Preparation method and application of metal polyphenol network coated polydopamine nanoparticle antibacterial material

Abstract

The application relates to a preparation method and application of metal polyphenol network coated polydopamine nanoparticle antibacterial material, and belongs to the technical field of antibacterial nanomaterials. The application aims to solve the problem that the existing polydopamine antibacterial material has insufficient antibacterial capacity when used alone, but cannot guarantee excellent biocompatibility, low environmental risk and low drug resistance risk after surface modification. The method comprises the following steps: 1, preparing a dopamine hydrochloride solution; 2, preparing an ethanol / water solution; 3, adding the dopamine hydrochloride solution into the ethanol / water solution; 4, preparing a polydopamine nanoparticle dispersion liquid; 5, preparing a quercetin solution; 6, preparing a polydopamine nanoparticle mixed solution containing quercetin; 7, preparing a copper nitrate solution; and 8, adding the copper nitrate solution into the polydopamine nanoparticle mixed solution containing quercetin. The application is used for sterilization of gram-positive bacteria and gram-negative bacteria, promotion of healing of bacterial infection wounds, or prevention of bacterial colonization.

Description

Technical Field

[0001] This invention belongs to the field of antibacterial nanomaterials technology. Background Technology

[0002] Bacteria, as tiny and ancient organisms, have a profound impact on human daily life. Apart from some beneficial probiotics, most bacteria can cause infectious diseases, which have become one of the most serious health problems worldwide. Antibiotic treatment is undoubtedly an effective strategy for combating bacterial infections. However, due to the abuse and overuse of antibiotics, many bacterial pathogens have developed antibiotic resistance, leading to a significantly increased risk of infection recurrence and death in patients. Therefore, there is an urgent need to develop safe, efficient, and controllable new antibacterial materials, while the preparation processes of these materials need to be simpler and easier to implement to facilitate their promotion and application.

[0003] Polydopamine has gradually emerged as a promising antibacterial material due to its excellent chemical and physical properties. Its superior photothermal conversion ability, abundant catechol and secondary amine structures, and the hydrogen peroxide formed by polydopamine can denature cell membrane proteins, disrupt bacterial cell membrane structure, and ultimately lead to bacterial death. Furthermore, thanks to its abundant chemical reaction sites and mild preparation strategies, polydopamine is frequently used for interfacial chemical modification of antibacterial composite materials to construct antibacterial interfaces. Its application prospects in medical devices and water treatment fields such as water purifiers, ceramic membranes, and activated carbon have been investigated. However, the following problems still exist regarding polydopamine antibacterial materials:

[0004] (1) Polydopamine itself has a relatively mild antibacterial ability, which makes it difficult to meet higher antibacterial standards and market demands.

[0005] (2) Currently, most antibacterial materials based on polydopamine need to be modified with antibiotics and organic molecules on the basis of already synthesized polydopamine to improve the antibacterial effect, but at the same time, there are potential risks to the drug resistance of microorganisms in the environment and biotoxicity.

[0006] (3) Although polydopamine antibacterial materials have begun to be studied in some specific fields, their application scope is still limited. For example, it is necessary to achieve the desired product performance while ensuring its high antibacterial ability, low environmental risk, and biotoxicity. Summary of the Invention

[0007] This invention aims to address the problem that existing polydopamine antibacterial materials have insufficient antibacterial ability when used alone, but cannot simultaneously guarantee excellent biocompatibility, low environmental risk, and low drug resistance risk after surface modification. Therefore, it provides a method for preparing and applying a metal polyphenol network-coated polydopamine nanoparticle antibacterial material.

[0008] A method for preparing a metal polyphenol network-coated polydopamine nanoparticle antibacterial material, comprising the following steps:

[0009] 1. Dissolve dopamine hydrochloride in ultrapure water to obtain a dopamine hydrochloride solution;

[0010] 2. Mix ethanol with ultrapure water to obtain an ethanol / water solution;

[0011] 3. Add the dopamine hydrochloride solution to the ethanol / water solution and stir to obtain a mixed system;

[0012] IV. Under stirring conditions, ammonia water is added to the mixed system to react, the supernatant is removed by centrifugation and resuspended to obtain a polydopamine nanoparticle dispersion.

[0013] 5. Dissolve quercetin in NaOH solution to obtain quercetin solution;

[0014] 6. Under stirring conditions, add quercetin solution to polydopamine nanoparticle dispersion and stir to obtain polydopamine nanoparticle mixture containing quercetin.

[0015] 7. Dissolve copper nitrate in ultrapure water to obtain a copper nitrate solution;

[0016] 8. Under stirring conditions, copper nitrate solution was added to a mixture of polydopamine nanoparticles containing quercetin for reaction. Finally, the supernatant was removed by centrifugation to obtain a metal polyphenol network-coated polydopamine nanoparticle antibacterial material.

[0017] An application of a metal polyphenol network-coated polydopamine nanoparticle antibacterial material, which is used for the sterilization of Gram-positive and Gram-negative bacteria and the promotion of wound healing caused by bacterial infection, or for use in combination with ceramic membranes or activated carbon in water purifiers to prevent bacterial colonization.

[0018] The beneficial effects of this invention are:

[0019] (1) This invention is the first to prepare polydopamine nanoparticles coated with a metal polyphenol network formed by quercetin and copper ions, which can be synthesized by a simple stirring reaction.

[0020] (2) The synthesis process of the metal polyphenol network-coated polydopamine nanoparticles prepared by this invention is simple, and the reaction temperature is mild and environmentally friendly. Polydopamine nanoparticles, as organic photothermal agents, have excellent biocompatibility and are often used in photothermal antibacterial therapy. Quercetin, as a natural polyphenol product, has good antioxidant and antibacterial effects, which reduces the use of antibiotics and thus reduces the risk of drug resistance.

[0021] (3) The metal polyphenol network-coated polydopamine nanoparticles synthesized by the present invention can kill more than two orders of magnitude of Staphylococcus aureus within 10 minutes, and can also kill more than three orders of magnitude of Escherichia coli within 10 minutes. They have good antibacterial effects against both Gram-positive and Gram-negative bacteria.

[0022] (4) The metal polyphenol network-coated polydopamine nanoparticles synthesized using the present invention can promote the healing rate of bacterial infected wounds by more than 93% within 9 days, while having no obvious toxic effects on biological cells, proving that the material has promising practical application value. Attached Figure Description

[0023] Figure 1 This is a schematic diagram of the process for preparing the antibacterial material of metal polyphenol network-coated polydopamine nanoparticles according to the present invention;

[0024] Figure 2 PDA / Cu prepared in Example 1 2+ -Q transmission electron microscope image, dark field transmission electron microscope image, and transmission electron elemental mapping image;

[0025] Figure 3 PDA / Cu prepared in Example 1 2+ -Q infrared spectrum;

[0026] Figure 4 PDA / Cu prepared in Example 1 2+ -Q photothermal temperature rise diagram;

[0027] Figure 5 PDA / Cu prepared in Example 1 2+ -Q Infrared thermograph of a mouse wound;

[0028] Figure 6 Cu 2+ Quercetin and the PDA / Cu prepared in Example 1 2+ - Comparison of antibacterial properties of Q: A is the colony plate image of Staphylococcus aureus, B is the survival rate of Staphylococcus aureus, C is the colony plate image of Escherichia coli, and D is the survival rate of Escherichia coli.

[0029] Figure 7 PBS and PDA / Cu prepared in Example 1 2+ -Q comparison of wound healing efficiency, A is the wound healing graph of mice in different treatment groups, B is the wound healing rate of mice in different treatment groups, 1 is PDA+NIR, 2 is PDA, 3 is PBS+NIR, 4 is PBS, C is the bacterial plate graph of mouse wound tissue after treatment in different treatment groups.

[0030] Figure 8 PDA / Cu prepared in Example 1 2+ -Q cytotoxicity assay results. Detailed Implementation

[0031] The technical solution of the present invention is not limited to the specific embodiments listed below, but also includes any combination of the specific embodiments.

[0032] Specific implementation method one, combined with Figure 1 Detailed description: This embodiment describes a method for preparing a metal polyphenol network-coated polydopamine nanoparticle antibacterial material, which is carried out according to the following steps:

[0033] 1. Dissolve dopamine hydrochloride in ultrapure water to obtain a dopamine hydrochloride solution;

[0034] 2. Mix ethanol with ultrapure water to obtain an ethanol / water solution;

[0035] 3. Add the dopamine hydrochloride solution to the ethanol / water solution and stir to obtain a mixed system;

[0036] IV. Under stirring conditions, ammonia water is added to the mixed system to react, the supernatant is removed by centrifugation and resuspended to obtain a polydopamine nanoparticle dispersion.

[0037] 5. Dissolve quercetin in NaOH solution to obtain quercetin solution;

[0038] 6. Under stirring conditions, add quercetin solution to polydopamine nanoparticle dispersion and stir to obtain polydopamine nanoparticle mixture containing quercetin.

[0039] 7. Dissolve copper nitrate in ultrapure water to obtain a copper nitrate solution;

[0040] 8. Under stirring conditions, copper nitrate solution was added to a mixture of polydopamine nanoparticles containing quercetin for reaction. Finally, the supernatant was removed by centrifugation to obtain a metal polyphenol network-coated polydopamine nanoparticle antibacterial material.

[0041] Steps one through eight of this embodiment are all performed at room temperature.

[0042] This embodiment uses polydopamine nanoparticles as the main antibacterial material, and coats its surface with a metal polyphenol network formed by the natural polyphenol compound quercetin and copper ions, ensuring excellent biocompatibility for human health. Simultaneously, quercetin, as a natural antibacterial compound, binds with copper ions, ensuring its highly effective antibacterial ability. Its unique metal polyphenol network structure, combined with photothermal therapy, can promote the further release of quercetin and copper ions, thereby achieving excellent bacterial killing effects.

[0043] The beneficial effects of this embodiment are:

[0044] (1) This embodiment is the first to prepare polydopamine nanoparticles coated with a metal polyphenol network formed by quercetin and copper ions, which can be synthesized by a simple stirring reaction.

[0045] (2) The synthesis process of the metal polyphenol network-coated polydopamine nanoparticles prepared in this embodiment is simple, and the reaction temperature is mild and environmentally friendly. Polydopamine nanoparticles have excellent biocompatibility as organic photothermal agents and are often used in photothermal antibacterial therapy. Quercetin, as a natural polyphenol product, has good antioxidant and antibacterial effects, which reduces the use of antibiotics and thus reduces the risk of drug resistance.

[0046] (3) The metal polyphenol network-coated polydopamine nanoparticles synthesized in this embodiment can kill more than two orders of magnitude of Staphylococcus aureus within 10 minutes, and can also kill more than three orders of magnitude of Escherichia coli within 10 minutes. They have good antibacterial effects against both Gram-positive and Gram-negative bacteria.

[0047] (4) The metal polyphenol network-coated polydopamine nanoparticles synthesized using this embodiment can promote the healing rate of bacterial infected wounds by more than 93% within 9 days, while having no obvious toxic effects on biological cells, proving that the material has promising practical application value.

[0048] Specific Implementation Method Two: This implementation method differs from Specific Implementation Method One in that the concentration of the dopamine hydrochloride solution mentioned in step one is 40 mg / mL to 50 mg / mL. Everything else is the same as in Specific Implementation Method One.

[0049] Specific Implementation Method Three: This implementation method differs from Specific Implementation Method One or Two in that the volume ratio of ethanol to ultrapure water in step two is 1:(2.25~2.5). Everything else is the same as in Specific Implementation Method One or Two.

[0050] Specific Implementation Method Four: This implementation method differs from Specific Implementation Methods One to Three in that: the concentration of dopamine hydrochloride in the mixed system described in step three is 3.5 mg / mL to 4 mg / mL; in step three, the dopamine hydrochloride solution is added to the ethanol / water solution and stirred for 10 to 20 minutes at a stirring speed of 1000 rpm to 1200 rpm. Everything else is the same as in Specific Implementation Methods One to Three.

[0051] Specific Implementation Method Five: This implementation method differs from Specific Implementation Methods One to Four in that: the concentration of ammonia in step four is 6.6 mg / mL to 7 mg / mL; the volume ratio of ammonia to the mixed system in step four is 1:(58~70); in step four, ammonia is added to the mixed system and reacted for 20 to 24 hours under a stirring speed of 1000 rpm to 1200 rpm, then centrifuged for 15 to 20 minutes at a centrifugation speed of 10000 rpm to 11000 rpm, and the supernatant is removed. Finally, ultrapure water is added to redisperse the mixture to obtain a polydopamine nanoparticle dispersion with a concentration of 2 mg / mL to 3 mg / mL. Everything else is the same as in Specific Implementation Methods One to Four.

[0052] Specific Implementation Method Six: This implementation method differs from Specific Implementation Methods One to Five in that the concentration of the NaOH solution in step five is 0.08 mol / L to 0.1 mol / L; and the concentration of the quercetin solution in step five is 4 mg / mL to 5 mg / mL. Everything else is the same as in Specific Implementation Methods One to Five.

[0053] Specific Implementation Method Seven: This implementation method differs from Specific Implementation Methods One to Six in that: the volume ratio of quercetin solution to polydopamine nanoparticle dispersion in step six is ​​1:(3~3.3); in step six, the quercetin solution is added to the polydopamine nanoparticle dispersion and stirred for 2 min to 5 min at a stirring speed of 1000 rpm to 1200 rpm. Everything else is the same as in Specific Implementation Methods One to Six.

[0054] Specific Implementation Method Eight: This implementation method differs from Specific Implementation Methods One to Seven in that the concentration of the copper nitrate solution mentioned in step Seven is 2 mg / mL to 2.5 mg / mL. Everything else is the same as in Specific Implementation Methods One to Seven.

[0055] Specific Implementation Method Nine: This implementation method differs from Specific Implementation Methods One to Eight in that: the volume ratio of the copper nitrate solution to the quercetin-containing polydopamine nanoparticle mixture in step eight is 1:(6.5~7); in step eight, the copper nitrate solution is added to the quercetin-containing polydopamine nanoparticle mixture under a stirring speed of 1000rpm~1200rpm and reacted for 6h~8h, then centrifuged at a centrifugation speed of 11000rpm~12000rpm for 15min~30min and the supernatant is removed to obtain the metal polyphenol network-coated polydopamine nanoparticle antibacterial material. Everything else is the same as in Specific Implementation Methods One to Eight.

[0056] Specific Implementation Method 10: This implementation method describes the application of a metal polyphenol network-coated polydopamine nanoparticle antibacterial material. It is used for the sterilization of Gram-positive and Gram-negative bacteria and the promotion of wound healing caused by bacterial infection, or for use in combination with ceramic membranes or activated carbon in water purifiers to prevent bacterial colonization.

[0057] The Gram-positive bacteria mentioned are Staphylococcus aureus; the Gram-negative bacteria mentioned are Escherichia coli.

[0058] The beneficial effects of the present invention are verified using the following embodiments:

[0059] Example 1:

[0060] A method for preparing a metal polyphenol network-coated polydopamine nanoparticle antibacterial material, comprising the following steps:

[0061] 1. Dissolve dopamine hydrochloride in ultrapure water to obtain a dopamine hydrochloride solution;

[0062] The concentration of the dopamine hydrochloride solution is 50 mg / mL;

[0063] 2. Mix ethanol with ultrapure water to obtain an ethanol / water solution;

[0064] The volume ratio of ethanol to ultrapure water is 4:9;

[0065] 3. Under the condition of stirring at 1200 rpm, add the hydrochloric acid dopamine solution to the ethanol / water solution and stir for 15 min to obtain a mixed system;

[0066] The concentration of dopamine hydrochloride in the aforementioned mixture is 3.6 mg / mL;

[0067] IV. Under the condition of stirring at 1200 rpm, ammonia water was added to the mixture and reacted for 20 h. Then, under the condition of centrifugation at 11000 rpm, the mixture was centrifuged for 15 min and the supernatant was removed. Finally, ultrapure water was added to disperse again to obtain a polydopamine nanoparticle dispersion with a concentration of 3 mg / mL.

[0068] The concentration of the ammonia solution is 6.6 mg / mL; the volume ratio of the ammonia solution to the mixed system is 1:70.

[0069] 5. Dissolve quercetin in NaOH solution to obtain quercetin solution;

[0070] The concentration of the NaOH solution is 0.1 mol / L; the concentration of the quercetin solution is 5 mg / mL.

[0071] 6. Under the condition of stirring at 1200 rpm, add quercetin solution to polydopamine nanoparticle dispersion and stir for 2 min to obtain polydopamine nanoparticle mixture containing quercetin.

[0072] The volume ratio of the quercetin solution to the polydopamine nanoparticle dispersion is 1:3.3;

[0073] 7. Dissolve copper nitrate in ultrapure water to obtain a copper nitrate solution;

[0074] The concentration of the copper nitrate solution is 2.5 mg / mL;

[0075] 8. Under a stirring speed of 1200 rpm, copper nitrate solution was added to a mixture of polydopamine nanoparticles containing quercetin and reacted for 6 hours. Then, the mixture was centrifuged at 11000 rpm for 15 minutes, and the supernatant was removed to obtain a metal polyphenol network-coated polydopamine nanoparticle antibacterial material (PDA / Cu). 2+ -Q);

[0076] The volume ratio of the copper nitrate solution to the polydopamine nanoparticle mixture containing quercetin is 1:6.5.

[0077] Steps one through eight in this embodiment are all performed at room temperature.

[0078] The antibacterial material of metal polyphenol network-coated polydopamine nanoparticles prepared in Example 1 was dispersed in sterile ultrapure water and centrifuged 5 times. Finally, it was dispersed in sterile ultrapure water to obtain metal polyphenol network-coated polydopamine nanoparticles (PDA / Cu). 2+ -Q) solution, i.e., PDA / Cu 2+ -Q solution.

[0079] The PDA / Cu prepared in Example 1 2+ -Q solution was dropped onto a copper grid, dried, and then subjected to transmission electron microscopy; Figure 2 PDA / Cu prepared in Example 1 2+ Transmission electron microscopy (TEM) images, dark-field TEM images, and TEM elemental mapping diagrams of the PDA / Cu nanoparticles are shown in the figure. As illustrated, TEM clearly reveals the internal structure and surface morphology of the material. The nanoparticles are well-dispersed, uniform in size, and exhibit regular spherical shapes. Compared to polydopamine nanoparticles, the material shows reduced surface smoothness and significant material adhesion. Statistical analysis of the particle size distribution in the TEM images indicates that the PDA / Cu nanoparticles... 2+ The average diameter of -Q is 231 nm. Dark-field imaging further confirmed the presence of a metal polyphenol network layer on the material surface, while energy-dispersive X-ray (EDX) spectroscopy investigated the elemental distribution of Cu, C, N, and O, confirming the presence of Cu. 2+Successful load.

[0080] Figure 3 PDA / Cu prepared in Example 1 2+ -Q infrared spectrum; results show that the material at 1610 cm⁻¹ -1 There is a distinct absorption peak at 3250 cm⁻¹, which may be related to the C=C stretching vibration of the benzene ring in quercetin. Simultaneously, there is an absorption peak at 3250 cm⁻¹. -1 The strong and broad absorption band indicates the presence of abundant hydroxyl groups (-OH).

[0081] Test Example 1: PDA / Cu 2+ -Q photothermal properties: PDA / Cu at a concentration of 200 μg / mL... 2+ -Q solution exposed to laser intensity of 0.6 W / cm 2 They were irradiated with an 808nm laser for 10 minutes, and the temperature changes were recorded using a photothermal imager. Figure 4 PDA / Cu prepared in Example 1 2+ -Q photothermal temperature rise diagram; as shown in the figure, the sample can be heated to 45℃ within 10 minutes and shows a temperature rise that is dependent on the irradiation time.

[0082] To verify the photothermal properties of the material in vivo, a PDA / Cu concentration of 200 μg / mL was used. 2+ -Q solution was added dropwise to a bacterially infected wound in a mouse, and the mouse was then exposed to a laser with an intensity of 1 W / cm². 2 They were irradiated with an 808nm laser for 5 minutes, and the results were recorded and photographed. Figure 5 PDA / Cu prepared in Example 1 2+ -Q Infrared thermography image of mouse wound; where PDA / Cu 2+ -Q is abbreviated as PDA; as shown in the figure, the material rapidly heats up to 45°C within 5 minutes at the wound site, proving that the material has excellent photothermal effects both in vitro and in vivo.

[0083] Test Example 1: PDA / Cu 2+ The bactericidal performance of -Q was tested as follows:

[0084] Bacterial activation and treatment: Remove *S. aureus* and *E. coli* from the 4°C freezer and place them in a clean bench. Using an inoculation loop, add one colony to LB medium (composition: NaCl 10 g / L, yeast extract 5 g / L, tryptone 10 g / L) and incubate at 37°C for 12 h in a constant temperature shaker at 150 rpm. Centrifuge the obtained bacterial solution (6000 rpm, 5 min) and resuspend in PBS buffer (0.01 M, pH=7), adjusting the bacterial concentration to OD0.05. 600 =0.2.

[0085] Materials Addition: Prepare 2.5 mL sterile centrifuge tubes, add 250 μL of the above bacterial culture to each tube. For the experimental group, add 250 μL of copper nitrate solution (concentration 37.2 μg / mL), 250 μL of quercetin solution (36 μg / mL), and 250 μL of PDA / Cu. 2+ -Q solution (concentration 400 μg / mL) was added to the bacterial cultures of *S. aureus* and *E. coli*, respectively. The blank control group was prepared by adding 250 μL of PBS solution and 250 μL of sterile water. The cultures were then placed under a laser with an intensity of 0.6 W / cm². 2 Irradiate with 808nm laser light for 10 minutes, or do not irradiate for 10 minutes.

[0086] Plate coating: Place the prepared sterile culture dishes into the laminar flow hood, take 100 μL of bacterial solution from different experimental groups and control groups, spread it evenly on the solid culture dishes with a sterile spreader, and incubate in a constant temperature incubator at 37℃ for 24 h.

[0087] Plate count: Calculate the sterilization efficiency after incubation with bacteria for different times.

[0088] Figure 6 Cu 2+ Quercetin and the PDA / Cu prepared in Example 1 2+ - Comparison of antibacterial properties of -Q: A is the colony plate image of Staphylococcus aureus, B is the survival rate of Staphylococcus aureus, C is the colony plate image of Escherichia coli, and D is the survival rate of Escherichia coli; as shown in Figures A and C, without near-infrared light irradiation, PDA / Cu 2+ -Q showed no significant bactericidal effect against Staphylococcus aureus and Escherichia coli within 10 minutes. However, thanks to its excellent photothermal conversion capability, PDA / Cu showed significant bactericidal effect after near-infrared light irradiation. 2+ -Q exhibits a bactericidal efficiency exceeding 99% against Staphylococcus aureus within 10 minutes and over 99.9% against Escherichia coli within 10 minutes (Figures B and D). These experimental results demonstrate that PDA / Cu... 2+ -Q enhances the bactericidal mechanism through photothermal effect, effectively killing common Gram-positive and Gram-negative pathogens.

[0089] Test Example 1: PDA / Cu 2+ The wound healing promotion performance of -Q was tested as follows:

[0090] Model construction: (1) The experimental animals were acclimatized for one week; (2) The bacterial solution was resuscitated the day before the experiment and prepared to the required concentration on the day of the experiment; (3) The experimental animals were anesthetized with isoflurane, and hair removal cream was used to remove hair from their backs after shaving. The surgical site was disinfected with povidone-iodine; (4) A circular full-thickness wound with a diameter of 8 mm was created on the back of the experimental animal. The shape of the wound was determined according to the experimental requirements. After cutting the wound, it was measured with a ruler and the diameter was 0.8 ± 0.1 cm; 10 μL of Staphylococcus aureus (concentration of 1 × 10⁻⁶) was inoculated into the wound. 6 The wound was sealed with a 3M membrane (CFU / mL), and the appearance of cloudy pus in the wound 24 hours after infection was considered a successful infection model.

[0091] Treatment: After the model was established, drug administration began and was recorded as day 0. Treatment was administered according to the experimental design, including PBS, PBS+NIR, and PDA / Cu. 2+ -Q-NIR and PDA / Cu 2+ In the Q+NIR group, 100 μL of PDA / Cu was added to the infected wound of mice on days 0, 1, 3, 5, and 7. 2+ -Q solution (concentration of 200 μg / mL) or PBS solution, and photothermal therapy (light intensity of 1 W / cm²) was performed. 2 (If photothermal therapy is not performed for 5 minutes, or if no photothermal therapy is performed, the wound is then bandaged with a 3M film and medical tape.)

[0092] Wound healing rate: During the observation period, the wound diameter was measured with calipers and the wound healing rate was calculated using the following formula: Wound healing rate (%) = (S0-Sn) / S0×100%, S0: wound area before medication on day 0, Sn: wound area before medication on day n.

[0093] Plate coating: On day 9 of the experiment, a sample was taken from the wound using a sterile cotton swab, placed in 1 mL PBS, sonicated for 5 min, the suspension was collected, serially diluted, and 100 μL of bacterial suspension was plated. The mixture was incubated overnight for 18 h, photographed, and counted.

[0094] Figure 7 PBS and PDA / Cu prepared in Example 1 2+ -Q comparison of wound healing efficiency, A shows the wound healing rate of mice in different treatment groups, B shows the wound healing rate of mice in different treatment groups, 1 represents PDA+NIR, 2 represents PDA, 3 represents PBS+NIR, 4 represents PBS, C shows the bacterial plate images of mouse wound tissue after treatment in different treatment groups; where PDA / Cu 2+ -Q is abbreviated as PDA, + indicates laser irradiation, and - indicates no laser irradiation; wound area monitoring (Figure A) and quantitative analysis (Figure B) results show that after PDA / Cu 2+-Q treatment significantly accelerated wound healing. It was observed that on day 3 of treatment, the PDA / Cu ratio... 2+ -Q-NIR group and PDA / Cu 2+ The wounds in the -Q+NIR group showed significant shrinkage, with healing rates of 53.3% and 59.0%, respectively. Under the same experimental conditions, the PBS group and the PBS+NIR control group showed healing rates of only 34.4% and 48.2%, respectively. With prolonged treatment, the wounds in the treated mice began to scab and continued to shrink. By day 9, the PDA / Cu... 2+ The wounds in the -Q+NIR group healed almost completely, with a healing rate of 93.3%, fully demonstrating the effectiveness of PDA / Cu. 2+ -Q exhibits excellent wound-healing properties. Bacterial samples were taken from the wound after day 9 of the experiment and diluted for plating (Figure C). The results showed that PDA / Cu... 2+ -Q-NIR group and PDA / Cu 2+ The number of bacteria at the wound site in the -Q+NIR group was reduced by more than 98.8%, thus confirming its excellent antibacterial effect in vivo.

[0095] To further verify the synthesis of PDA / Cu 2+ -Q cytotoxicity was assessed using mouse epithelial fibroblasts, with the mouse cells reacting with PDA / Cu. 2+ -Q (200 μg / mL) solution was mixed at 0.6 W / cm 2 After being irradiated with 808nm near-infrared light for 10 minutes, the samples were incubated for 4 hours and 8 hours, and their biocompatibility was verified by CCK-8 assay. Figure 8 PDA / Cu prepared in Example 1 2+ -Q cytotoxicity assay results; as shown in the figure, in PDA / Cu 2+ At a concentration of 200 μg / mL, the cell viability remained above 90% after 4 h and 8 h, indicating that the synthesized PDA / Cu 2+ -Q exhibits extremely low cytotoxicity and excellent biocompatibility in in vitro experiments.

Claims

1. A method for preparing a metal polyphenol network coated polydopamine nanoparticle antibacterial material, characterized by It is done in the following steps:

1. Dissolve dopamine hydrochloride in ultrapure water to obtain a dopamine hydrochloride solution; 2. Mix ethanol with ultrapure water to obtain an ethanol / water solution; 3. Add the dopamine hydrochloride solution to the ethanol / water solution and stir to obtain a mixed system; IV. Under stirring conditions, ammonia water is added to the mixed system to react, the supernatant is removed by centrifugation and resuspended to obtain a polydopamine nanoparticle dispersion.

5. Dissolve quercetin in NaOH solution to obtain quercetin solution; 6. Under stirring conditions, add quercetin solution to polydopamine nanoparticle dispersion and stir to obtain polydopamine nanoparticle mixture containing quercetin.

7. Dissolve copper nitrate in ultrapure water to obtain a copper nitrate solution; 8. Under stirring conditions, copper nitrate solution was added to a mixture of polydopamine nanoparticles containing quercetin for reaction. Finally, the supernatant was removed by centrifugation to obtain a metal polyphenol network-coated polydopamine nanoparticle antibacterial material.

2. The preparation method of a metal polyphenol network-coated polydopamine nanoparticle antibacterial material according to claim 1, characterized in that... The concentration of the dopamine hydrochloride solution mentioned in step one is 40 mg / mL to 50 mg / mL.

3. The preparation method of a metal polyphenol network-coated polydopamine nanoparticle antibacterial material according to claim 1, characterized in that... The volume ratio of ethanol to ultrapure water in step two is 1:(2.25~2.5).

4. The method for preparing a metal polyphenol network-coated polydopamine nanoparticle antibacterial material according to claim 1, characterized in that... In step three, the concentration of dopamine hydrochloride in the mixed system is 3.5 mg / mL to 4 mg / mL. In step three, the dopamine hydrochloride solution is added to the ethanol / water solution and stirred for 10 min to 20 min at a stirring speed of 1000 rpm to 1200 rpm.

5. The method for preparing a metal polyphenol network-coated polydopamine nanoparticle antibacterial material according to claim 1, characterized in that... The concentration of ammonia in step four is 6.6 mg / mL to 7 mg / mL; the volume ratio of ammonia to the mixed system in step four is 1:(58~70); in step four, ammonia is added to the mixed system and reacted for 20 h to 24 h under a stirring speed of 1000 rpm to 1200 rpm, then centrifuged for 15 min to 20 min under a centrifugation speed of 10000 rpm to 11000 rpm and the supernatant is removed. Finally, ultrapure water is added to redisperse the mixture to obtain a polydopamine nanoparticle dispersion with a concentration of 2 mg / mL to 3 mg / mL.

6. The method for preparing a metal polyphenol network-coated polydopamine nanoparticle antibacterial material according to claim 1, characterized in that... The concentration of the NaOH solution mentioned in step five is 0.08 mol / L to 0.1 mol / L; the concentration of the quercetin solution mentioned in step five is 4 mg / mL to 5 mg / mL.

7. The method for preparing a metal polyphenol network-coated polydopamine nanoparticle antibacterial material according to claim 1, characterized in that... The volume ratio of quercetin solution to polydopamine nanoparticle dispersion in step six is ​​1:(3~3.3); in step six, under the condition of stirring speed of 1000rpm~1200rpm, quercetin solution is added to polydopamine nanoparticle dispersion and stirred for 2min~5min.

8. The method for preparing a metal polyphenol network-coated polydopamine nanoparticle antibacterial material according to claim 1, characterized in that... The concentration of the copper nitrate solution mentioned in step seven is 2 mg / mL to 2.5 mg / mL.

9. The method for preparing a metal polyphenol network-coated polydopamine nanoparticle antibacterial material according to claim 1, characterized in that... The volume ratio of the copper nitrate solution to the polydopamine nanoparticle mixture containing quercetin in step eight is 1:(6.5~7). In step eight, the copper nitrate solution is added to the polydopamine nanoparticle mixture containing quercetin and reacted for 6h~8h under the condition of stirring speed of 1000rpm~1200rpm. Then, the mixture is centrifuged for 15min~30min under the condition of centrifugation speed of 11000rpm~12000rpm and the supernatant is removed to obtain the antibacterial material of polydopamine nanoparticles coated with metal polyphenol network.

10. The application of the antibacterial material of metal polyphenol network-coated polydopamine nanoparticles prepared according to claim 1, characterized in that... It is used to kill Gram-positive and Gram-negative bacteria and promote the healing of bacterial wounds, or to be combined with ceramic membranes or activated carbon in water purifiers to prevent bacterial colonization.

Images