Antibacterial nano-particles based on tannic acid and sophocarpidine as well as preparation method and application of antibacterial nano-particles

Abstract

The invention provides antibacterial nanoparticles based on tannic acid and sophocarpidine and a preparation method and application thereof, and belongs to the technical field of medicine preparations, tannic acid and sophocarpidine are self-assembled according to the mass ratio of 1: (3-20) to obtain the antibacterial nanoparticles, the antibacterial nanoparticles are used for resisting bacteria, and the application of the antibacterial nanoparticles is wide. The bacteria comprise methicillin-resistant staphylococcus aureus and escherichia coli, the antibacterial rate of the antibacterial nanoparticles for resisting the methicillin-resistant staphylococcus aureus is 89%-98.6%, and the biological membrane inhibition rate is 72%-83.2%.

Description

Technical Field

[0001] This invention belongs to the field of antibacterial drug formulation technology, specifically relating to an antibacterial nanoparticle based on tannic acid and matrine, its preparation method and application. Background Technology

[0002] Methicillin-resistant Staphylococcus aureus (MRSA), a typical "superbug," has seen its prevalence and infection rate continuously rise since its first discovery in the 1960s. In healthcare facilities, MRSA is one of the leading causes of nosocomial infections, frequently leading to serious conditions such as surgical site infections, bloodstream infections, and pneumonia, significantly increasing patient mortality. Simultaneously, MRSA is increasingly spreading in the community, with a growing number of community-acquired MRSA infections. Once infected, community members often experience rapid disease progression, and due to a lack of timely and effective treatment, it can easily lead to serious complications and even death.

[0003] Currently, antibiotics remain the primary means of treating bacterial infections in clinical practice. However, MRSA exhibits high resistance to many commonly used antibiotics, including β-lactams, macrolides, and aminoglycosides. Its resistance mechanisms are complex and diverse, primarily including the production of penicillin-binding protein 2a, altered cell wall permeability, and the production of inactivating enzymes. This significantly reduces the efficacy of traditional antibiotics against MRSA infections, and can even render them completely ineffective. Although researchers are continuously striving to develop new antibiotics, the development cycle for new drugs is long and costly, and the rate of bacterial resistance evolution often outpaces the speed of new drug development, making it difficult to fundamentally solve the problem of MRSA infections.

[0004] The development of nanotechnology has brought new opportunities to solve the problem of MRSA infection. Natural antibacterial nanomaterials possess unique physicochemical properties, which allow them to specifically interact with bacteria. They can precisely disrupt the integrity of bacterial cell membranes, causing bacterial contents to leak out; effectively inhibit bacterial metabolic activities, interfere with normal bacterial growth, and inhibit biofilm formation. For example, patent application CN202411303097 discloses a nano-antibacterial material based on bis(oxalate) and hypericin, its preparation method, and applications. This scheme self-assembles the chemiluminescent agent CPPO and the photosensitizer hypericin into nanoparticles, exhibiting excellent antibacterial biofilm performance through the generation of reactive oxygen species to kill bacteria and inhibit H2S from disrupting bacterial self-defense. Compared with traditional antibiotics and physical disinfection methods, natural antibacterial nanomaterials have significant advantages. They are less likely to induce bacterial resistance because their antibacterial mechanisms are diverse and complex, making it difficult for bacteria to develop resistance through a single mutation; they have a broad antibacterial spectrum, inhibiting or killing various types of bacteria; and their effects are long-lasting, maintaining antibacterial efficacy for a considerable period.

[0005] Tannic acid is a polyphenolic compound widely found in plants. It has a good inhibitory effect on a variety of bacteria. Due to its multi-target mechanism of action, unlike traditional antibiotics which target a single target, it is more difficult for drug-resistant bacteria such as MRSA to develop acquired resistance to it. However, existing tannic acid-based antibacterial nanoparticles mostly rely on metals or inorganic compounds as active components, which have bottlenecks such as potential biotoxicity and high synthesis costs. For example, patent CN120040749A discloses a scheme for assembling polyphenol nanodot sonosensitive agents from tannic acid through oxidative polymerization. This scheme requires ultrasound to activate its antibacterial activity, which may cause inconvenience for subsequent injection or oral administration. It also has potential toxicity due to the generation of ROS and the lack of verification of cytotoxicity under repeated ultrasound. Patent CN120286721A discloses a tannic acid-silver-palladium nano-antibacterial material. The preparation of this material depends on the precious metals silver / palladium, which poses potential biotoxicity and environmental risks (silver ion release, palladium uncertainty, heavy metal pollution). Patent CN118286447A discloses a tannic acid-selenium self-assembled antibacterial drug carrier. Its raw material is selenium tetrachloride, which is highly corrosive and toxic, posing a high safety risk.

[0006] Therefore, the development of tannic acid-based natural antibacterial nanomaterials targeting MRSA is of great scientific significance and clinical application value for overcoming the limitations of existing prevention and control methods and effectively controlling the spread and prevalence of MRSA infection. Summary of the Invention

[0007] In view of the problems existing in the above and / or prior art, the present invention is proposed.

[0008] Therefore, the purpose of this invention is to overcome the shortcomings of the prior art and provide antibacterial nanoparticles based on tannic acid and matrine.

[0009] To solve the above-mentioned technical problems, the present invention provides the following technical solution: the antibacterial nanoparticles are obtained by self-assembly of tannic acid and matrine in a mass ratio of 1:3 to 20.

[0010] As a preferred embodiment of the antibacterial nanoparticles based on tannic acid and matrine described in this invention, the self-assembled antibacterial nanoparticles have a tannic acid loading of 10% to 20% and a matrine loading of 80% to 90%.

[0011] It should be noted that self-assembly is a process in which molecules, nanoparticles, or macroscopic components spontaneously form ordered structures under specific conditions without direct external intervention. It relies on non-covalent interactions, such as hydrogen bonds, van der Waals forces, hydrophobic interactions, and electrostatic interactions, through intermolecular recognition and synergistic effects, enabling the system to transform from a disordered state to a thermodynamically stable, low-energy ordered structure.

[0012] Another object of the present invention is to provide a method for preparing antibacterial nanoparticles based on tannic acid and matrine.

[0013] To solve the above-mentioned technical problems, the present invention provides the following technical solution: including, Tannic acid and matrine were dissolved in methanol to obtain tannic acid methanol solution and matrine methanol solution, respectively. Tannic acid methanol solution and matrine methanol solution are mixed to obtain a mixture with a mass ratio of tannic acid to matrine of 1:3~20; The mixture is loaded into a syringe and injected into a beaker containing deionized water. The beaker is kept at a constant temperature and stirred. The mixture is then pushed into the beaker by the syringe to carry out a self-assembly reaction, resulting in a reaction solution. The reaction solution was dialyzed in the dark to obtain liquid nano-antibacterial materials, which were then freeze-dried to obtain nano-antibacterial materials based on tannic acid and matrine.

[0014] In a preferred embodiment of the method for preparing antibacterial nanoparticles based on tannic acid and matrine according to the present invention, the concentrations of the tannic acid methanol solution and the matrine methanol solution are 5~10 mg / mL.

[0015] As a preferred embodiment of the preparation method of antibacterial nanoparticles based on tannic acid and matrine described in this invention, the temperature of the constant temperature stirring state is 23~25℃ and the rotation speed is 300~350r / min.

[0016] In a preferred embodiment of the method for preparing antibacterial nanoparticles based on tannic acid and matrine as described in this invention, the injection rate of the mixture into the beaker via syringe is 0.2~0.3 mL / min.

[0017] In a preferred embodiment of the method for preparing antibacterial nanoparticles based on tannic acid and matrine as described in this invention, the reaction time of the self-assembly reaction is 5 to 10 minutes.

[0018] As a preferred embodiment of the method for preparing antibacterial nanoparticles based on tannic acid and matrine according to the present invention, the dialysis bag used for dialysis has a molecular weight cutoff of 500 Da and the dialysis time is 24 h.

[0019] As a preferred embodiment of the method for preparing antibacterial nanoparticles based on tannic acid and matrine according to the present invention, wherein the bacteria include methicillin-resistant Staphylococcus aureus and Escherichia coli.

[0020] Another object of the present invention is to provide an application of antibacterial nanoparticles based on tannic acid and matrine, wherein the antibacterial nanoparticles are used for antibacterial purposes, the bacteria including methicillin-resistant Staphylococcus aureus and Escherichia coli, and the antibacterial nanoparticles have an antibacterial rate of 89% to 98.6% and a biofilm inhibition rate of 72% to 83.2% against methicillin-resistant Staphylococcus aureus.

[0021] Beneficial effects of this invention: This invention provides antibacterial nanoparticles based on tannic acid and matrine, their preparation method, and applications. It innovatively selects tannic acid and matrine to efficiently self-assemble into stable nanoparticles. The preparation method is simple, has good stability, and good biocompatibility. Because natural antibacterial active substances are used as self-assembly raw materials, they are not prone to inducing drug resistance and exhibit significant antibacterial effects against a variety of common pathogens such as methicillin-resistant Staphylococcus aureus and Escherichia coli. Attached Figure Description

[0022] To more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings used in the following description of the embodiments will be briefly introduced. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0023] Figure 1 This is a photograph of the liquid nano-antibacterial material prepared in Example 1 of the present invention. Figure 2 This is a transmission electron microscope image of the tannic acid-matrine nano-antibacterial material prepared in Example 1 of the present invention. Figure 3 This is a particle size distribution diagram of the tannic acid-matrine nano-antibacterial material prepared in Example 1 of the present invention; Figure 4 This is a zeta potential diagram of the tannic acid-matrine nano-antibacterial material prepared in Example 1 of the present invention; Figure 5 This is a molecular dynamics simulation diagram of the tannic acid-matrine nano-antibacterial material prepared in Example 1 of the present invention; Figure 6 The image shows the antibacterial activity of the tannic acid-matrine nano-antibacterial material prepared in Example 1 of this invention against methicillin-resistant Staphylococcus aureus. Figure 7 This is a surface morphology image of methicillin-resistant Staphylococcus aureus treated with the tannic acid-matrine nano-antibacterial material prepared in Example 1 of this invention. Figure 8 The tannic acid-matrine nano-antibacterial material prepared in Example 1 of this invention exhibits antibacterial activity against Escherichia coli and Staphylococcus aureus. Figure 9 Crystal violet staining image of the inhibitory effect of the tannic acid-matrine nano-antibacterial material prepared in Example 1 of this invention on methicillin-resistant Staphylococcus aureus biofilm.

[0024] Figure 10 This is a comparison of the killing effect of the nano-antibacterial materials prepared in Example 1, Comparative Example 1, and Comparative Example 2 of the present invention on fibroblasts.

[0025] Figure 11 The study compared the antibacterial effects of chlorogenic acid and berberine alone and in combination on MRSA and Staphylococcus aureus in Comparative Example 6. Detailed Implementation

[0026] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the specific embodiments of the present invention will be described in detail below with reference to the examples in the specification.

[0027] Many specific details are set forth in the following description in order to provide a full understanding of the invention. However, the invention may also be practiced in other ways different from those described herein, and those skilled in the art can make similar extensions without departing from the spirit of the invention. Therefore, the invention is not limited to the specific embodiments disclosed below.

[0028] Secondly, the term "one embodiment" or "embodiment" as used herein refers to a specific feature, structure, or characteristic that may be included in at least one implementation of the present invention. The phrase "in one embodiment" appearing in different places in this specification does not necessarily refer to the same embodiment, nor is it a single or selective embodiment that is mutually exclusive with other embodiments.

[0029] Unless otherwise specified, all raw materials used in this invention are commercially available in the field.

[0030] Example 1 This embodiment provides a self-assembly preparation method for nano-antibacterial materials based on tannic acid and matrine, specifically: 1) Weigh 10 mg of tannic acid and dissolve it in 1 mL of methanol to obtain a tannic acid methanol solution with a mass concentration of 10 mg / mL; Weigh 100 mg of matrine and dissolve it in 10 mL of methanol to obtain a matrine methanol solution with a mass concentration of 10 mg / mL. Tannic acid methanol solution and matrine methanol solution were mixed to obtain a mixture in which the mass ratio of tannic acid to matrine was 1:10. 2) Add 20 mL of deionized water to a 50 mL beaker, place it in a magnetic thermostatic stirrer, set the temperature to 25℃ and the speed to 300 r / min; The mixture obtained in step 1) is loaded into a 5mL syringe, and the mixture is injected into the beaker containing deionized water at a rate of 0.2mL / min using a syringe pump. After all the mixture has been pushed into the beaker, the reaction is carried out for another 5min to obtain the reaction solution. 3) The reaction solution was placed in a 500 Da dialysis bag and dialyzed in PBS in the dark for 24 hours to obtain liquid nano-antibacterial material. Its appearance is as follows: Figure 1 As shown, the liquid product is freeze-dried in a freeze dryer to obtain the nano-antibacterial material based on tannic acid and matrine in this embodiment, denoted as tannic acid-matrine nano-antibacterial material.

[0031] The UV absorbance at 210 nm was measured using a UV spectrophotometer to calculate the loading of tannic acid and matrine in the nano-antibacterial material of this embodiment. The results showed that the loading of tannic acid and matrine (the final proportion of tannic acid and matrine in the nano-antibacterial material) were 15.7% and 84.3%, respectively.

[0032] The freeze-dried antibacterial nanomaterials based on tannic acid and matrine were dispersed in water. 10 μL of the nanomaterials was placed on a copper grid, dried, and then observed under a transmission electron microscope. The particle size, potential, and polydispersity index (PDI) of the nanoparticles were measured. The results are as follows: Figures 2-5 As shown.

[0033] Figure 2 This is a transmission electron microscope image of the tannic acid-matrine nanoparticles prepared in this embodiment. Figure 3 This is a particle size distribution diagram of the tannic acid-matrine nanoparticles prepared in this embodiment; Figure 4 This is a zeta potential diagram of the tannic acid-matrine nanoparticles prepared in this embodiment; Figure 5This is a molecular dynamics simulation diagram of the tannic acid-matrine nanoparticles prepared in this embodiment.

[0034] Depend on Figures 2-5 It can be seen that the antibacterial nanoparticles prepared in this embodiment are spherical in shape, uniform in size, and well dispersed. The particle size of the antibacterial nanoparticles is between 60 and 200 nm, and the zeta potential is -34 mV, which shows good stability.

[0035] Antibacterial test The antibacterial properties of the nano-antibacterial material prepared in Example 1 were tested, specifically: A: Antibacterial effect against MRSA 1) After thawing methicillin-resistant Staphylococcus aureus (MRSA) in a 37°C water bath, activate and inoculate the bacteria in a biosafety cabinet. Using an inoculation loop dipped into the bacterial suspension above an alcohol lamp flame, streak continuously onto a petri dish covered with tryptic soy peptone (TSB) solid medium. The streaks should be close but not connected. After streaking, flame the inoculation loop with an alcohol lamp. After cooling, streak parallel lines starting from the end of the previous streak. Repeat this process three times. Then, place the petri dish in a 37°C incubator and incubate for 24 hours to form colonies for later use.

[0036] 2) Using an inoculation loop, pick three single colonies from the TSB solid medium containing MRSA from step 1) and inoculate them into a tube containing 2.5 mL of TSB liquid medium. Loosen the cap and place the tube in a 37°C constant temperature air bath shaking incubator at 200 rpm for 18 hours to obtain stationary bacteria. Take 40 μL of the stationary bacterial culture and inoculate it into a culture tube containing 4 mL of TSB liquid medium. Incubate at 37°C and 200 rpm for 4 hours to reach the logarithmic phase. Centrifuge at 7000 rpm for 5 minutes until white bacterial plaques are visible at the bottom of the tube. Discard the supernatant and wash the bacteria with PBS buffer. After centrifugation and washing twice, add PBS buffer to adjust the OD600 to approximately 0.5 (maintain this value each time for easy bacterial count control and to ensure repeatability). At this point, the bacterial concentration is approximately 5 × 10⁻⁶. 9 CFU / mL, dilute this bacterium 10 times and use it for later use.

[0037] 3) Take an appropriate amount of MRSA suspension in the stable phase and adjust the concentration of the MRSA suspension to 2×10⁻⁶ with PBS buffer. 6 CFU / mL, add 50 μL of the diluted bacterial solution to a 96-well plate. Add PBS solution and PBS solution containing the antibacterial nanomaterials of Example 1 (512 μg / mL) to the microplate containing the bacterial solution, and incubate together at 37°C for 3 hours.

[0038] 4) To produce visible colonies, spread the diluted bacterial solution onto TSB solid medium and incubate it upside down in a 37°C incubator overnight. Five replicates were made for each sample, and the colonies were photographed and recorded.

[0039] The antibacterial effect of this embodiment on MRSA is as follows: Figure 6 As shown, the surface morphology of bacteria is as follows Figure 7 As shown, the results indicate that the antibacterial nanomaterial has good antibacterial effects and can disrupt the stability of cell membrane structures.

[0040] B: Antibacterial effect against Escherichia coli and Staphylococcus aureus The antibacterial effect of the nano-antibacterial material prepared in Example 1 against Escherichia coli and Staphylococcus aureus was determined according to the experimental method for the antibacterial effect on MRSA. The results are as follows. Figure 8 As shown, the results indicate that the nano-antibacterial material prepared in Example 1 of this invention also has excellent antibacterial effects against Escherichia coli and Staphylococcus aureus.

[0041] C: Performance test for inhibiting MRSA biofilm formation The antimicrobial nanomaterials prepared in Example 1 were subjected to an anti-MRSA biofilm formation test, specifically: 1) Take an appropriate amount of MRSA bacterial suspension in the logarithmic phase and dilute it with TSB liquid medium to a bacterial concentration of approximately 1×10⁻⁶. 6 After mixing CFU / mL thoroughly, add 0.9 mL of bacterial culture to each well of a 48-well microplate. Add 0.1 mL of PBS solution and the PBS solution of the antibacterial nanomaterial to the wells (final concentration 512 μg / mL), incubate at 37°C for 48 hours, discard the supernatant, and wash three times with PBS buffer. Finally, MRSA biofilm can be seen at the bottom of the well.

[0042] 2) Subsequently, 1% crystal violet dye was added to the micropores and stained for 30 minutes at room temperature. After staining, excess dye was washed off, and the inhibitory effect of the antibacterial nanomaterials on MRSA biofilms was evaluated.

[0043] The inhibitory effect of this embodiment on MRSA biofilm is as follows: Figure 9 As shown, the results indicate that the antibacterial nanomaterial has a strong inhibitory effect on the formation of MRSA biofilm.

[0044] Example 2 The difference between this embodiment and Example 1 is that the mixing ratio of tannic acid methanol solution and matrine methanol solution in step 1) is adjusted so that the mass ratio of tannic acid to matrine in the mixture is 1:20, 1:10, 1:5, and 1:3, respectively. The remaining steps are the same as in Example 1. Nanoparticles with different mass ratios of tannic acid and matrine were obtained in this embodiment, and the relevant properties were measured. The results are shown in Table 1.

[0045] Table 1

[0046] As can be seen from Table 1, although tannic acid and matrine of different mass ratios can form micro- and nano-particles of different sizes, the nanoparticles composed of tannic acid and matrine of different mass ratios have significant differences in dispersibility, antibacterial effect and biofilm inhibition rate.

[0047] Comparative Example 1 The difference between this comparative example and Example 1 is that tannic acid was used alone to prepare nano-antibacterial particles. The concentration of tannic acid was the same as the total concentration of tannic acid and matrine in Example 1. All other steps and processes were the same as in Example 1 to obtain the nano-antibacterial material of this comparative example.

[0048] Comparative Example 2 The difference between this comparative example and Example 1 is that matrine was used alone to prepare nano-antibacterial particles. The concentration of matrine was the same as the total concentration of tannic acid and matrine in Example 1. All other steps and processes were the same as in Example 1 to obtain the nano-antibacterial material of this comparative example.

[0049] The antibacterial effects of the nano-antibacterial materials prepared in Comparative Examples 1 and 2 on MRSA were determined and compared with those in Example 1. The results are shown in Table 2.

[0050] Table 2

[0051] As shown in Table 2, for MRSA, the antibacterial rates of tannic acid and matrine used alone were 86.3% and 32.8%, respectively, and the biofilm inhibition rates were 62.8% and 12.1%, respectively. When the two were self-assembled into nanoparticles, the antibacterial rate reached 98.6% and the biofilm inhibition rate reached 83.2%, achieving the best synergistic effect.

[0052] Toxicity testing The nano-antibacterial materials prepared in Example 1, Comparative Examples 1 and 2 were subjected to fibroblast toxicity tests. Specifically: 1) Remove fibroblasts from liquid nitrogen, thaw them in a 37°C water bath, centrifuge at 1000 rpm for 5 minutes and discard the supernatant. Add 10 mL of DMEM medium (hereinafter referred to as medium) containing 10% fetal bovine serum and 1% penicillin-streptomycin antibiotics to a cell culture dish with the centrifuged cells, and incubate at 37°C in a 5% CO2 cell culture incubator to allow the cells to adhere and grow.

[0053] 2) After 48 hours, remove the culture medium from the culture dish, add 3 mL of PBS and gently rinse twice, add 2 mL of trypsin and let it stand for 3 minutes to digest, add 3 mL of culture medium to stop digestion, and centrifuge at 1000 r / min for 5 minutes.

[0054] 3) Discard the supernatant and seed the precipitated fibroblasts into 96-well plates. Add an appropriate amount of cell suspension (100 μL, containing about 5 × 10³ cells) to each well and incubate in a cell culture incubator at 37°C and 5% CO2 for 12 hours to allow the cells to adhere to the plate.

[0055] 4) Remove the old culture medium from each well, and add fresh culture medium containing different concentrations of the nano-antibacterial material prepared in Example 1, as well as the same concentration equivalents of tannic acid, matrine, and PBS to the drug treatment group and the PBS control group, keeping the total volume of each well consistent (200 μL). Place the culture plate back into the cell culture incubator and continue culturing for 24 hours.

[0056] 5) After drug treatment, remove the culture medium from each well and add 100 μL of fresh culture medium containing MTT reagent (final concentration 0.5 mg / mL) to each well. Place the culture plate in a cell culture incubator and continue incubation for 4 hours to allow MTT to be reduced by succinate dehydrogenase in the mitochondria of living cells to formazan, a water-insoluble blue-purple crystal.

[0057] 6) After incubation, carefully aspirate the supernatant from each well, avoiding the removal of the purple crystals at the bottom. Add 150 μL LDMSO to each well and shake for 10 min to fully dissolve the formazan. Measure the absorbance of each well at 570 nm using a microplate reader. Calculate the killing rate as follows: Figure 10 As shown.

[0058] from Figure 10 It can be seen that, at the same concentration equivalent, matrine exhibits strong toxicity, but its toxicity is significantly reduced after self-assembling with tannic acid into nanoparticles. The cell survival rate at the maximum concentration can reach more than 90%, and it is essentially non-toxic to cells.

[0059] Comparative Example 3 This comparative example uses the scheme described in the literature "Co-assembled nanocomplexes comprising epigallocatechingallate and berberine for enhanced antibacterial activity against multidrug-resistant Staphylococcus aureus" as a comparison. This scheme, using nanoparticles self-assembled from berberine and epigallocatechingallate, only showed inhibitory effects against Gram-positive bacteria such as Staphylococcus aureus and MRSA, and did not exhibit broad-spectrum antibacterial activity. Furthermore, significant bacterial aggregation and adhesion were still observed on the biofilm surface after drug treatment, suggesting that although the biofilm structure was weakened, considerable residues remained.

[0060] Compared to the previous method, this invention exhibits a broad-spectrum inhibitory effect on bacteria, demonstrating good inhibitory activity not only against Gram-positive bacteria such as MRSA, but also against Gram-negative bacteria such as Escherichia coli. Furthermore, the treatment group of this invention shows less biofilm adhesion, lower staining intensity, and no large-area bacterial aggregation, resulting in a more significant inhibitory effect on biofilm.

[0061] Comparative Example 4 This comparative example uses the protocol from the literature "Noncovalent co-assembly of aminoglycoside antibiotics@tannic acid nanoparticles for off-the-shelf treatment of pulmonary and cutaneous infections" as a reference. This protocol uses tannic acid and aminoglycoside antibiotics to self-assemble and release antibiotics under weakly acidic conditions.

[0062] Compared with the present invention, the present invention has the technical defect of potentially causing bacterial drug resistance. In contrast, the present invention uses natural antibacterial active substances tannic acid and matrine as self-assembly raw materials, which are less likely to induce drug resistance. At the same time, the self-assembled nanoparticles significantly improve the antibacterial effect by increasing the local concentration of matrine.

[0063] Comparative Example 5 This comparative example uses the scheme in the literature "Targeted delivery of Chinese herb pair-based berberine / tannin acid self-assemblies for the treatment of ulcerative colitis" as a reference. This scheme uses tannin and berberine for self-assembly, and the PDI of the nanoparticles formed under the optimal ratio is 0.24, with an average particle size of 255.47.

[0064] Compared to the previous method, the present invention has a smaller particle size of 60-200 nm, a PDI of 0.1951, and a highly uniform size distribution, approaching that of an ideal monodisperse system. This characteristic can significantly improve the stability of antibacterial properties, the precision of drug release control, and biocompatibility.

[0065] Comparative Example 6 This comparative example uses chlorogenic acid and berberine as active components to prepare antibacterial materials, specifically: Weigh 10 mg of chlorogenic acid and dissolve it in 1 mL of deionized water to obtain an aqueous solution with a mass concentration of 10 mg / mL; weigh 100 mg of berberine and dissolve it in 10 mL of deionized water to obtain an aqueous solution with a mass concentration of 10 mg / mL; mix the aqueous solution of chlorogenic acid and the aqueous solution of berberine to obtain a mixed solution with a mass ratio of chlorogenic acid to berberine of 1:10.

[0066] The antibacterial effects of chlorogenic acid, berberine, and the antibacterial material prepared in this comparative example on MRSA were determined according to the experimental method for the antibacterial effect of nanoparticles on MRSA in Example 1. The concentrations of chlorogenic acid and berberine used were 512 μg / mL, and the antibacterial effects were as follows. Figure 11 As shown.

[0067] The results showed that chlorogenic acid and berberine, whether used alone or in combination, had significant antibacterial activity against Staphylococcus aureus, but limited antibacterial activity against MRSA, and the combination of the two did not show a significant synergistic effect.

[0068] In summary, this invention innovatively selects the natural alkaloid matrine as a synergistic partner, and forms stable nanoparticles through the efficient self-assembly of tannic acid and matrine. While avoiding the aforementioned defects, it exhibits a strong inhibitory effect on MRSA. The synthesis process effectively utilizes the characteristics of the two molecules (non-covalent forces mainly based on hydrogen bonds), overcoming the technical obstacle of poor effect when using matrine alone (the antibacterial rate of self-assembled nanoparticles of the same mass concentration is more than 3 times higher than that of matrine alone), providing a safer and more economical solution for combating drug-resistant bacterial infections.

[0069] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention, and all such modifications or substitutions should be covered within the scope of the claims of the present invention.

Claims

1. An antibacterial nanoparticle based on tannic acid and matrine, characterized in that: The antibacterial nanoparticles are self-assembled from tannic acid and matrine at a mass ratio of 1:3 to 20.

2. The antibacterial nanoparticles based on tannic acid and matrine as described in claim 1, characterized in that: The self-assembled antibacterial nanoparticles have a loading capacity of 10%–20% for tannic acid and 80%–90% for matrine.

3. A method for preparing antibacterial nanoparticles based on tannic acid and matrine as described in claim 1 or 2, characterized in that: include, Tannic acid and matrine were dissolved in methanol to obtain tannic acid methanol solution and matrine methanol solution, respectively. Tannic acid methanol solution and matrine methanol solution are mixed to obtain a mixture with a mass ratio of tannic acid to matrine of 1:3~20; The mixture is loaded into a syringe and injected into a beaker containing deionized water. The beaker is kept at a constant temperature and stirred. The mixture is then pushed into the beaker by the syringe to carry out a self-assembly reaction, resulting in a reaction solution. The reaction solution was dialyzed in the dark to obtain liquid nano-antibacterial materials, which were then freeze-dried to obtain nano-antibacterial materials based on tannic acid and matrine.

4. The method for preparing antibacterial nanoparticles based on tannic acid and matrine as described in claim 3, characterized in that: The concentrations of the tannic acid methanol solution and the matrine methanol solution are 5~10 mg / mL.

5. The method for preparing antibacterial nanoparticles based on tannic acid and matrine as described in claim 3, characterized in that: The temperature of the constant-temperature stirring state is 23~25℃, and the rotation speed is 300~350r / min.

6. The method for preparing antibacterial nanoparticles based on tannic acid and matrine as described in claim 3, characterized in that: The mixture is injected into the beaker via a syringe at a rate of 0.2–0.3 mL / min.

7. The method for preparing antibacterial nanoparticles based on tannic acid and matrine as described in claim 3, characterized in that: The reaction time for the self-assembly reaction is 5 to 10 minutes.

8. The method for preparing antibacterial nanoparticles based on tannic acid and matrine as described in claim 3, characterized in that: The dialysis bag used in the dialysis had a molecular weight cutoff of 500 Da, and the dialysis time was 24 hours.

9. The application of antibacterial nanoparticles based on tannic acid and matrine as described in claim 1 or 2, characterized in that: The antibacterial nanoparticles are used for antibacterial purposes, and the bacteria include methicillin-resistant Staphylococcus aureus and Escherichia coli.

10. The application of antibacterial nanoparticles based on tannic acid and matrine as described in claim 9, characterized in that: The antibacterial nanoparticles exhibit an antibacterial rate of 89%–98.6% and a biofilm inhibition rate of 72%–83.2% against methicillin-resistant Staphylococcus aureus.

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