A petal-shaped MoS2-based enhanced composite nanomaterial, a preparation method and application thereof

Abstract

The application relates to the technical field of materials, and discloses a reinforced composite nanomaterial based on petal-shaped MoS2, a preparation method and application, the preparation method comprising the following steps: step 1, adding ascorbic acid dropwise in a MoS2 dispersion liquid to obtain reduced MoS2 after sufficient reaction; step 2, adding chloroauric acid dropwise in the reaction liquid, washing after adsorption reaction, then continuously adding ascorbic acid, washing, centrifuging and drying after reduction reaction to obtain an Au / MoS2 precursor; step 3, calcining the Au / MoS2 precursor to obtain Au@MoS2; step 4, fully mixing the Au@MoS2 solution and a glucose oxidase Gox solution, centrifuging, freeze-drying to obtain the required composite nanomaterial Au@MoS2@Gox; and step 5, the composite nanomaterial obtained in the application can be used as an efficient CDT preparation through mutual cooperation and joint action of the substances.

Description

Technical Field

[0001] This invention relates to the field of materials preparation technology, specifically to an enhanced composite nanomaterial based on petal-shaped MoS2, its preparation method, and its application. Background Technology

[0002] In the field of cancer diagnosis and treatment, chemokinetic therapy (CDT) utilizes glutathione (GSH) and hydrogen peroxide (H2O2) overexpressed in the tumor microenvironment. A single-atom catalyst is used to consume GSH, thereby weakening the antioxidant defense capabilities of hesperamine, and catalyzes the generation of highly toxic hydroxyl radicals from H2O2. OH, thereby inducing tumor cell apoptosis. However, this method has the following problems: 1) The endogenous levels of GSH and H2O2 in tumors are limited, making it difficult to produce sufficient amounts of OH. OH to achieve efficient treatment; 2) Most single-atom catalysts have low enrichment efficiency at tumor sites and rapid metabolic clearance in vivo; 3) Insufficient catalyst surface activity limits the catalyst loading efficiency and reaction activity. Summary of the Invention

[0003] This invention addresses the problems existing in the prior art by providing an enhanced composite nanomaterial based on petal-shaped MoS2, its preparation method, and its application.

[0004] The technical solution adopted in this invention is: a method for preparing petal-shaped MoS2-based reinforced composite nanomaterials, comprising the following steps:

[0005] Step 1: Add ascorbic acid dropwise to the MoS2 dispersion and react completely to obtain reduced MoS2;

[0006] Step 2: Chloroauric acid is added dropwise to the reaction solution obtained in Step 1. After the adsorption reaction, the solution is washed. Then, ascorbic acid is added, and after the reduction reaction, the solution is washed, centrifuged, and dried to obtain the Au / MoS2 precursor.

[0007] Step 3: Calcining the Au / MoS2 precursor obtained in Step 2 will yield Au@MoS2;

[0008] Step 4: Thoroughly mix the Au@MoS2 solution obtained in Step 3 with the glucose oxidase Gox solution, and then centrifuge and freeze-dry to obtain Au@MoS2@Gox, which is the desired composite nanomaterial; wherein the mass ratio of Au@MoS2 to Gox is 1:3.

[0009] Furthermore, the method includes the following steps: the Au@MoS2@Gox solution obtained in step 4 is thoroughly mixed and reacted with chitosan CS in an acidic solvent, and the desired composite nanomaterial is obtained by centrifugation and freeze-drying; wherein the mass ratio of Au@MoS2@Gox to chitosan is 1:5.

[0010] Furthermore, the method for preparing MoS2 in step 1 is as follows:

[0011] Anhydrous sodium molybdate is added to a solvent containing citric acid and mixed thoroughly. Then, thiourea is added and reacted thoroughly at 200 °C. After washing, centrifugation, and freeze-drying, MoS2 can be obtained.

[0012] The molar ratio of molybdenum ions to sulfur ions is 1:4 to 5.

[0013] Furthermore, step 1 is carried out under ice-water bath conditions, wherein the mass ratio of MoS2 to ascorbic acid is 400:1, and the reaction time is 2 h.

[0014] Furthermore, the reaction in step 2 is carried out in an ice-water bath under light-protected conditions, wherein the mass ratio of reduced MoS2 to chloroauric acid is 3:1 and the adsorption reaction time is 8 h; the mass ratio of reduced MoS2 to ascorbic acid is 400:1 and the reduction reaction time is 2 h.

[0015] Furthermore, in step 3, the calcination temperature is 400 ℃ and the calcination time is 2 h.

[0016] Furthermore, step 4 is carried out under stirring and light-protected conditions, and the reaction time is 12-16 h.

[0017] Furthermore, in step 5, the acidic solvent is an acetic acid solution with a mass concentration of 36 wt%, and the reaction is carried out under stirring conditions for 16 h.

[0018] An enhanced composite nanomaterial based on petal-shaped MoS2, wherein the composite nanomaterial uses petal-shaped MoS2 as a matrix, gold atoms and glucose oxidase are adsorbed on the surface, and chitosan is coated on the surface of the petal-shaped MoS2.

[0019] Application of an enhanced composite nanomaterial based on petal-shaped MoS2, wherein the composite nanomaterial is used in the preparation of chemotherapy drugs for tumors.

[0020] The beneficial effects of this invention are:

[0021] The composite nanomaterial obtained in this invention uses petal-shaped MoS2 as the matrix, with gold single atoms and glucose oxidase adsorbed on the surface. The petal-shaped MoS2 surface is coated with chitosan. The gold single atoms can catalyze the formation of H2O2 in tumor cells, while Gox and glucose react to generate H2O2, and the gold single atoms further catalyze the formation of H2O2. OH; Gold single atoms can also catalyze the oxidation of GSH to GSSG within tumors, in large quantities. The generation of OH and the depletion of GSH together lead to the downregulation of GPX, causing lipid peroxidation and achieving a therapeutic effect. Furthermore, the surface coating with CS can reduce release during transport and maintain and enhance enzyme activity and stability, thereby improving the biocompatibility of the composite nanomaterial. Attached Figure Description

[0022] Figure 1 This is a SEM image of MoS2 used in step 1 of Embodiment 1 of the present invention.

[0023] Figure 2 The images show the X-ray diffraction pattern and SEM image of MoS2 after restoration in step 1 of Embodiment 1 of the present invention. a is the X-ray diffraction pattern and b is the SEM image.

[0024] Figure 3 The EPR test results of MoS2 after reduction in step 1 of Embodiment 1 of the present invention are shown. a is the magnetic field strength and b is the g factor.

[0025] Figure 4 This is the SEM image of Au@MoS2 obtained in step 3 of embodiment 1 of the present invention.

[0026] Figure 5 The results of high-angle annular dark-field scanning transmission electron microscopy imaging and energy-dispersive X-ray spectroscopy elemental surface scanning analysis and atomic resolution spherical aberration correction AC-HAADF-STEM are obtained in step 3 of Embodiment 1 of the present invention; a is the result of high-angle annular dark-field scanning transmission electron microscopy imaging and energy-dispersive X-ray spectroscopy elemental surface scanning, and b is the result of HAADF-STEM.

[0027] Figure 6 The X-ray photoelectron spectroscopy analysis results are for MoS2 and reduced MoS2 used in step 1 of Embodiment 1 of the present invention.

[0028] Figure 7 The X-ray photoelectron spectroscopy (XPS) spectra of Au@MoS2 obtained in step 3 of Embodiment 1 of the present invention are shown below. a is the full XPS spectrum of Au@MoS2, b is the Mo element spectrum, and c is the Au element spectrum.

[0029] Figure 8 This is a TEM image of the composite nanomaterial obtained in Example 1 of the present invention.

[0030] Figure 9 The X-ray diffraction analysis results of Au@MoS2 obtained in step 3 of Example 1 of this invention are shown.

[0031] Figure 10The results show the photothermal performance of the composite nanomaterials obtained in Examples 1 and 6 of this invention, using MoS2 in Example 1, obtaining Au@MoS2 in step 3, and the materials used in Examples 1 and 6. a and b are temperature rise curves for different materials, c and d are temperature rise curves for different concentrations of the same material, e is temperature rise curves for different powers, and f is temperature rise curves for five cycles.

[0032] Figure 11 The results show the catalytic performance of the composite nanomaterials obtained in Examples 1 and 6 of this invention, including the MoS2 used in Example 1, the Au@MoS2 obtained in step 3, and the reaction results of different materials, with a representing the reaction results of different concentrations and c representing the reaction results of different times.

[0033] Figure 12 The results show the in vivo catalytic performance of the composite nanomaterials obtained in Examples 1 and 6 of this invention after co-incubation with EC and 4T1 cells for 24 h, using MoS2 in Example 1 and Au@MoS2 obtained in step 3. a is the result of 4T1 cells and b is the result of EC cells.

[0034] Figure 13 The performance results of the composite nanomaterials obtained in Examples 1 and 6 of this invention are as follows: MoS2 used in Example 1, Au@MoS2 obtained in step 3, and the composite nanomaterials obtained in Examples 1 and 6. a represents the ROS detection result, and b represents the generated... The ability of OH.

[0035] Figure 14 The results of lipid peroxidation tests after co-incubating the composite nanomaterials with 4T1 cells for 6 h are as follows: MoS2 used in Example 1 of this invention, Au@MoS2 obtained in step 3, and the composite nanomaterials obtained in Examples 1 and 6.

[0036] Figure 15 The results of live and dead cell staining after co-incubating the composite nanomaterials with 4T1 cells for 12 h are as follows: MoS2 used in Example 1 of this invention, Au@MoS2 obtained in step 3, and live and dead cell staining results obtained in Examples 1 and 6.

[0037] Figure 16 The results of JC-1 staining test after co-incubating the composite nanomaterials with 4T1 cells for 6 h are as follows: MoS2 used in Example 1 of this invention, Au@MoS2 obtained in step 3, and the composite nanomaterials obtained in Examples 1 and 6. Detailed Implementation

[0038] The present invention will be further described below with reference to the accompanying drawings and specific embodiments.

[0039] A method for preparing petal-shaped MoS2-based reinforced composite nanomaterials includes the following steps:

[0040] Step 1: Add ascorbic acid dropwise to the MoS2 dispersion and react completely to obtain reduced MoS2;

[0041] The preparation method of MoS2 is as follows:

[0042] Anhydrous sodium molybdate was added to a solvent containing citric acid and stirred at 500 r / min for 30 min until the mixture gradually changed from a white milky substance to a colorless and transparent solution. After 30 min, thiourea was added, and the mixture was sonicated for 10 min. The reaction was carried out at 200 ℃ for 24 h. After washing, centrifugation, and drying under dry vacuum at 60 ℃ for 24 h, MoS2 was obtained. The solvent was a mixture of ultrapure water with added PEG and ethylene glycol.

[0043] The molar ratio of molybdenum ions to sulfur ions is 1:4–5. The molar ratio of molybdenum ions to sulfur ions in the molybdenum and sulfur sources should not be less than 1:4. A ratio lower than this will result in insufficient sulfur supply, leading to sulfur vacancy defects and making it difficult to form a flower-like morphology. The reaction temperature and time in the above reaction need to be strictly controlled. Too high a reaction temperature results in large particles, while too low a temperature results in small particles. Furthermore, excessively long reaction times lead to cluster formation, while insufficient time prevents the layered structure of molybdenum disulfide from stacking properly, thus failing to form a petal-like structure.

[0044] MoS2 was dispersed in deionized water and placed in an ice-water bath. Ascorbic acid was slowly added dropwise at a rate of 5 mL / min under stirring at 300 r / min, wherein the mass ratio of C6H8O6 to MoS2 was 1:100. The reaction was continued for 2 h to obtain reduced MoS2.

[0045] Using ascorbic acid as a mild reducing agent, uniformly dispersed sulfur vacancies can be generated on the surface of MoS2 while maintaining its structural integrity. Controlled reduction of MoS2 is achieved under low-temperature conditions (i.e., an ice-water bath). Compared to strong reducing agents like sodium borohydride, ascorbic acid weakens the Mo-S bond by donating electrons, causing S atoms coordinated to Mo atoms to detach and form vacancies. Simultaneously, the hydroxyl and carbonyl groups in its molecule can coordinate with exposed, highly reactive Mo atoms to form a temporary protective layer, preventing the erosion of S vacancies and stabilizing their uniform distribution. This mild reduction strategy prevents excessive aggregation of sulfur vacancies and merging of large-area defects caused by excessively rapid reactions at room temperature or high temperatures.

[0046] Step 2: Chloroauric acid is added dropwise to the reaction solution obtained in Step 1. After the reaction is complete, the Au / MoS2 precursor is obtained by washing, centrifugation and drying.

[0047] The process is as follows:

[0048] While maintaining an ice-water bath, HAuCl4 solution was slowly added dropwise at a rate of 5 mL / min with stirring at 300 r / min, and the reaction was continued for 8 h. Slow addition ensured sufficient diffusion and adsorption of HAuCl4 molecules onto the active sites of MoS2. Low temperature effectively inhibited their migration and rearrangement, resulting in a highly dispersed Au precursor adsorption system. After the reaction, the mixture was centrifuged at 8000 r / min for 10 min and washed three times with deionized water.

[0049] Subsequently, ascorbic acid solution was slowly added dropwise to the above system under continuous ice-water bath and stirring at 300 r / min, and the reaction was carried out for 3 h to reduce the Au / MoS2 precursor. The mass ratio of C6H8O6 to MoS2 was 1:400. The synergistic effect of slow feeding and low temperature environment can achieve controllable reduction and uniform nucleation, and significantly inhibit Au atom aggregation.

[0050] After reduction, the Au / MoS2 precursor was obtained by centrifugation at 8000 r / min for 10 min, washing with deionized water three times, and drying under dry vacuum at 60 ℃ for 24 h.

[0051] Step 3: The Au / MoS2 precursor obtained in Step 2 was placed in a tube furnace and calcined at 400 °C for 2 h to obtain structurally stable Au@MoS2 (Au-SAC in the attached figure also represents this material). High-temperature calcination not only enhances the bonding strength between Au atoms and the support, but also removes surface organic residues through thermal decomposition, exposing clean Au and MoS2 active sites, thereby optimizing catalytic performance.

[0052] Step 4: Thoroughly mix the Au@MoS2 solution obtained in Step 3 with the glucose oxidase Gox solution, and then centrifuge and freeze-dry to obtain Au@MoS2@Gox, which is the desired composite nanomaterial.

[0053] The specific process is as follows:

[0054] The Au@MoS2 solution and the glucose oxidase Gox solution were placed on a magnetic stirrer and stirred at 300 r / min for 16 h to ensure thorough mixing. The mass ratio of Au@MoS2 to Gox was 1:3. To ensure adequate Gox loading, the reaction was conducted in a dark, ice-water bath environment. After stirring overnight, the solution was centrifuged at 8000 rpm / min for 10 min and then freeze-dried at 60 °C to obtain Au@MoS2@Gox. The light-protected reaction was conducted to prevent photo-oxidative damage and photothermal denaturation, thus avoiding a decrease in enzyme activity or inactivation. It also prevented the aggregation of gold single atoms.

[0055] The process also includes the following steps: The Au@MoS2@Gox solution obtained in step 4 is mixed with chitosan CS in an acidic solvent on a magnetic stirrer (the mass ratio of Au@MoS2@Gox to CS is 1:5). The mixture is stirred continuously at 300 r / min for 16 h under ice-water bath conditions, ensuring effective encapsulation of the nanoparticles by CS. The encapsulation mechanism is based on the generation of numerous S-vacancy sites on the surface of reduced molybdenum disulfide, which can adsorb CS through electrostatic interactions.

[0056] After the reaction was completed, the mixed solution was centrifuged at 8000 r / min for 10 min, washed three times with deionized water, and then freeze-dried to obtain the desired composite nanomaterial Au@MoS2@Gox@CS.

[0057] Example 1

[0058] A method for preparing petal-shaped MoS2-based reinforced composite nanomaterials includes the following steps:

[0059] Step 1: Add ascorbic acid dropwise to the MoS2 dispersion and react completely to obtain reduced MoS2.

[0060] Place 4.06 g of Na2MoO4, 2.52 g of citric acid C6H8O7 and 0.9 g of PEG in a beaker. Pour 60 mL of a mixture of ethylene glycol and water into the beaker. The volume ratio of ethylene glycol to water is 1:2. Then place the mixture on a magnetic stirrer and stir at 500 r / min for 30 min until the mixture gradually changes from a white milky substance to a colorless and transparent solution.

[0061] After 30 min, 6 g of thiourea was added, and the mixture was placed in an ultrasonic machine and ultrasonically vibrated for 10 min until dissolved to obtain solution A. The solution was then poured into a 100 mL polytetrafluoroethylene high-pressure reactor, and the temperature was set to 200 °C. The reaction was carried out for 24 h. The final product was centrifuged at 8000 rpm for 10 min, washed three times with anhydrous ethanol, washed three times with deionized water, and finally freeze-dried at 60 °C for 24 h to obtain MoS2.

[0062] Dissolve 3 g of MoS2 in 150 mL of water and disperse thoroughly on a magnetic stirrer to obtain dispersion B. Dissolve 20 mg of ascorbic acid (C6H8O6) in 20 mL of water and sonicate for 8 min until completely dissolved to obtain solution C. Slowly add solution C to solution B at a rate of 5 mL / min, maintaining an ice-water bath environment throughout the process. React at 300 r / min for 2 h, then centrifuge at 8000 rpm for 10 min and wash three times with deionized water to obtain the reduced MoS2 solution.

[0063] Step 2: Chloroauric acid is added dropwise to the reaction solution obtained in Step 1. After the adsorption reaction, the solution is washed. Then, ascorbic acid is added, and after the reduction reaction, the solution is washed, centrifuged, and dried to obtain the Au / MoS2 precursor.

[0064] Solution D was obtained by adding 150 mL of water to the reduced MoS2 solution and stirring thoroughly. Solution E was obtained by dissolving 1 g of HAuCl4 in 20 mL of water and sonicating for 10 min. Solution E was slowly added dropwise to solution D at a rate of 5 mL / min. The solution was reacted at 300 r / min for 8 h, and the reaction was carried out in an ice-water bath environment throughout. After the reaction was completed, the solution was centrifuged at 8000 rpm for 10 min and washed once with deionized water to obtain the loaded solution F.

[0065] The washed solution F was dissolved in 100 mL of water and stirred until thoroughly mixed. 5 mg of C6H8O6 was dissolved in 20 mL of water and sonicated for 10 min until completely dissolved to obtain solution G. Solution G was slowly added dropwise to solution F at a rate of 10 mL / min, and the reaction was carried out in an ice-water bath environment at a stirring speed of 300 r / min for 3 h. After that, the mixture was centrifuged at 8000 rpm for 10 min, washed twice with deionized water, and finally freeze-dried for 24 h to obtain the Au / MoS2 precursor.

[0066] Step 3: Place the Au / MoS2 precursor obtained in Step 2 in a tube furnace, heat it to 400 °C, and hold it for 2 h to obtain Au@MoS2 anchored to Au.

[0067] Step 4: Thoroughly mix the Au@MoS2 solution obtained in Step 3 with the glucose oxidase Gox solution, and then centrifuge and freeze-dry to obtain Au@MoS2@Gox, which is the desired composite nanomaterial.

[0068] The procedure is as follows: Dissolve 500 mg of Au@MoS2 in 100 mL of aqueous solution and mix thoroughly. Place the solution on a magnetic stirrer, add 1.5 g of Gox, and stir the solution at 300 r / min for 16 h. The entire process should be carried out in a dark, ice-water bath environment. After the reaction is complete, centrifuge at 8000 rpm for 10 min, wash three times with deionized water, and finally freeze-dry to obtain Au@MoS2@Gox.

[0069] Step 5: Mix the Au@MoS2@Gox solution obtained in Step 4 with chitosan CS in an acidic solvent and react thoroughly. After centrifugation and freeze-drying, the desired composite nanomaterial Au@MoS2@Gox@CS can be obtained.

[0070] The process is as follows:

[0071] 1.25 g of CS was dissolved in 100 mL of acetic acid aqueous solution and placed on a magnetic stirrer to fully dissolve and mix to obtain solution H, in which the acetic acid content was 36% wt%. 250 mg of Au@MoS2@Gox was added to solution H and stirred, and the mixture was kept in a dark, ice-water bath environment throughout the process. After reacting at 300 r / min for 16 h, the mixture was centrifuged at 8000 rpm for 10 min, washed three times with deionized water, and finally freeze-dried to obtain Au@MoS2@Gox@CS nanocomposite material.

[0072] Example 2

[0073] A method for preparing petal-shaped MoS2-based reinforced composite nanomaterials includes the following steps:

[0074] Step 1: Add ascorbic acid dropwise to the MoS2 dispersion and react completely to obtain reduced MoS2.

[0075] Place 4.06 g of Na2MoO4, 2.52 g of citric acid C6H8O7 and 0.9 g of PEG in a beaker. Pour 60 mL of a mixture of ethylene glycol and water into the beaker. The volume ratio of ethylene glycol to water is 1:2. Then place the mixture on a magnetic stirrer and stir at 500 r / min for 30 min until the mixture gradually changes from a white milky substance to a colorless and transparent solution.

[0076] 12.38 g of thiourea was added after 30 min, and the mixture was placed in an ultrasonic machine and ultrasonically vibrated for 10 min until dissolved to obtain solution A. The solution was then poured into a 100 mL polytetrafluoroethylene high-pressure reactor, and the temperature was set to 200 °C. The reaction was carried out for 18 h. The final product was centrifuged at 8000 rpm for 10 min, washed three times with anhydrous ethanol, washed three times with deionized water, and finally freeze-dried at 60 °C for 24 h to obtain MoS2.

[0077] Dissolve 3 g of MoS2 in 150 mL of water and disperse thoroughly on a magnetic stirrer to obtain dispersion B. Dissolve 20 mg of ascorbic acid (C6H8O6) in 20 mL of water and sonicate for 8 min until completely dissolved to obtain solution C. Slowly add solution C to solution B at a rate of 5 mL / min, maintaining an ice-water bath environment throughout the process. React at 300 r / min for 2 h, then centrifuge at 8000 rpm for 10 min and wash three times with deionized water to obtain the reduced MoS2 solution.

[0078] Step 2: Chloroauric acid is added dropwise to the reaction solution obtained in Step 1. After the adsorption reaction, the solution is washed. Then, ascorbic acid is added, and after the reduction reaction, the solution is washed, centrifuged, and dried to obtain the Au / MoS2 precursor.

[0079] Solution D was obtained by adding 150 mL of water to the reduced MoS2 solution and stirring thoroughly. Solution E was obtained by dissolving 1 g of HAuCl4 in 20 mL of water and sonicating for 10 min. Solution E was slowly added dropwise to solution D at a rate of 5 mL / min. The solution was reacted at 300 r / min for 8 h, and the reaction was carried out in an ice-water bath environment throughout. After the reaction was completed, the solution was centrifuged at 8000 rpm for 10 min and washed once with deionized water to obtain the loaded solution F.

[0080] The washed solution F was dissolved in 100 mL of water and stirred until thoroughly mixed. 5 mg of ascorbic acid C6H8O6 was dissolved in 20 mL of water and sonicated for 10 min until completely dissolved to obtain solution G. Solution G was slowly added dropwise to solution F at a rate of 10 mL / min, and the reaction was carried out in an ice-water bath environment at a stirring speed of 300 r / min for 3 h. After that, the mixture was centrifuged at 8000 rpm for 10 min, washed twice with deionized water, and finally freeze-dried for 24 h to obtain the Au / MoS2 precursor.

[0081] Step 3: Place the Au / MoS2 precursor obtained in Step 2 in a tube furnace, heat it to 400 °C, and hold it for 2 h to obtain Au@MoS2 anchored to Au.

[0082] Step 4: Thoroughly mix the Au@MoS2 solution obtained in Step 3 with the glucose oxidase Gox solution, and then centrifuge and freeze-dry to obtain Au@MoS2@Gox, which is the desired composite nanomaterial.

[0083] The procedure is as follows: Dissolve 500 mg of Au@MoS2 in 100 mL of aqueous solution and mix thoroughly. Place the solution on a magnetic stirrer, add 1.5 g of Gox, and stir the solution at 300 r / min for 16 h. The entire process should be carried out in a dark, ice-water bath environment. After the reaction is complete, centrifuge at 8000 rpm for 10 min, wash three times with deionized water, and finally freeze-dry to obtain Au@MoS2@Gox.

[0084] Step 5: Mix the Au@MoS2@Gox solution obtained in Step 4 with chitosan CS in an acidic solvent and react thoroughly. After centrifugation and freeze-drying, the desired composite nanomaterial Au@MoS2@Gox@CS can be obtained.

[0085] The process is as follows:

[0086] 1.25 g of CS was dissolved in 100 mL of acetic acid aqueous solution and placed on a magnetic stirrer to fully dissolve and mix to obtain solution H, in which the acetic acid content was 36% wt%. 250 mg of Au@MoS2@Gox was added to solution H and stirred, and the mixture was kept in a dark, ice-water bath environment throughout the process. After reacting at 300 r / min for 16 h, the mixture was centrifuged at 8000 rpm for 10 min, washed three times with deionized water, and finally freeze-dried to obtain Au@MoS2@Gox@CS nanocomposite material.

[0087] Example 3

[0088] A method for preparing petal-shaped MoS2-based reinforced composite nanomaterials includes the following steps:

[0089] Step 1: Add ascorbic acid dropwise to the MoS2 dispersion and react completely to obtain reduced MoS2.

[0090] Place 4.06 g of Na2MoO4, 2.52 g of citric acid C6H8O7 and 0.9 g of PEG in a beaker. Pour 60 mL of a mixture of ethylene glycol and water into the beaker. The volume ratio of ethylene glycol to water is 1:1. Then place the mixture on a magnetic stirrer and stir at 500 r / min for 30 min until the mixture gradually changes from a white milky substance to a colorless and transparent solution.

[0091] After 30 min, 6 g of thiourea was added, and the mixture was ultrasonically vibrated for 10 min until dissolved to obtain solution A. The solution was then poured into a 100 mL polytetrafluoroethylene high-pressure reactor, and the temperature was set to 200 °C. The reaction was carried out for 18 h. The final product was centrifuged at 8000 rpm for 10 min, washed three times with anhydrous ethanol, washed three times with deionized water, and finally freeze-dried at 60 °C for 24 h to obtain MoS2.

[0092] Dissolve 3 g of MoS2 in 150 mL of water and disperse thoroughly on a magnetic stirrer to obtain dispersion B. Dissolve 30 mg of ascorbic acid (C6H8O6) in 20 mL of water and sonicate for 8 min until completely dissolved to obtain solution C. Slowly add solution C to solution B at a rate of 5 mL / min, maintaining an ice-water bath environment throughout the process. React at 300 r / min for 2 h, then centrifuge at 8000 rpm for 10 min and wash three times with deionized water to obtain the reduced MoS2 solution.

[0093] Step 2: Chloroauric acid is added dropwise to the reaction solution obtained in Step 1. After the adsorption reaction, the solution is washed. Then, ascorbic acid is added, and after the reduction reaction, the solution is washed, centrifuged, and dried to obtain the Au / MoS2 precursor.

[0094] Solution D was obtained by adding 150 mL of water to the reduced MoS2 solution and stirring thoroughly. Solution E was obtained by dissolving 1 g of HAuCl4 in 20 mL of water and sonicating for 10 min. Solution E was slowly added dropwise to solution D at a rate of 5 mL / min. The solution was reacted at 300 r / min for 8 h, and the reaction was carried out in an ice-water bath environment throughout. After the reaction was completed, the solution was centrifuged at 8000 rpm for 10 min and washed once with deionized water to obtain the loaded solution F.

[0095] The washed solution F was dissolved in 100 mL of water and stirred until thoroughly mixed. 5 mg of ascorbic acid C6H8O6 was dissolved in 20 mL of water and sonicated for 10 min until completely dissolved to obtain solution G. Solution G was slowly added dropwise to solution F at a rate of 10 mL / min, and the reaction was carried out in an ice-water bath environment at a stirring speed of 300 r / min for 3 h. After that, the mixture was centrifuged at 8000 rpm for 10 min, washed twice with deionized water, and finally freeze-dried for 24 h to obtain the Au / MoS2 precursor.

[0096] Step 3: Place the Au / MoS2 precursor obtained in Step 2 in a tube furnace, heat it to 400 °C, and hold it for 2 h to obtain Au@MoS2 anchored to Au.

[0097] Step 4: Thoroughly mix the Au@MoS2 solution obtained in Step 3 with the glucose oxidase Gox solution, and then centrifuge and freeze-dry to obtain Au@MoS2@Gox, which is the desired composite nanomaterial.

[0098] The procedure is as follows: Dissolve 500 mg of Au@MoS2 in 100 mL of aqueous solution and mix thoroughly. Place the solution on a magnetic stirrer, add 1.5 g of Gox, and stir the solution at 300 r / min for 16 h. The entire process should be carried out in a dark, ice-water bath environment. After the reaction is complete, centrifuge at 8000 rpm for 10 min, wash three times with deionized water, and finally freeze-dry to obtain Au@MoS2@Gox.

[0099] Step 5: Mix the Au@MoS2@Gox solution obtained in Step 4 with chitosan CS in an acidic solvent and react thoroughly. After centrifugation and freeze-drying, the desired composite nanomaterial Au@MoS2@Gox@CS can be obtained.

[0100] The process is as follows:

[0101] 1.25 g of CS was dissolved in 100 mL of acetic acid aqueous solution and placed on a magnetic stirrer to fully dissolve and mix to obtain solution H, in which the acetic acid content was 36% wt%. 250 mg of Au@MoS2@Gox was added to solution H and stirred, and the mixture was kept in a dark, ice-water bath environment throughout the process. After reacting at 300 r / min for 16 h, the mixture was centrifuged at 8000 rpm for 10 min, washed three times with deionized water, and finally freeze-dried to obtain Au@MoS2@Gox@CS nanocomposite material.

[0102] Example 4

[0103] A method for preparing petal-shaped MoS2-based reinforced composite nanomaterials includes the following steps:

[0104] Step 1: Add ascorbic acid dropwise to the MoS2 dispersion and react completely to obtain reduced MoS2.

[0105] Place 4.06 g of Na2MoO4, 2.52 g of citric acid C6H8O7 and 0.9 g of PEG in a beaker. Pour 60 mL of a mixture of ethylene glycol and water into the beaker. The volume ratio of ethylene glycol to water is 1:2. Then place the mixture on a magnetic stirrer and stir at 500 r / min for 30 min until the mixture gradually changes from a white milky substance to a colorless and transparent solution.

[0106] After 30 min, 6 g of thiourea was added, and the mixture was placed in an ultrasonic machine and ultrasonically vibrated for 10 min until dissolved to obtain solution A. The solution was then poured into a 100 mL polytetrafluoroethylene high-pressure reactor, and the temperature was set to 200 °C. The reaction was carried out for 18 h. The final product was centrifuged at 8000 rpm for 10 min, washed three times with anhydrous ethanol, washed three times with deionized water, and finally freeze-dried at 60 °C for 24 h to obtain MoS2.

[0107] Dissolve 3 g of MoS2 in 150 mL of water and disperse thoroughly on a magnetic stirrer to obtain dispersion B. Dissolve 30 mg of ascorbic acid (C6H8O6) in 20 mL of water and sonicate for 8 min until completely dissolved to obtain solution C. Slowly add solution C to solution B at a rate of 5 mL / min, maintaining an ice-water bath environment throughout the process. React at 300 r / min for 2 h, then centrifuge at 8000 rpm for 10 min and wash three times with deionized water to obtain the reduced MoS2 solution.

[0108] Step 2: Chloroauric acid is added dropwise to the reaction solution obtained in Step 1. After the adsorption reaction, the solution is washed. Then, ascorbic acid is added, and after the reduction reaction, the solution is washed, centrifuged, and dried to obtain the Au / MoS2 precursor.

[0109] Solution D was obtained by adding 150 mL of water to the reduced MoS2 solution and stirring thoroughly. Solution E was obtained by dissolving 1 g of HAuCl4 in 20 mL of water and sonicating for 10 min. Solution E was slowly added dropwise to solution D at a rate of 5 mL / min. The solution was reacted at 300 r / min for 8 h, and the reaction was carried out in an ice-water bath environment throughout. After the reaction was completed, the solution was centrifuged at 8000 rpm for 10 min and washed once with deionized water to obtain the loaded solution F.

[0110] The washed solution F was dissolved in 100 mL of water and stirred until thoroughly mixed. 5 mg of ascorbic acid C6H8O6 was dissolved in 20 mL of water and sonicated for 10 min until completely dissolved to obtain solution G. Solution G was slowly added dropwise to solution F at a rate of 10 mL / min, and the reaction was carried out in an ice-water bath environment at a stirring speed of 300 r / min for 3 h. After that, the mixture was centrifuged at 8000 rpm for 10 min, washed twice with deionized water, and finally freeze-dried for 24 h to obtain the Au / MoS2 precursor.

[0111] Step 3: Place the Au / MoS2 precursor obtained in Step 2 in a tube furnace, heat it to 400℃, and hold it for 2 h to obtain Au@MoS2 anchored to Au.

[0112] Step 4: Thoroughly mix the Au@MoS2 solution obtained in Step 3 with the glucose oxidase Gox solution, and then centrifuge and freeze-dry to obtain Au@MoS2@Gox, which is the desired composite nanomaterial.

[0113] The procedure is as follows: Dissolve 500 mg of Au@MoS2 in 100 mL of aqueous solution and mix thoroughly. Place the solution on a magnetic stirrer, add 1.5 g of Gox, and stir the solution at 300 r / min for 16 h. The entire process should be carried out in a dark, ice-water bath environment. After the reaction is complete, centrifuge at 8000 rpm for 10 min, wash three times with deionized water, and finally freeze-dry to obtain Au@MoS2@Gox.

[0114] Step 5: Mix the Au@MoS2@Gox solution obtained in Step 4 with chitosan CS in an acidic solvent and react thoroughly. After centrifugation and freeze-drying, the desired composite nanomaterial Au@MoS2@Gox@CS can be obtained.

[0115] The process is as follows:

[0116] 1.25 g of CS was dissolved in 100 mL of acetic acid aqueous solution and placed on a magnetic stirrer to fully dissolve and mix to obtain solution H, in which the acetic acid content was 36% wt%. 250 mg of Au@MoS2@Gox was added to solution H and stirred, and the mixture was kept in a dark, ice-water bath environment throughout the process. After reacting at 300 r / min for 16 h, the mixture was centrifuged at 8000 rpm for 10 min, washed three times with deionized water, and finally freeze-dried to obtain Au@MoS2@Gox@CS nanocomposite material.

[0117] Example 5

[0118] A method for preparing petal-shaped MoS2-based reinforced composite nanomaterials includes the following steps:

[0119] Step 1: Add ascorbic acid dropwise to the MoS2 dispersion and react completely to obtain reduced MoS2.

[0120] Place 4.06 g of Na2MoO4, 2.52 g of citric acid C6H8O7 and 0.9 g of PEG in a beaker. Pour 60 mL of a mixture of ethylene glycol and water into the beaker. The volume ratio of ethylene glycol to water is 1:2. Then place the mixture on a magnetic stirrer and stir at 500 r / min for 30 min until the mixture gradually changes from a white milky substance to a colorless and transparent solution.

[0121] After 30 min, 6 g of thiourea was added and placed in an ultrasonic machine for 10 min of ultrasonic vibration until dissolved to obtain solution A. The solution was then poured into a 100 mL polytetrafluoroethylene high-pressure reactor, and the temperature was set to 180℃. The reaction was carried out for 18 h. The final product was centrifuged at 8000 rpm for 10 min, washed three times with anhydrous ethanol, washed three times with deionized water, and finally freeze-dried at 60℃ for 24 h to obtain MoS2.

[0122] Dissolve 3 g of MoS2 in 150 mL of water and disperse thoroughly on a magnetic stirrer to obtain dispersion B. Dissolve 30 mg of ascorbic acid (C6H8O6) in 20 mL of water and sonicate for 8 min until completely dissolved to obtain solution C. Slowly add solution C to solution B at a rate of 5 mL / min, maintaining an ice-water bath environment throughout the process. React at 300 r / min for 2 h, then centrifuge at 8000 rpm for 10 min and wash three times with deionized water to obtain the reduced MoS2 solution.

[0123] Step 2: Chloroauric acid is added dropwise to the reaction solution obtained in Step 1. After the adsorption reaction, the solution is washed. Then, ascorbic acid is added, and after the reduction reaction, the solution is washed, centrifuged, and dried to obtain the Au / MoS2 precursor.

[0124] Solution D was obtained by adding 150 mL of water to the reduced MoS2 solution and stirring thoroughly. Solution E was obtained by dissolving 1 g of HAuCl4 in 20 mL of water and sonicating for 10 min. Solution E was slowly added dropwise to solution D at a rate of 5 mL / min. The solution was reacted at 300 r / min for 8 h, and the reaction was carried out in an ice-water bath environment throughout. After the reaction was completed, the solution was centrifuged at 8000 rpm for 10 min and washed once with deionized water to obtain the loaded solution F.

[0125] The washed solution F was dissolved in 100 mL of water and stirred until thoroughly mixed. 5 mg of ascorbic acid C6H8O6 was dissolved in 20 mL of water and sonicated for 10 min until completely dissolved to obtain solution G. Solution G was slowly added dropwise to solution F at a rate of 10 mL / min, and the reaction was carried out in an ice-water bath environment at a stirring speed of 300 r / min for 3 h. After that, the mixture was centrifuged at 8000 rpm for 10 min, washed twice with deionized water, and finally freeze-dried for 24 h to obtain the Au / MoS2 precursor.

[0126] Step 3: Place the Au / MoS2 precursor obtained in Step 2 in a tube furnace, heat it to 400℃, and hold it for 2 h to obtain Au@MoS2 anchored to Au.

[0127] Step 4: Thoroughly mix the Au@MoS2 solution obtained in Step 3 with the glucose oxidase Gox solution, and then centrifuge and freeze-dry to obtain Au@MoS2@Gox, which is the desired composite nanomaterial.

[0128] The procedure is as follows: Dissolve 500 mg of Au@MoS2 in 100 mL of aqueous solution and mix thoroughly. Place the solution on a magnetic stirrer, add 1.5 g of Gox, and stir the solution at 300 r / min for 16 h. The entire process should be carried out in a dark, ice-water bath environment. After the reaction is complete, centrifuge at 8000 rpm for 10 min, wash three times with deionized water, and finally freeze-dry to obtain Au@MoS2@Gox.

[0129] Step 5: Mix the Au@MoS2@Gox solution obtained in Step 4 with chitosan CS in an acidic solvent and react thoroughly. After centrifugation and freeze-drying, the desired composite nanomaterial Au@MoS2@Gox@CS can be obtained.

[0130] The process is as follows:

[0131] 1.25 g of CS was dissolved in 100 mL of acetic acid aqueous solution and placed on a magnetic stirrer to fully dissolve and mix to obtain solution H, in which the acetic acid content was 36% wt%. 250 mg of Au@MoS2@Gox was added to solution H and stirred, and the mixture was kept in a dark, ice-water bath environment throughout the process. After reacting at 300 r / min for 16 h, the mixture was centrifuged at 8000 rpm for 10 min, washed three times with deionized water, and finally freeze-dried to obtain Au@MoS2@Gox@CS nanocomposite material.

[0132] Example 6

[0133] A method for preparing petal-shaped MoS2-based reinforced composite nanomaterials includes the following steps:

[0134] Step 1: Add ascorbic acid dropwise to the MoS2 dispersion and react completely to obtain reduced MoS2.

[0135] Place 4.06 g of Na2MoO4, 2.52 g of citric acid C6H8O7 and 0.9 g of PEG in a beaker. Pour 60 mL of a mixture of ethylene glycol and water into the beaker. The volume ratio of ethylene glycol to water is 1:2. Then place the mixture on a magnetic stirrer and stir at 500 r / min for 30 min until the mixture gradually changes from a white milky substance to a colorless and transparent solution.

[0136] After 30 min, 6 g of thiourea was added and placed in an ultrasonic machine for 10 min of ultrasonic vibration until dissolved to obtain solution A. The solution was then poured into a 100 mL polytetrafluoroethylene high-pressure reactor, and the temperature was set to 200℃. The reaction was carried out for 24 h. The final product was centrifuged at 8000 rpm for 10 min, washed three times with anhydrous ethanol, washed three times with deionized water, and finally freeze-dried at 60℃ for 24 h to obtain MoS2.

[0137] Dissolve 3 g of MoS2 in 150 mL of water and disperse thoroughly on a magnetic stirrer to obtain dispersion B. Dissolve 20 mg of ascorbic acid (C6H8O6) in 20 mL of water and sonicate for 8 min until completely dissolved to obtain solution C. Slowly add solution C to solution B at a rate of 5 mL / min, maintaining an ice-water bath environment throughout the process. React at 300 r / min for 2 h, then centrifuge at 8000 rpm for 10 min and wash three times with deionized water to obtain the reduced MoS2 solution.

[0138] Step 2: Chloroauric acid is added dropwise to the reaction solution obtained in Step 1. After the adsorption reaction, the solution is washed. Then, ascorbic acid is added, and after the reduction reaction, the solution is washed, centrifuged, and dried to obtain the Au / MoS2 precursor.

[0139] Solution D was obtained by adding 150 mL of water to the reduced MoS2 solution and stirring thoroughly. Solution E was obtained by dissolving 1 g of HAuCl4 in 20 mL of water and sonicating for 10 min. Solution E was slowly added dropwise to solution D at a rate of 5 mL / min. The solution was reacted at 300 r / min for 8 h, and the reaction was carried out in an ice-water bath environment throughout. After the reaction was completed, the solution was centrifuged at 8000 rpm for 10 min and washed once with deionized water to obtain the loaded solution F.

[0140] The washed solution F was dissolved in 100 mL of water and stirred until thoroughly mixed. 5 mg of C6H8O6 was dissolved in 20 mL of water and sonicated for 10 min until completely dissolved to obtain solution G. Solution G was slowly added dropwise to solution F at a rate of 10 mL / min, and the reaction was carried out in an ice-water bath environment at a stirring speed of 300 r / min for 3 h. After that, the mixture was centrifuged at 8000 rpm for 10 min, washed twice with deionized water, and finally freeze-dried for 24 h to obtain the Au / MoS2 precursor.

[0141] Step 3: Place the Au / MoS2 precursor obtained in Step 2 in a tube furnace, heat it to 400℃, and hold it for 2 h to obtain Au@MoS2 anchored to Au.

[0142] Step 4: Thoroughly mix the Au@MoS2 solution obtained in Step 3 with the glucose oxidase Gox solution, and then centrifuge and freeze-dry to obtain Au@MoS2@Gox, which is the desired composite nanomaterial.

[0143] The procedure is as follows: Dissolve 500 mg of Au@MoS2 in 100 mL of aqueous solution and mix thoroughly. Place the solution on a magnetic stirrer, add 1.5 g of Gox, and stir the solution at 300 r / min for 16 h. The entire process should be carried out in a dark, ice-water bath environment. After the reaction is complete, centrifuge at 8000 rpm for 10 min, wash three times with deionized water, and finally freeze-dry to obtain Au@MoS2@Gox.

[0144] Figure 1 The image shows a SEM image of MoS2 used in Example 1. As can be seen from the image, the MoS2 sample exhibits a uniform three-dimensional flower-like microsphere structure with a diameter of approximately 300-500 nm, composed of a large number of interwoven nanosheets.

[0145] Figure 2 The images show the X-ray diffraction pattern (a) and SEM image (b) of MoS2 after reduction in step 1 of Example 1, where a represents the results of reduction at different times according to the method of Example 1 and the unreduced result. As can be seen from the images, reduction removes S atoms from the lattice, generating abundant anchoring sites without compromising the structural integrity of the three-dimensional nanoflower framework.

[0146] The reduced MoS2 is rich in defects. Using this defect-rich nanostructure as a support, HAuCl4 is loaded by initial wet impregnation and then subjected to thermal carbonization at 400°C under N2 atmosphere. This carbonization process can decompose the Au precursor and promote strong covalent interactions between Au atoms and unsaturated Mo atoms adjacent to S vacancies. This is due to the significant thermal stability of the robust nanoflower structure.

[0147] Figure 3The figure shows the EPR test results of MoS2 after reduction in step 1 of Example 1, where a represents the magnetic field strength and b represents the g factor. As can be seen from the figure, g=2.005 is a typical S-vacancy-related defect signal. When S atoms are selectively removed from the lattice through reduction, positively charged defects are generated at the original S atom sites. To maintain local charge neutrality, each S vacancy traps an unpaired electron. This unpaired electron undergoes energy level splitting in the external magnetic field, and when the applied microwave energy matches its energy level difference, it is resonantly absorbed, thus generating a characteristic EPR signal (a symmetrical Lorentz linear single peak in the range of g≈2.002~2.010). This result provides crucial defect structure evidence for the subsequent uniform and stable anchoring of Au single atoms on the support, because the S vacancy is the core site where strong interactions occur between the S vacancy and the metal precursor through its unpaired electron.

[0148] Figure 4 The image shows a SEM image of Au@MoS2 obtained in step 3 of Example 1. It can be seen from the image that the characteristic interconnected petal-like nanosheets of MoS2 did not change significantly after carbonization.

[0149] Figure 5 The high-angle annular dark-field scanning transmission electron microscopy imaging and energy-dispersive X-ray spectroscopy elemental surface scanning analysis (a) and atomic resolution spherical aberration corrected AC-HAADF-STEM (b) of Au@MoS2 obtained in step 3 of Example 1 are shown. Figure 5 As can be seen from Figure a, step 3 yielded the distribution of catalytic sites in Au@MoS2. The Au elemental signal exhibits a continuous and uniform spatial distribution, which is consistent with the morphology of the MoS2 nanoflower support. This result indicates that the Au / MoS2 precursor was effectively dispersed after reduction and uniformly anchored at defect sites during the subsequent high-temperature carbonization process, without any macroscopic phase separation or aggregation.

[0150] Figure 5 In the middle b image, isolated Au atoms can be directly observed. Numerous high-contrast bright spots are visible, uniformly dispersed across the MoS2 lattice. These atomic-scale bright spots are evenly distributed throughout the scanning area, and no nanoparticles or sub-nano clusters were detected.

[0151] Figure 6 The figures show the X-ray photoelectron spectroscopy (XPS) analysis results of MoS2 and reduced MoS2 used in step 1 of Example 1. The figures show that in the unreduced MoS2 nanoparticles, molybdenum is present in the form of Mo... 4+The Mo 3d5 / 2 and 3d3 / 2 doublets are located around 229.0 eV and 232.2 eV respectively, and the spectrum shape is symmetrical, indicating that Mo is in a complete S-Mo-S coordination environment. After reduction, the formation of S vacancies disrupts local electroneutrality. When the S atom is missing, the local electron density of the Mo atoms coordinated to it increases relatively due to the electron compensation effect, resulting in a decrease in the apparent oxidation state, i.e., some Mo atoms are oxidized. 4+ Reduced to lower Mo³ + Therefore, the change in local coordination environment and charge redistribution caused by the partial loss of S atoms leads to a significant change in the chemical state of Mo, providing direct electronic structure evidence for the reduction treatment-induced formation of S vacancies.

[0152] Figure 7 The X-ray photoelectron spectroscopy (XPS) spectra of Au@MoS2 obtained in step 3 of Example 1 are shown in the figures. a is the full XPS spectrum of Au@MoS2, b is the Mo elemental spectrum, and c is the Au elemental spectrum. As can be seen from the figures, compared to the reduced MoS2, the Mo 3d spectrum after Au loading shows a higher Mo content. 3+ / Mo 4+ The proportion of Mo changes. 3+ The relative area of ​​the components decreased. This indicates that the anchored Au atoms partially compensated for the electron density of the neighboring Mo atoms at the S vacancy through electron transfer, leading to a fine-tuning of the local charge distribution. The Au 4f spectrum of the Au-SAC sample exhibits a sharp and symmetrical double peak. Their binding energies are located at 84.1 eV and 87.8 eV, corresponding to the metallic state of Au. 0 The typical characteristics of Au are evident. Furthermore, a stable positive shift of approximately 0.3–0.4 eV was observed compared to the standard binding energy of bulk Au. This shift indicates a partial transfer of electrons from gold atoms to the MoS2 support, resulting in a slightly electron-deficient state for Au atoms. The symmetrical peak shape and the absence of any discernible shoulder peaks at low binding energies confirm the homogeneity of the chemical environment of the Au species, consistent with the atomically dispersed active site state observed by aberration-corrected AC-HAADF-STEM.

[0153] Figure 8 The image shows a TEM image of the composite nanomaterial obtained in Example 1. The image shows that after being coated with CS, Au@MoS2@Gox@CS is distributed in a dispersed state, and the increased surface roughness proves the effective loading of CS. The nanomaterial particle size in the image is approximately 400-500 nm, with no obvious nanoclusters formed, demonstrating that the stability and dispersibility of the material are significantly improved after CS loading.

[0154] Figure 9The X-ray diffraction analysis results of MoS2 used in Example 1 and Au@MoS2 obtained in step 3 are shown in the figure. As can be seen from the figure, the XRD pattern of the Au@MoS2 sample is mainly dominated by the characteristic diffraction peaks of the hexagonal 2H-MoS2 phase. The clear peaks located at 14.4°, 32.7°, 39.5°, and 58.3° can be indexed as (002), (100), (103), and (110) crystal planes, respectively. The sharp and enhanced (002) peak indicates a well-stacked layered structure along the c-axis, confirming that the three-dimensional nanoflower morphology is composed of highly crystalline molybdenum disulfide nanosheets. Furthermore, even under conditions of high signal-to-noise ratio, no diffraction peaks corresponding to metallic Au or any other crystalline gold compound were detected. The absence of these features strongly suggests that the Au species do not exist in the form of nanoparticles or large clusters. This result is consistent with the atomic-level dispersion of Au directly observed by AC-HAADF-STEM.

[0155] Furthermore, comparison with the XRD patterns of the original MoS2 nanoflowers revealed that the positions of the MoS2 diffraction peaks did not shift significantly after the introduction of S vacancies and anchoring of Au. This indicates that the overall long-range order and layered crystal structure of the MoS2 support were maintained throughout the synthesis process, which is consistent with the morphological stability observed by SEM.

[0156] Figure 10 The figures show the photothermal performance results of the MoS2 used in Example 1, the Au@MoS2 obtained in step 3, and the composite nanomaterials obtained in Examples 1 and 6. Figures a and b show the temperature rise curves for different materials, c and d show the temperature rise curves for different concentrations of the same material, e shows the temperature rise curves for different powers, and f shows the temperature rise curves for five cycles. As can be seen from the figures, MoS2 is a semiconductor. Under NIR irradiation, interband transitions and nonradiative relaxation of photogenerated carriers lead to a temperature rise. Furthermore, the localized surface plasmon resonance effect of Au atoms further increases the temperature. After surface coating with CS, the temperature can reach 53.7 °C. Because CS coating improves the dispersion stability of the environment, it releases the photothermal properties of the material. With the increase of the concentration of the nanocomposite material, the temperature also increases, reaching 56.8 °C. Figure 10 As can be seen from Figure e, the temperature increases with the increase of photothermal power, and the temperature range changes very little in the five photothermal cycles, further proving the photothermal stability of its nanocomposite material.

[0157] Figure 11The figures show the catalytic performance results of the MoS2 used in Example 1, the Au@MoS2 obtained in step 3, and the composite nanomaterials obtained in Examples 1 and 6. Figure a shows the reaction results for different materials, figure b shows the reaction results for different concentrations, and figure c shows the reaction results for different times. As can be seen from the figures, the original MoS2 nanoflowers exhibit weak activity, consistent with their limited intrinsic peroxidase-mimicking properties. The significant increase in activity after introducing gold single atoms is attributed to their efficient catalytic production of H2O2 decomposition. The exceptional capabilities of OH. The atomic-level dispersion of Au maximizes atomic utilization, and its unique electronic structure also facilitates redox cycles. The further significant enhancement of the Au@MoS2@Gox system is attributed to the establishment of a highly efficient enzyme-metal hybrid cascade reaction. Gox first oxidizes glucose to gluconic acid and generates H2O2 in situ. The in-situ generated H2O2 is immediately utilized by the underlying Au-SAC as a peroxidase nanozyme, producing… OH oxidation of TMB. The addition of CS provides a biocompatible matrix, which helps maintain the conformation and activity of glucose oxidase. Its amino groups create a slightly acidic local microenvironment near the catalyst surface, which is optimal for both glucose oxidase activity and the peroxidase-like reaction of Au single atom / MoS2. For each catalytic system, light irradiation resulted in a consistent and significant increase in the TMB oxidation rate. This generalized photoresponse is mainly attributed to the photothermal effect of the Au single atom / MoS2 complex. The atomically dispersed Au species enable it to efficiently absorb light energy and convert it into local heat. The thermal energy increases the local temperature, accelerating enzyme turnover, diffusion rate, and catalytic cycling on Au@MoS2.

[0158] The therapeutic effects of this nanozyme on mouse breast cancer 4T1 cells and normal endothelial cells (ECs) were evaluated using the MTT assay. The results are as follows: Figure 12 As shown, a represents the results for 4T1 cells, and b represents the results for EC cells. Under 24-hour darkness, the survival rate of 4T1 cells co-incubated with MoS2, Au@MoS2, Au@MoS2@Gox, and Au@MoS2@Gox@CS gradually decreased from 85% to 59%, 43%, and finally reached 25%. This result corresponds to the in vitro TMB oxidation activity, confirming the cytotoxicity and catalytic production... The OH-induced significant cell death was directly proportional to the cell death. The Au single-atom / MoS2 group validated its effectiveness as a peroxidase-like nanozyme for CDT. The group effects were further enhanced with the introduction of Gox, highlighting the key role of the glucose-driven cascade in amplifying intracellular oxidative stress. Under light irradiation, all treatment groups showed significant and generalized enhancements in cytotoxicity: cell viability decreased to 55%, 30%, 15%, and 6%, respectively. Compared to dark conditions, this photoresponse equates to a 1.5 to 4-fold increase in cell-killing efficacy. This enhancement is attributed to the photothermal effect of the Au single-atom / MoS2 complex, which accelerates the catalytic kinetics of the nanozyme and immobilized Gox, leading to… An OH burst causes cell death.

[0159] In contrast to the results in 4T1 cells, the Au@MoS2@Gox@CS group exhibited extremely low toxicity after 24 hours of co-incubation with EC cells, maintaining cell viability at 80% and 75% under dark and light conditions, respectively. The approximately 70% difference in survival between normal and cancer cells under light in the same treatment group provides strong evidence for its high tumor selectivity. This selectivity mechanism is rooted in the glucose-dependent effects of the system. Compared to the highly glycolytic 4T1 cancer cells, normal endothelial cells have significantly lower glycolytic flux and intracellular glucose concentration. Therefore, the Gox-mediated in situ H2O2 generation cascade does not fully react in endothelial cells, producing only trace levels of toxicity even under light. OH.

[0160] Figure 13 The performance results of the composite nanomaterials obtained in Examples 1 and 6 are as follows: MoS2 used in Example 1, Au@MoS2 obtained in step 3, and the composite nanomaterials obtained in Examples 1 and 6. a represents the ROS detection result, and b represents the generated... The ability of OH to oxidize. As shown in the figure, the Au@MoS2@Gox@CS+ light-illuminated group (NIR) exhibited the strongest fluorescence intensity, with each group showing a significant increase under light irradiation. This quantifies the progressively increasing intracellular oxidative stress, consistent with in vitro TMB oxidation and MTT results. The Au@MoS2@Gox@CS+ light-illuminated group (NIR) induced the strongest ROS burst, confirming the system's remarkable ability to disrupt cellular redox homeostasis. The figure also shows that the fluorescence intensity of the Au@MoS2@Gox@CS+ and Au@MoS2@Gox+ light-illuminated groups was significantly increased compared to the Au@MoS2+ light-illuminated group, indicating a synergistic effect between Au@MoS2 and Gox.

[0161] Figure 14The results of lipid peroxidation assays after co-incubating 4T1 cells with MoS2 (used in Example 1), Au@MoS2 obtained in step 3, and the composite nanomaterials obtained in Examples 1 and 6 for 6 h are shown in the figure. As can be seen from the figure, the fluorescence intensity gradually increases and the signal weakens in the order of MoS2, Au@MoS2 obtained in step 3, the composite nanomaterials obtained in Example 6, and the composite nanomaterials obtained in Example 1. Illumination amplifies this change. Quantitative fluorescence intensity ratios show a significant increase in lipid peroxidation levels, especially in the Au@MoS2@Gox@CS+ illumination group (NIR). This result indicates that the lipid peroxidation produced by the cascade catalytic system... OH effectively attacks polyunsaturated fatty acids in the plasma membrane and organelle membranes, leading to ferroptosis-like damage in cells, which is an important contributing factor to the overall cytotoxic outcome.

[0162] Figure 15 The results of live and dead cell staining after co-incubating 4T1 cells with MoS2 (used in Example 1), Au@MoS2 obtained in step 3, and the composite nanomaterials obtained in Examples 1 and 6 for 12 h are presented. As can be seen from the figures, Calcein-AM / PI staining provides direct macroscopic data. Following the order of MoS2, Au@MoS2 obtained in step 3, and the composite nanomaterials obtained in Examples 6 and 1, red fluorescence gradually increases while green fluorescence gradually decreases, confirming the MTT quantification results. In the Au@MoS2@Gox@CS+ light-illuminated group (NIR), red fluorescence dominates, indicating overwhelming and widespread cell death.

[0163] Figure 16 The results of JC-1 staining assays after co-incubating the composite nanomaterials (MoS2 used in Example 1, Au@MoS2 obtained in step 3, and those obtained in Examples 1 and 6) with 4T1 cells for 6 h are shown in the figure. As can be seen from the figure, the fluorescence gradually changes from red (JC-1 polymer, high mitochondrial membrane potential ΔΨm) to green (JC-1 monomer, low mitochondrial membrane potential ΔΨm). The most significant change occurred in the Au@MoS2@Gox@CS group under light irradiation, indicating severe mitochondrial dysfunction. The collapse of ΔΨm is a key condition in the mitochondrial apoptosis pathway, confirming that oxidative damage triggers programmed cell death.

[0164] This invention employs a nucleation-layer stacking method to obtain molybdenum disulfide nanoflower materials. Low-temperature reduction generates S vacancies on the surface, which are then combined with Au ions via the attraction between positive and negative charges. A low-temperature reduction followed by high-temperature stabilization yields an Au@MoS2 catalyst. Photothermal conversion enhances the generation of reactive oxygen species (ROS), amplifying oxidative stress and inducing ferroptosis. Gox loading promotes the production of exogenous H2O2, and CS encapsulation improves the biocompatibility and stability of the material. These three elements work synergistically. The resulting nanocomposite material exhibits synergistic effects among its components, selectively triggering a powerful, photo-amplified intracellular catalytic chain reaction by exploiting abnormal tumor metabolism. This reaction ultimately leads to catastrophic oxidative damage, mitochondrial exhaustion, and ultimately, selective clearance of cancer cells.

Claims

1. A method for preparing an enhanced composite nanomaterial based on petal-shaped MoS2, characterized in that, Includes the following steps: Step 1: Add ascorbic acid dropwise to the MoS2 dispersion and react completely to obtain reduced MoS2; Step 2: Chloroauric acid is added dropwise to the reaction solution obtained in Step 1. After the adsorption reaction, the solution is washed. Then, ascorbic acid is added, and after the reduction reaction, the solution is washed, centrifuged, and dried to obtain the Au / MoS2 precursor. Step 3: Calcining the Au / MoS2 precursor obtained in Step 2 will yield Au@MoS2; Step 4: Thoroughly mix the Au@MoS2 solution obtained in Step 3 with the glucose oxidase Gox solution, and then centrifuge and freeze-dry to obtain Au@MoS2@Gox, which is the desired composite nanomaterial; wherein the mass ratio of Au@MoS2 to Gox is 1:

3.

2. The method for preparing a petal-shaped MoS2-based reinforced composite nanomaterial according to claim 1, characterized in that, It also includes the following steps: The Au@MoS2@Gox solution obtained in step 4 is thoroughly mixed with chitosan CS in an acidic solvent, and the desired composite nanomaterial Au@MoS2@Gox@CS is obtained by centrifugation and freeze-drying; wherein the mass ratio of Au@MoS2@Gox to chitosan is 1:

5.

3. The method for preparing a petal-shaped MoS2-based reinforced composite nanomaterial according to claim 1, characterized in that, The method for preparing MoS2 in step 1 is as follows: Anhydrous sodium molybdate is added to a solvent containing citric acid and mixed thoroughly. Then, thiourea is added and reacted thoroughly at 200 °C. After washing, centrifugation, and freeze-drying, MoS2 can be obtained. The molar ratio of molybdenum ions to sulfur ions is 1:4 to 5.

4. The method for preparing a petal-shaped MoS2-based reinforced composite nanomaterial according to claim 1, characterized in that, Step 1 is carried out under ice-water bath conditions, wherein the mass ratio of MoS2 to ascorbic acid is 100:1, and the reaction time is 2 h.

5. The method for preparing a petal-shaped MoS2-based reinforced composite nanomaterial according to claim 1, characterized in that, In step 2, the reaction is carried out in an ice-water bath under light-protected conditions, wherein the mass ratio of reduced MoS2 to chloroauric acid is 3:1 and the adsorption reaction time is 8 h; the mass ratio of reduced MoS2 to ascorbic acid is 400:1 and the reduction reaction time is 2 h.

6. The method for preparing a petal-shaped MoS2-based reinforced composite nanomaterial according to claim 1, characterized in that, In step 3, the calcination temperature is 400 ℃ and the calcination time is 2 h.

7. The method for preparing a petal-shaped MoS2-based reinforced composite nanomaterial according to claim 1, characterized in that, Step 4 is carried out under stirring and light-protected conditions, and the reaction time is 12-16 h.

8. The method for preparing a petal-shaped MoS2-based reinforced composite nanomaterial according to claim 2, characterized in that, The acidic solvent is an acetic acid solution with a mass concentration of 36 wt.%, and the reaction is carried out under stirring conditions for 16 h.

9. The petal-shaped MoS2-based reinforced composite nanomaterial obtained by any one of the preparation methods of claims 1 to 8, characterized in that, The composite nanomaterial uses petal-shaped MoS2 as a matrix, with gold atoms and glucose oxidase adsorbed on the surface, and chitosan is coated on the surface of the petal-shaped MoS2.

10. The application of the petal-shaped MoS2-based reinforced composite nanomaterial as described in claim 9, characterized in that, The application of the composite nanomaterials in the preparation of tumor chemotherapy drugs.

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