A dual-functional nanomaterial for "antibacterial synergistic-mineralization regulation" and a preparation method and application thereof

Abstract

The application provides a kind of "antibacterial synergistic-mineralization regulation" bifunctional nanomaterial and its preparation method and application, belongs to the technical field of biomedical materials.The application first mixes sodium hydrogen phosphate solution and calcium chloride solution to obtain amorphous calcium phosphate suspension;Then amorphous calcium phosphate suspension and tannic acid solution are mixed to obtain ACP@TA suspension;Finally, ACP@TA suspension and hydroxypropyltrimethylammonium chloride chitosan solution are mixed to obtain bifunctional nanomaterial.Through the electrostatic adsorption of tannic acid and antibacterial layer hydroxypropyltrimethylammonium chloride chitosan to form a crosslinked shell, amorphous calcium phosphate is effectively wrapped, which can significantly delay the crystallization process of amorphous calcium phosphate, ensure long-term calcium and phosphorus ion release, and effectively exert antibacterial function, provide an ideal local microenvironment for the remineralization of dental hard tissue, and ultimately realize the biomimetic mineralization of dental enamel and the deep mineralization of dentin tubules.

Description

Technical Field

[0001] This invention relates to the field of biomedical materials technology, and in particular to a dual-functional nanomaterial with "antibacterial synergy-mineralization regulation" and its preparation method and application. Background Technology

[0002] Dental caries is listed by the World Health Organization as the third leading chronic non-communicable disease after cancer and cardiovascular disease, seriously affecting human oral health and overall well-being. In recent years, remineralization has become a popular research area in oral treatment, aimed at halting caries progression and repairing damaged hard tissue. Remineralization therapy refers to a treatment method that uses remineralizing solutions to remineralize demineralized enamel or cementum, restoring its hardness and terminating or eliminating early caries lesions. With ongoing research, its application has gradually shifted from early caries lesions to experimental treatment of other stages of caries. The principle of remineralization therapy is to deliver a neutral solution containing a certain proportion of calcium and phosphate ions to the demineralized area of ​​hard tissue. The relatively high concentration of inorganic ions in the solution mineralizes and accumulates in situ, filling the demineralized gaps, thereby repairing the damaged micro-area. Because mineralization has a repair cycle, the mineralizing solution needs to remain on the tooth surface for a certain period of time to stably provide calcium and phosphorus ions to promote mineralization progress. Simultaneously, the local pH required for the solid-phase transformation process of remineralization—the conversion of amorphous calcium phosphate into hydroxyapatite and its continued growth—is around 6.2. Ingestion of high sugars or carbohydrates can lead to increased metabolic activity of cariogenic bacteria in the oral cavity, producing large amounts of organic acids that easily alter the environmental pH, disrupting the dynamic balance of mineralization and demineralization on the tooth surface, ultimately gradually damaging the hard tooth tissue and causing caries progression. Therefore, efficient remineralization treatment requires, on the one hand, providing a high concentration of calcium and phosphorus ions to the demineralized area of ​​the tooth to achieve long-term mineralization; on the other hand, it requires effective local antibacterial action in the hard tooth tissue while promoting remineralization to prevent further demineralization and inhibition of remineralization caused by continuous acid production by cariogenic bacteria. Therefore, researching a dual-functional nanomaterial with "antibacterial synergy and mineralization regulation" and its preparation method for use in products for remineralization and antibacterial treatment of hard tooth tissue is of great significance. Summary of the Invention

[0003] The purpose of this invention is to provide a bifunctional nanomaterial with "antibacterial synergy-mineralization regulation" and its preparation method and application, so as to solve the problem of dental caries progression caused by remineralization process in the prior art.

[0004] To achieve the above-mentioned objectives, the present invention provides the following technical solution:

[0005] This invention provides a method for preparing a bifunctional nanomaterial with "antibacterial synergy and mineralization regulation". The preparation steps of the bifunctional nanomaterial are as follows:

[0006] (1) Mix disodium hydrogen phosphate solution and calcium chloride solution to obtain amorphous calcium phosphate (ACP) suspension;

[0007] (2) Mix the amorphous calcium phosphate suspension and tannic acid (TA) solution to obtain ACP@TA suspension;

[0008] (3) Mix the ACP@TA suspension with the hydroxypropyltrimethylammonium chloride chitosan (HACC) solution to obtain the bifunctional nanomaterial (ACP@TH).

[0009] Preferably, in step (1), the molar ratio of Ca in the calcium chloride solution to P in the disodium hydrogen phosphate solution is 1.2 to 1.5:1; the concentration of the disodium hydrogen phosphate solution is 0.002 to 0.006 mol / L; and the concentration of the calcium chloride solution is 0.004 to 0.008 mol / L.

[0010] Preferably, the concentration of the tannic acid solution in step (2) is 6-12 mg / mL and the pH value is 8.

[0011] Preferably, the volume ratio of the amorphous calcium phosphate suspension and the tannic acid solution in step (2) is 60:0.10 to 0.14.

[0012] Preferably, in steps (2) and (3), the mixing temperature is independently 0 to 6°C, and the mixing time is independently 3 to 8 minutes.

[0013] Preferably, the concentration of the hydroxypropyltrimethylammonium chloride chitosan solution in step (3) is 6–15 mg / mL.

[0014] Preferably, the volume ratio of the amorphous calcium phosphate suspension to the hydroxypropyltrimethylammonium chloride chitosan solution is 60:3-5.

[0015] Preferably, in step (3), the hydroxypropyltrimethylammonium chloride chitosan solution is added to the ACP@TA suspension in batches during mixing, and incubated for 3 to 8 minutes after each addition.

[0016] The present invention also provides a bifunctional nanomaterial prepared by the above-described method for preparing "antibacterial synergy-mineralization regulation" bifunctional nanomaterials.

[0017] The present invention also provides an application of the above-described bifunctional nanomaterial in the preparation of tooth remineralization products or anti-dentin hypersensitivity products.

[0018] Antibacterial synergistic remineralization principle:

[0019] The core mechanism of remineralization therapy lies in the targeted replenishment of mineral components needed by the hard tissues of the tooth. This is achieved by delivering calcium and phosphorus ions to demineralized areas, creating a locally high-concentration mineralized environment that triggers the biomineralization process. Minerals then crystallize and regenerate in an orderly manner within the demineralized matrix, gradually filling the microporous network formed by acid etching, ultimately rebuilding the tooth's natural mineralized structure and restoring its mechanical strength. However, simple remineralization therapy still faces challenges because dental plaque biofilm, as a carrier of cariogenic microecology, not only provides an adhesion matrix for bacteria but also prolongs the duration of the acidic microenvironment due to the osmotic barrier formed by its extracellular polysaccharides, interfering with the remineralization process. The key to caries treatment lies in balancing the repair of hard tissues with the effective control of cariogenic bacteria. Antimicrobial therapy reduces plaque biofilm formation by inhibiting the colonization and proliferation of cariogenic bacteria such as *Streptococcus mutans* and *Lactobacillus acidophilus*, thus preventing further demineralization at its source. Remineralization therapy, on the other hand, replenishes calcium and phosphorus ions, using a guiding mechanism to promote mineral deposition and repair damaged hard tissues of the tooth. This dual mechanism allows the remineralization of dental hard tissues and antibacterial treatment to work synergistically, effectively repairing early caries lesions and significantly reducing the occurrence of secondary caries, thus enhancing the durability and effectiveness of treatment.

[0020] The beneficial effects of this invention are:

[0021] This invention utilizes the electrostatic adsorption of plant polyphenol tannins with the antibacterial layer of hydroxypropyltrimethylammonium chloride chitosan to form a cross-linked shell, effectively encapsulating amorphous calcium phosphate. This design not only significantly slows down the crystallization process of amorphous calcium phosphate, ensuring long-term release of calcium and phosphate ions, but also effectively exerts antibacterial functions after being adsorbed onto the surface of dental hard tissues. It provides an ideal local microenvironment for the remineralization of dental hard tissues, ultimately achieving biomimetic mineralization of enamel and deep mineralization and sealing of dentinal tubules. Attached Figure Description

[0022] Figure 1 The images shown are state images and optical images of the ACP@TH nano-assembly of Example 1, where A is a state image and B is an optical image.

[0023] Figure 2 The XRD pattern of the ACP@TH nanoassembly in Example 1;

[0024] Figure 3 This is a TEM crystallization trend diagram of the ACP@TH nanoassembly in Example 1;

[0025] Figure 4 Figure 1 shows the dilution plate count results of the antibacterial experiment for the control group and the ACP@TH group.

[0026] Figure 5 SEM images of bacterial morphology in the antibacterial experiment of the control group and the ACP@TH group;

[0027] Figure 6 SEM images of tooth enamel slices from the control group and the ACP@TH group after 7 days of in vitro mineralization at different magnifications;

[0028] Figure 7 Comparison of Vickers hardness of mineralized enamel in healthy tooth enamel group, control group and ACP@TH group;

[0029] Figure 8 SEM images of dentin slices from the control group and ACP@TH group after 7 days of in vitro mineralization;

[0030] Figure 9 Comparison of Vickers hardness of mineralized enamel in the healthy dentin group, control group and ACP@TH group;

[0031] Figure 10 SEM images of the surface of mineralized dentin slices from the ACP@TH group after mechanical friction and acid etching treatment;

[0032] Figure 11 This study compares the changes in air tightness of mineralized dentin before and after mechanical friction and acid etching treatment in the control group and the ACP@TH group.

[0033] Figure 12 SEM images comparing the dentinal tubule sealing effects between the control group and the ACP@TH group;

[0034] Figure 13 SEM images of the dentinal tubule occlusion depth observed under low magnification in the ACP@TH group. Detailed Implementation

[0035] This invention provides a method for preparing a bifunctional nanomaterial with "antibacterial synergy and mineralization regulation". The preparation steps of the bifunctional nanomaterial are as follows:

[0036] (1) Mix disodium hydrogen phosphate solution and calcium chloride solution to obtain an amorphous calcium phosphate suspension;

[0037] (2) Mix the amorphous calcium phosphate suspension and the tannic acid solution to obtain the ACP@TA suspension;

[0038] (3) Mix ACP@TA suspension and hydroxypropyltrimethylammonium chloride chitosan solution to obtain bifunctional nanomaterials.

[0039] In this invention, in step (1), the molar ratio of Ca in the calcium chloride solution to P in the disodium hydrogen phosphate solution is 1.2 to 1.5:1; the concentration of the disodium hydrogen phosphate solution is 0.002 to 0.006 mol / L, preferably 0.003 to 0.005 mol / L, and more preferably 0.004 mol / L; the concentration of the calcium chloride solution is 0.004 to 0.008 mol / L, preferably 0.005 to 0.007 mol / L, and further optimized to 0.006 mol / L.

[0040] As a precursor in the non-classical crystallization pathway of mineralization, amorphous calcium phosphate possesses excellent bioactivity and the ability to release large amounts of calcium and phosphate ions, and is often used as a calcium and phosphate source for remineralization, added to bone cement, repair resins, or adhesives. However, due to its low surface energy and extreme thermodynamic instability, amorphous calcium phosphate readily and spontaneously transforms into the more stable crystalline hydroxyapatite.

[0041] In this invention, the concentration of the tannic acid solution in step (2) is 6-12 mg / mL, preferably 7-11 mg / mL, and more preferably 8-10 mg / mL; the pH value is 8.

[0042] Tannic acid is a polyphenol compound with antioxidant, metal chelating, free radical scavenging, and protein complexing properties due to its multi-hydroxyl structure. As a mixture of diphenols and triphenols, tannic acid possesses a unique dendritic structure, which allows it to act as a multidentate ligand to chelate metal ions, forming a three-dimensional stable metal-phenolic network. The synthesis of this coordination compound is rapid and stable, offering a low-cost and quick method for preparing functional materials. It also provides another pathway for stabilizing amorphous calcium phosphate and delaying crystal growth.

[0043] In this invention, the volume ratio of the amorphous calcium phosphate suspension to the tannic acid solution is 60:0.10 to 0.14, preferably 60:0.11 to 0.13, and more preferably 60:0.12.

[0044] In this invention, in steps (2) and (3), the mixing temperature is independently 0 to 6°C, preferably 1 to 5°C, and more preferably 2 to 4°C; the mixing time is independently 3 to 8 min, preferably 4 to 7 min, and more preferably 5 to 6 min.

[0045] In this invention, the concentration of the hydroxypropyltrimethylammonium chloride chitosan solution in step (3) is 6-15 mg / mL, preferably 7-13 mg / mL, and more preferably 8-12 mg / mL.

[0046] Chitosan, the only alkaline polysaccharide discovered in nature to date, possesses excellent biocompatibility, biodegradability, antibacterial properties, and wound-healing capabilities, leading to its widespread application in medicine, food, and functional materials. However, its high crystallinity and poor water solubility, allowing it to dissolve only in a few acidic solutions such as acetic acid and hydrochloric acid, significantly limit its broad applicability. Hydroxypropyltrimethylammonium chloride chitosan, a successful example of chitosan modification, introduces quaternary ammonium groups into the chitosan molecular chain through substitution and copolymerization. This modification not only retains the original properties of chitosan but also greatly improves its water solubility and antibacterial properties, playing a crucial role in scar treatment, tumor growth inhibition, and anti-infection.

[0047] In this invention, the volume ratio of the amorphous calcium phosphate suspension to the hydroxypropyltrimethylammonium chloride chitosan solution is 60:3 to 5, preferably 60:4.

[0048] In this invention, during step (3), the hydroxypropyltrimethylammonium chloride chitosan solution is added to the ACP@TA suspension in batches, and incubated for 3 to 8 minutes after each addition.

[0049] The present invention also provides a bifunctional nanomaterial prepared by the above-described method for preparing "antibacterial synergy-mineralization regulation" bifunctional nanomaterials.

[0050] The present invention also provides an application of the above-described bifunctional nanomaterial in the preparation of tooth remineralization products or anti-dentin hypersensitivity products.

[0051] The technical solutions provided by the present invention will be described in detail below with reference to the embodiments, but they should not be construed as limiting the scope of protection of the present invention.

[0052] Example 1

[0053] Under magnetic stirring in a constant-temperature cold trap at 4℃, 30 mL of 0.004 mol / L Na2HPO4 solution and 30 mL of 0.006 mol / L CaCl2 solution were rapidly mixed to obtain an amorphous calcium phosphate suspension. Then, 120 μL of 8 mg / mL tannic acid solution (pH = 8) was added to the amorphous calcium phosphate suspension and stirred for 5 min to obtain an ACP@TA suspension. Finally, 800 μL of 8 mg / mL hydroxypropyltrimethylammonium chloride chitosan solution was added to the ACP@TA suspension in 5 portions, and incubated for 5 min after each addition to obtain a bifunctional nanomaterial, denoted as ACP@TH nanoassembly.

[0054] The preparation of ACP@TH nanoassemblies mainly relies on metal-phenolic networks and electrostatic attraction. This unique assembly method provides new ideas and possibilities for the synergistic effect of remineralization and antibacterial treatment of dental hard tissues. During the remineralization process of dental hard tissues, amorphous calcium phosphate, as a mineralization precursor, can be gradually converted into HAP on the surface of dental hard tissues, thereby effectively promoting the repair of tooth defects. Tannic acid, as a natural polyphenol compound, interacts with the CaO in amorphous calcium phosphate through its catechol groups. 2+ The metal coordination of the hydroxypropyltrimethylammonium chloride (HCP) forms a dynamically cross-linked metal-phenolic network, providing a confined space for the rapid nucleation of amorphous calcium phosphate (HAp), thus effectively delaying the transformation of amorphous calcium phosphate into crystalline HAp and ensuring the stability and durability of the material on the tooth surface. Hydroxypropyltrimethylammonium chloride chitosan, as a cationic polymer, possesses excellent biocompatibility and antibacterial properties. Its quaternary ammonium groups on the molecular chain combine with negatively charged ACP@TA nanoassemblies through electrostatic attraction, forming a stable double-layered core-shell structure. This multi-level assembly strategy not only achieves molecular-level assembly of inorganic-organic components, but the quaternary ammonium salt groups can also interact with the negative charge on the bacterial cell membrane, thereby disrupting the integrity of the bacterial cell membrane and achieving an antibacterial effect. This nanoassembly can not only effectively release antibacterial components and inhibit the growth of cariogenic bacteria in the oral cavity, but also promote the remineralization of dental hard tissues while simultaneously providing antibacterial protection.

[0055] Example 2

[0056] Under magnetic stirring in a constant-temperature cold trap at 4℃, 30 mL of 0.005 mol / L Na2HPO4 solution and 30 mL of 0.006 mol / L CaCl2 solution were rapidly mixed to obtain an amorphous calcium phosphate suspension. Then, 140 μL of 8 mg / mL tannic acid solution (pH = 8) was added to the amorphous calcium phosphate suspension and stirred for 5 min to obtain an ACP@TA suspension. Finally, 600 μL of 8 mg / mL hydroxypropyltrimethylammonium chloride chitosan solution was added to the ACP@TA suspension in 5 portions, and incubated for 5 min after each addition to obtain a bifunctional nanomaterial, denoted as ACP@TH nanoassembly.

[0057] Example 3

[0058] Under magnetic stirring in a constant-temperature cold trap at 4℃, 30 mL of 0.004 mol / L Na2HPO4 solution and 30 mL of 0.006 mol / L CaCl2 solution were rapidly mixed to obtain an amorphous calcium phosphate suspension. Then, 100 μL of 8 mg / mL tannic acid solution (pH = 8) was added to the amorphous calcium phosphate suspension and stirred for 5 min to obtain an ACP@TA suspension. Finally, 1000 μL of 8 mg / mL hydroxypropyltrimethylammonium chloride chitosan solution was added to the ACP@TA suspension in 5 portions, and each addition was incubated for 5 min to obtain a bifunctional nanomaterial, denoted as ACP@TH nanoassembly.

[0059] Performance determination of the ACP@TH nanoassembly of Example 1:

[0060] (1) Figure 1 These are state images and optical images of the ACP@TH nanoassembly from Example 1. Figure 1 The results showed that no obvious particle aggregation was observed in the ACP@TH nanoassemblies, indicating that they have good dispersibility. When irradiated with a laser, a bright "pathway" appeared in the suspension, further confirming the uniform distribution of the nanoassemblies in the solution.

[0061] (2) X-ray diffraction was used to identify the crystallinity of the freeze-dried ACP@TH nanoassemblies and to determine their Cu Kα radiation. The voltage was 40 kV, 30 mA, and the scanning 2θ range was 10°–60° with a step size of 0.02°. The characterization results are as follows: Figure 2 As shown, the XRD pattern of the ACP@TH nanoassembly exhibits a broad band at approximately 2θ = 30°, ruling out the presence of HAp or other CaP crystalline phases.

[0062] (3) The particle morphology and elemental composition distribution of the ACP@TH nanoassemblies in Example 1 were characterized by transmission electron microscopy at 110 kV, and the crystallization trend of the nanoassemblies was characterized by selected area electron diffraction. When preparing the TEM sample, the sample solution was first sonicated, then 5 μL of the sample solution was dropped onto a carbon-coated copper grid and allowed to stand for 30 s. Excess liquid was then absorbed from the edge of the droplet with filter paper and the sample was dried and stored. The characterization results are as follows: Figure 3 As shown, the ACP@TH nanoassemblies are spherical with a diameter of approximately 60 nm. They only began to crystallize after being placed at 4°C for five days.

[0063] (4) The killing effect of ultrapure water and the ACP@TH nanoassembly of Example 1 on free Streptococcus mutans was tested. The test procedure was as follows: after resuscitation, Streptococcus mutans was incubated in BHI medium at 37°C and 5% CO2. Hydroxyapatite sheets were used to simulate the tooth surface and placed in a 24-well plate. 500 μL of bacterial suspension (10) was added to each well. 6 The sample solution (CFU / mL) was then added in equal volumes (ultrapure water or ACP@TH, with three replicates per group; ultrapure water served as the control group, and ACP@TH as the ACP@TH group). After thorough mixing, the mixture was incubated at 37°C and 5% CO2 for 4 hours. After incubation, the supernatant from each well was collected for bacterial dilution and plate counting. The antibacterial performance (R) of the ACP@TH group was analyzed using the following formula:

[0064] R(%) = (Nc - N) / Nc × 100%

[0065] Where Nc represents the colony count in the control group and N represents the colony count in the experimental group.

[0066] After 4 hours of antibacterial incubation, scanning electron microscopy (SEM) was performed simultaneously. Hydroxyapatite slides were gently rinsed with PBS buffer to remove non-adhesive bacteria, then transferred to a 2.5% glutaraldehyde solution at 4°C for fixation overnight. Following this, the slides were dehydrated using gradients of ethanol solutions (100%, 90%, 75%, 50%, and 25% ethanol, 15 min each). After dehydration, the samples were dried, sputter-coated with gold, and finally, the morphology of the bacteria in each group was analyzed using SEM to observe the morphological differences of *Streptococcus mutans* in each group. The test results are as follows: Figure 4 , 5 As shown, the ACP@TH group exhibited significant antibacterial ability, with a bactericidal rate of up to 97.3% against free Streptococcus mutans. The bacteria in this group also showed obvious shrinkage and deformation under a scanning electron microscope.

[0067] (5) In vitro mineralization test procedure for enamel and dentin: Healthy premolars and third molars aged 18-25 years without caries, cracks, or defects were used to prepare dentin / enamel slices of 4×3×1mm³. The surface of the slices was polished with silicon carbide sandpaper. To simulate the acid etching and demineralization of the tooth surface, the dentin slices were etched with 17% EDTA solution (pH=7) for 8 min, and the enamel slices were etched with 37% phosphoric acid for 30 s. The etched slices were ultrasonically cleaned in ultrapure water for 10 min and finally stored in 0.05% thymol solution at 4℃.

[0068] Dental slides were placed in 5 mL of freshly prepared sample solution (ultrapure water or ACP@TH, with ultrapure water as the control group and ACP@TH as the ACP@TH group) for 5 min. After gently rinsing the surface with ultrapure water, the slides were immersed in 1.5× simulated body fluid. Each slide was mineralized with 10 mL of solution in separate tubes, and all slides were placed in a shaker at 37°C. The remineralization solution was changed daily for 7 days. After the mineralization experiment, the slides were removed and sonicated with ultrapure water for 30 seconds to remove loose mineral deposits on the surface. They were then placed in a desiccant box and dried overnight for later use.

[0069] The remineralization effect of each group of glazes was characterized by scanning electron microscopy, and the results are as follows: Figure 6 As shown, in the control group, only a thin mineral layer was formed on the enamel surface, and the enamel pillar structure before acid etching was still clearly visible; in the ACP@TH group, large mineral deposits were observed on the mineralized enamel surface, and it showed a "fish scale" structure similar to that before acid etching.

[0070] Vickers hardness testing procedure: Vickers hardness tests were performed on healthy enamel, healthy dentin, and mineralized enamel and dentin slides to quantify their hardness changes. Three slides were randomly selected from each group, and five points were randomly chosen on each slide. A load of 25 gf was applied and held for 10 seconds to measure the hardness value. Results are as follows: Figure 7 and Figure 9 As shown. Figure 7 The results showed that the enamel hardness value of the ACP@TH group was significantly higher than that of the control group.

[0071] Figure 8 , 9 This corresponds to the scanning electron microscopy and Vickers hardness results of mineralized dentin. Figure 8 The results show that a continuous and dense mineralized layer formed on the dentin surface of the ACP@TH group, completely covering the openings of the dentinal tubules. Figure 9 The results showed that the mechanical strength of the mineralized dentin in the ACP@TH group was significantly higher than that in the control group and could be restored to the level of healthy dentin.

[0072] (6) To comprehensively evaluate the sealing effect of ACP@TH on dentinal tubules, the study also tested the airtightness of mineralized dentin using a bursting device: dentin sheets were fixed between two "O"-shaped rubber rings, ensuring that the holes in the middle of the rubber rings were completely covered. A pressure gauge and syringe were connected to the left side via a three-way connector for precise control and measurement of air pressure; a water droplet was used to create a sealed environment on the right side. When gas was injected into the device by the syringe, if the water droplet moved, it indicated that the gas had successfully penetrated the dentin sheet. The pressure gauge reading at this point could be used to quantify the airtightness of each group of dentin sheets.

[0073] The study also subjected each group of mineralized dentin to mechanical abrasion and acid etching: dentin slices were brushed continuously for 20 minutes, then immersed in a 2% EDTA solution for 1 minute. After rinsing and drying, the airtightness of each group of dentin slices was tested again. Figure 10 As shown, after combined mechanical friction and acid etching treatment, a thin layer of minerals can still be observed continuously covering the surface of the mineralized dentin in the ACP@TH group, and the dentinal tubules remain closed, with minerals blocking the lumen. Figure 11 The airtightness results also showed that the airtightness level of the ACP@TH group remained stable after mechanical abrasion and acid erosion tests on mineralized dentin.

[0074] Figure 12 , 13 The effect of ACP@TH mineralization on dentinal tubule sealing was tested. Dense and continuous columnar minerals were observed to form in the dentinal tubules of the ACP@TH group, and the sealing depth of the dentinal tubules reached about 70μm.

[0075] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A method for preparing a "synergistic antibacterial and mineralization-regulated" bifunctional nanomaterial, characterized in that, The preparation steps of the bifunctional nanomaterial are as follows: (1) Mix disodium hydrogen phosphate solution and calcium chloride solution to obtain an amorphous calcium phosphate suspension; (2) Mix the amorphous calcium phosphate suspension and the tannic acid solution to obtain the ACP@TA suspension; (3) Mix ACP@TA suspension and hydroxypropyltrimethylammonium chloride chitosan solution to obtain bifunctional nanomaterials; The concentration of the tannic acid solution mentioned in step (2) is 6-12 mg / mL, and the pH value is 8; The volume ratio of the amorphous calcium phosphate suspension and the tannic acid solution in step (2) is 60:0.10 to 0.

14.

2. The preparation method of the "antibacterial synergy-mineralization regulation" bifunctional nanomaterial according to claim 1, characterized in that, In step (1), the molar ratio of Ca in the calcium chloride solution to P in the disodium hydrogen phosphate solution is 1.2 to 1.5:1; the concentration of the disodium hydrogen phosphate solution is 0.002 to 0.006 mol / L; and the concentration of the calcium chloride solution is 0.004 to 0.008 mol / L.

3. The preparation method of the "antibacterial synergy-mineralization regulation" bifunctional nanomaterial according to claim 2, characterized in that, In steps (2) and (3), the mixing temperature is independently 0-6°C, and the mixing time is independently 3-8 min.

4. The preparation method of the "antibacterial synergy-mineralization regulation" bifunctional nanomaterial according to claim 1, characterized in that, The concentration of the hydroxypropyltrimethylammonium chloride chitosan solution in step (3) is 6–15 mg / mL.

5. The preparation method of the "antibacterial synergy-mineralization regulation" bifunctional nanomaterial according to claim 2 or 4, characterized in that, The volume ratio of the amorphous calcium phosphate suspension to the hydroxypropyltrimethylammonium chloride chitosan solution is 60:3-5.

6. The preparation method of the "antibacterial synergy-mineralization regulation" bifunctional nanomaterial according to claim 1, characterized in that, In step (3), the hydroxypropyltrimethylammonium chloride chitosan solution is added to the ACP@TA suspension in batches during mixing, and incubated for 3 to 8 minutes after each addition.

7. The bifunctional nanomaterial prepared by the preparation method of the "antibacterial synergy-mineralization regulation" bifunctional nanomaterial according to any one of claims 1 to 6.

8. The use of the bifunctional nanomaterial of claim 7 in the preparation of tooth remineralization products or anti-dentin hypersensitivity products.

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