Method for cysteine-assisted liquid-phase stripping of iron oxychloride and application of cysteine-assisted liquid-phase stripping of iron oxychloride

Abstract

The invention belongs to the technical field of nano material preparation and application, and discloses a method for liquid-phase stripping of iron oxychloride by cysteine and application. The method comprises the following steps: firstly, preparing blocky iron oxychloride through partial thermal decomposition of ferric chloride hexahydrate; and adding L-cysteine into the iron oxychloride solution, and carrying out ultrasonic treatment at 20-40kHz and 10-40 DEG C for 0.5-6 hours to finally prepare the cysteine-iron oxychloride nano material. The average size of the material is 20-200nm, and the material is strip-shaped, is rich in ferrous iron and oxygen vacancies, and has excellent peroxidase-like activity and Fenton reaction activity. The method is green, simple, convenient and low in cost. The prepared nano material can efficiently catalyze and generate active oxygen species such as hydroxyl free radicals, effectively kills drug-resistant escherichia coli and staphylococcus aureus through multiple mechanisms such as initiation of bacterial lipid peroxidation, DNA degradation and protein leakage consumption, shows good biocompatibility in a cytotoxicity test, and can be used for preparing a drug-resistant nano material. Wide application prospects are realized in the field of antibacterial preparations.

Description

Technical Field

[0001] This invention belongs to the field of nanomaterial preparation and application technology, specifically relating to a method for preparing and applying cysteine-exfoliated ferric chloride nanomaterials. Ferric chloride nanomaterials (FeOCl) are obtained by pyrolysis. Based on the ferric chloride nanomaterials, cysteine ​​(Cys) is added and subjected to liquid-phase exfoliation to prepare cysteine-ferric chloride nanomaterials. The enzyme-like properties and catalytic activity of the cysteine-ferric chloride nanomaterials are utilized to achieve the purpose of sterilization. Background Technology

[0002] The overuse and misuse of antibiotics has led to an increase in drug-resistant bacteria, exacerbating global morbidity and mortality. According to statistics released in 2022, approximately 5 million people worldwide die annually from complications caused by antibiotic resistance, and nearly 1.3 million are directly victims of infections caused by drug-resistant bacteria. It is predicted that if left unchecked, by 2050, antibiotic-resistant bacterial infections could become the leading cause of death globally, causing more than 10 million deaths annually. In recent years, the emergence of nanozymes, nanomaterials with enzyme-like catalytic activity, has provided a new approach to solving the problem of bacterial antibiotic resistance. As a promising alternative combining the advantages of natural enzymes and nanomaterials, nanozymes have gradually attracted widespread attention due to their low cost, environmental resistance, high stability, and high catalytic activity.

[0003] Two-dimensional materials possess abundant active edge sites and efficient surface electron transfer capabilities, both of which jointly drive their superior nanozyme catalytic activity. Reducing the size of two-dimensional materials and increasing their specific surface area facilitates the formation of surface defects and further enhances the exposure of active sites; therefore, the synthesis of few-layer materials has also sparked the interest of researchers.

[0004] Ferric oxychloride (FeOCl) is a highly efficient and pH-insensitive Fenton catalyst, significantly outperforming other iron-based catalysts. FeOCl possesses a controllable electronic structure, exhibiting a free radical generation efficiency 2–4 orders of magnitude higher than traditional iron-based materials. As a traditional functional material, FeOCl possesses a self-packing structure known for decades as the VanderWaals layer, a layered mineral formed by Cl-Cl van der Waals interactions creating octahedral FeO4Cl2 layers. FeOCl contains Fe 2+ Fe 3+FeOCl, a typical metal chloride oxide, has attracted particular attention due to its abundant chlorine storage, which leads to novel material properties. Previous reports have offered two explanations for the good catalytic performance of FeOCl. First, Fe(III) is readily reduced to Fe(II) via electron transfer between FeOCl and the intercalated material. Therefore, it can be inferred that H₂O₂ is particularly effective in reducing Fe(III), thereby promoting the recombination of Fe(II). Second, the linear configuration [O-Fe-Cl] in FeOCl is thought to contribute to the high yield of ·OH, because the linear oxygen-bridged configuration ([Fe-O-Fe)) is... 4+ FeOCl has previously been considered more effective in promoting photochemical Fenton processes. The synthesis of FeOCl via partial pyrolysis is the simplest and most convenient method, but the resulting FeOCl is typically large, and the bulk material poses significant challenges for later biomedical applications. Ferric oxychloride, as a typical material with a high free radical generation rate, will benefit from optimized size and increased defects in its biomedical applications.

[0005] Liquid-phase exfoliation, a top-down approach to materials synthesis, presents a challenge in balancing the production quality and large-area yield of two-dimensional layered materials. It is the simplest, most convenient, and mass-producible method for two-dimensional materials. This method involves appropriately increasing energy in the liquid to induce atomic layers to split and separate from their corresponding atomic layers in bulk materials, thus enabling the production of nanosheets from various layered materials. Among these methods, liquid-phase exfoliation of two-dimensional materials using natural active small molecules is environmentally friendly and biocompatible. Furthermore, these natural active small molecules act not only as exfoliating agents but also as functionalizing agents.

[0006] Among amino acids, cysteine ​​(L-Cys) exhibits high reactivity as a nucleophile, metal ligand, and participant in redox and free radical reactions. Its molecular structure contains functional groups such as amino, carboxyl, and thiol groups. It can participate in various biological processes through specific disulfide bond cross-linking, including detoxification, secondary protein synthesis, and metabolism. The sulfur atom in the L-Cys thiohydroxyl group has lower electronegativity than the oxygen atom, making it more likely to donate its lone pair electrons, thus forming stronger coordination bonds with metal ions. In organisms, iron-sulfur clusters coordinated to the protein backbone via cysteine ​​ligands are commonly found in twisted tetrahedral or cubic arrangements. These clusters are multimetallic Fe(II) / Fe(III) junctions connected by sulfur bridges. Proteins containing iron-sulfur clusters are commonly referred to as iron-sulfur proteins.

[0007] Therefore, it is necessary to develop a simple, green, and pollution-free method to prepare cysteine-iron oxychloride nanomaterials with high catalytic performance using cysteine ​​and iron oxychloride. Summary of the Invention

[0008] The purpose of this invention is to overcome the shortcomings of existing technologies and to provide a method for preparing and applying cysteine-iron chloride oxychloride nanomaterials, including the preparation process and bactericidal application, as follows: Figure 1 As shown, bulk ferric chloride was synthesized by pyrolysis, and then cysteine ​​was added to the ferric chloride solution as a stripping agent to prepare cysteine-ferric chloride nanomaterials through liquid-phase stripping. The prepared cysteine-ferric chloride nanomaterials have peroxidase-like activity and good biocompatibility, and can achieve highly efficient sterilization.

[0009] To achieve the above objectives, the present invention includes the following technical solutions:

[0010] A method for cysteine-assisted liquid-phase stripping of ferric chloride oxychloride includes the following steps:

[0011] (1) Preparation of ferric chloride: Ferric chloride hexahydrate was heated at 200-250°C for 0.5-2 hours at a heating rate of 5-15°C / min to partially decompose it, and blocky ferric chloride was obtained; the obtained product was centrifuged, washed and freeze-dried to obtain purified ferric chloride powder.

[0012] (2) Liquid phase exfoliation: The iron oxychloride powder obtained in step (1) is dispersed in water to form an iron oxychloride aqueous solution with a concentration of 0.1-1 mg / mL; then cysteine ​​is added to the solution and ultrasonically treated at 10-40℃ for 0.5-6 hours at an ultrasonic power of 20-40 kHz. After the reaction is completed, freeze-drying is performed to obtain cysteine-iron oxychloride nanomaterials.

[0013] Furthermore, in the above method, the cysteine ​​is L-cysteine.

[0014] Furthermore, in the above method, the centrifugation speed in step (1) is 5000-15000 r / min, and the solvent used for washing is acetone and ultrapure water.

[0015] Furthermore, in the above method, the mass-to-volume ratio of cysteine, ferric chloride oxychloride, and water in step (2) is 20 mg: 20 mg: 40 mL.

[0016] The present invention also discloses a cysteine-iron chloride nanomaterial prepared by the above method.

[0017] Furthermore, the cysteine-iron chloride nanomaterial has an average size of 20–200 nm, an elongated morphology, and contains ferrous iron and oxygen vacancies.

[0018] Furthermore, cysteine-iron chloride nanomaterials exhibit peroxidase-like activity and Fenton reaction activity.

[0019] The present invention also discloses an antibacterial preparation comprising the cysteine-iron chloride nanomaterial described in any one of the above claims.

[0020] The present invention also discloses the application of the above-mentioned cysteine-iron chloride nanomaterials in the preparation of antibacterial drugs or disinfectant products for killing drug-resistant bacteria.

[0021] Furthermore, in the above applications, the drug-resistant bacteria include drug-resistant Escherichia coli and drug-resistant Staphylococcus aureus.

[0022] Compared with the prior art, the present invention has the following outstanding advantages:

[0023] 1. The preparation method is green and efficient, and the process is simple: This invention uses L-cysteine ​​with good biocompatibility as a liquid phase stripping agent and functionalizing agent, and the reaction is carried out in the aqueous phase. There is no need to use toxic and harmful organic solvents or complex equipment. The whole process is environmentally friendly, simple to operate, low in cost, and easy to prepare on a large scale.

[0024] 2. Significantly Enhanced Catalytic Activity: Through cysteine-assisted exfoliation, nanomaterials with smaller dimensions (20–200 nm) and larger specific surface areas were successfully prepared. Crucially, this method introduces abundant oxygen vacancy defects and increases the proportion of ferrous iron in the material from 43.07% to over 51.44%. These characteristics collectively greatly enhance its peroxidase-like catalytic activity, with catalytic efficiency far superior to untreated ferric chloride, cysteine, or simple physical mixtures thereof.

[0025] 3. Possesses multiple synergistic bactericidal mechanisms, with excellent effects against drug-resistant bacteria: The nanomaterials can not only efficiently catalyze hydrogen peroxide to produce a variety of reactive oxygen species, but also specifically trigger lipid peroxidation reactions in bacterial cell membranes, leading to leakage of contents and proteins. This results in the synergistic destruction of bacterial structure and disruption of its redox balance through multiple pathways, exhibiting a strong killing effect on drug-resistant Escherichia coli and Staphylococcus aureus, providing a new strategy for solving the problem of antibiotic resistance.

[0026] 4. High biocompatibility and good stability: Cytotoxicity tests (CCK-8 assay) showed that the material had no significant toxicity to L929 fibroblasts and exhibited good biocompatibility. Furthermore, the material maintained excellent antibacterial properties after 3 months of storage, demonstrating strong stability and potential for practical application. Attached Figure Description

[0027] Figure 1 This invention relates to a schematic diagram illustrating the synthesis and bactericidal principle of cysteine-iron chloride oxychloride nanomaterials.

[0028] Figure 2The images shown are transmission electron microscope (TEM), scanning electron microscope (SEM), and X-ray diffraction (XRD) images of the iron oxychloride nanomaterials prepared in Example 1 of this invention; wherein A is a transmission electron microscope image, B is a scanning electron microscope image, and C is an XRD image.

[0029] Figure 3 Transmission electron microscope (TEM) image and energy dispersive spectroscopy (EDS) image of the cysteine-iron chloride nanomaterial prepared in Example 1 of this invention; where A is the TEM image and B is the EDS image;

[0030] Figure 4 These are X-ray diffraction (XPS) spectra of ferric chloride oxychloride and cysteine-ferric chloride oxychloride prepared in Example 1, where A is the Fe 2p orbital spectrum; B is the O 1s orbital spectrum; C is the Cl 2p orbital spectrum; and D is the S 2p orbital spectrum.

[0031] Figure 5 These are the Fourier transform infrared (FT-IR) spectra and oxygen vacancy maps of the cysteine-ferric chloride oxychloride prepared in Example 1. A is the FT-IR spectrum, and B is the oxygen vacancy map.

[0032] Figure 6 This diagram illustrates the results of enzyme activity determination using cysteine-iron chloride nanomaterials obtained by ultrasound in Example 1 of this invention, where the mass ratio of cysteine ​​to iron chloride oxychloride is 1:1. A represents the peroxidase activity determination using cysteine-iron chloride nanomaterials; B represents a comparative experiment on the peroxidase activity of cysteine-iron chloride nanomaterials with iron chloride oxychloride, cysteine, and a mixture of cysteine ​​and iron chloride oxychloride.

[0033] Figure 7 This is a schematic diagram showing the enzyme activity determination results of the cysteine-iron chloride oxychloride nanomaterials involved in this invention. In this diagram, A represents the peroxidase activity determination of the cysteine-iron chloride oxychloride nanomaterials obtained after ultrasonication at different mass ratios of cysteine ​​and iron chloride oxychloride in Example 2; and B represents the peroxidase activity determination of the cysteine-iron chloride oxychloride nanomaterials of Example 1 at different reaction times.

[0034] Figure 8 This invention relates to the determination of the types of reactive oxygen species produced by the cysteine-iron chloride nanomaterial in Example 1 of the present invention, wherein A is the determination of singlet oxygen produced by the cysteine-iron chloride nanomaterial; B is the determination of superoxide anion produced by the cysteine-iron chloride nanomaterial; and C is the determination of hydroxyl radical produced by the cysteine-iron chloride nanomaterial.

[0035] Figure 9This is a schematic diagram of the in vitro antibacterial experiment results of Example 5 of the present invention, which involved the treatment of cysteine-iron chloride nanomaterials with a mixture of cysteine ​​and iron chloride.

[0036] Figure 10 This invention relates to Example 5, which is a comparative in vitro antibacterial test of cysteine-iron chloride oxychloride nanomaterials versus cysteine ​​and iron chloride oxychloride materials;

[0037] Figure 11 Example 5 of the present invention is a schematic diagram of the results of an in vitro antibacterial experiment on cysteine-iron chloride nanomaterials after storage for 3 months;

[0038] Figure 12 This invention relates to Example 6, which studies the bactericidal mechanism of cysteine-iron chloride nanomaterials. Specifically, A represents the determination of the reactive oxygen species production capacity of drug-resistant bacteria treated with cysteine-iron chloride nanomaterials; B represents the determination of the lipid peroxidation capacity of drug-resistant bacteria treated with cysteine-iron chloride nanomaterials; C represents the determination of the lipoprotein leakage capacity of drug-resistant bacteria treated with cysteine-iron chloride nanomaterials; and D represents the determination of the lipid DNA degradation capacity of drug-resistant bacteria treated with cysteine-iron chloride nanomaterials.

[0039] Figure 13 This is a schematic diagram of the cytotoxicity test results of the cysteine-iron chloride nanomaterial in Example 7 of the present invention. Detailed Implementation

[0040] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0041] Table 1 Raw Material List

[0042]

[0043]

[0044] Table 2 Instruments and Equipment

[0045]

[0046] Example 1

[0047] This embodiment relates to a method for preparing a cysteine-iron chloride oxychloride nano-antibacterial material, the specific process steps of which are as follows:

[0048] (1) Preparation of bulk ferric chloride nanomaterials: Ferric chloride hexahydrate was weighed and placed in a covered ceramic boat. The mixture was heated at 230°C for 1 hour at a heating rate of 10°C / min. The sample was removed from the ceramic boat, mixed with acetone, and centrifuged at 8000 r / min for 10–15 minutes. The supernatant was removed, and the precipitate was collected. The precipitate was mixed with acetone, centrifuged at 8000 r / min for 10–15 minutes, the supernatant was removed, and the precipitate was collected. Acetone was added... Repeat the centrifugation, supernatant removal, and precipitate collection steps several times until the supernatant is clear and transparent. Then remove the supernatant, collect the precipitate, add ultrapure water, centrifuge at 8000 r / min for 10-15 minutes, remove the supernatant, collect the precipitate, add ultrapure water, and repeat the centrifugation, supernatant removal, and precipitate collection steps several times until the supernatant is clear and transparent after centrifugation. Then freeze-dry the precipitate for 24-48 hours at a freezing temperature of -35 to -50℃.

[0049] (2) Preparation of cysteine-ferric chloride oxychloride nanomaterials: 20 mg of L-cysteine ​​was added to 40 mL of 0.5 mg / mL ferric chloride oxychloride (prepared in step 1) solution, and the ultrasonic power was 40 kHz for 3 hours. Then, the mixture was freeze-dried for 24–48 hours at a temperature of -35–-50 °C. Cysteine-ferric chloride oxychloride nanomaterials were obtained.

[0050] The iron oxychloride nanomaterials were then characterized as follows:

[0051] The bulk iron oxychloride nanomaterials were characterized using transmission electron microscopy, scanning electron microscopy, and XRD, and the results are as follows: Figure 2 As shown in AC, bulk iron oxychloride nanomaterials were successfully synthesized.

[0052] The following characterization was performed using cysteine-iron chloride nanomaterials as an example:

[0053] like Figure 3 As shown in TEM, the cysteine-iron chloride nanomaterials have a size of 20–200 nm and a strip-like morphology. Figure 3 As shown in the B EDS image, Fe, O, Cl and S elements are uniformly distributed in the cysteine-iron chloride nanomaterial. Figure 4 AD is the XPS spectrum of cysteine-iron chloride nanomaterials, from which... Figure 4 A shows that the Fe 2p spectral line in cysteine-ferric chloride oxychloride shifts towards lower binding energies, indicating the formation of lower valence iron species. The relative content of ferrous iron, calculated from the peak area, increases from 43.07% to 51.44%. Figure 5 As shown in the FT-IR, cysteine ​​is located at 2549 cm⁻¹ in the infrared spectrum.-1 The disappearance of the spectral band (attributable to the stretching vibration of the -SH group) in the spectrum of cysteine-iron chloride oxychloride nanomaterials indicates that the -SH group was altered during the material synthesis process. Electron paramagnetic resonance (EPR) testing of the prepared cysteine-iron chloride oxychloride nanomaterials provides evidence of surface defects, such as... Figure 5 As shown in Figure B, the oxygen vacancies in the cysteine-iron chloride nanomaterials trap more electrons than those in the bulk iron chloride nanomaterials, indicating that the cysteine-iron chloride nanomaterials have more oxygen vacancies.

[0054] Example 2

[0055] This embodiment relates to the determination of peroxidase-like activity of cysteine-iron chloride nanomaterials.

[0056] The peroxidase-like activity assay of the cysteine-iron chloride nanomaterials involved in this embodiment was performed in the presence of hydrogen peroxide (H2O2) and 3,3',5,5'-tetramethylbenzidine (TMB).

[0057] The specific steps for determining the peroxidase-like activity of the cysteine-iron chloride nanomaterials involved in this embodiment are as follows: 1 mL of the reaction system contains sodium acetate buffer (pH 3), 10 μL of 20 mmol / L TMB ethanol solution, and 10 μL of 500 μg / mL... -1 The reaction mixture consisted of an aqueous solution of cysteine-ferric chloride nanomaterials and 10 μL of a 100 mmol / L H2O2 aqueous solution. The reaction system was then incubated at room temperature for 10 minutes, and the absorbance was measured at a wavelength range of 500-800 nm. Under the same conditions, the absorbance values ​​of TMB+H2O2, TMB+Cys-FeOCl, and Cys-FeOCl+H2O2 were measured at wavelengths of 500-800 nm, respectively. The results are as follows: Figure 6 As shown in A and 6B. From Figure 6 As can be seen from A, when cysteine-iron chloride nanomaterials, TMB, and H2O2 are present simultaneously, the reaction system exhibits the maximum absorbance at 652 nm, indicating that cysteine-iron chloride nanomaterials possess excellent peroxidase-like activity. From... Figure 6 As shown in Figure B, the comparative experiment shows that the peroxidase-like activity of the cysteine-iron chloride nanomaterial is higher than that of iron chloride, cysteine, and the peroxidase activity of the mixture of cysteine ​​and iron chloride.

[0058] Example 3

[0059] This example demonstrates the peroxidase-like activity determination of cysteine-iron chloride nanomaterials synthesized under different conditions (mass ratio of cysteine ​​to iron chloride oxychloride, ultrasonic time).

[0060] (1) Cysteine-iron chloride nanomaterials synthesized by ultrasound with different mass ratios of cysteine ​​to iron chloride.

[0061] The material synthesis steps were the same as in Example 1, except that different masses of cysteine ​​(0, 5, 10, 15, 20, 25, 30, 35 mg) were added to 40 mL of 0.5 mg / mL ferric chloride solution to prepare the cysteine-ferric chloride nanomaterials, while the other conditions remained unchanged. The peroxidase activity assay steps were the same as in Example 2, such as... Figure 7 As shown in Figure A, the prepared cysteine-iron oxychloride nanomaterials with different masses of cysteine ​​and iron oxychloride exhibit good peroxidase-like catalytic activity.

[0062] (2) The peroxidase-like catalytic activity of the cysteine-iron chloride nanomaterials synthesized under the same synthesis steps as in Example 1, with the mass ratio of cysteine ​​to iron chloride oxychloride being 1:1 and the ultrasonic time being varied (30, 60, 90, 120, 150, 180 minutes), was observed. Figure 7 As shown in Figure B, the prepared cysteine-iron chloride nanomaterials exhibit good peroxidase-like catalytic activity.

[0063] Example 4

[0064] This embodiment relates to the in vitro production of various types of reactive oxygen species (singlet oxygen) using cysteine-iron oxychloride nanomaterials. 1 O2, superoxide anion·O 2- The determination of hydroxyl radicals (·OH). The specific steps are as follows:

[0065] (1) The in vitro production of cysteine-iron chloride nanomaterials involved in this embodiment 1 The O2 reaction system consisted of 880 μL water, 1000 μL 9,10-dimethylanthracene (DMA) (32 mmol / L), 20 μL H2O2 (100 mmol / L), and 100 μL Lys-FeOCl nanomaterial aqueous solution (500 μg / mL). -1 The reaction was carried out at room temperature for 10 minutes, and the fluorescence intensity was measured. Under the same conditions, the fluorescence intensities of DMA, DMA+H2O2, DMA+Cys-FeOCl, and H2O2+Cys-FeOCl were measured respectively, and the results are as follows. Figure 8 As shown in A. From Figure 8 A shows that, 1A specific reaction between O2 and the fluorescent probe 9,10-dimethylanthracene (DMA) forms a corresponding internal peroxide (DMA-O2). In the presence of Cys-FeOCl and H2O2, the fluorescence intensity of DMA decreases rapidly, indicating the formation of [a specific chemical process] in this system. 1 O2.

[0066] (2) The in vitro production of ·O from the cysteine-iron chloride nanomaterials involved in this embodiment 2- The reaction system consisted of 1700 μL water, 100 μL dihydroetidium (DHE) (5 mmol / L), 100 μL H₂O₂ (100 mmol / L), and 100 μL Lys-FeOCl nanomaterial aqueous solution (500 μg / mL). -1 The reaction was carried out at room temperature for 10 minutes, and the fluorescence intensity was measured. Under the same conditions, the fluorescence intensities of DHE, DHE+H2O2, DHE+Cys-FeOCl, and H2O2+Cys-FeOCl were measured respectively, and the results are as follows. Figure 8 As shown in B. From Figure 8 As can be seen from B, the fluorescence intensity of ethidium dihydrogen phosphate increased after treatment with Cys-FeOCl. Figure 8 B), which indicates that O 2- It is induced by Cys-FeOCl peroxidase-like activity.

[0067] (3) The in vitro ·OH production reaction system of the cysteine-ferric chloride nanomaterial involved in this embodiment is 1700 μL water, 100 μL coumarin (C9H6O2) (concentration of 5 mmol / L), 100 μL H2O2 (concentration of 100 mmol / L) and 100 μL Lys-FeOCl nanomaterial aqueous solution (concentration of 500 μg / mL). -1 The reaction was carried out at room temperature for 10 minutes, and the fluorescence intensity was measured. Under the same conditions, the fluorescence intensities of C9H6O2, C9H6O2+H2O2, C9H6O2+Cys-FeOCl, and H2O2+Cys-FeOCl were measured respectively, and the results are as follows. Figure 8 As shown in C. From Figure 8 As can be seen from Figure C, after treatment with H₂O₂ + Cys-FeOCl, C₉H₆O₂ combines with short-lived ·OH groups to form a stable fluorescent product of 7-hydroxycoumarin (7-OH-coumarin, C₉H₆O₃). This indicates that the ·OH group is induced by the peroxidase-like activity of Cys-FeOCl.

[0068] Example 5

[0069] This embodiment relates to the application experiment of cysteine-iron oxychloride nanomaterials in in vitro antibacterial activity. The cysteine-iron oxychloride nanomaterials prepared in Example 1 were applied to the in vitro antibacterial experiment. The specific steps are as follows: Drug-resistant bacteria (drug-resistant Escherichia coli or drug-resistant Staphylococcus aureus) were extracted from pure cultures frozen at -80℃ and streaked overnight on LB agar. Single colonies of drug-resistant bacteria on solid LB agar were inoculated into 50 mL of sterile liquid LB agar (containing 0.5 g tryptone, 0.25 g yeast extract and 0.5 g NaCl). The suspension containing drug-resistant bacteria was then placed in an incubator and cultured overnight at 37℃ at 180 rpm / min. Subsequently, the bacteria were diluted to 1 × 10⁻⁶ using a bacterial turbidimeter and sterile water. 6 CFU / mL, the obtained bacterial suspension (100 μL) was mixed with 100 μL of Cys-FeOCl (where the concentration of material for inactivating drug-resistant Staphylococcus aureus was 2 μg / mL). -1 The material concentration for inactivating drug-resistant E. coli was 10 μg / mL. -1 The bacterial suspension was incubated with 100 μL H2O2 (0.5 mmol / L) and 200 μL sterile water at 37°C for 30 minutes. Then, 100 μL of the mixture was evenly spread onto LB solid medium and incubated upside down at 37°C for 12 hours. Bacterial colony counts were performed using the CFU method. The blank control group used bacterial suspensions containing 100 μL H2O2 (0.5 mmol / L) and 100 μL Lys-FeOCl (with a material concentration of 2 μg / mL for inactivating drug-resistant Staphylococcus aureus). -1 The material concentration for inactivating drug-resistant E. coli was 10 μg / mL. -1 The bacterial suspension was used as the control group, and the experimental results are as follows: Figure 9 As shown. From Figure 9 It can be seen that there are significant differences in bacterial colonies between the Cys-FeOCl nanomaterial treatment group and the cysteine ​​and ferric chloride mixture treatment group. Cys-FeOCl exhibits extremely high antibacterial rates against both drug-resistant Escherichia coli and drug-resistant Staphylococcus aureus, indicating that the cysteine-ferric chloride nanomaterial effectively kills drug-resistant bacteria and possesses extremely strong antibacterial properties. Figure 10 It can be seen that at the same concentration (50 μg mL) -1 When cysteine-ferric chloride nanomaterials are used, their bactericidal effect is significantly higher than that of cysteine ​​and ferric chloride alone. Further experiments show that, for example... Figure 11 Cysteine-iron chloride nanomaterials remained effective in inactivating drug-resistant Staphylococcus aureus even after 3 months of storage.

[0070] Example 6

[0071] This embodiment relates to the study of the in vitro antibacterial mechanism of cysteine-iron chloride nanomaterials. Specific steps were verified according to the instructions of the reactive oxygen species detection kit, lipid peroxidation (MDA) detection kit, Bradford protein concentration assay kit, and bacterial genomic DNA extraction kit. Figure 12 As shown in Figure A, treatment with cysteine-ferric chloride nanomaterials increased the total reactive oxygen species (ROS) content in bacteria; the intensity of lipid peroxidation was determined by the malondialdehyde (MDA) content. MDA, as a product of lipid peroxidation, can react with thiobarbituric acid (TBA) to form the red product MDA-TBA adduct, which has maximum absorption at 535 nm. Cysteine-ferric chloride nanomaterials can undergo lipid peroxidation with MRSA, but there was no significant difference in extended-spectrum β-lactamase-producing *E. coli*. Figure 12 B). Simultaneously, experiments were conducted to investigate protein leakage in these two bacteria after treatment with cysteine-ferric chloride nanomaterials. For example... Figure 12 As shown in Figure C, cysteine-iron chloride nanomaterials can induce protein leakage in both bacteria. The DNA damage state induced by the catalytic activity of cysteine-iron chloride nanomaterials in drug-resistant *E. coli* and *MARS* was evaluated using DNA gel electrophoresis. Figure 12 D) Compared with the control group, significant DNA degradation was observed after the addition of cysteine-iron chloride nanomaterials. The results indicate that the catalytic process of cysteine-iron chloride nanomaterials can cause serious damage to genomic DNA, ultimately leading to irreversible cell inactivation.

[0072] Example 7

[0073] This example demonstrates the application of cysteine-ferric chloride oxychloride materials in biotoxicity testing. L929 fibroblasts were used as a cell model, and cell viability was determined using a CCK-8 assay kit. Cells were cultured in 96-well plates for 24 hours, and then treated with aqueous solutions of cysteine-ferric chloride oxychloride nanomaterials at different concentrations (0, 25, 50, and 100 μg / mL). -1 After treatment and incubation for 24 hours, experiments were conducted according to the CCK-8 kit instructions. The results are as follows: Figure 13 As shown. From Figure 13 It can be seen that the cell viability did not decrease after treatment with cysteine-iron chloride nanomaterials, proving that the prepared cysteine-iron chloride nanomaterials have low cytotoxicity.

[0074] Summary: Examples 1-7 of this invention systematically verified the feasibility of the disclosed method and the excellent performance of the product. Through these examples, cysteine-iron chloride nanomaterials rich in divalent iron and oxygen vacancies were successfully prepared, and their excellent peroxidase-like activity was demonstrated, capable of efficiently catalyzing the generation of various reactive oxygen species such as hydroxyl radicals, superoxide anions, and singlet oxygen. Antibacterial experiments showed that the material has a strong killing effect on drug-resistant Staphylococcus aureus and Escherichia coli, with mechanisms including inducing bacterial lipid peroxidation, DNA degradation, and protein leakage. Cytotoxicity tests further demonstrated the material's good biocompatibility, and it maintained stable activity even after three months of storage, comprehensively verifying its great potential in antibacterial applications.

[0075] The above are merely a few preferred embodiments of the present invention, described in a relatively specific and detailed manner, but they should not be construed as limiting the scope of the present invention. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these all fall within the protection scope of the present invention.

Claims

1. A method for cysteine-assisted liquid-phase stripping of ferric chloride, characterized in that, Includes the following steps: (1) Preparation of ferric chloride: Ferric chloride hexahydrate was heated at 200-250°C for 0.5-2 hours at a heating rate of 5-15°C / min to partially decompose it, and blocky ferric chloride was obtained; the obtained product was centrifuged, washed and freeze-dried to obtain purified ferric chloride powder. (2) Liquid phase exfoliation: The iron oxychloride powder obtained in step (1) is dispersed in water to form an iron oxychloride aqueous solution with a concentration of 0.1-1 mg / mL; then cysteine ​​is added to the solution and ultrasonically treated at 10-40℃ for 0.5-6 hours at an ultrasonic power of 20-40 kHz. After the reaction is completed, freeze-drying is performed to obtain cysteine-iron oxychloride nanomaterials.

2. The method according to claim 1, characterized in that, The cysteine ​​in question is L-cysteine.

3. The method according to claim 1, characterized in that, The centrifugation speed in step (1) is 5000-15000 r / min, and the solvents used for washing are acetone and ultrapure water.

4. According to the method of claim 1, the mass-volume ratio of cysteine, ferric chloride oxychloride and water in step (2) is 20 mg: 20 mg: 40 mL.

5. A cysteine-iron chloride nanomaterial prepared by the method described in any one of claims 1-4.

6. The cysteine-iron chloride nanomaterial according to claim 5, characterized in that, Its average size is 20-200 nm, and its morphology is elongated, containing divalent iron and oxygen vacancies.

7. The cysteine-iron chloride oxychloride nanomaterial according to claim 5, characterized in that, It possesses peroxidase-like activity and Fenton reaction activity.

8. An antibacterial preparation, characterized in that, The cysteine-iron chloride nanomaterial comprises any one of claims 5-7.

9. The use of the cysteine-iron chloride nanomaterial as described in any one of claims 5-7 in the preparation of antibacterial drugs or disinfectant products for killing drug-resistant bacteria.

10. The application according to claim 9, characterized in that, The drug-resistant bacteria include drug-resistant Escherichia coli and drug-resistant Staphylococcus aureus.

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