Antibacterial remineralized nano material self-adaptive to caries environment as well as preparation method and application of antibacterial remineralized nano material

Abstract

The invention discloses a caries environment self-adaptive antibacterial remineralized nano material and a preparation method and application thereof, and the preparation method comprises the following steps: in an inert atmosphere, divalent metal ions, trivalent metal ions and alkali are mixed, and then coprecipitation and hydrothermal reaction are performed to prepare an iron-based nano material DL; reacting the iron-based nano material DL with fluoride in an inert atmosphere to obtain a fluorine-containing nano material DLF; the fluorine-containing nano material DLF and lactate oxidase react in an inert atmosphere, and the antibacterial remineralized nano material DLFL is obtained. The prepared DLFL with the acid degradation characteristic can be degraded at the caries part, chemical dynamic antibiosis is carried out while fluorine is released, remineralization is promoted, further demineralization of the tooth surface is inhibited, and the sterilization effect can be remarkably improved.

Description

Technical Field

[0001] The present invention relates to the field of functional materials, and in particular to an antibacterial remineralization nano material which is adaptive to a dental caries environment, and a preparation method and application of the material. Background Art

[0002] Dental caries is the most common oral disease in the world. It is caused by the accumulation of dental plaque biofilm on the tooth surface. The cariogenic bacteria in the biofilm secrete acid by metabolizing sugars, which leads to a decrease in the local pH value of the oral cavity, thereby destroying the dynamic balance between demineralization and remineralization in the hard tissue of the tooth, causing mineral loss on the surface of the enamel. Therefore, the treatment of dental caries requires promoting the remineralization of the demineralized area on the one hand, and removing the cariogenic bacteria and the biofilm formed on the tooth surface on the other hand.

[0003] In recent years, amorphous calcium phosphate (ACP) has shown an ideal remineralization effect in the prevention and treatment of dental caries. However, ACP requires stabilizers to maintain its amorphous form, such as the additional introduction of some amphoteric polymers. In addition, the use of fluoride in caries is also an effective option. The main component of enamel is hydroxyapatite, and fluoride ions can replace the hydroxyl groups in hydroxyapatite to obtain more acid-resistant fluoroapatite. However, if fluoride is improperly released in the oral environment and causes an explosive release, its biological toxicity and the hidden dangers of fluorosis formation cannot be ignored.

[0004] At present, antimicrobial dynamic therapy (ADT) is becoming a mainstream drug-free treatment method due to its advantages such as no generation of drug-resistant pathogens and fast sterilization speed. It can be simply divided into two categories: exogenous ADT and endogenous ADT. Exogenous ADT relies on the absorption of external energy, such as light and ultrasound, to produce reactive oxygen for sterilization, but it is extremely dependent on the external environment and lacks microenvironmental reactivity. Endogenous ADT, mainly referring to chemodynamic therapy, produces reactive oxygen for sterilization through the Fenton reaction of divalent iron and endogenous H2O2. This strategy can well circumvent the shortcomings of the exogenous strategy, but it has the disadvantage of insufficient endogenous H2O2.

[0005] Therefore, there is an urgent need to develop a safe material that combines high-efficiency antibacterial and remineralization for the prevention and treatment of dental caries. Summary of the invention

[0006] One object of the present invention is to provide a method for preparing an antibacterial remineralization nanomaterial that is adaptive to a caries environment. The preparation method prepares a layered double hydroxide (LDH) using divalent metal ions and trivalent metal ions, and then uses LDH to carry fluorine and lactate oxidase. The obtained antibacterial remineralization nanomaterial with acid degradation characteristics can be degraded at the caries site, and chemical dynamic antibacterial is carried out while releasing fluorine, which not only promotes remineralization and inhibits further demineralization of the tooth surface, but also can effectively eradicate caries-causing bacteria.

[0007] The present invention is achieved through the following technical solutions:

[0008] The method for preparing an antibacterial remineralization nanomaterial that is adaptive to a dental caries environment comprises the following steps:

[0009] Under an inert atmosphere, divalent metal ions, trivalent metal ions and alkali are mixed and then subjected to coprecipitation and hydrothermal reaction to obtain the iron-based nanomaterial DL.

[0010] The iron-based nanomaterial DL and fluoride react in an inert atmosphere to obtain the fluorine-containing nanomaterial DLF;

[0011] Fluorine-containing nanomaterial DLF and lactate oxidase react under an inert atmosphere to obtain the antibacterial remineralization nanomaterial DLFL;

[0012] Wherein, the divalent metal ion is Fe 2+ Mg 2+ , Ca 2+ , Cu 2+ At least one of the trivalent metal ions is Al 3+ , Fe 3+ 、Co 3+ , Mn 3+ At least one of .

[0013] In the technical scheme, a coprecipitation reaction occurs after a divalent metal ion and a trivalent metal ion are mixed with a base. During the coprecipitation reaction, an inert gas is introduced into the reaction system to reduce the interference of oxygen during the reaction. In one or more embodiments, the inert gas is preferably nitrogen or argon. The divalent metal ion can be Fe 2+ Mg 2+ , Ca 2+ , Cu 2+ At least one of the trivalent metal ions may be Al 3+ , Fe 3+ 、Co 3+ , Mn 3+ In some preferred embodiments, in order to ensure the subsequent ideal chemical dynamic antibacterial effect and biosafety, the divalent metal ions and trivalent metal ions are Fe 2+ and Al 3+. In the present technical scheme, the pH value of the reaction system is adjusted by adjusting the alkali to induce the simultaneous precipitation of cationic hydroxides. Preferably, the pH value of the reaction system is 9 to 11. In some preferred embodiments, the alkali can be sodium hydroxide, potassium hydroxide, or urea. In some embodiments, the solvent is preferably deionized water. Further preferably, in order to reduce the influence of oxygen on the reaction system, deionized water with an inert gas to remove dissolved oxygen is preferably used. For example, in one or more embodiments, divalent metal ions and trivalent metal ions can be first dissolved in deoxygenated water, and then the alkali is dissolved in deoxygenated water, and then the alkali solution is added dropwise to the metal salt mixed solution under an inert atmosphere and stirred for co-precipitation. In the present technical scheme, after the co-precipitation reaction, the reaction system undergoes a hydrothermal reaction to obtain an iron-based nanomaterial DL, that is, a layered double hydroxide (LDH). LDH is a lamellar structure for subsequent loading of fluoride ions and lactate oxidase.

[0014] In some preferred embodiments, the temperature of the hydrothermal reaction is 100-140° C., and the time of the hydrothermal reaction is 8-24 hours, so as to further improve the crystallinity and purity of the iron-based nanomaterial DL.

[0015] In the present technical scheme, the divalent or trivalent metal salt used for coprecipitation is a chloride, such as ferrous chloride tetrahydrate or aluminum chloride hexahydrate. Therefore, in the generated layered double hydroxide, the metal cations are electrostatically bonded to the Cl - Compared with Cl - , LDH to F - With greater affinity, the iron-based nanomaterial DL is reacted with fluoride in an inert atmosphere to complete Cl - With F - The metal cations electrostatically bind to F - Combination, thereby achieving LDH to F - The fluorine-containing nanomaterial DLF is obtained by loading the fluoride. Preferably, the fluoride is sodium fluoride. - After that, when LDH, as a hydroxide, is applied to the acidic oral environment of dental caries, it can undergo responsive degradation, thereby slowly releasing the F - . F - The slow release of F can reduce the risk of biotoxicity or fluorosis. - Not only does it have a certain bactericidal effect, but more importantly, F - It can act on hydroxyapatite, the main component of tooth enamel, and then replace the hydroxyl group to form more acid-resistant fluoroapatite, thereby promoting remineralization and inhibiting further demineralization of the tooth surface.

[0016] In some preferred embodiments, fluoride is fully dissolved in deoxygenated water to obtain a fluorine-containing solution, and then the fluorine-containing solution is added dropwise to the solution of the iron-based nanomaterial DL, accompanied by an inert gas, and a fluorine-containing nanomaterial DLF solution is obtained through continuous stirring and an ion balance process. Further, in one or more embodiments, after the balance process is completed, the fluorine-containing nanomaterial DLF solution is collected, centrifuged to remove loosely bound ions, and washed and centrifuged, repeated several times, and then placed in a freeze dryer for freeze drying to obtain LDH containing a large amount of fluorine between the layers, that is, the fluorine-containing nanomaterial DLF. In some embodiments, DLF can also be obtained by drying in an oven.

[0017] In this technical solution, the fluorine-containing nanomaterial DLF further reacts with lactate oxidase under an inert atmosphere to obtain an antibacterial remineralization nanomaterial DLFL loaded with lactate oxidase on the surface. The surface-loaded lactate oxidase can catalyze the lactic acid produced by the metabolism of cariogenic bacteria to form hydrogen peroxide. The consumption of lactic acid can slow down the formation of an acidic environment to a certain extent, thereby reducing the loss of minerals. At the same time, the hydrogen peroxide produced by consuming lactic acid solves the problem of insufficient endogenous hydrogen peroxide in chemodynamic therapy for antibacterial treatment. The formed hydrogen peroxide can further react with the iron in the antibacterial remineralization nanomaterial DLFL to produce toxic active oxygen to eradicate bacteria. In addition, DLFL utilizes the local micro-acidity of caries and the lactic acid produced in situ by cariogenic bacteria to exert its effect, thereby improving the safety and efficiency of the material and avoiding its impact on normal tissues.

[0018] In some preferred embodiments, in order to maintain the activity of the enzyme, the reaction temperature of the fluorine-containing nanomaterial DLF and lactate oxidase should not be too high. In some preferred embodiments, the reaction can be carried out at room temperature or in an ice bath for 2 to 6 hours. Since temperature is one of the factors affecting the reaction rate, the reaction time can be extended under ice bath conditions.

[0019] In some preferred embodiments, the mixed solution after the reaction is collected, centrifuged to remove the loosely bound lactate oxidase, washed, centrifuged, and then placed in a freeze dryer for freeze drying to obtain the final antibacterial remineralization nanomaterial DLFL.

[0020] As a preferred embodiment of the present invention, after dissolving the divalent metal ions and trivalent metal ions, alkali and dextran are added to obtain a mixed solution, and the mixed solution is subjected to coprecipitation and hydrothermal reaction to obtain the iron-based nanomaterial DL.

[0021] In the technical scheme, during the synthesis of the iron-based nanomaterial DL, dextran is additionally added to participate in the coprecipitation of cationic hydroxides. Specifically, after the divalent and trivalent metal ions are dissolved, the alkaline solution and the dextran solution are respectively added to the metal salt mixed solution, and the coprecipitation reaction is carried out by continuous stirring during the addition process.

[0022] In this technical solution, dextran is a polysaccharide that can target bacteria and penetrate into bacterial biofilms. Free bacteria can secrete extracellular polysaccharides, and there are corresponding receptors on their membranes, which can promote mutual recognition and aggregation between free bacteria, thereby forming a bacterial biofilm that is more difficult to remove. Dextran, which also has a polysaccharide structure, can be used for similar targeted binding with bacteria, thereby targeting bacteria and penetrating into biofilms, achieving the purpose of thorough sterilization of subsequent nanomaterials.

[0023] Furthermore, the concentration of the dextran in the mixed solution is 4 to 6 mg / mL. By utilizing the polysaccharide receptors on the surface of the bacterial membrane, the introduction of dextran can improve the targeting effect of the nanomaterial on bacteria and their biofilms. To ensure that the additionally introduced dextran does not affect the crystal structure of pure LDH, etc., preferably, the concentration of dextran in the reaction solution system is 4 to 6 mg / mL.

[0024] Furthermore, the molar ratio of the divalent metal ion to the trivalent metal ion is 2 to 4. In the present technical solution, in order to ensure the formation of high-purity and high-crystalline LDH, the molar ratio of the divalent metal ion to the trivalent metal ion is preferably 2 to 4, and more preferably 2 to 3.

[0025] Furthermore, the fluoride is sodium fluoride, and the mass ratio of the iron-based nanomaterial DL to sodium fluoride is 1 to 2. When sodium fluoride is added to carry out anion replacement reaction, if F - If the concentration is too low, the subsequent remineralization effect will be affected. - The concentration is too high, due to the limited interlayer capacity of LDH, F - Not only will it enter the LDH interlayer, but it may also be adsorbed on the surface of the LDH material, which not only reduces the adsorption points of subsequent lactate oxidase, but also, when applied in the oral environment, the F adsorbed on the surface - It may be released suddenly in the early stage of treatment, causing uncontrollable fluoride release in the caries area.

[0026] Furthermore, the mass ratio of the fluorine-containing nanomaterial DLF to lactate oxidase is 50 to 200. In the technical solution, considering the efficiency and cost of subsequent catalytic antibacterial, the mass ratio of the fluorine-containing nanomaterial DLF to lactate oxidase is set to 50 to 200.

[0027] Another object of the present invention is to provide an antibacterial remineralizing nanomaterial that is adaptive to a caries environment and is prepared based on any of the aforementioned preparation methods. After degradation in the oral environment, the nanomaterial can release fluoride ions that can kill bacteria, and the fluoride ions can also replace the hydroxyl groups in hydroxyapatite to form fluoroapatite, thereby inhibiting the risk of demineralization of the tooth surface; in addition, the nanomaterial can also perform chemical dynamic antibacterial activities, significantly improving the effect of killing caries-causing bacteria.

[0028] In the technical solution, the prepared antibacterial remineralization nanomaterial DLFL is an iron-containing lamellar structure, the interlayers of the lamellar structure contain a large amount of fluorine, and the surface of the lamellar structure contains lactate oxidase.

[0029] In the slightly acidic environment of caries, the fluoride ions slowly released after the degradation of the antibacterial remineralization nanomaterial DLFL can replace the hydroxyl groups in hydroxyapatite to form fluoroapatite, making the tooth surface more acid-resistant and suppressing the risk of tooth surface demineralization. At the same time, fluoride itself has a certain killing power against bacteria. In addition, DLFL can also carry out chemical dynamic antibacterial. The lactate oxidase loaded by DLFL can consume the lactic acid produced by bacterial metabolism and produce hydrogen peroxide in situ. The hydrogen peroxide then reacts with iron to produce deadly reactive oxygen to kill caries-causing bacteria.

[0030] The present invention also provides the use of any of the aforementioned antibacterial remineralization nanomaterials that are adaptive to the dental caries environment, and the antibacterial remineralization nanomaterial can be used to prepare drugs or oral hygiene products for preventing and treating dental caries, and the oral hygiene products include toothpaste, mouthwash, etc. By using DLFL as an active ingredient of drugs or oral hygiene products, it can spontaneously degrade in slightly acidic dental caries sites, release fluoride, and perform chemical dynamic antibacterial, thereby achieving dental caries prevention and treatment that integrates high-efficiency antibacterial and remineralization.

[0031] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0032] 1. When the antibacterial remineralization nanomaterial DLFL of the present invention is applied to the acidic oral environment of dental caries, it can be responsively degraded, thereby slowly releasing the F - , F - The slow release of F can reduce the risk of biotoxicity or fluorosis. - Not only does it have a certain bactericidal effect, but more importantly, F - It can act on hydroxyapatite, the main component of tooth enamel, and then replace the hydroxyl group to form more acid-resistant fluoroapatite, which promotes remineralization and inhibits further demineralization of the tooth surface;

[0033] 2. The lactate oxidase loaded on the surface of the antibacterial remineralization nanomaterial DLFL of the present invention can catalyze the lactic acid produced by the metabolism of cariogenic bacteria to form hydrogen peroxide. The consumption of lactic acid can slow down the formation of an acidic environment to a certain extent, thereby reducing the loss of minerals. At the same time, the hydrogen peroxide produced by consuming lactic acid solves the problem of insufficient endogenous hydrogen peroxide in chemodynamic antibacterial therapy. The formed hydrogen peroxide can further undergo a Fenton reaction with the iron in the antibacterial remineralization nanomaterial DLFL to produce toxic active oxygen to eradicate bacteria.

[0034] 3. The present invention introduces dextran during the coprecipitation process, which can be targeted and combined with bacteria, thereby targeting bacteria and penetrating into the biofilm, achieving the purpose of thorough sterilization of subsequent nanomaterials;

[0035] 4. The antibacterial remineralization nanomaterial DLFL of the present invention utilizes the local micro-acidity of caries and the lactic acid produced in situ by cariogenic bacteria to exert its effects, thereby improving the safety and efficiency of the material and avoiding its influence on normal tissues;

[0036] 5. The present invention adjusts the amount of fluoride in the antibacterial remineralization nanomaterial DLFL so that F - The concentration can meet the needs of remineralization, and will not accumulate on the surface of the final DLFL, reducing the adsorption of lactate oxidase and causing uncontrollable fluoride release treatment at the caries site;

[0037] 6. The present invention can ensure that the additionally introduced dextran will not affect the crystal structure of pure LDH by adjusting the dosage of dextran, which is beneficial to improving the crystallinity of DL.

[0038] 7. The DLFL prepared by the present invention can be used to prepare drugs or oral hygiene products for preventing and treating dental caries. It can be degraded at the site of caries and perform chemical dynamic antibacterial while releasing fluoride, which not only promotes remineralization and inhibits further demineralization of the tooth surface, but also can significantly improve the bactericidal effect. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] The drawings described herein are used to provide a further understanding of the embodiments of the present invention, constitute a part of this application, and do not constitute a limitation of the embodiments of the present invention. In the drawings:

[0040] Figure 1 It is a flowchart of the preparation method in a specific embodiment of the present invention;

[0041] Figure 2 is a scanning electron microscope image of the iron-based nanomaterial DL under different hydrothermal conditions in a specific embodiment of the present invention, wherein Figure 2 a. Figure 2 b are iron-based nanomaterials DL and DL-8, respectively;

[0042] Figure 3 The ion release of the fluorine-containing nanomaterials in different pH environments in the specific embodiment of the present invention is shown in FIG. Figure 3 a is the release of fluoride ions, Figure 3 b is the release of iron ions;

[0043] Figure 4 It is a diagram showing the efficiency of different nanomaterials in oxidizing TMB in a specific embodiment of the present invention;

[0044] Figure 5 The antibacterial effects of different nanomaterials on Streptococcus mutans in the specific embodiments of the present invention are shown in FIG. Figure 5 a is a photo of bacterial residues. Figure 5 b is the bacterial survival rate, Figure 5 c is a photo of bacteria being stained alive and dead. Figure 5 d is the ratio of live bacteria to dead bacteria;

[0045] Figure 6 Remineralization of acid-etched enamel flakes by different nanomaterials in specific embodiments of the present invention; DETAILED DESCRIPTION

[0046] In order to make the objectives, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with embodiments and drawings. The exemplary embodiments of the present invention and their description are only used to explain the present invention and are not intended to limit the present invention.

[0047] All raw materials of the present invention are not particularly limited to their sources, and can be purchased on the market or prepared according to conventional methods well known to those skilled in the art. All raw materials of the present invention are not particularly limited to their purity, and the present invention preferably adopts analytically pure or conventional purity requirements in the field of functional materials. All raw materials of the present invention, their brands and abbreviations belong to conventional brands and abbreviations in this field, and each brand and abbreviation is clear and definite in the field of its related use. Those skilled in the art can purchase from commercial or prepare by conventional methods according to the brand, abbreviation and corresponding use.

[0048] 1. Preparation of antibacterial remineralizing nanomaterials

[0049] [Example 1]

[0050] S1: Preparation of iron-based nanomaterials DL

[0051] S11, put 100 mL of deionized water in a two-necked flask, wrap it tightly with a sealing film, and pass nitrogen gas for 30 minutes to obtain deoxygenated water;

[0052] S12, dissolving 397.50 mg of ferrous chloride tetrahydrate and 241.34 mg of aluminum chloride hexahydrate in 10 mL of deoxygenated water to obtain a metal salt solution for standby use;

[0053] S13, dissolving 240 mg of sodium hydroxide in 40 mL of deoxygenated water to obtain a sodium hydroxide solution, and dissolving 322 mg of dextran in 10 mL of deoxygenated water to obtain a dextran solution;

[0054] S14, under a nitrogen atmosphere, slowly drop the sodium hydroxide solution into the metal salt solution, and keep stirring, and after 20 minutes, drop the dextran solution into the reaction system, and keep stirring for 10 minutes;

[0055] S15, transferring the reaction system to a polytetrafluoroethylene reactor, and placing the reactor in an oven at 120° C. for 24 h;

[0056] S16. The mixed solution obtained after the reaction in S15 is transferred to a centrifuge tube, centrifuged and washed at a speed of 9000 r / min, and repeated three times. The supernatant is removed and freeze-dried, which is recorded as iron-based nanomaterial DL.

[0057] In some embodiments, the mixed solution obtained after centrifugal washing of S16 can be further used in the subsequent preparation of fluorine-containing nanomaterial DLF without freeze-drying to obtain iron-based nanomaterial DL.

[0058] S2: Preparation of fluorine-containing nanomaterials DLF

[0059] S21, dissolving the iron-based nanomaterial DL in 25 mL of deoxygenated water, wherein the concentration of DL is 4 mg / mL, to obtain an iron-based nanomaterial solution;

[0060] S22, dissolving sodium fluoride in 25 mL of deoxygenated water to obtain a sodium fluoride solution, wherein the concentration of sodium fluoride is 2 mg / mL;

[0061] S23, under a nitrogen atmosphere, gradually adding the sodium fluoride solution to the iron-based nanomaterial solution, and continuously stirring for 24 hours;

[0062] S24, transferring the solution obtained in S23 to a centrifuge tube, centrifuging and washing at a speed of 9000 r / min, repeating three times, removing the supernatant and freeze-drying, and recording as fluorine-containing nanomaterial DLF;

[0063] In some embodiments, the mixed solution obtained after centrifugal washing of S24 can be further used in the subsequent preparation of antibacterial remineralization nanomaterial DLFL without freeze-drying to obtain the fluorine-containing nanomaterial DLF.

[0064] S3: Preparation of antibacterial remineralization nanomaterials DLFL

[0065] S31, dissolving the fluorine-containing nanomaterial DLF in 50 mL of deoxygenated water, wherein the concentration of DLF is 4 mg / mL;

[0066] S32, dissolving lactate oxidase in 1 mL of deoxygenated water, wherein the concentration of lactate oxidase is 4 mg / mL;

[0067] S33, under nitrogen atmosphere, placing the fluorine-containing nanomaterial solution in an ice bath environment, and slowly adding the lactate oxidase solution dropwise with continuous stirring for 4 hours;

[0068] S34. The solution obtained in S34 was transferred to a centrifuge tube, centrifuged and washed at a speed of 9000 r / min, and the process was repeated three times. The supernatant was removed and freeze-dried, and the result was recorded as the antibacterial remineralization nanomaterial DLFL.

[0069] [Example 2]

[0070] The preparation steps of Example 2 are similar to those of Example 1, except that in Example 2, the molar ratio of the divalent metal ion to the trivalent metal ion is 3.

[0071] [Example 3]

[0072] The preparation steps of Example 3 are similar to those of Example 1, except that in Example 3, the molar ratio of the divalent metal ion to the trivalent metal ion is 4.

[0073] [Example 4]

[0074] The preparation steps of Example 4 are similar to those of Example 1, except that in Example 4, the mass ratio of the iron-based nanomaterial DL to the sodium fluoride is 1.2.

[0075] [Example 5]

[0076] The preparation steps of Example 5 are similar to those of Example 1, except that in Example 5, the mass ratio of the iron-based nanomaterial DL to sodium fluoride is 1.5.

[0077] [Example 6]

[0078] The preparation steps of Example 6 are similar to those of Example 1, except that in Example 6, the mass ratio of the fluorine-containing nanomaterial DLF to lactate oxidase is 200.

[0079] [Example 7]

[0080] The preparation steps of Example 7 are similar to those of Example 1, except that in Example 6, the mass ratio of the fluorine-containing nanomaterial DLF to lactate oxidase is 100.

[0081] [Example 8]

[0082] The preparation steps of Example 8 are similar to those of Example 1, except that in Example 8, in step S15, the reaction time in the oven is adjusted to 8 h. Figure 2 The scanning electron microscope images of the iron-based nanomaterial DL and DL-8 prepared by S1 of Example 8 are shown. It can be seen from the figure that the time of the hydrothermal reaction will change the morphology and size of the nanomaterial. Therefore, if the hydrothermal reaction time is too short, for example, less than 8 hours, it will be unfavorable for the formation of crystals.

[0083] [Example 9]

[0084] The preparation steps of Example 9 are similar to those of Example 1, except that in Example 9, the concentration of sodium fluoride is reduced to 1 mg / mL to obtain a fluorine-containing nanomaterial.

[0085] [Example 10]

[0086] The preparation steps of Example 10 are similar to those of Example 1, except that in Example 10, the stirring reaction time in step S33 is 6 hours.

[0087] 2. Performance test of antibacterial remineralization nanomaterials

[0088] [Example 11]

[0089] In this example, the ion release performance of the fluorine-containing nanomaterial was tested.

[0090] Specifically, 10 mg of fluorine-containing nanomaterial DLF was dissolved in 10 mL of aqueous solution with different pH values ​​(pH=5.0, 6.5, 7.4), put into a dialysis bag with Mw=2000, and the dialysis bag was put into 10 mL of corresponding aqueous solution with different pH values, placed on a shaker, and samples were taken at regular intervals.

[0091] The cumulative fluoride release of fluorine-containing nanomaterial DLF under different pH environments was tested using a fluoride ion potentiometer. The results are as follows: Figure 3 As shown in a, the lower the environmental pH value, the more F released by DLF - The more.

[0092] The cumulative iron release of fluorine-containing nanomaterial DLF under different pH environments was tested by o-phenanthroline spectrophotometry. Figure 3 As shown in (b), the lower the environmental pH value, the more Fe is released by DLF, which proves the acid-responsive degradation characteristics of the material and can adapt to the caries environment.

[0093] [Example 12]

[0094] In this example, the catalytic performance of different nanomaterials was tested.

[0095] Specifically, different materials (DL, DLF, DLFL) were dissolved in acetate buffer at a concentration of 1 mg / mL, TMB (3,3',5,5'-tetramethylbenzidine) solution was added to a concentration of 1mM, and 1mM H2O2 or a mixture of 1mH2O2 and 2mM lactic acid (LA) was added to the DLFL test group, followed by high-speed centrifugation, and 1mL of supernatant was taken to test its absorbance at 500-800nm. There are five groups in total: DL, DLF, DLFL, DLFL+H2O2, and DLFL+H2O2+LA.

[0096] The experimental results are as follows Figure 4 As shown, the pure DL, DLF, and DLFL material groups have almost no ability to oxidize TMB to turn blue. When hydrogen peroxide is added to DLFL, the absorbance of TMB is significantly improved. On this basis, the addition of lactic acid further improves the absorbance of TMB, which confirms the catalytic ability of DLFL in the presence of hydrogen peroxide / lactic acid.

[0097] [Example 13]

[0098] In this example, the antibacterial properties of different nanomaterials against Streptococcus mutans were tested.

[0099] Specifically, Streptococcus mutans was diluted to 10 6 CFU / mL, and 100 μL of the diluted bacterial solution was co-cultured with 100 μL of different nanomaterials (DL, DLF, DLFL). The concentration of the nanomaterial was set to 1 mg / mL. Another group of DLFL+LA was set up. After 4 h of co-culture, the bacterial solution of each group was diluted 10 4 times, take 100 μL of the diluted bacterial solution and apply it to the solid culture medium and incubate for 12 hours. Figure 5 As shown in Figures 5a and 5b, after DLF and DLFL were loaded with fluoride ions, the fluoride ions had a certain bactericidal ability, and after adding lactic acid, the antibacterial rate of DLFL against Streptococcus mutans was significantly improved to more than 99%. It can be expected that in the dental environment, DLFL can further consume lactic acid to produce hydrogen peroxide, making up for the problem of insufficient endogenous hydrogen peroxide, so as to significantly improve the bactericidal ability of DLFL.

[0100] In addition, DMAO / PI dyes were added to the co-cultured bacterial solution to color the live / dead bacteria. The live bacteria were stained with green fluorescence, and the dead bacteria were stained with red and green fluorescence. The fluorescence was superimposed to show yellow fluorescence. The experimental results are as follows Figure 5 As shown in c and 5d, almost all the bacteria in the DLFL+LA group were dead, which once again verified the bacterial killing effect of the nanomaterial.

[0101] [Example 14]

[0102] In this example, the remineralization performance of different nanomaterials on acid-etched tooth enamel slices was tested.

[0103] Specifically, the enamel slices were etched with phosphoric acid for 30 seconds to obtain acid-etched enamel slices, which were then immersed in simulated saliva as the control group. In the experimental group, different nanomaterials (DL, DLF, DLFL) were additionally added to the simulated saliva. The remineralization of the acid-etched enamel slices in different groups was observed using a scanning electron microscope. The experimental results are shown in Figure 2. Figure 6 As shown, the teeth of the fluoride-containing groups (DLF, DLFL) became smoother and had obvious mineral accumulation.

[0104] The specific implementation methods described above further illustrate the objectives, technical solutions and beneficial effects of the present invention in detail. It should be understood that the above description is only a specific implementation method of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A method for preparing an antibacterial remineralizing nanomaterial that is adaptive to a dental caries environment, characterized in that: The following steps are involved: Under an inert atmosphere, divalent metal ions, trivalent metal ions and alkali are mixed and then subjected to coprecipitation and hydrothermal reaction to obtain the iron-based nanomaterial DL. The iron-based nanomaterial DL and fluoride react in an inert atmosphere to obtain the fluorine-containing nanomaterial DLF; Fluorine-containing nanomaterial DLF and lactate oxidase react under an inert atmosphere to obtain the antibacterial remineralization nanomaterial DLFL; Wherein, the divalent metal ion is Fe 2+ Mg 2+ , Ca 2+ , Cu 2+ At least one of the trivalent metal ions is Al 3 + , Fe 3+ 、Co 3+ , Mn 3+ At least one of .

2. The method for preparing the antibacterial remineralization nanomaterial that is adaptive to the dental caries environment according to claim 1, characterized in that: After dissolving the divalent metal ions and trivalent metal ions, alkali and dextran are added to obtain a mixed solution, and the mixed solution is subjected to coprecipitation and hydrothermal reaction to obtain the iron-based nanomaterial DL.

3. The method for preparing the antibacterial remineralization nanomaterial that is adaptive to the dental caries environment according to claim 2, characterized in that: The concentration of the dextran in the mixed solution is 4-6 mg / mL.

4. The method for preparing the antibacterial remineralizing nanomaterial that is adaptive to the dental caries environment according to claim 1, characterized in that: The molar ratio of the divalent metal ions to the trivalent metal ions is 2-4.

5. The method for preparing the antibacterial remineralization nanomaterial that is adaptive to the dental caries environment according to claim 1, characterized in that: The fluoride is sodium fluoride, and the mass ratio of the iron-based nanomaterial DL to sodium fluoride is 1-2.

6. The method for preparing the antibacterial remineralization nanomaterial that is adaptive to the dental caries environment according to claim 1, characterized in that: The mass ratio of the fluorine-containing nanomaterial DLF to lactate oxidase is 50-200.

7. The method for preparing an antibacterial remineralizing nanomaterial that is adaptive to a dental caries environment according to any one of claims 1 to 6, characterized in that: The temperature of the hydrothermal reaction is 100 to 140° C., and the time of the hydrothermal reaction is 8 to 24 hours.

8. The method for preparing an antibacterial remineralizing nanomaterial that is adaptive to a dental caries environment according to any one of claims 1 to 6, characterized in that: The reaction between the fluorine-containing nanomaterial DLF and lactate oxidase is carried out in an ice bath, and the reaction time is 2 to 6 hours.

9. An antibacterial remineralizing nanomaterial that is adaptive to the dental caries environment, characterized in that: The antibacterial remineralization nano material is prepared by the preparation method described in any one of claims 1 to 8.

10. Use of the antibacterial remineralizing nanomaterial that is adaptive to the dental caries environment as claimed in claim 9 in the preparation of drugs or oral hygiene products for preventing dental caries.

Images