Iron-zinc diatomic nano-enzyme with oxidase-like activity as well as preparation method and application of iron-zinc diatomic nano-enzyme

Abstract

The invention discloses an iron-zinc diatomic nano enzyme with oxidase-like activity as well as a preparation method and application thereof, and belongs to the technical field of nano materials and antibiosis. The preparation method comprises the following steps: reacting dimethylimidazole with zinc nitrate hexahydrate in methanol to obtain a ZIF-8 nano-material, taking the ZIF-8 nano-material subjected to high-temperature annealing as a carbon source and a nitrogen source, the zinc nitrate hexahydrate as a zinc source, ferric nitrate nonahydrate as an iron source and ethanol as a solvent, and carrying out hot solvent loading and high-temperature annealing to obtain the FeZn diatomic nano-enzyme with a stable structure. The composite material is stable in configuration and good in biocompatibility, has efficient oxidase-like catalytic activity, does not need to additionally add hydrogen peroxide, is combined with a photothermal therapy, directly and efficiently generates active oxygen by catalyzing oxygen, is high in antibacterial activity, and has an excellent curative effect in deep drug-resistant bacterial infected wounds. The raw materials used in the invention have the advantages of low cost, good safety, mild synthesis conditions and simple synthesis steps, and can be industrially manufactured and applied on a large scale.

Description

Technical Field

[0001] The present invention relates to the field of nanomaterials and antibacterial technology, and in particular to an iron-zinc diatomic nanozyme with oxidase-like activity, a preparation method thereof, and an application thereof. Background Art

[0002] Overuse of antibiotics has led to the emergence of bacterial resistance, posing significant challenges to therapeutic interventions and negatively impacting public health and environmental integrity. Therefore, the development of new antimicrobial strategies is urgently needed. Innovative approaches proposed to replace antibiotics in the treatment of drug-resistant bacteria and inhibit bacterial biofilms include phage therapy, cytolysin therapy, antimicrobial peptides, gene editing, bacteriocins, cytolysins, defense-modulating peptides, probiotics, and antibody therapy. However, these strategies face limitations such as toxicity, immunogenicity, high cost, hydrolysis, and disruption of normal bacterial flora. Nanozymes are inorganic nanomaterials with intrinsic enzyme-like activity that have attracted significant attention for their broad-spectrum antimicrobial properties and potential to reduce drug resistance. Since the discovery of peroxidase-like activity in ferroferric oxide nanoparticles in 2007, nanozymes have attracted widespread global attention. Over the years, their applications have expanded to include target molecule detection, pollutant degradation, tumor therapy, and anti-oxidative stress therapy. Nanozymes can eliminate bacteria under specific conditions through their enzymatic activity, without the limitations of natural enzymes. Unlike traditional small-molecule antibiotics, nanozymes act at the nanoscale and exhibit unique magnetic, dimensional, and photothermal properties. Their bactericidal mechanisms differ significantly from those of traditional antibiotics, which typically inhibit bacterial growth and reproduction, often leading to drug resistance. Given their low cost and unique properties, nanozymes represent a promising new approach to combat bacterial infections.

[0003] Numerous studies have demonstrated the remarkable antibacterial effects of nanozymes. Among them, peroxidase-like nanozymes, the most common antibacterial nanozymes, hold great potential as alternatives to antibiotics. However, the antibacterial efficacy of peroxidase-like nanozymes for bacterial infections relies on hydrogen peroxide. Exogenous hydrogen peroxide supplementation can lead to cytotoxicity and immunogenicity. Oxidase-like nanozymes, which can directly activate oxygen and generate superoxide anions, overcome these limitations of peroxidase-like nanozymes and represent promising next-generation antibacterial nanozymes. The efficacy of nanozymes is closely related to their structural properties, including size, shape, composition, and surface characteristics. Based on their structural composition, nanozymes can be categorized into metal-based nanozymes, carbon-based nanozymes, metal-covalent framework-based nanozymes, single-atom nanozymes, and other nanozymes. As an extension of single-atom nanozymes, diatomic nanozymes exhibit synergistic interactions between two adjacent metal atoms, offer a rich modulation space, and can enhance catalytic activity, potentially broadening the application of oxidase-like nanozymes in treating bacterial infections. Summary of the Invention

[0004] The present invention aims to address the above-mentioned problems existing in the prior art and provides an iron-zinc diatomic nanozyme with oxidase-like activity, as well as its preparation method and application. This iron-zinc (FeZn) diatomic nanozyme has efficient oxidase-like activity, has both bactericidal and healing-promoting effects on deep wound infections, and can be used to prepare a new antimicrobial agent for eliminating drug-resistant bacteria and inhibiting bacterial biofilm formation. It can also be used as an antimicrobial agent loaded into wound infection dressings to treat wound infections caused by drug-resistant bacteria and promote the rapid healing of infected wounds.

[0005] The technical solution adopted by the present invention is as follows: A method for preparing an iron-zinc diatomic nanozyme with oxidase-like activity comprises the following steps:

[0006] S1. Weigh zinc nitrate hexahydrate and dissolve it in methanol with sufficient stirring.

[0007] S2. Weigh dimethylimidazole and dissolve it in methanol with thorough stirring;

[0008] S3, mix the solutions obtained in S1 and S2, and stir on a magnetic stirrer at 25°C for 12 h;

[0009] S4. Centrifuge the solution obtained in S3, take the precipitate, wash it with methanol, and centrifuge it again. Repeat the methanol washing and centrifugation operations several times until the supernatant becomes colorless; dry the precipitate at the bottom of the centrifuge tube under vacuum at 60° C. for 6 h to obtain a white powder, namely the metal-organic framework material ZIF-8;

[0010] S5. Take the white powder obtained in S4 and perform high-temperature annealing in a tube furnace to obtain a black powder, which is then fully ground;

[0011] S6. Take the ground black powder, zinc nitrate ethanol solution, and ferric nitrate ethanol solution in S5 and dissolve them in ethanol so that the molar mass of the added iron element and zinc element is 0.01 mmol and the molar ratio is 1:1, and ultrasonically disperse to obtain a black bimetallic solution;

[0012] S7, stirring the black bimetallic solution in S6 at 80°C for 6 hours on a magnetic stirrer, cooling to 25°C, and then centrifuging the solution at 13,000 rpm for 20 minutes, discarding the supernatant, and drying the precipitate at the bottom of the centrifuge tube at 80°C under vacuum for 6 hours to obtain a black bimetallic powder;

[0013] S8. Place the black bimetallic powder in S7 in an alumina quartz crucible, perform high-temperature annealing in a tube furnace, obtain black powder and grind it thoroughly to obtain the iron-zinc diatomic nanozyme.

[0014] Preferably, the centrifugation in S4 is performed at 5000 rpm for 10 min.

[0015] Preferably, the high temperature annealing treatment in S5 is: under argon gas, the heating rate is 10° C. / min, high temperature annealing is performed at 1000° C. for 2 hours, and then the temperature is naturally lowered to room temperature.

[0016] Preferably, the preparation method of the zinc nitrate ethanol solution is: weighing 50 mg of zinc nitrate hexahydrate, adding it to 5 ml of ethanol and mixing it thoroughly to obtain a zinc nitrate ethanol solution with a concentration of 10 mg / ml; the preparation method of the ferric nitrate ethanol solution is: weighing 50 mg of zinc nitrate nonahydrate, adding it to 5 ml of ethanol and mixing it thoroughly to obtain a ferric nitrate ethanol solution with a concentration of 10 mg / ml.

[0017] Preferably, the high temperature annealing treatment in S8 is: annealing at 700° C. for 2 h at a heating rate of 5° C. / min under argon, and then naturally cooling to room temperature.

[0018] The present invention also provides an iron-zinc diatom nanozyme with oxidase-like activity obtained by the above preparation method.

[0019] The present invention also provides the use of the above-mentioned iron-zinc diatomic nanozyme with oxidase-like activity in the preparation of an antibacterial agent, wherein the antibacterial agent is used in combination with photothermal therapy; the photothermal therapy is an 808nm near-infrared (NIR) laser (2W / cm 2 ) irradiated for 5 minutes; the antibacterial agent had an inhibition rate of 99.99% against Gram-positive bacteria methicillin-resistant Staphylococcus aureus.

[0020] The present invention also provides the use of the above-mentioned iron-zinc diatomic nanozyme with oxidase-like activity in the preparation of wound infection dressings, wherein the wound infection dressing is an iron-zinc diatomic nanozyme phosphate buffered saline (PBS) solution with a concentration of 80 μg / mL.

[0021] Preferably, the wound infection dressing is dripped onto the wound surface and combined with photothermal therapy for the treatment of deep drug-resistant bacterial infection wounds; the photothermal therapy is to use 808nm NIR laser (1W / cm 2 ) Intermittently irradiate the wound for 5 minutes.

[0022] The beneficial effects of the present invention are:

[0023] 1. The present invention uses dimethylimidazole and zinc nitrate hexahydrate to react in methanol to obtain ZIF-8 nanomaterials, uses high-temperature annealed ZIF-8 nanomaterials as carbon and nitrogen sources, zinc nitrate hexahydrate as a zinc source, ferric nitrate nonahydrate as an iron source, and ethanol as a solvent, and obtains structurally stable FeZn diatomic nanozymes through high-temperature annealing. The nanozymes have stable configuration, good biocompatibility, and high-efficiency oxidase-like catalytic activity, and can be applied to antibacterial and anti-inflammatory, tumor treatment, pollution degradation, and other aspects.

[0024] 2. The raw materials used in the present invention are low in cost and have good safety. The synthesis conditions are mild and the synthesis steps are simple. A large amount of FeZn diatomic nanozymes can be synthesized in a short period of time, and there is great prospect for their application in large-scale industrial manufacturing in the future.

[0025] 3. The FeZn diatomic nanozyme synthesized in the present invention does not require the additional addition of hydrogen peroxide. By combining with photothermal therapy, it can efficiently produce reactive oxygen by catalyzing oxygen, and has strong antibacterial activity, and has excellent therapeutic effects in deep wounds infected with drug-resistant bacteria. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 XRD characterization of NC and FeZn diatomic nanozymes.

[0027] Figure 2 Spherical aberration electron microscopy characterization of FeZn diatomic nanozyme, the yellow dotted box shows the FeZn atom pair.

[0028] Figure 3 Characterization of the elemental energy spectrum distribution of FeZn diatomic nanozyme.

[0029] Figure 4 This is the K-edge analysis map of Fe and Zn elements of the FeZn diatomic nanozyme using synchrotron radiation.

[0030] Figure 5 This is the R-space analysis map of the synchrotron radiation Fe and Zn elements of the FeZn diatomic nanozyme.

[0031] Figure 6 This is the K-space fitting map of the synchrotron radiation Fe element of the FeZn diatomic nanozyme (with Fe foil as the standard sample).

[0032] Figure 7 This is the K-space fitting spectrum of the synchrotron radiation Zn element of the FeZn diatomic nanozyme (with Zn foil as the standard sample).

[0033] Figure 8 Fitting of the Michaelis-Menten curve of the oxidase activity of FeZn diatomic nanozyme.

[0034] Figure 9 Superoxide anion test results for FeZn diatom nanozymes and NC.

[0035] Figure 10 The temperature changes of FeZn diatomic nanozymes with different concentrations under 808nm laser irradiation.

[0036] Figure 11 Infrared imaging of FeZn diatomic nanozymes with different concentrations under 808nm laser irradiation.

[0037] Figure 12 Relative bacterial activity of MRSA under different treatment conditions (***P<0.001).

[0038] Figure 13 The wound sites of the different treatment groups were photographed.

[0039] Figure 14 Figure 3 Statistics of wound areas in different treatment groups (***P < 0.001).

[0040] Figure 15 Statistics of colony count results at wound sites in different treatment groups.

[0041] Figure 16 The results of H&E staining of wound sites in different treatment groups. DETAILED DESCRIPTION

[0042] The present invention will be further described below with reference to the accompanying drawings and specific embodiments.

[0043] Example 1

[0044] The preparation of FeZn diatomic nanozymes includes the following steps:

[0045] Step 1: Weigh 2.38 g of zinc nitrate hexahydrate and 45 mL of methanol in a beaker and stir thoroughly with a glass stirring rod to dissolve evenly.

[0046] Step 2: Weigh 2.63 g of dimethylimidazole and 75 mL of methanol in a beaker and stir thoroughly with a glass stirring rod to dissolve evenly;

[0047] Step 3: Mix the solutions obtained in step 1 and step 2, and stir on a magnetic stirrer at 25°C for 12 h;

[0048] Step 4: The solution obtained in step 3 was centrifuged at 5000 rpm for 10 min. The precipitate was washed with methanol and centrifuged as described above, and the process was repeated several times until the supernatant became colorless. Finally, the precipitate at the bottom of the centrifuge tube was dried at 60°C under vacuum for 6 h to obtain a white powder, namely, ZIF-8 nanomaterial.

[0049] Step 5: The white powder obtained in step 4 was annealed in a tube furnace at 1000°C for 2 hours at a heating rate of 10°C / min, followed by natural cooling to room temperature. The entire process was carried out under argon. The resulting black powder was then placed in a quartz mortar and thoroughly ground to obtain the black powder, i.e., the carbonitride (NC) substrate.

[0050] Step 6: Weigh 50 mg of zinc nitrate hexahydrate and add it to 5 ml of ethanol and mix thoroughly to obtain a zinc nitrate ethanol solution with a concentration of 10 mg / ml. Weigh 50 mg of zinc nitrate nonahydrate and add it to 5 ml of ethanol and mix thoroughly to obtain a ferric nitrate ethanol solution with a concentration of 10 mg / ml.

[0051] Step 7: Dissolve 20 mg of the black powder obtained in step 5, 298 μL of the zinc nitrate ethanol solution obtained in step 6, and 404 μL of the ferric nitrate ethanol solution in 20 mL of ethanol so that the molar ratio of the iron element to the zinc element added to the black solution is approximately 1:1. Use a cell disruptor to ultrasonically disperse for 30 minutes at a power of 300 W to obtain a black bimetallic solution.

[0052] Step 8: The black bimetallic solution obtained in step 7 was stirred on a magnetic stirrer at 80°C for 6 hours;

[0053] Step 9: After the stirring in step 8 is completed, the black bimetallic solution is cooled to 25°C, and then the solution is centrifuged at 13000 rpm for 20 minutes, the supernatant is discarded, and the sediment at the bottom of the centrifuge tube is dried at 80°C under vacuum for 6 hours to obtain black bimetallic loaded NC powder;

[0054] Step 10: The powder obtained in step 9 is placed in an alumina quartz crucible and subjected to high-temperature annealing treatment in a tube furnace at a heating rate of 5°C / min, and high-temperature annealing at 700°C for 2 hours, and then naturally cooled to room temperature. The entire process is carried out under argon; the obtained black powder is placed in a quartz mortar and fully ground to obtain a black powder, which is the FeZn diatomic nanozyme.

[0055] The FeZn diatomic nanozyme prepared in this example was characterized, and the results are as follows:

[0056] Figure 1 The XRD spectrum of the FeZn diatomic nanozyme prepared in this example is shown. The figure shows that the prepared FeZn diatomic nanozyme has a broad carbon diffraction peak at 2θ = 26°, and no peaks for iron nanoparticles or zinc nanoparticles are detected, indicating that there is no aggregation of iron and zinc nanoparticles.

[0057] Figure 2A spherical aberration-corrected transmission electron micrograph of the FeZn diatomic nanozyme is shown. The image demonstrates the uniform octahedral structure of ZIF-8. The metal atoms are uniformly dispersed in pairs, with no iron or zinc nanoparticles observed. This demonstrates that the iron and zinc exist as atomic pairs.

[0058] Figure 3 The EDS elemental distribution map of the FeZn diatomic nanozyme is shown. In the EDS elemental distribution map, we found that in addition to carbon and nitrogen, iron and zinc were also detected. The EDS energy spectrum further confirmed the presence of iron and zinc, and that they were anchored to the NC substrate in a diatomic form.

[0059] Figure 4 Synchrotron radiation data of the FeZn diatomic nanozyme are presented. The Fe K-edge shows that near the edge front peak, the K-edge line of the nanozyme Fe lies between Fe2O3 and Fe foil, indicating that the valence state of Fe ranges from 0 to +3. The Zn K-edge shows that near the edge front peak, the K-edge line of the nanozyme Fe lies between ZnO and Zn foil, indicating that the valence state of Zn ranges from 0 to +2.

[0060] Figure 5 The R-space of synchrotron radiation iron and zinc is shown. The R-space data of iron is shown in There is a Fe-N bond nearby, and the R-space data of zinc is shown in The presence of a Zn-N bond nearby confirms that the iron in the sample exists in a diatomic dispersed form on the NC substrate.

[0061] Figure 6 The Fe element K-space data fitting of FeZn diatomic nanozyme is shown. Figure 7 The Zn element K-space data fitting of the FeZn diatomic nanozyme was demonstrated, showing that the data fitting was very good, which once again verified the FeZn diatomic configuration of the sample in Example 1.

[0062] Example 2

[0063] FeZn diatomic nanozyme (prepared in Example 1) oxidase activity assay and superoxide anion detection

[0064] 1. Oxidase activity assay

[0065] The FeZn diatomic nanozyme was dispersed in ultrapure water to prepare a nanozyme aqueous solution with a concentration of 2 mg / mL and ultrasonicated for 10 minutes. The number of nanoparticles of the FeZn diatomic nanozyme was measured using a nanoparticle tracking analyzer, and its molar concentration was calculated to be 7.8*10 -11mol / L. TMB was dissolved in dimethyl sulfoxide to prepare solutions of 25mM, 50mM, 75mM, 100mM and 125mM. 10μL of FeZn diatomic nanozyme aqueous solution was placed in a quartz cuvette, followed by the addition of 1.98mL of acetic acid-sodium acetate (HAc-NaAc) buffer (0.1M, pH=4.0) and 10μL of TMB solutions of different concentrations, so that the concentration of TMB in the final reaction system was 0.125mM, 0.25mM, 0.375mM, 0.5mM and 0.625mM. It was then quickly placed in an ultraviolet spectrophotometer for absorbance measurement (OD=652nm), and the data of absorbance changes with reaction time were recorded. Each group was repeated 3 times. Lambert-Beer's law was used to convert the absorbance of oxidized TMB (oxTMB) into concentration. The molar absorption coefficient of oxTMB is 39000M -1 cm -1 Finally, the initial reaction rate at different concentrations was obtained based on the change of the slope of the initial absorbance over time. The initial reaction rate obtained under different TMB concentrations was used to fit the Michaelis-Menten curve using the following formula to finally obtain the K of the FeZn diatomic nanozyme: m and V max Value. k cat Calculated as 4*10 9 s -1 , k cat / K m Used to measure the activity of FeZn diatomic nanozymes, k cat / K m Calculated as 1.43*10 10 mM -1 s -1 .

[0066] v=V max ×[S] / K m +[S]

[0067] k cat =V max / E

[0068] Where v represents the initial reaction rate of FeZn diatomic nanozymes at different concentrations of TMB, S represents the TMB concentration, and V max represents the maximum reaction rate of the nanozyme, K m represents the Michaelis constant, E is the molar concentration of the nanozyme, k cat is the catalytic constant.

[0069] Figure 8The fitting of the Michaelis-Menten curve of the oxidase activity of the FeZn diatomic nanozyme is shown, and the V of the FeZn diatomic nanozyme is obtained according to the formula max 1.56 μM s -1 , K m is 0.28mM.

[0070] 2. Superoxide anion generation detection

[0071] A 1 mg / ml methanol solution of the FeZn diatomic nanozyme was prepared and homogenized by sonication. Then, 200 μL of this solution was added to 200 μL of a 100 mM 5,5-dimethyl-1-pyrroline-N-oxide (DMPO) solution. After mixing, the sample was loaded into a capillary tube and tested in the dark and once in the light for 10 minutes each. The FeZn diatomic nanozyme was replaced with NC as a control, while all other test conditions remained unchanged. Illumination was performed using a 300W xenon lamp with a central magnetic field of 3500.00 G, a sweep width of 200.00 G, a sweep time of 30.00 s, a microwave power of 19.45 mW, a modulation amplitude of 1.000 G, a switching time of 40.0 ms, and a frequency of 9.852508 GHz.

[0072] Figure 9 The superoxide anion test results of FeZn diatomic nanozyme and NC are shown. The characteristic peak of 1:1:1:1 represents the generation of superoxide anions, and FeZn diatomic nanozyme has stronger oxidase activity than NC.

[0073] Example 3

[0074] Photothermal activity test of FeZn diatomic nanozyme (prepared in Example 1)

[0075] Ultrapure aqueous solutions of FeZn diatomic nanozymes with different concentrations (0, 50, 100, 200 and 400 μg / mL) were prepared and homogenized by ultrasonication. 1 mL of each solution was added to a quartz cuvette and ultrasonicated at 2.0 W / cm 2 The laser was irradiated at 808 nm with a power density of 10 minutes. The infrared thermal imaging system was used to record the photothermal images of the ultrapure aqueous solution of FeZn diatomic nanozymes every 2 minutes during the laser irradiation process. Figure 9 As shown in the figure, after laser irradiation, the temperature of the 400 μg / mL FeZn diatomic nanozyme ultrapure aqueous solution increased significantly, indicating that the FeZn diatomic nanozyme has good photothermal performance.

[0076] Figure 10The ultrapure aqueous solutions of FeZn diatomic nanozymes with different concentrations (0, 50, 100, 200 and 400 μg / mL) were shown to be able to absorb the FeZn diatomic nanozymes at 2.0 W / cm 2 Temperature changes after 10 minutes of 808 nm laser irradiation with high power density.

[0077] Figure 11 The ultrapure aqueous solution of FeZn diatomic nanozyme with different concentrations (0, 50, 100, 200 and 400 μg / mL) was heated at 2.0 W / cm 2 Infrared imaging under 808 nm laser irradiation for 10 minutes at a high power density.

[0078] Example 4

[0079] Effect of FeZn diatomic nanozyme (prepared in Example 1) against drug-resistant bacteria

[0080] The antibacterial test was conducted using Gram-positive methicillin-resistant Staphylococcus aureus (MRSA, ATCC43300). MRSA was cultured in standard LB (Luria-Bertani) medium. The MRSA suspension was prepared so that the final OD 600nm =0.1. 1 mL of MRSA suspension was incubated with phosphate buffered saline (PBS), PBS+NIR, FeZn, and FeZn+NIR, respectively. The samples were illuminated with 808 nm NIR laser (2 W / cm 2 ) irradiation for 5 minutes, the results are as follows Figure 12 The experimental results show that after the FeZn+NIR treatment of methicillin-resistant Staphylococcus aureus, the relative bacterial activity was significantly reduced, and the inhibition rate reached 99.99%, which was significantly better than that of NIR and FeZn alone, indicating that the bactericidal effect was caused by the combined action of oxidase-like activity and photothermal effect.

[0081] Example 5

[0082] Application of FeZn diatomic nanozyme (prepared in Example 1) in drug-resistant deep wound infection

[0083] The mice were depilated and anesthetized with tribromoethanol. A circular, full-thickness skin wound with a diameter of 8 mm was created on the back of the mice using a punch, and the muscles were exposed to establish a deep infection incision animal model. 20 μL of MRSA suspension (1×10 9CFU). Mice were randomly divided into 4 groups (n=5) as follows: (1) PBS; (2) PBS+NIR; (3) vancomycin; (4) FeZn+NIR. After 24 h, vancomycin PBS solution was prepared to a concentration of 80 μg / mL, and FeZn diatomic nanozyme PBS solution was prepared to a concentration of 80 μg / mL. Group (1) dripped 20 μL of PBS solution on the wound surface, and group (2) dripped 20 μL of PBS solution on the wound surface and then irradiated with 808 nm NIR laser (1 W / cm 2 ) irradiated for 5 min, group (3) dropped 20 μL of vancomycin PBS solution on the wound surface, and group (4) dropped FeZn diatomic nanozyme PBS solution on the wound surface and then irradiated with 808 nm NIR laser (1 W / cm 2 ) irradiation for 5 minutes. Intermittent laser irradiation was used to avoid burning of the wound. The wounds of each group were photographed and the wound area was measured every day (eg Figure 13 On day 9, the wound skin tissue was ground and diluted with LB medium. 100 μL of the dilution was added to an agar plate and incubated at 37°C for 24 hours. The in vivo antibacterial activity was tested by CFU. In addition, the wound sections of all mice were taken for H&E staining. Figure 14-16 As shown in the figure, compared with other groups, the therapeutic effect of the FeZn+NIR group was the most significant, indicating that the oxidase-like activity of the FeZn diatomic nanozyme combined with the photothermal effect had a joint antibacterial effect.

[0084] The description and drawings of the present invention are considered to be illustrative rather than restrictive. On the basis of the present invention, those skilled in the art can make some substitutions and modifications to some of the technical features according to the disclosed technical content without creative work, and all of them are within the scope of protection of the present invention.

Claims

1. A method for preparing an iron-zinc diatomic nanozyme with oxidase-like activity, characterized in that: The following steps are involved: S1. Weigh zinc nitrate hexahydrate and dissolve it in methanol with sufficient stirring. S2. Weigh dimethylimidazole and dissolve it in methanol with thorough stirring; S3, mix the solutions obtained in S1 and S2, and stir on a magnetic stirrer at 25°C for 12 h; S4. Centrifuge the solution obtained in S3, take the precipitate, wash it with methanol, and centrifuge it again. Repeat the methanol washing and centrifugation operations several times until the supernatant becomes colorless; dry the precipitate at the bottom of the centrifuge tube under vacuum at 60° C. for 6 h to obtain a white powder, namely the metal-organic framework material ZIF-8; S5. Take the white powder obtained in S4 and perform high-temperature annealing in a tube furnace to obtain a black powder, which is then fully ground; S6. Take the ground black powder, zinc nitrate ethanol solution, and ferric nitrate ethanol solution in S5 and dissolve them in ethanol so that the molar mass of the added iron element and zinc element is 0.01 mmol and the molar ratio is 1:1, and ultrasonically disperse to obtain a black bimetallic solution; S7, stirring the black bimetallic solution in S6 at 80°C for 6 hours on a magnetic stirrer, cooling to 25°C, and then centrifuging the solution at 13,000 rpm for 20 minutes, discarding the supernatant, and drying the precipitate at the bottom of the centrifuge tube at 80°C under vacuum for 6 hours to obtain a black bimetallic powder; S8. Place the black bimetallic powder in S7 in an alumina quartz crucible, perform high-temperature annealing in a tube furnace, obtain black powder and grind it thoroughly to obtain the iron-zinc diatomic nanozyme.

2. The preparation method according to claim 1, characterized in that The molar ratio of zinc nitrate hexahydrate to dimethylimidazole in S3 is 1:

4.

3. The preparation method according to claim 1, characterized in that The centrifugation in S4 is performed at a speed of 5000 rpm for 10 minutes.

4. The preparation method according to claim 1, characterized in that The high temperature annealing treatment in S5 is as follows: annealing at 1000° C. for 2 h at a heating rate of 10° C. / min under argon gas, and then naturally cooling to room temperature.

5. The preparation method according to claim 1, characterized in that The preparation method of the zinc nitrate ethanol solution in S6 is: weighing 50 mg of zinc nitrate hexahydrate, adding it to 5 ml of ethanol and mixing it thoroughly to obtain a zinc nitrate ethanol solution with a concentration of 10 mg / ml; the preparation method of the ferric nitrate ethanol solution is: weighing 50 mg of zinc nitrate nonahydrate, adding it to 5 ml of ethanol and mixing it thoroughly to obtain a ferric nitrate ethanol solution with a concentration of 10 mg / ml.

6. The preparation method according to claim 1, characterized in that The high temperature annealing treatment in S8 is as follows: annealing at 700° C. for 2 h at a heating rate of 5° C. / min under argon, and then naturally cooling to room temperature.

7. An iron-zinc diatom nanozyme having oxidase-like activity obtained by the preparation method according to any one of claims 1 to 6.

8. The use of the iron-zinc diatomic nanozyme with oxidase-like activity in the preparation of an antibacterial agent according to claim 7, characterized in that: The antibacterial agent is used in combination with photothermal therapy; the photothermal therapy is 808nm near-infrared (NIR) laser (2W / cm 2 ) irradiated for 5 minutes; the antibacterial agent had an inhibition rate of 99.99% against Gram-positive bacteria methicillin-resistant Staphylococcus aureus.

9. The use of the iron-zinc diatomic nanozyme with oxidase-like activity in the preparation of wound infection dressing according to claim 7, characterized in that: The wound infection dressing is an iron-zinc diatomic nanozyme phosphate buffered saline (PBS) solution with a concentration of 80 μg / mL.

10. The use according to claim 9, characterized in that The wound infection dressing is dripped onto the wound surface and combined with photothermal therapy for the treatment of deep drug-resistant bacterial infection wounds; the photothermal therapy is to use 808nm NIR laser (1W / cm 2 ) Intermittently irradiate the wound for 5 minutes.

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