Self-driven nano antibacterial material as well as preparation method and application thereof

Abstract

The invention discloses a self-driven nano antibacterial material as well as a preparation method and application thereof, and belongs to the technical field of biomedical antibacterial materials. The preparation method comprises the following steps: firstly preparing mesoporous silica nanoparticles loaded with calcium peroxide, then adsorbing polyacrylic acid, precipitating on the nanoparticles by utilizing island-shaped nucleation and seed polymerization processes of a PDA layer, generating anisotropic coverage of the PDA layer on the nanoparticles by seed polymerization of dopamine, and preparing Janus structure nanoparticles by controlling polymerization time. Then L-arginine is further grafted on the polydopamine to obtain a self-driven nano-antibacterial material, and the self-driven nano-antibacterial material is mixed with sterile PBS to prepare paste for root canal disinfection. The paste generates an asymmetrically distributed photothermal effect and nitric oxide gas under the excitation of 808nm near-infrared light, and the formed dual-fuel pushes a nano motor to go deep into narrow intertubule traffic and dentin tubules, so that the targeting and penetrating capabilities on a biological membrane are improved, and an excellent sterilizing effect is achieved.

Description

Technical Field

[0001] The present invention relates to the technical field of biomedical antibacterial materials, and more particularly to a self-driven nano antibacterial material and a preparation method and application thereof. Background Art

[0002] Oral apical periodontitis is a disease caused by microbial infection that can lead to gingival fistulas, alveolar abscesses, chronic apical periodontitis, root resorption, and even tooth loss. Currently, the most effective treatment is root canal therapy, which aims to control infection within the root canal and promote healing of the apical tissue. According to statistics, the success rate of root canal therapy is 86%-97%, while the success rate of root canal retreatment is 74%-86%. Patients with incomplete healing experience pain, tooth mobility and loss, and even infection of surrounding tissues, placing an additional burden on patients. After invading the root canal system, microorganisms exist in both free and suspended forms and in biofilms. Free bacteria can cause acute infection but are easily eliminated. When bacteria adhere and colonize within the root canal and periapical areas, forming biofilms, they easily adhere to the root canal walls and invade the dentinal tubules, creating their own microecological environment, resisting host immunity, exerting pathogenic effects such as drug resistance, and making them difficult to eliminate. Furthermore, the root canal system is complex and diverse. In addition to the main root canal, there are also lateral root canals, apical bifurcations, furcations, accessory root canals, and isthmuses. Foreign researchers have conducted histological examinations of the root apex of failed root canal treatments and found that the detection rate of bacteria in the isthmus and lateral root canals was 88%. The complexity of the root canal structure makes it difficult for conventional antimicrobial drugs to penetrate deeply and be effective.

[0003] The success rate of root canal treatment depends on the control of infection, and inter-office sealing is a good way to control infection. Currently, the most commonly used drug for inter-office sealing is calcium hydroxide paste. The problems are as follows: calcium hydroxide paste relies on the alkaline environment to kill most free bacteria in the root canal, but it is not sensitive to Enterococcus faecalis; its low solubility leads to unsatisfactory drug diffusion effect and poor penetration of bacterial biofilms; it cannot be used for long-term sealing, and its strong alkalinity will weaken the mechanical strength of dentin, reduce dentin hardness, and pose a risk of root fracture. Ideal control of root canal infection requires penetrating into the complex root canal system to remove adherent bacterial biofilms. Current inter-office sealing drugs have not yet fully met the needs, and traditional root canal treatment cannot completely eliminate microorganisms in infected root canals. More efficient and safe root canal biofilm removal methods are the focus of future root canal treatment research.

[0004] In view of this, the invention of a self-propelled nano antibacterial material and its preparation method and application are of great significance for clinical treatment. Summary of the Invention

[0005] In view of this, the present invention provides a self-propelled nano-antibacterial material, a preparation method and application thereof. First, calcium peroxide is loaded on mesoporous silica, and then a Janus-structured polydopamine layer is generated on its surface using polyacrylic acid. Arginine is further grafted on the surface of the polydopamine to obtain the final self-propelled nano-antibacterial material.

[0006] In order to achieve the above object, the present invention adopts the following technical solutions:

[0007] First, the present application provides a method for preparing a self-propelled nano antibacterial material, which specifically includes the following steps:

[0008] S1 Synthesis of calcium peroxide-loaded mesoporous silica

[0009] Mesoporous silica was dispersed in methanol to prepare an MSNs-methanol mixture; CaCl2 solution was added to the MSNs-methanol mixture and vigorously stirred at room temperature for 2.5 hours; then an ammonia solution was added to react; then H2O2 solution was added through a syringe pump, and vigorously stirred at room temperature for 10 minutes, followed by centrifugation and washing with methanol and ethanol to obtain mesoporous silica loaded with calcium peroxide, denoted as CM.

[0010] The reaction principle is as follows: CaCl2 dissociates into calcium ions in methanol, which diffuse into the pores of mesoporous silica. Then, ammonia water is added to precipitate the calcium ions, forming calcium hydroxide precipitates inside the mesopores. Hydrogen peroxide and calcium hydroxide react to form calcium peroxide precipitates in the mesopores, thus obtaining mesoporous silica loaded with calcium peroxide.

[0011] Synthesis of S2 Janus-structured CM@PDA

[0012] CM was added to a mixture of polyacrylic acid solution, ammonia solution, and water and stirred for 30 minutes. Then, isopropyl alcohol and ammonia solution were added, and dopamine hydrochloride was added under vigorous stirring. The mixture was stirred at 60°C for 4 hours to obtain Janus structure CM@PDA, which was denoted as CMP.

[0013] The specific principle is: polyacrylic acid is adsorbed on the CM surface and provides an alkaline environment to trigger the polymerization of dopamine, forming PDA islands as seeds. The PDA layer is deposited on the nanoparticles through island nucleation and seed polymerization processes. The seed polymerization of dopamine produces anisotropic coverage of the PDA layer on the nanoparticles. Janus structured nanoparticles are prepared by controlling the polymerization time.

[0014] Synthesis of S3 CM@PDA-La

[0015] CMP and L-arginine were added to Tris-HCl buffer, ultrasonically dispersed, stirred for 24 hours, and vacuum dried to obtain CM@PDA-La powder, which is the self-propelled nano-antibacterial material, recorded as CMPL powder.

[0016] The principle is: since the surface of polydopamine is rich in active groups, L-arginine can be easily grafted onto the PDA surface in the form of covalent bonds.

[0017] The mesoporous silica in step S1 has a particle size of 105 nm and a pore size of 8 nm. The amount of mesoporous silica used is 15 mg. The volume of methanol is 30 mL. The concentration of the CaCl2 solution is 2 mol / L, and the volume is 1.5 mL. The concentration of the ammonia solution is 1 mol / L, and the volume is 4.5 mL. The flow rate of the syringe pump is 1 μL / s, and the concentration of the H2O2 is 3 v / v%, and the volume is 1.5 mL.

[0018] The mass of CM in step S2 is 10 mg. The polyacrylic acid concentration in the mixture of polyacrylic acid solution, ammonia solution, and water is 0.2 g / mL, the volume is 200 μL, and the Mw is 2000; the ammonia solution concentration is 2 mol / L, the volume is 300 μL, and the volume of water is 20 mL. In the addition of isopropyl alcohol and ammonia solution, the volume of isopropyl alcohol is 80 mL; the ammonia solution concentration is 15 mol / L, and the volume is 1 mL. The concentration of dopamine hydrochloride is 50 mg / mL, and the volume is 500 μL.

[0019] In step S3, the mass of CMP is 10 mg, the mass of arginine is 20 mg, and the concentration of the Tris-HCl buffer is 1 mol / L, pH 8.5, and the volume is 10 mL.

[0020] The present invention also provides a self-propelled nano antibacterial material prepared by the above method.

[0021] In addition, the present invention also provides the use of the self-propelled nano antibacterial material in preparing a root canal disinfection paste, which is characterized in that CMPL powder is added to sterile PBS and uniformly mixed into a paste to obtain the paste.

[0022] The concentration of the sterile PBS was (1×), pH 7.4.

[0023] The concentration of CMPL in the paste is 0.5-2 mg / mL.

[0024] It can be seen from the above technical solutions that compared with the prior art, the present invention has the following distinguishing technical features:

[0025] (1) The root canal disinfection paste designed by the present invention produces a photothermal effect and nitric oxide gas, which has strong specificity for bacteria and a strong killing effect; it has the ability to penetrate into the biofilm and effectively improves the plaque biofilm clearance rate.

[0026] (2) The root canal disinfection paste designed in the present invention acts as a nanomotor. Under the excitation of 808nm near-infrared light, due to the asymmetric structure of the nanoparticles themselves, an asymmetric distribution of photothermal effect and nitric oxide gas is generated. The dual fuels constitute the nanomotor to produce directional self-propelled motion, penetrate into the narrow inter-canal traffic and dentinal tubules, improve the targeting and penetration ability of the biofilm, achieve longer path diffusion, adapt to the complex structure of the root canal, cooperate with near-infrared light excitation to achieve deep tissue penetration, in situ remove pathogenic microorganisms deep in the root canal, improve the sterilization rate of Enterococcus faecalis and bacterial biofilm, achieve the purpose of effectively controlling the infection in the root canal, make up for the shortcomings of mechanical preparation, and greatly improve the effectiveness of clinical operation.

[0027] (3) The root canal disinfection paste designed by the present invention has no significant effect on the hardness of dentin. At the same time, the reactions involved in the process of action are all normal physiological reactions of the human body. The by-products are non-toxic and harmless, and the biosafety is high. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are merely embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without paying any creative work.

[0029] Figure 1 Schematic diagram of self-propelled nano-antibacterial material.

[0030] Figure 2 Schematic diagram of the action of root canal disinfectant.

[0031] Figure 3 TEM images of CM and CMP.

[0032] Figure 4 NIR-mediated photothermal performance of nanomotors.

[0033] Figure 5 In vitro antibacterial effect.

[0034] Figure 6 Effect of CMPL root canal disinfectant paste on dentin microhardness. DETAILED DESCRIPTION

[0035] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0036] Preparation of mesoporous silica

[0037] 10 mL of tetraethyl orthosilicate was thoroughly mixed with 80 mL of cyclohexane in a round-bottom flask to form an oil phase. 25 g of hexadecyltrimethylammonium chloride (CTAC) and 0.6 g of triethanolamine were dissolved in 240 mL of ultrapure water and added to the flask. The biphasic reaction system was stirred at 60°C for 12 hours, centrifuged to dry, and calcined at 550°C for 6 hours to remove the surfactant template of CTAC. The product was then washed with ethanol and dried under vacuum to obtain mesoporous silica with a particle size of 105 nm and a pore size of 8 nm.

[0038] Example 1

[0039] A method for preparing a self-propelled nano antibacterial material comprises the following steps:

[0040] S1 Synthesis of calcium peroxide-loaded mesoporous silica

[0041] 15 mg of mesoporous silica was dispersed in 30 mL of methanol to prepare an MSNs-methanol mixture; 1.5 mL of a 2 mol / L CaCl2 solution was added to the MSNs-methanol mixture and vigorously stirred at room temperature for 2.5 h; then 4.5 mL of a 1 mol / L ammonia solution was added to react; then 1.5 mL of a 3 v / v% H2O2 solution was added via a syringe pump at a flow rate of 1 μL / s and vigorously stirred at room temperature for 10 min to obtain a product, which was centrifuged and washed with methanol and ethanol solutions, respectively, to obtain calcium peroxide-loaded mesoporous silica, denoted as CM;

[0042] Synthesis of S2 Janus-structured CM@PDA

[0043] 10 mg of CM was added to a mixture of polyacrylic acid solution, ammonia solution, and water. The concentration of the polyacrylic acid in the mixture was 0.2 g / mL, the volume was 200 μL, and the Mw was 2000; the concentration of the ammonia solution was 2 mol / L, the volume was 300 μL; the volume of the water was 20 mL. Stirring was carried out for 30 minutes. Then, 80 mL of isopropanol and 1 mL of 15 mol / L ammonia solution were added. 500 μL of 50 mg / mL dopamine hydrochloride solution was added under vigorous stirring. The mixture was stirred at 60°C for 4 hours to obtain Janus structure CM@PDA, denoted as CMP.

[0044] Synthesis of S3 CM@PDA-La

[0045] 10 mg of CMP and 20 mg of L-arginine were added to 10 mL of 1 mol / L, pH 8.5 Tris-HCl buffer, ultrasonically dispersed, stirred for 24 h, and vacuum-dried to obtain CM@PDA-La powder, which is the self-propelled nano-antibacterial material, recorded as CMPL powder.

[0046] Figure 1 Schematic diagram of the synthesis of self-driven nano antibacterial materials for this application. Figure 2 Schematic diagram of the action of root canal disinfectant.

[0047] As can be seen from the schematic diagram, the present invention first loads calcium peroxide through mesoporous silica, then induces polydopamine to form a Janus structure through polyacrylic acid, and further grafts L-arginine to obtain the final self-driven nano antibacterial material.

[0048] The material works as follows:

[0049] Hydrogen ions exist in bacterial biofilms and infection environments. Calcium peroxide generates hydrogen peroxide under the action of hydrogen ions, and hydrogen peroxide reacts with arginine to generate nitric oxide. At the same time, polydopamine generates heat energy under 808nm near-infrared irradiation, thereby promoting the self-propulsion of nanoparticles. Its working principle is:

[0050] CaO2+2H + →Ca 2+ +H2O2

[0051] L-Arg+H2O2→L-Cit+H2O+NO↑

[0052]

[0053] TEM characterization

[0054] The structure of CM and CMP nanoparticles was observed using transmission electron microscopy. Figure 3TEM results show that compared with CM, the outer surface of CMP has a semi-enclosed structure, indicating the successful construction of Janus particles.

[0055] Example 2

[0056] Preparation of root canal disinfection paste

[0057] The CMPL powder was added to sterile PBS with a concentration of (1×) and a pH of 7.4 to prepare 0.5 mg / mL, and the mixture was uniformly mixed into a paste to obtain the paste.

[0058] Example 3

[0059] Preparation of root canal disinfection paste

[0060] The CMPL powder was added to sterile PBS with a concentration of (1×) and a pH of 7.4 to prepare a 1 mg / mL solution, and the mixture was uniformly mixed into a paste to obtain the paste.

[0061] Example 4

[0062] Preparation of root canal disinfection paste

[0063] The CMPL powder was added to sterile PBS with a concentration of (1×) and a pH of 7.4 to prepare a 2 mg / mL solution, and the mixture was uniformly mixed into a paste to obtain the paste.

[0064] NIR-mediated photothermal performance of nanomotors

[0065] The pastes of Examples 2-4 and pure sterile PBS were placed in 1 mL Eppendorf tubes and tested at 1 W cm -2 The temperature changes under power density lasted for 5 minutes. The real-time temperature was collected and monitored using an infrared thermal imaging camera. The results are as follows: Figure 4 .

[0066] The results show that compared with the pure sterile PBS group, all experimental groups exhibited a very significant photothermal effect. The temperature gradually increased with increasing irradiation time. The photothermal effect showed a concentration-dependent pattern. When the concentration increased to 2 mg / mL, the temperature rapidly increased from 28.4°C to 51.2°C. In contrast, the temperature of the PBS solution did not change significantly. These results demonstrate that CMPL can rapidly convert NIR into heat energy.

[0067] Comparative Example 1

[0068] S1 Synthesis of calcium peroxide-loaded mesoporous silica

[0069] 15 mg of mesoporous silica was dispersed in 30 mL of methanol to prepare an MSNs-methanol mixture; 1.5 mL of a 2 mol / L CaCl2 solution was added to the MSNs-methanol mixture and vigorously stirred at room temperature for 2.5 h; then 4.5 mL of a 1 mol / L ammonia solution was added to react; then 1.5 mL of a 3 v / v% H2O2 solution was added via a syringe pump at a flow rate of 1 μL / s and vigorously stirred at room temperature for 10 min to obtain a product, which was centrifuged and washed with methanol and ethanol solutions, respectively, to obtain calcium peroxide-loaded mesoporous silica, denoted as CM;

[0070] The CM powder was added to sterile PBS with a concentration of (1×) and a pH of 7.4 to prepare a 2 mg / mL solution, and the mixture was uniformly mixed into a paste to obtain the paste.

[0071] Comparative Example 2

[0072] S1 Synthesis of calcium peroxide-loaded mesoporous silica

[0073] 15 mg of mesoporous silica was dispersed in 30 mL of methanol to prepare an MSNs-methanol mixture; 1.5 mL of a 2 mol / L CaCl2 solution was added to the MSNs-methanol mixture and vigorously stirred at room temperature for 2.5 h; then 4.5 mL of a 1 mol / L ammonia solution was added to react; then 1.5 mL of a 3 v / v% H2O2 solution was added via a syringe pump at a flow rate of 1 μL / s and vigorously stirred at room temperature for 10 min to obtain a product, which was centrifuged and washed with methanol and ethanol solutions, respectively, to obtain calcium peroxide-loaded mesoporous silica, denoted as CM;

[0074] Synthesis of S2 Janus-structured CM@PDA

[0075] 10 mg of CM was added to a mixture of polyacrylic acid solution, ammonia solution, and water. The concentration of the polyacrylic acid in the mixture was 0.2 g / mL, the volume was 200 μL, and the Mw was 2000; the concentration of the ammonia solution was 2 mol / L, the volume was 300 μL; the volume of the water was 20 mL. Stirring was carried out for 30 minutes. Then, 80 mL of isopropanol and 1 mL of 15 mol / L ammonia solution were added. 500 μL of 50 mg / mL dopamine hydrochloride solution was added under vigorous stirring. The mixture was stirred at 60°C for 4 hours to obtain Janus structure CM@PDA, denoted as CMP.

[0076] The CMP powder was added to sterile PBS with a concentration of (1×) and a pH of 7.4 to prepare a concentration of 2 mg / mL, and the mixture was uniformly mixed into a paste to obtain the paste.

[0077] In vitro antibacterial effects of NIR-mediated nanomotors

[0078] The pastes prepared in Example 4 and Comparative Examples 1 and 2 were subjected to an in vitro antibacterial test. Enterococcus faecalis was cultured in BHI medium at 37°C under aerobic conditions. When the bacteria reached the logarithmic growth phase, the optical density of the bacterial suspension at 600 nm (OD600) was measured using a spectrophotometer. The concentration of the free bacterial suspension was adjusted to 2×10 7 CFU mL -1 , used for subsequent anti-free bacteria experiments. 100 μL of bacterial suspension was mixed with 100 μL of paste in each well to make the final concentration of each group 1 mg / mL. The plate was incubated in a constant temperature shaker at 80 rpm and 37°C for 10 min. The 808 nm, 1 W cm -2 The treated mixture was then diluted 104-fold using PBS, and 100 μL of the dilution was applied to fresh BHI solid medium. The mixture was aerobically cultured at 37°C for 24 hours, and the colonies were counted. Figure 5 .

[0079] The results showed that compared with the control group, the CM group showed no difference in performance, while the CMP and CMPL groups showed differences, confirming that the CMP and CMPL groups had good antibacterial properties. Compared with the CM group, the CMMP and CMPL groups showed differences. The results confirmed that CMPL has excellent antibacterial activity, and its antibacterial components come from PDA and L-Arg.

[0080] Effect of CMPL disinfectant paste on dentin microhardness

[0081] Teeth extracted for reasons such as caries, orthodontics, and pericoronitis were collected. Teeth with largely intact coronal dentin and no endodontic treatment were selected. Dental calculus adhering to the tooth surface was removed, and soft tissues such as the periodontal ligament were scraped off. The excised teeth were then immersed in physiological saline and stored at room temperature. A precision cutter was used to partially excise the crown, exposing the dentin. These were then cut into 4 mm × 4 mm × 1 mm (length × width × height) dentin slices. After cleaning, the slices were placed in clean, sterile packaging bags and sterilized in a pressure steam autoclave to confirm sterilization. The surface moisture of the dentin slices was then blotted dry. Microhardness values ​​at three different points on the surface, middle, and bottom of each slice were measured using a micro-Vickers hardness tester. These values ​​were used as the initial hardness values ​​for the slices. Sterile PBS, calcium hydroxide paste, or CMPL paste were applied evenly to the dentin slices, respectively. The slices were then placed in a 24-well plate and allowed to stand in a humidified environment. On the 14th day, the surface paste was cleaned and dried, and the dentin slices were measured again using a Vickers microhardness tester to obtain the microhardness value after treatment, and the difference in microhardness values ​​was calculated. The results are as follows: Figure 6 .

[0082] The results showed that compared with the control group, the hardness of the dentin slices treated with calcium hydroxide decreased, while the microhardness of the dentin slices in the CMPL group increased after material treatment. This confirmed that the use of CMPL as a root canal disinfectant paste does not cause a decrease in dentin hardness.

[0083] Biosafety analysis

[0084] Mouse fibroblast L929 cells were cultured in DMEM medium supplemented with 1% penicillin-streptomycin solution and 10% fetal bovine serum at a volume of 100 μL / well. 2×10 3 Cells were seeded at a density of 100 μL / well in a 96-well plate and cultured in a humidified environment containing 5% CO2 and 37°C for 24 hours until the cells adhered. Subsequently, the culture medium was discarded and CMPL culture medium extracts (prepared into complete culture medium) at concentrations of 0.5 mg / mL, 1 mg / mL, and 2 mg / mL were added and cultured for 24, 48, and 72 hours. Complete culture medium without drug extract was used as the control group. At the set time point, the culture medium was discarded and DMEM culture medium containing 10% CCK-8 solution was added to L929 cells at a volume of 100 μL / well. The cells were incubated in an incubator for 4 hours and then the absorbance value at a wavelength of 450 nm (OD450) was measured. DMEM culture medium without L929 cells and containing only 10% CCK-8 solution was used as a blank well. The relative growth rate (RGR) of the cells was calculated and evaluated according to the cytotoxicity grade evaluation criteria. RGR = A value of the experimental group / A value of the control group × 100%. According to the United States Pharmacopeia, cytotoxicity was graded using a 5-point scale based on RGR: Grade 0, RGR ≥ 100%; Grade 1, RGR 75%-99%; Grade 2, RGR 50%-74%; Grade 3, RGR 25%-49%; Grade 4, RGR 1%-24%; and Grade 5, RGR <1%. Grades 0 and 1 were considered acceptable, while Grade 2 was evaluated based on comprehensive evaluation of cell morphology. Grades 3-5 were considered unacceptable. The results are shown in Table 1.

[0085] Table 1 Cytotoxicity levels of each group

[0086]

[0087]

[0088] The data showed that the L929 cell viability in the 0.5 mg / mL, 1 mg / mL, and 2 mg / mL groups always remained above 75%, indicating that CMPL has good cell compatibility.

[0089] The foregoing description of the disclosed embodiments enables a person skilled in the art to make or use the application. Modifications of these embodiments will occur to persons of skill in the art, and that the appended claims are intended to cover all such modifications that do not depart from the true spirit and scope of the application. Therefore, the application is not limited to the embodiments shown but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method for preparing a self-propelled nano antibacterial material, characterized in that: The specific steps include: S1 Synthesis of calcium peroxide-loaded mesoporous silica Mesoporous silica was dispersed in methanol to prepare an MSNs-methanol mixture; CaCl2 solution was added to the MSNs-methanol mixture and vigorously stirred at room temperature for 2.5 hours; then an ammonia solution was added to react; then H2O2 solution was added via a syringe pump and vigorously stirred at room temperature for 10 minutes, followed by centrifugation and washing with methanol and ethanol solutions to obtain calcium peroxide-loaded mesoporous silica, denoted as CM; Synthesis of S2 Janus-structured CM@PDA CM was added to a mixture of polyacrylic acid solution, ammonia solution, and water and stirred for 30 minutes. Then, isopropyl alcohol and ammonia solution were added, and dopamine hydrochloride was added under vigorous stirring. The mixture was stirred at 60°C for 4 hours to obtain Janus structure CM@PDA, which was denoted as CMP. Synthesis of S3 CM@PDA-La CMP and L-arginine were added to Tris-HCl buffer, ultrasonically dispersed, stirred for 24 hours, and vacuum dried to obtain CM@PDA-La powder, which is the self-propelled nano-antibacterial material, recorded as CMPL powder.

2. The method for preparing a self-propelled nano antibacterial material according to claim 1, characterized in that: The particle size of the mesoporous silica in step S1 is 105 nm, the pore size is 8 nm, and the amount of the mesoporous silica used is 15 mg; The volume of the methanol was 30 mL.

3. The method for preparing a self-propelled nano antibacterial material according to claim 1, characterized in that: The concentration of the CaCl2 solution in step S1 is 2 mol / L and the volume is 1.5 mL.

4. The method for preparing a self-propelled nano antibacterial material according to claim 1, characterized in that: The concentration of the ammonia solution in step S1 is 1 mol / L and the volume is 4.5 mL; The flow rate of the syringe pump is 1 μL / s, the concentration of H 2 O 2 is 3 v / v%, and the volume is 1.5 mL.

5. The method for preparing a self-propelled nano antibacterial material according to claim 1, characterized in that: The mass of CM in step S2 is 10 mg; In the mixture of polyacrylic acid solution, ammonia solution and water, the concentration of polyacrylic acid solution is 0.2 g / mL, the volume is 200 μL, and the Mw is 2000; the concentration of ammonia solution is 2 mol / L, the volume is 300 μL; and the volume of water is 20 mL.

6. The method for preparing a self-propelled nano antibacterial material according to claim 1, characterized in that: In the step S2 of adding isopropyl alcohol and ammonia solution, the volume of isopropyl alcohol is 80 mL; the concentration of ammonia solution is 15 mol / L, and the volume is 1 mL. The concentration of the dopamine hydrochloride was 50 mg / mL, and the volume was 500 μL.

7. The method for preparing a self-propelled nano antibacterial material according to claim 1, characterized in that: The mass of the CMP in step S3 is 10 mg; The mass of the L-arginine is 20 mg; The concentration of the Tris-HCl buffer is 1 mol / L, pH 8.5, and the volume is 10 mL.

8. A self-propelled nano antibacterial material prepared by the method according to any one of claims 1 to 7.

9. Use of the self-propelled nano antibacterial material according to claim 8 in preparing a root canal disinfection paste, characterized in that: The CMPL powder was added to sterile PBS and uniformly mixed into a paste to obtain the paste; The concentration of the sterile PBS (1×), pH 7.4; The concentration of CMPL in the paste is 0.5-2 mg / mL.

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