved global problem. Current treatments for implant infections focus on removing bacteria using antibiotics, scaling, and surgery. However, complications such as bacterial resistance, plaque buildup, postoperative implant exposure, and even implant dislodgement have prompted dentists to explore optimal treatment methods. Many antimicrobial strategies based on implant surface modification have been developed, such as loading with metal ions or modifying with quaternary ammonium-based polymers. However, their clinical application is often limited by dose dependence, short-term antimicrobial efficacy, or potential side effects on adjacent tissues. Therefore, there is an urgent need for a biocompatible implant surface piezoelectric electroactive material with on-demand, non-invasive, highly effective antimicrobial properties and bone-promoting properties—that converts mechanical stimulation into electrical signals, exhibiting a piezoelectric effect similar to natural bone.

[0003] Patent CN202011158393.0 discloses a piezoelectric material with surface-loaded metal, its preparation method, and its application. The piezoelectric material consists of nanopiezoelectric particles with a particle size of 100-500 nm and metal nanoparticles with a diameter of 1-30 nm loaded on their surface; the piezoelectric particles are barium titanate, lithium niobate, or lead titanate; the metal is Au, Pt, Pd, Al, or Ni. The preparation method of the piezoelectric material with surface-loaded metal includes the following steps: (1) dispersing the piezoelectric particles in anhydrous ethanol, adding a mercapto-based reagent, stirring evenly, and then ultrasonically treating; then centrifuging, washing, and drying to obtain mercapto-based piezoelectric particles; (2) dispersing the mercapto-based piezoelectric particles in a dispersant, adding a metal salt solution and a methanol aqueous solution, stirring evenly, adjusting the pH of the system to 9-10, and then ultrasonically treating; then centrifuging, washing, and drying to obtain the piezoelectric material with surface-loaded metal. Although the metal-loaded piezoelectric materials prepared by this method have certain antibacterial properties, the properties are not strong and they do not promote bone growth. Summary of the Invention

[0004] The purpose of this invention is to provide a piezoelectric nanocoating for implants, its preparation method, and its application.

[0005] A piezoelectric nanocoating for implants, the nanocoating consisting of barium titanate in the form of nanoflowers and gold nanoparticles loaded on its surface.

[0006] The preparation method of the implant piezoelectric nanocoating is carried out according to the following steps:

[0007] (1) Preparation of titanium dioxide: Polish the titanium sheet with sandpaper, then clean it with acetone, anhydrous ethanol and deionized water in sequence for 10-20 min, dry it in a drying oven and seal it in a bag for later use; place the titanium sheet in an aqueous solution containing 0.3-0.7 wt% hydrofluoric acid for anodic oxidation, the anode is a pure titanium sheet sample and the cathode is a carbon electrode; after oxidation, clean it with ultrapure water for 3-7 min and dry it, and record it as TiO2 nanotubes;

[0008] (2) Preparation of nano-flower-shaped barium titanate: TiO2 nanotubes were placed in a polytetrafluoroethylene reactor, 0.05-0.15M barium hydroxide solution was added, a stainless steel reactor sleeve was placed in and the screw locking device was tightened; the temperature was heated to 200-240℃ at a heating rate of 4-6℃ / min and held for 70-90min, cooled with the furnace and then taken out, dried and used for later use, denoted as nBTO;

[0009] (3) Preparation of gold-loaded nanoflower-like barium titanate: Sodium citrate solution, tetrachloroauric acid solution and nBTO were placed in an Erlenmeyer flask containing ultrapure water, sonicated for 0.5-1.5 min, and then heated and stirred in a constant temperature magnetic stirring oil bath until boiling for 8-12 min. The solution color gradually turned wine red. After cooling to room temperature, the implant piezoelectric nanocoating was obtained, denoted as nBTO@Au.

[0010] The sandpaper polishing is performed sequentially using 600#, 1000#, and 1500# sandpaper.

[0011] The titanium sheet has a diameter of 1-2 cm and a thickness of 0.05-0.15 cm.

[0012] The oxidation process uses a stable DC power supply with a working voltage of 15-25V and an oxidation time of 20-40 minutes.

[0013] The concentration of the sodium citrate solution is 30-50 mM, and the concentration of the tetrachloroauric acid solution is 5-15 mM; the volume ratio of sodium citrate solution, tetrachloroauric acid solution and ultrapure water is (2-4):(1-3):80.

[0014] The application of the implant piezoelectric nanocoating in antibacterial applications.

[0015] The application of the implant piezoelectric nanocoating in promoting osteogenesis.

[0016] The beneficial effects of this invention are as follows: This invention utilizes the method of reducing tetrachloroauric acid with sodium citrate to deposit gold nanoparticles onto barium titanate nanoparticles at high temperature. The nBTO@Au prepared using this method exhibits significant osteogenic properties, and its bactericidal activity is enhanced under ultrasonic response. This invention provides a highly reactive, catalytic, and non-invasive immediate treatment modality for peri-implantitis, with broad application potential in post-implant disinfection, peri-implantitis treatment, and improving implant survival rates. The coating prepared by this invention has significant antibacterial effects, reducing the probability of infection and alleviating patient suffering clinically. It also has a significant osteogenic effect, potentially overcoming the current bottleneck of titanium implants lacking osteogenic properties. Attached Figure Description

[0017] Figure 1 Electron micrographs of Ti, BTO, and nBTO@Au surfaces.

[0018] Figure 2 This is the result of alkaline phosphatase staining.

[0019] Figure 3 The results show the staining results for extracellular matrix mineralization.

[0020] Figure 4 The results of plate colony spreading. Detailed Implementation

[0021] To facilitate understanding of the present invention, a more comprehensive description will be given below. However, the present invention can be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided to provide a thorough and complete understanding of the disclosure of the present invention.

[0022] Example 1

[0023] A method for preparing a piezoelectric nanocoating for implants, comprising the following steps:

[0024] (1) Preparation of titanium dioxide: Titanium sheets (diameter 1.5cm, thickness 0.1cm) were polished with 600#, 1000# and 1500# sandpaper in sequence to obtain a smooth and uniform surface; then ultrasonically cleaned with acetone, anhydrous ethanol and deionized water for 15min in sequence, and then dried in a drying oven and sealed in a bag for later use; the titanium sheets were placed in an aqueous solution containing 0.5wt% hydrofluoric acid for anodic oxidation, the anode was a pure titanium sheet sample, the cathode was a carbon electrode, a DC stable power supply was used, the working voltage was 20V, and the oxidation time was 30min; the obtained sample was ultrasonically cleaned with ultrapure water for 5min, dried and labeled as TiO2 nanotubes;

[0025] (2) Preparation of nano-flower-shaped barium titanate: The TiO2 nanotubes prepared in step (1) were placed in a polytetrafluoroethylene reactor, 30 mL of 0.1 M barium hydroxide solution was added, a stainless steel reactor sleeve was placed in and the screw locking device was tightened; the temperature was raised to 220 °C at a heating rate of 5 °C / min and held for 80 min. After cooling with the furnace, the sample was taken out, dried and used for later use, and denoted as nBTO.

[0026] (3) Preparation of gold-loaded nanoflower-like barium titanate: Gold nanoparticles were prepared by reducing tetrachloroauric acid with sodium citrate. 7.5 ml of sodium citrate (40 mM), 5 ml of tetrachloroauric acid (10 mM) and 4 titanium sheets with nBTO coating were placed in a conical flask containing 190 ml of ultrapure water. After sonication for 1 min, the solution was heated and stirred in a constant temperature magnetic stirring oil bath until boiling for 10 min. The solution gradually turned wine red. After cooling to room temperature, the implant piezoelectric nanocoating was obtained and denoted as nBTO@Au.

[0027] Example 2

[0028] A method for preparing a piezoelectric nanocoating for implants, comprising the following steps:

[0029] (1) Preparation of titanium dioxide: Titanium sheets (diameter 1.0 cm, thickness 0.08 cm) were polished with 600#, 1000# and 1500# sandpaper in sequence to obtain a smooth and uniform surface; then, they were ultrasonically cleaned with acetone, anhydrous ethanol and deionized water for 10 min in sequence, and then dried in a drying oven and sealed in a bag for later use; the titanium sheets were placed in an aqueous solution containing 0.4 wt% hydrofluoric acid for anodic oxidation. The anode was a pure titanium sheet sample and the cathode was a carbon electrode. A DC stable power supply was used with a working voltage of 15 V and an oxidation time of 40 min; the obtained sample was ultrasonically cleaned with ultrapure water for 4 min and dried, and was recorded as TiO2 nanotubes;

[0030] (2) Preparation of nano-flower-shaped barium titanate: The TiO2 nanotubes prepared in step (1) were placed in a polytetrafluoroethylene reactor, 40 mL of 0.05 M barium hydroxide solution was added, and a stainless steel reactor sleeve was placed in the reactor and the screw locking device was tightened. The temperature was increased to 200℃ at a heating rate of 4℃ / min and held for 70 min. After cooling with the furnace, the sample was taken out, dried and used for later use. It was recorded as a titanium sheet with an nBTO coating.

[0031] (3) Preparation of gold-loaded nanoflower-like barium titanate: Gold nanoparticles were prepared by reducing tetrachloroauric acid with sodium citrate. 7.5 ml of sodium citrate (40 mM), 5 ml of tetrachloroauric acid (10 mM) and 4 titanium sheets with nBTO coating were placed in a conical flask containing 190 ml of ultrapure water. After sonication for 1 min, the solution was heated and stirred in a constant temperature magnetic stirring oil bath until boiling for 8 min. The solution gradually turned wine red. After cooling to room temperature, the implant piezoelectric nanocoating was obtained and denoted as nBTO@Au.

[0032] Example 3

[0033] A method for preparing a piezoelectric nanocoating for implants, comprising the following steps:

[0034] (1) Preparation of titanium dioxide: Titanium sheets (2 cm in diameter and 0.1 cm in thickness) were polished sequentially with 600#, 1000# and 1500# sandpaper to obtain a smooth and uniform surface; then ultrasonically cleaned with acetone, anhydrous ethanol and deionized water for 20 min respectively, and then dried in a drying oven and sealed in a bag for later use; the titanium sheets were placed in an aqueous solution containing 0.6 wt% hydrofluoric acid for anodic oxidation, with pure titanium sheet specimens as the anode and carbon electrode as the cathode, using a DC stable power supply with a working voltage of 25 V and an oxidation time of 25 min; the obtained samples were ultrasonically cleaned with ultrapure water for 6 min, dried and labeled as TiO2 nanotubes;

[0035] (2) Preparation of nano-flower-shaped barium titanate: The TiO2 nanotubes prepared in step (1) were placed in a polytetrafluoroethylene reactor, 30 mL of 0.15 M barium hydroxide solution was added, a stainless steel reactor sleeve was placed in and the screw locking device was tightened; the temperature was raised to 240 °C at a heating rate of 6 °C / min and held for 85 min. After cooling with the furnace, the sample was taken out, dried and used for later use, and denoted as nBTO.

[0036] (3) Preparation of gold-loaded nanoflower-like barium titanate: Gold nanoparticles were prepared by reducing tetrachloroauric acid with sodium citrate. 7.5 ml of sodium citrate (40 mM), 5 ml of tetrachloroauric acid (10 mM) and 4 titanium sheets with nBTO coating were placed in a conical flask containing 190 ml of ultrapure water. After sonication for 1.5 min, the solution was heated and stirred in a constant temperature magnetic stirring oil bath until boiling for 12 min. The solution gradually turned wine red. After cooling to room temperature, the implant piezoelectric nanocoating was obtained and denoted as nBTO@Au.

[0037] Experimental Example 1: Material Characterization

[0038] The nBTO@Au prepared in Example 1 was used as the detection target.

[0039] Characterization method: The sample was fixed on a tray using a conductive adhesive, and a thin layer of platinum (Pt) was sputtered to improve its conductivity. The surface features of the sample were then observed using a field emission scanning electron microscope.

[0040] The results are as follows Figure 1 As shown, the Ti surface is basically smooth except for a few scratches left by polishing; the microstructure of the BTO surface formed under hydrothermal conditions of 220℃ and 80min shows a coral-like arrangement and uniform morphology; gold nanoparticles can be seen to be successfully grown in situ on BTO in nBTO@Au, and the diameter of the gold particles is relatively uniform and the distribution is relatively even.

[0041] Experimental Example 2: Alkaline Phosphatase Staining

[0042] The nBTO@Au prepared in Example 1 was used as the detection target.

[0043] With 2×10 4 BMSCs were seeded into each group of samples at a cell density of / ml. Osteogenic induction was initiated when the cell confluence reached 75%. The cells were induced and cultured for 7 days. Then, ALP staining was performed using a kit. The specific operation steps are as follows:

[0044] (1) Remove the osteogenic induction medium and wash twice with PBS;

[0045] (2) Add 1 ml of 4% paraformaldehyde solution to each well and fix at room temperature for 30 min;

[0046] (3) Remove the fixative and wash twice with PBS to ensure that all the fixative is washed away;

[0047] (4) Add 500 μL of alkaline phosphatase staining working solution to each well and fix at room temperature for 10 min;

[0048] (5) Remove the alkaline phosphatase staining working solution, wash twice with PBS to thoroughly remove excess staining solution;

[0049] (6) Observe and photograph under a stereomicroscope.

[0050] The working solution for alkaline phosphatase detection is prepared as follows: 3 ml of colorimetric buffer, 10 μl of BCIP (300X), and 20 μl of NBT (150X).

[0051] The results showed that, according to the kit instructions, under the action of intracellular ALP, BCIP hydrolysates reacted strongly with NBT to form insoluble dark blue to blue-purple compounds. The experimental results indicated that after 7 days of osteogenic induction, insoluble compounds were formed in all groups, and the intensity of the color was directly proportional to ALP activity. Figure 2

[0052] ALP activity is nBTO@Au > BTO > Ti.

[0053] Experimental Example 3: Alizarin Red Staining

[0054] The nBTO@Au prepared in Example 1 was used as the detection target.

[0055] With 2×10 4 BMSCs were seeded into each group of samples at a cell density of / ml. Osteogenic induction was initiated when the cell confluence reached 75%. After 14 days of induction culture, staining was performed using an ARS kit. The specific operation steps are as follows:

[0056] (1) Remove the osteogenic induction medium and wash twice with PBS;

[0057] (2) Add 1 ml of 4% paraformaldehyde solution to each well and fix at room temperature for 30 min;

[0058] (3) Remove the fixative and wash twice with PBS to ensure that all the fixative is washed away;

[0059] (4) Add 500 μL of alizarin red working solution to each well and fix at room temperature for 10 min;

[0060] (5) Remove the alizarin red working solution and wash twice with PBS to thoroughly remove excess staining solution;

[0061] (6) Observe and photograph under a stereomicroscope.

[0062] Figure 3 The results showed the extracellular matrix mineralization on the coating surface of each group 14 days after osteogenic induction. Alizarin Red staining solution mainly chelated with calcium ions in the solution to form an insoluble complex that could be directly observed under a microscope. The staining intensity was positively correlated with the degree of extracellular matrix mineralization. Alizarin Red staining results showed that the nBTO@Au group stained the deepest, followed by the BTO group, while the Ti group stained the lightest.

[0063] In summary, we believe that the nBTO@Au piezoelectric coating constructed on the titanium surface has the ability to promote osteogenic formation.

[0064] Experiment Example 4: Plate Coating Experiment

[0065] The nBTO@Au prepared in Example 1 was used as the detection target.

[0066] The materials required for the experiment were sterilized by irradiating both sides with ultraviolet light for 30 minutes. Then, using sterile forceps, each group of samples was placed into a 24-well plate with the treated side facing up. 1 mL of approximately 1×10⁻⁶ solution was added to each group using a micropipette. 6A suspension of Staphylococcus aureus at CFU / mL was incubated at 37°C for 6 hours, followed by sonication of the ultrasonic group for 5 minutes at a power of 1.0 MHz and 1.5 W / cm². 2 With a 50% duty cycle, the samples were sonicated and cultured for another 24 hours. After culture, the culture medium was aspirated in a clean bench, and the samples were gently rinsed three times with PBS. 1 mL of PBS was added to each well, and the plate was placed in an ultrasonic transducer and sonicated for 5 minutes (300 W, 40 kHz) to resuspend the bacteria adhering to the sample surface in the PBS solution. The bacterial suspension adhering to the sample surface was collected, and PBS was added to 5 mL to dilute it to a 10⁻⁶ ppm. 5 After doubling, take 100 μL and spread it evenly on the culture medium. Incubate in an aerobic incubator at 37°C until the observation point is reached, then count the colonies.

[0067] To evaluate the survival rate of single bacterial species under ultrasound, a plate coating experiment was conducted. The results of the Staphylococcus aureus plate coating are as follows: Figure 4 As shown, the number of bacteria in the BTO and nBTO@Au groups was slightly reduced compared to the Ti group. This may be because the BTO coating structure affects the stress response of bacteria, leading to cell membrane rupture and a reduction in bacterial count. However, this antibacterial effect is too poor to eliminate bacteria and prevent the spread of infection. In contrast, the bacterial survival rate in the US(+) groups decreased to varying degrees, with the nBTO@Au+US group showing the best antibacterial effect. Our results show that the addition of Au NPs significantly shortened the ultrasound treatment time, and the antibacterial rate increased significantly within 5 minutes. This is mainly because the deposition of Au NPs on TNT prevents electron / hole recombination, resulting in higher ROS yield and enhanced acoustic dynamics. Furthermore, within the same treatment time, the nBTO@Au+US group had a higher antibacterial rate than the BTO+US group, further demonstrating that ROS plays a crucial role in the SDT-mediated antibacterial effect.

[0068] The embodiments described above are merely illustrative of several implementations of the present invention, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these all fall within the protection scope of the present invention. Therefore, the protection scope of this invention patent should be determined by the appended claims.

Claims

1. A method for preparing a piezoelectric nano-coating of an implant, characterized in that, Follow these steps: (1) Preparation of titanium dioxide: Polish the titanium sheet with sandpaper, then clean it with acetone, anhydrous ethanol and deionized water in sequence for 10-20 min, dry it in a drying oven and seal it in a bag for later use; place the titanium sheet in an aqueous solution containing 0.3-0.7wt% hydrofluoric acid for anodic oxidation, the anode is a pure titanium sheet sample and the cathode is a carbon electrode; after oxidation, clean it with ultrapure water for 3-7 min and dry it, and record it as TiO2 nanotubes; (2) Preparation of nano-flower-shaped barium titanate: The TiO2 nanotubes prepared in step (1) were placed in a polytetrafluoroethylene reactor, and 0.05-0.15M barium hydroxide solution was added. The reactor was then placed in a stainless steel reactor sleeve and the screw locking device was tightened. The temperature was raised to 200-240℃ at a rate of 4-6℃ / min and held for 70-90min. After cooling with the furnace, the product was taken out, dried, and stored for later use. It was recorded as a titanium sheet with an nBTO coating. (3) Preparation of gold-loaded nanoflower-shaped barium titanate: Sodium citrate solution, tetrachloroauric acid solution and titanium sheet containing nBTO coating were placed in an Erlenmeyer flask containing ultrapure water. After sonication for 0.5-1.5 min, the solution was heated and stirred in a constant temperature magnetic stirring oil bath until boiling for 8-12 min. The solution color gradually turned wine red. After cooling to room temperature, the implant piezoelectric nano-coating was obtained, denoted as nBTO@Au.

2. The method of claim 1, wherein the piezoelectric nano-coating of the implant is prepared by the steps of: The sandpaper polishing is performed sequentially using 600#, 1000#, and 1500# sandpaper.

3. The method of claim 1, wherein the piezoelectric nano-coating of the implant is prepared by the steps of: The titanium sheet has a diameter of 1-2 cm and a thickness of 0.05-0.15 cm.

4. The method of claim 1, wherein the piezoelectric nano-coating of the implant is prepared by, The oxidation process uses a stable DC power supply with a working voltage of 15-25V and an oxidation time of 20-40 minutes.

5. The method of claim 1, wherein the piezoelectric nano-coating of the implant is prepared by the steps of: The concentration of the sodium citrate solution is 30-50 mM, and the concentration of the tetrachloroauric acid solution is 5-15 mM; the volume ratio of sodium citrate solution, tetrachloroauric acid solution and ultrapure water is (2-4):(1-3):

80.

6. The application of the implant piezoelectric nanocoating prepared by the method of claim 1 in the preparation of implants that promote osteogenesis.

Images