Novel metal polyphenol network-loaded metal oxide antibacterial nanoparticles, preparation method and application

Abstract

The present invention provides a novel metal polyphenol network-loaded metal oxide antibacterial nanoparticle and a preparation method thereof. A uniformly dispersed and stable metal-polyphenol complex network is prepared by a one-step blending method with a large number of phenolic hydroxyl groups carried by polyphenols as active sites. The "sensitization" effect of the network on metal oxides and the excellent photothermal conversion ability and naturalness of the network are utilized to obtain antibacterial nanoparticles with high stability and high photothermal conversion ability without the aid of traditional photosensitizers / photothermal agents.

Description

Technical Field

[0001] The invention relates to the technical field of antibacterial materials, and in particular to a novel metal polyphenol network-loaded metal oxide antibacterial nanoparticle, a preparation method and application thereof. Background Art

[0002] The traditional antibacterial strategy is to use antibacterial materials containing antibiotics, but the widespread use of antibiotics has led to bacterial resistance, which has increased the cost and difficulty of antibacterial pollution. Therefore, in recent years, research in the field of antibacterials has been committed to preventing the emergence of bacterial resistance and exploring broad-spectrum antibacterial strategies.

[0003] Photodynamic antibacterial strategy and photothermal antibacterial strategy are new non-antibiotic antibacterial strategies that do not induce bacterial resistance.

[0004] Photodynamic therapy uses photosensitizers to produce reactive oxygen species under an excitation light source of appropriate wavelength, causing oxidative damage to surrounding biomolecules such as lipids, proteins, and nucleic acids, thereby killing cancer cells or pathogenic microorganisms; photothermal therapy uses photothermal agents to convert the energy of near-infrared light into thermal energy, thereby using thermal energy to kill bacteria. Compared with traditional non-photodynamic free radical activation antibacterial therapy, photodynamic antibacterial therapy has the following advantages: 1) With the help of light sources, antibacterial treatment is more targeted (local treatment); 2) It is not limited by the concentration of hydrogen peroxide in the microenvironment of the infected site; 3) There are rich types of reactive oxygen species.

[0005] The synergistic effect produced by the combination of photothermal antimicrobial therapy and photodynamic antimicrobial therapy can improve the antimicrobial specificity and therapeutic effect, and reduce the damage to normal cells and tissues caused by excessive temperature.

[0006] But at present, on the one hand, traditional photosensitizers / photothermal agents may have a certain impact on the environment; on the other hand, traditional photosensitizers / photothermal agents need to reach a certain content to achieve the ideal photodynamic / thermal effect for biofilm ablation, but too high a dose may cause the photosensitizer / photothermal agent to aggregate, thereby affecting the photothermal conversion rate, and may cause harm to healthy cells, limiting its application in antibacterial applications. Summary of the invention

[0007] The purpose of the present invention is to provide a novel metal polyphenol network loaded metal oxide antibacterial nanoparticles and a preparation method thereof in view of the deficiencies in the prior art. A uniformly dispersed and stable metal-polyphenol complex network coated with metal oxide is prepared by a one-step blending method. The metal-polyphenol complex network can not only enhance the utilization rate of visible light by metal oxide semiconductors, but also convert light energy into heat energy, and can also locally increase the temperature while generating reactive oxygen species ROS online. No external photosensitizer or photothermal agent is required, and oxygen toxicity and thermal ablation can be generated on bacterial cells, thereby achieving an antibacterial effect.

[0008] According to the first aspect of the present invention, a novel metal polyphenol network-loaded metal oxide antibacterial nanoparticle is provided, wherein the nanoparticle comprises a metal-polyphenol complex network formed by coordination of metal ions and polyphenols, wherein the metal-polyphenol complex network is encapsulated with metal oxides;

[0009] Wherein, the metal ion is a metal ion having near infrared absorption and / or a metal ion capable of undergoing dd transition;

[0010] The metal oxide is a nanometer semiconductor metal oxide.

[0011] Preferably, when only near-infrared light irradiation is selected, metal ions that absorb in the near-infrared are used.

[0012] Preferably, when only sunlight irradiation is selected, metal ions capable of undergoing dd transition are used.

[0013] Preferably, when either sunlight or near-infrared light is selected, metal ions are used that have both near-infrared absorption and the ability to undergo dd transition.

[0014] According to the second aspect of the present invention, there is provided a method for preparing the aforementioned novel metal polyphenol network-loaded metal oxide antibacterial nanoparticles, comprising the following steps:

[0015] Dissolving polyphenol and metal salt in deionized water respectively to obtain polyphenol aqueous solution and metal precursor salt solution; wherein the metal ions in the metal salt are metal ions having near infrared absorption and / or metal ions capable of dd transition;

[0016] Dissolving a metal oxide in a Tris-HCl buffer solution to obtain a first solution; wherein the metal oxide is a nano-semiconductor metal oxide;

[0017] Adding the polyphenol aqueous solution and the metal precursor salt solution to the first solution simultaneously, stirring and adjusting the pH to ≥ 7, to obtain a second solution;

[0018] The second solution is centrifuged, and the product after centrifugation is washed, vacuum dried, crushed and ground to obtain the novel metal polyphenol network-loaded metal oxide antibacterial nanoparticles.

[0019] Preferably, the metal salt is ferric chloride hexahydrate, cupric chloride dihydrate, zinc chloride, vanadium chloride or ruthenium chloride.

[0020] Preferably, the metal oxide is nano titanium dioxide, nano zinc oxide, nano copper oxide or nano molybdenum dioxide.

[0021] Preferably, the polyphenol is epigallocatechin gallate, black wattle tannin or tannic acid.

[0022] Preferably, the mass concentration ratio of the polyphenol aqueous solution to the metal ion in the metal precursor salt solution is 1:(1-4).

[0023] Preferably, in the first solution, the mass ratio of the metal oxide to the Tris-HCl buffer solution is 1:(1-2), and the pH value of the Tris-HCl buffer solution is 7-8.

[0024] Preferably, the polyphenol aqueous solution and the metal precursor salt solution are added to the first solution at the same time, stirred and the pH is adjusted to 7-8 to obtain the second solution.

[0025] According to the third aspect of the present invention, there is provided a use of the aforementioned novel metal polyphenol network-loaded metal oxide antibacterial nanoparticles in the preparation of antibacterial materials.

[0026] It can be seen from the above technical scheme of the present invention that the novel metal polyphenol network loaded metal oxide antibacterial nanoparticles proposed in the present invention, under the irradiation of near-infrared light, the polyphenol-metal complex network will absorb light energy, and the metal ions in the network will form electrons and holes, and the electron energy will be released in the non-radiative attenuation channel, causing the lattice vibration to emit abundant phonons and lattice heat, generate heat, form a photothermal platform, denature proteins and collagen, and permeate cell membranes, and effectively solve the toxic and side effects of photothermal agents during synthesis and use.

[0027] At the same time, the polyphenol-metal complex network can transfer the absorbed light energy to the nano-semiconductor, narrowing the band gap of the nano-semiconductor and making the conduction band potential more negative, which is more conducive to reducing the oxygen adsorbed on the surface to O2· — , and further turns into singlet oxygen, which is used to damage proteins, fats and other biological molecules around the photosensitized site, thereby killing cells. This effectively solves the problems of photosensitizer aggregation and limited absorption, and avoids the problem of excessive temperature in photothermal therapy, which may accidentally damage normal and healthy cells.

[0028] In this way, the synergistic effect of photodynamic force and photothermal force can not only disperse the energy to photodynamic force for antibacterial effect, but also avoid the excessive temperature of photothermal therapy; it can also utilize the polyphenol metal network with high photothermal conversion efficiency to achieve a certain antibacterial effect.

[0029] The novel metal polyphenol network-loaded metal oxide antibacterial nanoparticles of the present invention can also satisfy the requirement of antibacterial performance under sunlight by adjusting the type of metal ions. The polyphenol-metal complex network absorbs sunlight and, on the one hand, transfers part of the energy to the nano-metal oxide semiconductor, thereby narrowing the band gap of the nano-metal oxide semiconductor and making the conduction band potential more negative, which is more conducive to reducing the oxygen adsorbed on the surface to O2·— , further converted into singlet oxygen; on the other hand, another part of the energy absorbed by sunlight is transferred to the unoccupied d orbital in the metal ion to undergo internal dd transition, thereby reducing the band gap of polyphenols and further improving the light absorption capacity and total photothermal effect of the obtained polyphenol materials. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 It is a schematic structural diagram of the novel metal polyphenol network-loaded metal oxide antibacterial nanoparticles of the present invention.

[0031] Figure 2 This is a picture of the novel metal polyphenol network-loaded metal oxide antibacterial nanoparticles after re-dissolution.

[0032] Figure 3 This is a picture of the novel metal polyphenol network-loaded metal oxide antibacterial nanoparticles after re-dissolution.

[0033] Figure 4 It is a test chart of the antibacterial performance of the nanoparticles obtained in Example 1 of the present invention and the material obtained in the comparative example. DETAILED DESCRIPTION

[0034] In order to better understand the technical content of the present invention, specific embodiments are given and described as follows in conjunction with the accompanying drawings.

[0035] Various aspects of the present invention are described in this disclosure with reference to the accompanying drawings, in which many illustrative embodiments are shown. The embodiments of the present disclosure are not necessarily intended to include all aspects of the present invention. It should be understood that the various concepts and embodiments introduced above, as well as those described in more detail below, can be implemented in any of many ways.

[0036] The principle of photodynamic therapy is: under the irradiation of a light source with the same absorption wavelength as the photosensitizer molecule, the photosensitizer absorbs electrons and transforms from the singlet ground state to the singlet excited state; part of the energy is radiated in the form of fluorescent quanta, and the remaining energy transforms the photosensitizer molecule into a triplet state (a form that can be used for treatment), and the energy of the triplet state is transferred to the ground state oxygen molecule, causing the oxygen molecule to transform from the ground state to the excited state to produce singlet oxygen.

[0037] The principle of photothermal therapy is: under the irradiation of near-infrared light (700-1100nm), the photothermal agent is transformed into an excited state, forming electrons and holes, and the electron energy is released in the non-radiative attenuation channel (which can cause lattice vibration to emit abundant phonons and lattice heat), generating heat, causing protein and collagen denaturation and cell membrane permeability.

[0038] Traditional photodynamic therapy requires the use of photosensitizers, and the use of large amounts of photosensitizers causes them to easily aggregate. The limited penetration of lasers into deep tissues and the limited absorption of lasers by photosensitizers affect the efficacy of traditional photodynamic therapy. The large-scale use of photosensitizers will also have a certain impact on the environment.

[0039] The synthesis process of traditional photothermal agents is complicated and requires the use of complex chemicals and toxic additives, which is not environmentally friendly. In addition, the use of a large amount of photothermal agents causes them to easily aggregate, affecting their efficacy. At the same time, the large amount of heat generated by the photothermal agents can cause the temperature to be too high, thereby damaging normal cells and tissues.

[0040] Therefore, the present invention provides a novel metal polyphenol network-loaded metal oxide antibacterial nanoparticles and a preparation method thereof. A uniformly dispersed and stable metal-polyphenol complex network is prepared by a one-step blending method using a large number of phenolic hydroxyl groups carried by polyphenols as active sites. The "sensitization" effect of the network on metal oxides and the excellent photothermal conversion ability and naturalness of the network are utilized to obtain antibacterial nanoparticles with high stability and high photothermal conversion ability without the aid of traditional photosensitizers / photothermal agents.

[0041] In an exemplary embodiment of the present invention, a novel metal polyphenol network-loaded metal oxide antibacterial nanoparticle is provided. The nanoparticle comprises a metal-polyphenol complex network formed by coordination of metal ions and polyphenols, wherein the metal-polyphenol complex network is encapsulated with metal oxides.

[0042] Wherein, the metal ion is a metal ion having near-infrared absorption and / or a metal ion capable of undergoing dd transition.

[0043] The metal oxide is a nanometer semiconductor metal oxide.

[0044] like Figure 1 As shown, metal ions and polyphenols coordinate to form a metal-polyphenol complex network, and the metal-polyphenol complex network is coated on the surface of the metal oxide. Because the network is dense and uniform, it will be coated in many aspects and directions, thereby wrapping the metal oxide.

[0045] In one preferred embodiment, when only near-infrared light irradiation is selected, metal ions that absorb in the near-infrared are used, for example, trivalent iron ions, gold ions, vanadium ions, ruthenium ions, etc.

[0046] In one preferred embodiment, when only sunlight is selected for irradiation, metal ions that can undergo dd transition are used, for example, transition metal ions, trivalent iron ions, gold ions, vanadium ions, ruthenium ions, copper ions, zinc ions, etc.

[0047] In one preferred embodiment, when both sunlight and near-infrared light can be selected, metal ions that have both absorption in the near-infrared and the ability to undergo dd transition are used, such as trivalent iron ions, gold ions, vanadium ions, ruthenium ions, zinc ions, etc.

[0048] The present invention also provides a method for preparing the aforementioned novel metal polyphenol network-loaded metal oxide antibacterial nanoparticles. Through a one-step blending method, a large number of phenolic hydroxyl groups carried by the polyphenols can be complexed with metal ions, and can exhibit stable coordination properties on the surface of metal oxides. Moreover, the material can be formed in water in a few minutes without the need for additional conditions and additives, and the preparation cost is low and green and environmentally friendly.

[0049] In another exemplary embodiment of the present invention, a method for preparing the aforementioned novel metal polyphenol network-loaded metal oxide antibacterial nanoparticles is provided, comprising the following steps:

[0050] The polyphenol and the metal salt are dissolved in deionized water respectively to obtain a polyphenol aqueous solution and a metal precursor salt solution; wherein the metal ions in the metal salt are metal ions having near infrared absorption and / or metal ions capable of undergoing dd transition.

[0051] The metal oxide is dissolved in a Tris-HCl buffer solution to obtain a first solution; wherein the metal oxide is a nano-semiconductor metal oxide.

[0052] The polyphenol aqueous solution and the metal precursor salt solution are added to the first solution at the same time, stirred and adjusted to pH ≥ 7 to obtain a second solution.

[0053] The second solution is centrifuged, and the product after centrifugation is washed, vacuum dried, crushed and ground to obtain the novel metal polyphenol network-loaded metal oxide antibacterial nanoparticles.

[0054] In a preferred embodiment, the metal salt is ferric chloride hexahydrate, cupric chloride dihydrate, zinc chloride, vanadium chloride or ruthenium chloride.

[0055] In a preferred embodiment, the metal oxide is nano titanium dioxide, nano zinc oxide, nano copper oxide or nano molybdenum dioxide.

[0056] In a preferred embodiment, the polyphenol is epigallocatechin gallate (EGCG), tannin (OPC) or tannic acid (TA).

[0057] In a preferred embodiment, the mass concentration ratio of the polyphenol aqueous solution to the metal ion in the metal precursor salt solution is 1:(1-4).

[0058] In a preferred embodiment, in the first solution, the mass ratio of the metal oxide to the Tris-HCl buffer solution is 1:(1-2), and the pH value of the Tris-HCl buffer solution is 7-8.

[0059] In a preferred embodiment, the polyphenol aqueous solution and the metal precursor salt solution are added to the first solution at the same time, stirred and the pH is adjusted to 7-8 to obtain a second solution.

[0060] The pH is used to control the degree of deprotonation of the hydroxyl group. When pH ≤ 2, it is a single complex with enhanced protonation; when pH is 3-6, it is a dicomplex; when pH ≥ 7, it is a tricomplex with the weakest protonation.

[0061] The selection of appropriate pH conditions can inhibit the protonation of phenolic hydroxyl groups, allowing the phenolic hydroxyl groups to play their role.

[0062] In another exemplary embodiment of the present invention, there is also provided a use of the aforementioned novel metal polyphenol network-loaded metal oxide antibacterial nanoparticles in the preparation of antibacterial materials.

[0063] like Figure 2 , Figure 3 As shown, after the above nanoparticles are redissolved, they are a solution with a certain viscosity ( Figure 2 and Figure 3 It can be seen that the solution has a certain wall-hanging property, which indicates that the solution has a certain viscosity). Therefore, it can be used for the following applications:

[0064] ① Spray on medical devices to form an antibacterial film, reduce bacterial adhesion and increase the service life of the device

[0065] ② Spray on clothing, insoles, bed sheets, quilt covers, and fruits to inhibit bacteria

[0066] ③ Antibacterial by simple dip coating on the outermost layer of glasses, goggles, masks, etc.

[0067] ④Surface modified nanofiltration membrane to prevent biofilm contamination and bacterial infection

[0068] ⑤ Make hydrogels as wound dressings or purify sewage while improving bacterial contamination

[0069] The application of the aforementioned novel metal polyphenol network-loaded metal oxide antibacterial nanoparticles in the preparation of antibacterial materials includes but is not limited to the above-mentioned application scenarios.

[0070] For better understanding, the present invention is further described below in conjunction with several specific examples, but the materials and processing techniques are not limited thereto, and the content of the present invention is not limited thereto.

[0071] Example 1

[0072] Step 1: Dissolve 0.2 g of black wattle tannin and 0.242 g of ferric chloride hexahydrate in 50 mL of deionized water at room temperature to obtain a 4 mg / mL tannin aqueous solution and a 1 mg / mL ferric chloride aqueous solution.

[0073] Step 2: Dissolve 100 mg of nano-titanium dioxide powder in 50 mL of Tris-HCl buffer solution with a pH of 8.

[0074] Step 3: Add the aqueous solution obtained in step 1 to the solution obtained in step 2 at the same time, stir and adjust the pH to 7 with 0.1 M sodium hydroxide solution.

[0075] Step 4: centrifuge the solution obtained in step 3 at 8000 rpm for 10 min, rinse with deionized water three times, and then vacuum dry at 60° C., crush and grind to obtain novel metal-polyphenol network-loaded metal oxide antibacterial particles.

[0076] Example 2

[0077] Step 1: Dissolve 0.2 g of black wattle tannin and 0.484 g of ferric chloride hexahydrate in 50 mL of deionized water at room temperature to obtain a 4 mg / mL tannin aqueous solution and a 2 mg / mL ferric chloride aqueous solution.

[0078] Step 2: Dissolve 100 mg of nano zinc oxide powder in 50 mL of Tris-HCl buffer solution with a pH of 8.

[0079] Step 3: Add the aqueous solution obtained in step 1 to the solution obtained in step 2 at the same time, stir and adjust the pH to 8 with 0.1 M sodium hydroxide solution.

[0080] Step 4: centrifuge the solution obtained in step 3 at 9000 rpm for 10 min, rinse with deionized water three times, and then vacuum dry at 80° C., crush and grind to obtain novel metal-polyphenol network-loaded metal oxide antibacterial particles.

[0081] Example 3

[0082] Step 1: Dissolve 0.2 g of tannic acid and 0.968 g of ferric chloride hexahydrate in 50 mL of deionized water at room temperature to obtain a 4 mg / mL tannic acid aqueous solution and a 4 mg / mL ferric chloride aqueous solution.

[0083] Step 2: Dissolve 100 mg of nano-titanium dioxide powder in 50 mL of Tris-HCl buffer solution with a pH of 8.

[0084] Step 3: Add the aqueous solution obtained in step 1 to the solution obtained in step 2 at the same time, stir and adjust the pH to 7 with 0.1 M sodium hydroxide solution.

[0085] Step 4: centrifuge the solution obtained in step 3 at a speed of 10,000 rpm for 5 minutes, rinse with deionized water for 3 times, and then vacuum dry at 70° C., crush and grind to obtain novel metal-polyphenol network-loaded metal oxide antibacterial particles.

[0086] Example 4

[0087] Step 1: Dissolve 0.2 g of black wattle tannin and 0.968 g of vanadium chloride in 50 mL of deionized water at room temperature to obtain 4 mg / mL of tannin aqueous solution and 4 mg / mL of vanadium chloride aqueous solution.

[0088] Step 2: Dissolve 100 mg of nano molybdenum dioxide powder in 50 mL of Tris-HCl buffer solution with a pH of 8.

[0089] Step 3: Add the aqueous solution obtained in step 1 to the solution obtained in step 2 at the same time, stir and adjust the pH to 7 with 0.1 M sodium hydroxide solution.

[0090] Step 4: centrifuge the solution obtained in step 3 at a speed of 10,000 rpm for 5 minutes, rinse with deionized water for 3 times, and then vacuum dry at 70° C., crush and grind to obtain novel metal-polyphenol network-loaded metal oxide antibacterial particles.

[0091] Example 5

[0092] Step 1: Dissolve 0.2 g of black wattle tannin and 0.968 g of ruthenium chloride in 50 mL of deionized water at room temperature to obtain 4 mg / mL of tannin aqueous solution and 4 mg / mL of ruthenium chloride aqueous solution.

[0093] Step 2: Dissolve 100 mg of nano-titanium dioxide powder in 50 mL of Tris-HCl buffer solution with a pH of 8.

[0094] Step 3: Add the aqueous solution obtained in step 1 to the solution obtained in step 2 at the same time, stir and adjust the pH to 7 with 0.1 M sodium hydroxide solution.

[0095] Step 4: centrifuge the solution obtained in step 3 at a speed of 10,000 rpm for 5 minutes, rinse with deionized water for 3 times, and then vacuum dry at 70° C., crush and grind to obtain novel metal-polyphenol network-loaded metal oxide antibacterial particles.

[0096] Example 6

[0097] Step 1: Dissolve 0.2 g of black wattle tannin and 0.968 g of cupric chloride dihydrate in 50 mL of deionized water at room temperature to obtain a 4 mg / mL tannin aqueous solution and a 4 mg / mL vanadium chloride aqueous solution.

[0098] Step 2: Dissolve 100 mg of nano copper oxide powder in 50 mL of Tris-HCl buffer solution with a pH of 8.

[0099] Step 3: Add the aqueous solution obtained in step 1 to the solution obtained in step 2 at the same time, stir and adjust the pH to 7 with 0.1 M sodium hydroxide solution.

[0100] Step 4: centrifuge the solution obtained in step 3 at a speed of 10,000 rpm for 5 minutes, rinse with deionized water for 3 times, and then vacuum dry at 70° C., crush and grind to obtain novel metal-polyphenol network-loaded metal oxide antibacterial particles.

[0101] Example 7

[0102] Step 1: Dissolve 0.2 g of black wattle tannin and 0.968 g of zinc chloride in 50 mL of deionized water at room temperature to obtain a 4 mg / mL tannin aqueous solution and a 4 mg / mL ruthenium chloride aqueous solution.

[0103] Step 2: Dissolve 100 mg of nano-titanium dioxide powder in 50 mL of Tris-HCl buffer solution with a pH of 8.

[0104] Step 3: Add the aqueous solution obtained in step 1 to the solution obtained in step 2 at the same time, stir and adjust the pH to 7 with 0.1 M sodium hydroxide solution.

[0105] Step 4: centrifuge the solution obtained in step 3 at a speed of 10,000 rpm for 5 minutes, rinse with deionized water for 3 times, and then vacuum dry at 70° C., crush and grind to obtain novel metal-polyphenol network-loaded metal oxide antibacterial particles.

[0106] Comparative Example

[0107] Step 1: Dissolve 0.2 g of black wattle tannin and 0.242 g of ferric chloride hexahydrate in 50 mL of deionized water at room temperature to obtain a 4 mg / mL tannin aqueous solution and a 1 mg / mL ferric chloride aqueous solution.

[0108] Step 2: Add the aqueous solution obtained in step 1 to a Tris-HCl buffer solution at pH 8, stir, and adjust the pH to 7 with a 0.1 M sodium hydroxide solution.

[0109] Step 3: Centrifuge the solution obtained in step 2 at 8000 rpm for 10 min, rinse with deionized water three times, then vacuum dry at 60° C., crush and grind to obtain the control group experimental sample.

[0110] Antimicrobial testing

[0111] The nanoparticles (FOT) obtained in Example 1, the material (FO) obtained in the comparative example, and TiO2 were used for antibacterial testing, and a pure bacterial solution (Escherichia coli) was used as a blank control group.

[0112] Under near infrared light (700-1100nm)

[0113] Experimental steps: Prepare a sample bacterial suspension mixture with a sample concentration of 5 mg / mL, specifically a mixture of sample + Escherichia coli bacterial suspension in sterile PBS, place it in a 37°C incubator for 0.5 h, and then illuminate it under a near-infrared light source for 10 min.

[0114] Then, the mixture was diluted with sterilized 1X PBS solution, 100 μL of the mixture was placed in a culture dish with solid culture medium, and the bacteria were plated using a spreading rod. The plated culture dish was placed in a 37°C incubator for 16-24 hours, and the number of colonies on the surface of the solid culture medium was observed and photographed for record.

[0115] Simulated sunlight conditions

[0116] Experimental steps: Prepare a sample bacterial suspension mixture with a sample concentration of 5 mg / mL, specifically a mixture of sample + Escherichia coli bacterial suspension in sterile PBS, place it in a 37°C incubator for 0.5 hours, and then use a 300W xenon lamp to simulate sunlight for 30 minutes. Then dilute the mixture with sterilized 1X PBS, take 100 μL of the above mixture solution and place it in a culture dish with solid culture medium, and use a coating rod to spread bacteria. After the culture dish is placed in a 37°C incubator for 16-24 hours, observe the number of colonies on the surface of the solid culture medium and take photos to record.

[0117] The results are as follows Figure 4 As shown in Table 1 and Table 2, combined Figure 4 It can be seen from Table 1 and Table 2 that, whether under near-infrared light conditions or under sunlight conditions, the antibacterial effect of the material with added metal oxides is better than that of the material without added metal oxides, and the antibacterial efficiency can reach more than 95% under near-infrared conditions, and the antibacterial efficiency can also reach 90% under sunlight, indicating that the antibacterial particles of the present invention can not only absorb near-infrared light to achieve the antibacterial effect, but also use sunlight to achieve better antibacterial performance through the "sensitization" effect of the tannin metal complex network and the dd transition of metal ions.

[0118] Table 1 Antibacterial test under near infrared light

[0119]

[0120] Table 2 Antibacterial test under simulated sunlight

[0121]

[0122] Although the present invention has been disclosed as above with preferred embodiments, it is not intended to limit the present invention. A person with ordinary knowledge in the technical field to which the present invention belongs may make various changes and modifications without departing from the spirit and scope of the present invention. Therefore, the protection scope of the present invention shall be determined by the definition of the claims.

Claims

1. A metal polyphenol network-loaded metal oxide antibacterial nanoparticle, characterized in that: The nanoparticles include a metal-polyphenol complex network formed by coordination of metal ions and polyphenols, wherein the metal-polyphenol complex network is wrapped with metal oxides; Wherein, the metal ion is a trivalent iron ion, the metal oxide is nano titanium dioxide, and the polyphenol is epigallocatechin gallate, black wattle tannin or tannic acid; The method for preparing nanoparticles comprises the following steps: Dissolving polyphenol and metal salt in deionized water respectively to obtain polyphenol aqueous solution and metal precursor salt solution; wherein the metal salt is ferric chloride hexahydrate; Dissolving a metal oxide in a Tris-HCl buffer solution to obtain a first solution; wherein the metal oxide is nano-titanium dioxide; Adding the polyphenol aqueous solution and the metal precursor salt solution to the first solution simultaneously, stirring and adjusting the pH to ≥ 7, to obtain a second solution; The second solution is centrifuged, and the product after centrifugation is washed, vacuum dried, crushed and ground to obtain the metal polyphenol network-loaded metal oxide antibacterial nanoparticles.

2. The metal polyphenol network-loaded metal oxide antibacterial nanoparticles according to claim 1, characterized in that: The mass concentration ratio of the polyphenol aqueous solution to the metal ion in the metal precursor salt solution is 1:(1~4).

3. The metal polyphenol network-loaded metal oxide antibacterial nanoparticles according to claim 1, characterized in that: In the first solution, the mass ratio of the metal oxide to the Tris-HCl buffer solution is 1:(1-2), and the pH value of the Tris-HCl buffer solution is 7-8.

4. The metal polyphenol network-loaded metal oxide antibacterial nanoparticles according to claim 1, characterized in that: The polyphenol aqueous solution and the metal precursor salt solution are added to the first solution at the same time, stirred and the pH is adjusted to 7-8 to obtain a second solution.

5. Use of the metal polyphenol network-loaded metal oxide antibacterial nanoparticles according to any one of claims 1 to 4 in the preparation of antibacterial materials.

Images