Preparation method and application of low-temperature synthesized copper-doped iron disulfide nano-enzyme

Abstract

The invention discloses a preparation method for synthesizing copper-doped iron disulfide nano-enzyme at low temperature. The preparation method comprises the following steps: 1) preparing ferroferric oxide; (2) low-temperature vulcanization reaction: mixing the ferroferric oxide obtained in the step (1) with a sulfur source, introducing protective gas at 150-200 DEG C, and calcining for 1-8 hours to obtain iron disulfide powder; and (3) preparing the nano-enzyme: adding the iron disulfide powder in the step (2) into a copper source solution, mixing, stirring and reacting, centrifuging, washing and drying the obtained reaction product, introducing protective gas at 120-200 DEG C, and calcining for 1-6 hours to obtain the copper-doped iron disulfide nano-enzyme, and meanwhile, providing the application of the nano-enzyme. Uniform doping of copper is achieved under the low-temperature mild condition, the copper element is successfully embedded into iron disulfide crystal lattices, a stable doping type nano-enzyme structure is formed, and the excellent peroxidase activity of the material is reserved and enhanced.

Description

Technical Field

[0001] This invention belongs to the field of nanomaterial preparation technology, specifically relating to a method for preparing and applying a low-temperature synthesized copper-doped iron disulfide nanoenzyme. Background Technology

[0002] In recent years, with the long-term, widespread, and irrational use of antibiotics in clinical treatment and agricultural breeding, the problem of drug resistance in Staphylococcus aureus has become increasingly serious. Among them, methicillin-resistant Staphylococcus aureus (MRSA) has become one of the important pathogens causing hospital-acquired and community-acquired infections worldwide. MRSA's drug resistance is mainly mediated by its mecA gene, which encodes a special penicillin-binding protein PBP2a. This protein has a significantly reduced affinity for traditional β-lactam antibiotics (such as penicillin, cephalosporins, and methicillin), allowing the bacteria to synthesize their cell walls even in the presence of antibiotics, thus evading the bactericidal effects of the drugs and resulting in extremely limited available drugs for clinical treatment.

[0003] Currently, in the non-pharmacological treatment of MRSA infection, existing technologies have many shortcomings. For example, MRSA colonization on the surface of medical devices (such as catheters and implants) can easily lead to iatrogenic infections. Currently used surface antibacterial modification technologies (such as silver ion loading and antibacterial coatings) have some problems such as difficulty in controlling the release of metal ions (excessive release can easily cause cytotoxicity), short duration of antibacterial effect, and easy peeling of coatings. In terms of environmental disinfection, although traditional disinfectants (such as chlorine-containing disinfectants and alcohol) can quickly kill MRSA, they have drawbacks such as strong irritation, corrosiveness to some surfaces, and inability to achieve long-term antibacterial effect.

[0004] Furthermore, in the field of antimicrobial materials and formulation development, traditional antimicrobial agents mostly work by directly killing bacteria, which easily induces drug resistance with long-term use. While some novel antimicrobial strategies, such as phage therapy and antimicrobial peptide applications, have advantages such as strong targeting and low resistance, they still face challenges such as narrow phage host spectrum, poor stability of antimicrobial peptides, high production costs, and difficulties in large-scale industrial application, making it difficult to meet the diverse needs of clinical and practical applications. Therefore, developing novel, efficient, safe, and drug-resistant anti-Staphylococcus aureus and MRSA technologies, including but not limited to novel antimicrobial drugs, antimicrobial materials, disinfectants, and surface modification technologies, has become an urgent need in the fields of biomedicine and materials science, and is of great significance for reducing infection rates and ensuring public health safety.

[0005] Nanozymes, as a class of nanomaterials with enzymatic catalytic activity, have shown broad application prospects in fields such as biosensing, disease treatment, and environmental remediation due to their advantages of high stability, low cost, and ease of modification. Among them, iron disulfide (FeS2) nanomaterials, due to their unique crystal structure (such as pyrite structure) and electronic properties, exhibit excellent peroxidase activity and a unique antibacterial mechanism. The sulfide components they contain gradually release polysulfides, which not only significantly enhances antibacterial activity but also plays a positive supporting role in intracellular metabolic regulation. During the antibacterial process, iron sulfide nanozymes can directly attack the bacterial cell wall and membrane structure by releasing reactive oxygen species (ROS), thereby disrupting their integrity. At the same time, the released iron ions react chemically with key components in bacterial metabolism, such as thiols and glutathione, interfering with normal bacterial metabolism and effectively inhibiting their growth and reproduction. Of particular note is the remarkable performance of iron sulfide nanozymes in combating drug-resistant bacteria, such as methicillin-resistant Staphylococcus aureus (MRSA), which successfully broke through its resistance defenses and demonstrated strong antibacterial efficacy, making it a research hotspot in the biomedical field.

[0006] Currently, the main methods for preparing copper-doped iron disulfide nanomaterials include high-temperature solid-state methods, hydrothermal methods, and solvothermal methods. However, existing preparation methods have the following shortcomings: (1) High temperature dependence leads to impaired activity: Traditional high temperature solid phase method requires sulfidation reaction at a high temperature of 600-800 ℃. High temperature easily leads to nanoparticle aggregation and crystal structure distortion, destroying the catalytic active sites of iron disulfide and reducing its peroxidase activity. Although hydrothermal method is a liquid phase reaction, it usually requires a high temperature and high pressure environment of more than 200 ℃, which not only consumes a lot of energy, but may also cause solvent decomposition, producing impurities that affect the purity of the product.

[0007] (2) Complex process and poor controllability: Existing methods often require complex precursor preparation processes (such as high-temperature calcination to prepare iron oxide precursors) or rely on special equipment (such as high-pressure reactors), and the operation steps are cumbersome; at the same time, the reaction rate is difficult to control precisely at high temperatures, which can easily lead to uneven particle size distribution of the product (usually with a deviation of more than 30%), affecting the batch stability of nanozymes.

[0008] (3) High industrialization cost: The high temperature and high pressure reaction conditions require a large amount of energy, and the investment and maintenance costs of special equipment are high.

[0009] To address the aforementioned issues, developing a low-temperature, efficient, and controllable method for preparing iron disulfide nanozymes is crucial for overcoming existing technological bottlenecks and promoting their industrial application. Summary of the Invention

[0010] The purpose of this invention is to provide a method for preparing copper-doped iron disulfide nanozymes at low temperature, and providing its application is another objective of this invention.

[0011] To achieve the above objectives, the present invention adopts the following technical solution: A method for preparing copper-doped iron disulfide nanozymes at low temperature includes the following steps: 1) Preparation of iron(III) oxide; 2) Low-temperature sulfidation reaction: The iron(III) oxide from step 1) is mixed with a sulfur source and calcined at 150-200 °C with a protective gas for 1-8 h to obtain iron(II) disulfide powder. 3) Preparation of nanozymes: The iron disulfide powder from step 2) was added to the copper source solution, mixed and stirred to react. The resulting reaction product was centrifuged, washed and dried, and then calcined at 120-200 °C with protective gas for 1-6 h to obtain copper-doped iron disulfide nanozymes (particle size 100-420 nm).

[0012] In step 1), ferric oxide is prepared by chemical co-precipitation; in step 2), the mass ratio of ferric oxide to sulfur source is (1-2):(1-8), the protective gas is nitrogen, and the nitrogen flow rate is 50-100 mL / min.

[0013] Step 1), the preparation of Fe3O4 includes the following steps: a) Preparation of the precursor solution: [The process involves adding Fe3O4 to a solution containing Fe...] 2 ⁺ and Fe 3+ Add an alkaline solution dropwise to the salt solution until the pH value is 4.5-6.5, mix, and obtain the precursor solution; b. Purification and drying: Centrifuge the precursor solution from step a, collect the precipitate, wash and dry it to obtain ferric oxide.

[0014] In step a, Fe 2 The salt solution of ⁺ is a mixture of one or more of the following: ferrous chloride solution, ferrous sulfate solution, and ferrous nitrate solution, containing Fe. 3+ The salt solution is a mixture of one or more of the following: ferric chloride solution, ferric sulfate solution, and ferric nitrate solution. 2 ⁺∶Fe 3+ The molar ratio is (1-2):(1-3), and the alkaline solution is sodium hydroxide solution, ammonia water or potassium hydroxide solution; in step 2), the sulfur source is sulfur powder, sodium sulfide or L-cysteine; in step 3), the copper source solution is copper chloride solution, copper sulfate solution or copper nitrate solution.

[0015] In step a, Fe 2 The salt solution of ⁺ is a ferrous chloride solution, containing Fe. 3+ The salt solution is a ferric chloride solution, Fe2 ⁺∶Fe 3+ The molar ratio is 1:2, and the alkaline solution is sodium hydroxide solution; in step b, the drying conditions are: temperature 40-90℃, time 6-15 h; in step 2), the sulfur source is sulfur powder; in step 3), the copper source solution is copper chloride solution.

[0016] In step 3), the mass concentration of the copper chloride solution is 1-5 wt%, the ratio of iron disulfide powder to copper chloride solution is (1-5) g: 10 mL, the protective gas is a mixture of H2 / N2, the volume concentration of H2 in the mixture is 2-20 vol%, and the flow rate of the mixture is 50-100 mL / min.

[0017] Application of copper-doped iron disulfide nanozymes prepared by the method in the preparation of antibacterial drugs.

[0018] The antibacterial drug is an anti-Staphylococcus aureus drug.

[0019] Compared with the prior art, the present invention has the following beneficial effects: (1) Low-temperature sulfidation breaks through traditional limitations: The reaction temperature is controlled below 200 ℃, which is lower than the traditional method of above 300 ℃. This avoids the damage of high temperature to the crystal structure of nanozymes, ensures product dispersibility, and completely preserves the catalytic active sites. The peroxidase activity of the prepared nanozymes is 15% to 30% higher than that of the products prepared by high-temperature hydrothermal method. (2) Uniform copper doping was achieved under low temperature and mild conditions. Copper elements were successfully embedded in the iron disulfide lattice to form a stable doped nanozyme structure, which preserved and enhanced the excellent peroxidase activity of the material. The nanozyme of the present invention has the dual effects of electronic regulation effect of copper doping and low temperature complete crystal form, making the peroxidase activity of the nanozyme far superior to that of pure iron disulfide nanozyme. (3) The raw materials are cheap and readily available, and the preparation cost is low. The raw materials such as iron, sulfur and copper do not require complicated purification, which greatly reduces the experimental and industrial production costs. (4) Strong controllability and precise preparation: By adjusting the ratio of iron oxide, sulfur powder and copper chloride, reaction temperature and time, the particle size of nanozymes (100-420 nm) can be precisely controlled, and the stability is good. (5) Simplified process and reduced industrialization cost: The steps are simple and highly repeatable, including four steps: preparation of iron oxide, low temperature sulfidation, and doping. Key parameters such as pH value, mass ratio, and gas atmosphere are clearly controllable, which facilitates the repetition of experiments in different batches and can achieve large-scale production by increasing the volume. Attached Figure Description

[0020] Figure 1 shows the XRD patterns of the nanozymes prepared in Examples 1 and 2 and Comparative Examples 1 and 2; Figure 2 is a statistical diagram of the particle size distribution of the copper-doped iron disulfide nanozyme prepared in Example 2; Figure 3 is a Zeta diagram of the copper-doped iron disulfide nanozyme prepared in Example 2; Figure 4 shows the peroxidase activity test curves of the nanozymes in Examples 1 and 2 and Comparative Examples 1 and 2. Figure 5 The peroxidase activity of nanozymes in Examples 1 and 2 and Comparative Examples 1 and 2 over time is shown in the test curves. Figure 6 shows the antibacterial properties of copper-doped iron disulfide nanozymes prepared in Examples 1 and 2 and Comparative Examples 1 and 2. Figure 7 This is a SEM image of the copper-doped iron disulfide nanozyme of Example 2 of the present invention. Detailed Implementation

[0021] The present invention will be further described below with reference to specific embodiments and accompanying drawings.

[0022] In the following embodiments, Iron source: ferrous chloride and ferric chloride with a purity of ≥99% are selected to avoid introducing impurity ions that may affect catalytic activity; Sulfur source: Sulfur powder is selected; Copper source: copper chloride; Solvent: Water (H2O) is selected.

[0023] Example 1 Ferrous chloride solution was prepared by adding 1.27 g (0.01 mol) FeCl2 to 40 ml of water and stirring at 500 rpm until dispersed at room temperature; ferric chloride solution was prepared by adding 3.25 g (0.02 mol) FeCl3 to 40 ml of water and stirring at 500 rpm until dispersed at room temperature; sodium hydroxide solution was prepared by dissolving 0.4 g NaOH in 100 ml of water to obtain a 0.1 mol / L NaOH solution.

[0024] A method for preparing copper-doped iron disulfide nanozymes at low temperature includes the following steps: 1) Preparation of Fe3O4: including the following steps: a. Preparation of precursor solution: add sodium hydroxide solution dropwise to ferrous chloride solution and ferric chloride solution until the pH value is 6, stir and mix for 15 min to obtain precursor solution; b. Purification and drying: Centrifuge the precursor solution from step a at 8000 rpm, collect the precipitate, wash it alternately with water and ethanol, and dry it under vacuum at 60 °C for 10 h to obtain ferric oxide. 2) Low-temperature sulfidation reaction: The iron(III) oxide from step 1) is mixed with sulfur powder at a mass ratio of 1:2. Nitrogen gas is introduced at 200°C at a flow rate of 60 mL / min, and the mixture is calcined for 2 h to obtain iron disulfide powder. 3) Preparation of nanozymes: 1 g of iron disulfide powder from step 2) was added to 10 ml of 1.5 wt% copper chloride solution, mixed and stirred for 3 h. The resulting reaction product was centrifuged, washed with deionized water, dried under vacuum at 50 °C for 8 h, and calcined at 160 °C with a 6 vol% H2 / N2 mixed gas flow rate of 65 mL / min to obtain copper-doped iron disulfide nanozymes.

[0025] Example 2 The preparation of ferrous chloride solution, ferric chloride solution, and sodium hydroxide solution is the same as in Example 1.

[0026] The difference from Example 1 is that, 2) low-temperature sulfidation reaction: the iron oxide and sulfur powder from step 1) are mixed evenly at a mass ratio of 1:2, and nitrogen gas is introduced at 200 °C at a flow rate of 60 mL / min. The mixture is then calcined for 4 h to obtain iron disulfide powder. The rest is the same as in Example 1.

[0027] Example 3 The preparation of ferrous chloride solution, ferric chloride solution, and sodium hydroxide solution is the same as in Example 1.

[0028] A method for preparing copper-doped iron disulfide nanozymes at low temperature includes the following steps: 1) Preparation of Fe3O4: including the following steps: a. Preparation of precursor solution: add sodium hydroxide solution dropwise to ferrous chloride solution and ferric chloride solution until the pH value is 6, stir and mix for 15 min to obtain precursor solution; b. Purification and drying: Centrifuge the precursor solution from step a at 8000 rpm, collect the precipitate, wash it alternately with water and ethanol, and dry it under vacuum at 40 °C for 13 h to obtain ferric oxide. 2) Low-temperature sulfidation reaction: The iron(III) oxide from step 1) is mixed with sulfur powder at a mass ratio of 1:5. Nitrogen gas is introduced at 150°C at a flow rate of 80 mL / min, and the mixture is calcined for 5 h to obtain iron(II) disulfide powder. 3) Preparation of nanozymes: 1 g of iron disulfide powder from step 2) was added to 10 ml of 3.5 wt% copper chloride solution, mixed and stirred for 3 h. The resulting reaction product was centrifuged, washed with deionized water, dried under vacuum at 50 °C for 7 h, and calcined at 180 °C with a H2 / N2 mixed gas of 6 vol% H2 volume concentration at a gas flow rate of 60 mL / min for 3 h to obtain copper-doped iron disulfide nanozymes.

[0029] Example 4 The preparation of ferrous chloride solution, ferric chloride solution, and sodium hydroxide solution is the same as in Example 1.

[0030] A method for preparing copper-doped iron disulfide nanozymes at low temperature includes the following steps: 1) Preparation of Fe3O4: including the following steps: a. Preparation of precursor solution: add sodium hydroxide solution dropwise to ferrous chloride solution and ferric chloride solution until the pH value is 6, stir and mix for 15 min to obtain precursor solution; b. Purification and drying: Centrifuge the precursor solution from step a at 9000 rpm, collect the precipitate, wash it alternately with water and ethanol, and dry it under vacuum at 80 °C for 12 h to obtain ferric oxide. 2) Low-temperature sulfidation reaction: The iron(III) oxide from step 1) is mixed with sulfur powder at a mass ratio of 1:7. Nitrogen gas is introduced at 200°C at a flow rate of 100 mL / min, and the mixture is calcined for 3 h to obtain iron disulfide powder. 3) Preparation of nanozymes: 1 g of iron disulfide powder from step 2) was added to 10 ml of copper chloride solution with a mass concentration of 4.5 wt%, mixed and stirred for 3 h, the resulting reaction product was centrifuged, washed with deionized water, dried under vacuum at 60 °C for 5 h, and calcined at 120 °C with a H2 / N2 mixed gas concentration of 6 vol% at a gas flow rate of 60 mL / min for 5 h to obtain copper-doped iron disulfide nanozymes.

[0031] Comparative Example 1 The preparation of ferrous chloride solution, ferric chloride solution, and sodium hydroxide solution is the same as in Example 1.

[0032] A method for preparing low-temperature iron disulfide nanozymes includes the following steps: 1) Preparation of Fe3O4: including the following steps: a. Preparation of precursor solution: add sodium hydroxide solution dropwise to ferrous chloride solution and ferric chloride solution until the pH value is 6, stir and mix for 15 min to obtain precursor solution; b. Purification and drying: Centrifuge the precursor solution from step a at 8000 rpm, collect the precipitate, wash it alternately with water and ethanol, and dry it under vacuum at 60 °C for 10 h to obtain ferric oxide. 2) Low-temperature sulfidation reaction: The iron oxide and sulfur powder from step 1) are mixed evenly at a mass ratio of 1:3. Nitrogen gas is introduced at 180°C at a flow rate of 60 mL / min, and the mixture is calcined for 4 h to obtain iron disulfide nanozyme.

[0033] Comparative Example 2 The preparation of ferrous chloride solution, ferric chloride solution, and sodium hydroxide solution is the same as in Example 1.

[0034] A method for preparing low-temperature iron disulfide nanozymes includes the following steps: 1) Preparation of Fe3O4: including the following steps: a. Preparation of precursor solution: add sodium hydroxide solution dropwise to ferrous chloride solution and ferric chloride solution until the pH value is 6, stir and mix for 15 min to obtain precursor solution; b. Purification and drying: Centrifuge the precursor solution from step a at 8000 rpm, collect the precipitate, wash it alternately with water and ethanol, and dry it under vacuum at 60 °C for 10 h to obtain ferric oxide. 2) Low-temperature sulfidation reaction: The iron(III) oxide from step 1) is mixed with sulfur powder at a mass ratio of 1:3. Nitrogen gas is introduced at 500℃ with a flow rate of 60 mL / min, and the mixture is calcined for 2 h to obtain iron disulfide powder. 3) Preparation of nanozymes: 1 g of iron disulfide powder from step 2) was added to 10 ml of 3.5 wt% copper chloride solution, mixed and stirred for 3 h. The resulting reaction product was centrifuged, washed with deionized water, dried under vacuum at 50 °C for 8 h, and calcined at 300 °C with a H2 / N2 mixed gas of 6 vol% H2 volume concentration at a gas flow rate of 65 mL / min for 4 h to obtain copper-doped iron disulfide nanozymes.

[0035] Example 5 5.1 Performance Characterization XRD analysis was performed on the nanozyme samples of Examples 1 and 2, and Comparative Examples 1 and 2. The particle size distribution and zeta potential physicochemical properties of the sample in Example 2 were tested using a Malvern Zetasizer Pro nanoparticle size potentiostat. The results are as follows: Figure 1 , 2 As shown in Figure 3. Morphological analysis of the nanozyme sample from Example 2 was performed, and the results are as follows. Figure 7 The image is shown in the scanning electron microscope (SEM).

[0036] Depend on Figure 2 It was found that the product exhibited obvious diffraction peaks at 2θ = 28.5°, 33.0°, 37.0°, 40.5°, 47.2°, and 56.0°, corresponding to the (111), (200), (210), (211), (220), and (311) crystal planes of the pyrite structure FeS2. There were no impurity peaks, indicating good crystallinity. No characteristic diffraction peaks of metallic Cu were observed, which indicates that Cu was uniformly dispersed on the surface of the FeS2 support.

[0037] Depend on Figure 2 It was found that the particle size distribution curve of the nanozyme sample in Example 2 was sharp and concentrated, indicating that the particle size uniformity of the sample particles was good and there was no obvious large or small particle impurities mixed in.

[0038] Depend on Figure 3 It was found that the Zeta potential of the sample in Example 2 was 31.21 mV (positive value), indicating that its dispersion system has good electrostatic stability, strong electrostatic repulsion between particles, and is not prone to agglomeration.

[0039] Depend on Figure 7 As can be seen, the nanozyme material of Example 2 exhibits continuous pores and a cross-linked network framework. This porous / network structure is typically formed by the aggregation and growth of nanoparticles, providing a large specific surface area. Furthermore, the overall surface of the nanozyme material is uneven, with abundant bumps and particles attached. Surface roughness is important for the catalytic activity of the nanozyme (increasing the exposure of active sites). This also indicates that the nanozyme material prepared in this invention has the characteristic of having more active sites (Cu and Fe doping sites) exposed due to its porous and rough surface, which can enhance the catalytic activity of peroxidases / oxidases, etc.

[0040] Peroxidase activity test The peroxidase (POD) activity of the nanozyme samples from Examples 1 and 2, and Comparative Examples 1 and 2, was tested. The test method was as follows: the initial concentration was 0.01 mg / mL. The sample was first added to a 96-well plate, and the plate was placed in a microplate reader (with the detection method enabled). Then, 90 μL of premixed reagent (Buffer, H2O2, TMB) was added using a multi-channel pipette. The instrument was quickly started to read the plate, and the absorbance at 652 nm was measured every 30 seconds for 5 minutes. The peroxidase activity test curve is shown below. Figure 4 As shown in the figure, the test curve of peroxidase activity changing over time is as follows: Figure 5 As shown.

[0041] Depend on Figure 4It was found that the nanozyme of Example 2 had the highest specific activity (approximately 9 U / mg), followed by Example 1 (approximately 8 U / mg), and the specific activities of the nanozymes of Comparative Examples 1 and 2 decreased sequentially (approximately 5 U / mg and 4 U / mg, respectively).

[0042] Depend on Figure 5 It was found that at a concentration of 0.01 mg / mL, the OD of Example 2 increased the fastest, indicating the highest reaction rate; Example 1 was next, while the reaction rates of Comparative Examples 1 and 2 were relatively slow.

[0043] Antibacterial performance test Preparation of nanozyme stock solution: Accurately weigh 1 mg of nanozyme sample, disperse it in 1 mL of ultrapure water, and sonicate for 5–10 min to ensure uniform dispersion, thus preparing a nanozyme stock solution with a concentration of 1 mg / mL.

[0044] Test method: Add 800 μL of sterile water, 100 μL of nanozyme stock solution, and 100 μL of 1×10⁶ CFU / mL bacterial suspension (S. aureus, MRSA) to a 1.5 mL EP tube. Mix well and incubate at 37°C on a shaker for 3 h. Dilute the incubated solution 100-fold with sterile water and take 100 μL to plate. Incubate the plate upside down at 37°C overnight. Count the number of colonies after incubation. Figure 6 As shown.

[0045] Figure 6 The sample is divided into four groups, from left to right, corresponding to the nanozyme samples of Comparative Example 1, Example 1, Example 2, and Comparative Example 2.

[0046] Comparative Examples 1 and 2: The plates were covered with colonies, indicating that the nanozyme sample had no antibacterial effect on S. aureus and MRSA. In Example 2, the plates were almost devoid of colonies, indicating that the sample had a significant antibacterial effect on both S. aureus and MRSA. In Example 1, the plates had a small number of colonies, indicating that the sample had a significant antibacterial effect on both S. aureus and MRSA.

Claims

1. A method for preparing copper-doped iron disulfide nanozymes at low temperature, characterized in that, Includes the following steps: 1) Preparation of iron(III) oxide; 2) Low-temperature sulfidation reaction: The iron(III) oxide from step 1) is mixed with a sulfur source and calcined at 150-200 °C with a protective gas for 1-8 h to obtain iron(II) disulfide powder. 3) Preparation of nanozymes: The iron disulfide powder from step 2) is added to the copper source solution, mixed and stirred to react. The resulting reaction product is centrifuged, washed and dried, and then calcined at 120-200 °C with a protective gas for 1-6 h to obtain copper-doped iron disulfide nanozymes.

2. The method for preparing copper-doped iron disulfide nanozymes at low temperature as described in claim 1, characterized in that, In step 1), ferric oxide is prepared by chemical co-precipitation; in step 2), the mass ratio of ferric oxide to sulfur source is (1-2):(1-8), the protective gas is nitrogen, and the nitrogen flow rate is 50-100 mL / min.

3. The method for preparing copper-doped iron disulfide nanozymes at low temperature as described in claim 2, characterized in that, Step 1), the preparation of Fe3O4 includes the following steps: a) Preparation of the precursor solution: [The process involves adding Fe3O4 to a solution containing Fe...] 2 ⁺ and Fe 3+ Add an alkaline solution dropwise to the salt solution until the pH value is 4.5-6.5, mix, and obtain the precursor solution; b. Purification and drying: Centrifuge the precursor solution from step a, collect the precipitate, wash and dry it to obtain ferric oxide.

4. The method for preparing copper-doped iron disulfide nanozymes at low temperature as described in claim 3, characterized in that, In step a, Fe is present 2 The salt solution of ⁺ is a mixture of one or more of the following: ferrous chloride solution, ferrous sulfate solution, and ferrous nitrate solution, containing Fe. 3+ The salt solution is a mixture of one or more of the following: ferric chloride solution, ferric sulfate solution, and ferric nitrate solution. 2 ⁺∶Fe 3+ The molar ratio is (1-2):(1-3), and the alkaline solution is sodium hydroxide solution, ammonia water or potassium hydroxide solution; in step 2), the sulfur source is sulfur powder, sodium sulfide or L-cysteine; in step 3), the copper source solution is copper chloride solution, copper sulfate solution or copper nitrate solution.

5. The method for preparing copper-doped iron disulfide nanozymes at low temperature as described in claim 4, characterized in that, In step a, Fe is present 2 The salt solution of ⁺ is a ferrous chloride solution, containing Fe. 3+ The salt solution is a ferric chloride solution, Fe 2 ⁺∶Fe 3+ The molar ratio is 1:2, and the alkaline solution is sodium hydroxide solution; in step b, the drying conditions are: temperature 40-90℃, time 6-15 h; in step 2), the sulfur source is sulfur powder; in step 3), the copper source solution is copper chloride solution.

6. The method for preparing copper-doped iron disulfide nanozymes at low temperature as described in claim 5, characterized in that, In step 3), the mass concentration of the copper chloride solution is 1-5 wt%, the ratio of iron disulfide powder to copper chloride solution is (1-5) g: 10 mL, the protective gas is a mixture of H2 / N2, the volume concentration of H2 in the mixture is 2-20 vol%, and the flow rate of the mixture is 50-100 mL / min.

7. The application of the copper-doped iron disulfide nanozyme prepared by any one of claims 1-6 in the preparation of antibacterial drugs.

8. The application as described in claim 7, characterized in that, The antibacterial drug is an anti-Staphylococcus aureus drug.

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