A zinc sulfide-graphene oxide composite material with near-infrared photocatalytic effect, preparation method and application thereof, and antibacterial agent

Abstract

The present invention relates to the technical field of antimicrobial materials and provides a zinc sulfide-graphene oxide composite material with a near-infrared photocatalytic effect, a preparation method thereof, applications thereof, and an antimicrobial agent. The present invention comprises mixing a thiourea solution, a dispersion of graphene oxide nanosheets, and a soluble zinc salt solution to react, thereby obtaining the zinc sulfide-graphene oxide composite material with a near-infrared photocatalytic effect. The zinc sulfide-graphene oxide composite material prepared by the present invention exhibits a good near-infrared photocatalytic effect, enabling efficient photothermal and photodynamic conversion, and exhibits good antimicrobial activity against both Gram-positive and Gram-negative bacteria. It can be used as an effective, non-invasive strategy to combat pathogens, particularly against drug-resistant pathogens, and has promising application prospects.

Description

Technical Field

[0001] The present invention relates to the technical field of antibacterial materials, and in particular to a zinc sulfide-graphene oxide composite material with near-infrared photocatalytic effect, a preparation method and application thereof, and an antibacterial agent. Background Art

[0002] Bacterial infections are infectious inflammations of tissues caused by bacteria. Prolonged inflammation can lead to the dissolution and necrosis of normal tissue areas. The oral cavity is a contaminated environment and is commonly home to a variety of bacterial infections, such as periodontal abscesses, alveolar abscesses, dry sockets, pericoronitis, and gingivitis. For common oral infections, the current mainstream medical approach remains to administer topical antimicrobial measures or medications. In recent years, photothermal / photodynamic therapy (PTT / PDT) has garnered increasing attention as an effective, non-invasive strategy for combating pathogens. PTT / PDT leverages the excellent absorption and conversion efficiency of photosensitive materials to convert light energy into heat. Simultaneously, the photoresponsive materials, under photocatalysis, produce active factors, including hydroxyl radicals, which disrupt the bacterial antioxidant system, leading to DNA bond breakage, protein denaturation, and increased cell membrane permeability. This in turn triggers the release of a large amount of bacterial proteins, causing bacterial rupture and death, resulting in a highly effective antibacterial effect. Therefore, the research and development of PTT / PDT synergistically responsive photosensitive materials has become a research hotspot and difficulty in the antibacterial field, and is of great significance to the clinical promotion and application of PTT / PDT synergistically responsive therapy in infectious diseases.

[0003] Currently, PTT / PDT synergistically responsive photosensitive materials are typically synthesized by combining indocyanine green (ICG), which exhibits photodynamic antibacterial properties, with noble metal nanoparticles (NPs), which exhibit photothermal antibacterial properties. However, the complex preparation of ICG and the high cost of the NPs limit their application in PTT / PDT synergistically responsive therapies. There is an urgent need for a photosensitive material with a simple preparation method, low cost, and excellent photodynamic / photothermal conversion effects. Summary of the Invention

[0004] In view of this, the present invention provides a zinc sulfide-graphene oxide composite material with near-infrared photocatalytic effect, its preparation method, application, and antibacterial agent. The zinc sulfide-graphene oxide composite material with near-infrared photocatalytic effect provided by the present invention has a simple preparation method and low cost, and exhibits good photodynamic and photothermal conversion effects under near-infrared light irradiation, with significant antibacterial effects.

[0005] In order to achieve the above-mentioned object of the invention, the present invention provides the following technical solutions:

[0006] A method for preparing a zinc sulfide-graphene oxide composite material having a near-infrared photocatalytic effect comprises the following steps:

[0007] The thiourea solution, the graphene oxide nanosheet dispersion and the soluble zinc salt solution are mixed and reacted to obtain the zinc sulfide-graphene oxide composite material with near-infrared photocatalytic effect.

[0008] Preferably, the concentration of thiourea in the thiourea solution is 10 to 20 mg / mL; and the pH value of the thiourea solution is 7.35 to 7.45.

[0009] Preferably, the preparation method of the thiourea solution comprises: dissolving thiourea in water, and then adjusting the pH value to 7.35-7.45 with aqueous ammonia to obtain the thiourea solution.

[0010] Preferably, the concentration of the graphene oxide nanosheet dispersion is 1.8-7.2 mg / mL; the mass ratio of the graphene oxide nanosheets in the graphene oxide nanosheet dispersion to the thiourea in the thiourea solution is 9-36:100-300.

[0011] Preferably, the concentration of the soluble zinc salt solution is 0.3-0.4 mol / L; the soluble zinc salt includes one or more of zinc sulfate, zinc nitrate and zinc chloride.

[0012] Preferably, the molar ratio of thiourea in the thiourea solution to zinc ions in the soluble zinc salt solution is 1:1 to 1.6.

[0013] Preferably, the reaction time is 20 to 30 minutes.

[0014] The present invention also provides a zinc sulfide-graphene oxide composite material with near-infrared photocatalytic effect prepared by the preparation method described in the above scheme, comprising graphene oxide and zinc sulfide modified on the surface of the graphene oxide.

[0015] The present invention also provides the use of the zinc sulfide-graphene oxide composite material with near-infrared photocatalytic effect described in the above scheme in the preparation of an antibacterial agent.

[0016] The present invention also provides an antibacterial agent, comprising a photosensitive material and a drug-carrying matrix; the photosensitive material is the zinc sulfide-graphene oxide composite material with near-infrared photocatalytic effect described in the above scheme.

[0017] The present invention provides a method for preparing a zinc sulfide-graphene oxide composite material with near-infrared photocatalytic effect, comprising the following steps: mixing a thiourea solution, a graphene oxide nanosheet dispersion and a soluble zinc salt solution and reacting them to obtain the zinc sulfide-graphene oxide composite material with near-infrared photocatalytic effect. The present invention adopts thiourea as a sulfur source and a soluble zinc salt to provide zinc ions, and in-situ generates zinc sulfide on the surface of graphene oxide, thereby achieving uniform modification of the graphene oxide surface with zinc sulfide. The zinc sulfide-graphene oxide composite material prepared by the present invention has a good near-infrared photocatalytic effect and can achieve effective photothermal and photodynamic conversion. Under near-infrared light conditions, based on the photocatalytic effect, hydroxyl radicals can be generated, causing an imbalance in the antioxidant system in bacteria, increasing cell membrane permeability, and further triggering a large amount of protein leakage in the bacteria, causing the bacteria to rupture and die, and having a good antibacterial effect on both Staphylococcus aureus (Gram-positive bacteria) and Escherichia coli (Gram-negative bacteria). At the same time, because graphene oxide has excellent optical absorption performance and thermal conductivity, when light energy is irradiated to the surface of graphene oxide, photons are absorbed and converted into heat energy, causing the graphene oxide to generate heat, and the heat is radiated to the surrounding system, causing the system to heat up. In summary, the zinc sulfide-graphene oxide composite material prepared by the present invention has good photodynamic / photothermal antibacterial effect and can be used as an effective and non-invasive strategy to combat pathogens, especially in the fight against drug-resistant pathogens.

[0018] In addition, the preparation method provided by the present invention has a wide range of raw material sources, low cost, and simple operation, which is conducive to large-scale preparation. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 The results of the methylene blue degradation experiment in Example 4 are shown, with the left side showing the degree of fading of methylene blue and the right side showing the concentration of methylene blue;

[0020] Figure 2 The results of the methylene blue degradation experiment under different ZnS / GO concentrations in Example 4 are shown, where the left side shows the fading degree of methylene blue and the right side shows the methylene blue concentration;

[0021] Figure 3 The antibacterial performance test results under non-near infrared light in Example 5;

[0022] Figure 4 The antibacterial performance test results under near-infrared light conditions in Example 5;

[0023] Figure 5 The results of bacterial protein leakage detection in Example 6 are shown on the left, where the protein concentration is measured by Coomassie Brilliant Blue method, and the results of protein concentration quantitative analysis are shown on the right;

[0024] Figure 6 The test results of the material heating curve in Example 7 are as follows;

[0025] Figure 7 The thermal stability test results of the material in Example 7 are shown. DETAILED DESCRIPTION

[0026] The present invention provides a method for preparing a zinc sulfide-graphene oxide composite material having a near-infrared photocatalytic effect, comprising the following steps:

[0027] The thiourea solution, the graphene oxide nanosheet dispersion and the soluble zinc salt solution are mixed and reacted to obtain the zinc sulfide-graphene oxide composite material with near-infrared photocatalytic effect.

[0028] In the present invention, the concentration of thiourea in the thiourea solution is preferably 10 to 20 mg / mL, more preferably 13 to 15 mg / mL; the pH of the thiourea solution is preferably 7.35 to 7.45, more preferably 7.4. The preparation method of the thiourea solution comprises dissolving thiourea in water and then adjusting the pH to 7.35 to 7.45 with aqueous ammonia to obtain the thiourea solution; the concentration of the aqueous ammonia is preferably 7 wt%. Controlling the pH of the thiourea solution within the above range promotes the reaction between thiourea and zinc ions, thereby obtaining zinc sulfide of uniform particle size.

[0029] In the present invention, the concentration of the graphene oxide nanosheet dispersion is preferably 1.8 to 7.2 mg / mL; the method for preparing the graphene oxide nanosheet dispersion preferably comprises: adding the graphene oxide nanosheets to deionized water, and then sonicating until the graphene oxide nanosheets are uniformly dispersed.

[0030] In the present invention, the mass ratio of the graphene oxide nanosheets in the graphene oxide nanosheet dispersion to the thiourea in the thiourea solution is preferably 9-36:100-300, specifically 9:150, 18:150 or 36:150.

[0031] In the present invention, the concentration of the soluble zinc salt solution is preferably 0.3 to 0.4 mol / L, more preferably 0.3 to 0.35 mol / L; the soluble zinc salt preferably includes one or more of zinc sulfate, zinc nitrate and zinc chloride, more preferably zinc sulfate; the molar ratio of thiourea in the thiourea solution to zinc ions in the soluble zinc salt solution is preferably 1:1 to 1.6.

[0032] In a specific embodiment of the present invention, the graphene oxide nanosheet dispersion is preferably first added to the thiourea solution and stirred for 15 to 20 minutes to obtain a mixed solution, and then the soluble zinc salt solution is dropwise added to the mixed solution to react.

[0033] In the present invention, the reaction temperature is preferably room temperature, the reaction time is preferably 20 to 30 minutes, and the reaction time is counted from the completion of the dropwise addition of the soluble zinc salt; the reaction is preferably carried out under stirring.

[0034] After the reaction is completed, the present invention preferably centrifuges the obtained reaction solution to collect the solid product, and then washes and dries the solid product to obtain the zinc sulfide-graphene oxide composite material with near-infrared photocatalytic effect; the centrifugal speed is preferably 12000 rpm, and the centrifugal time is preferably 10 min; the washing is preferably performed alternately with deionized water and ethanol until the supernatant is colorless; the drying is preferably vacuum drying, and the vacuum drying temperature is preferably 60°C.

[0035] The present invention also provides a zinc sulfide-graphene oxide composite material with near-infrared photocatalytic effect prepared by the preparation method described in the above scheme, comprising graphene oxide and zinc sulfide modified on the surface of the graphene oxide.

[0036] The present invention also provides the use of the zinc sulfide-graphene oxide composite material with near-infrared photocatalytic effect described in the above scheme in the preparation of an antibacterial agent; the antibacterial agent is specifically an antibacterial agent with photothermal and photodynamic synergistic response, and the zinc sulfide-graphene oxide composite material is specifically used as a photosensitive material in the antibacterial agent; the zinc sulfide-graphene oxide composite material provided by the present invention can perform effective photothermal and photodynamic conversion under near-infrared light irradiation, showing significant antibacterial therapeutic effect, and showing antibacterial activity against both Gram-positive and Gram-negative bacteria.

[0037] The present invention also provides an antibacterial agent, which preferably includes a photosensitive material and a drug-carrying matrix, wherein the photosensitive material is the zinc sulfide-graphene oxide composite material with near-infrared photocatalytic effect described in the above scheme; the present invention has no special requirements for the drug-carrying matrix, and any material familiar to those skilled in the art can be used, such as a gel; in a specific embodiment of the present invention, the antibacterial agent can be applied locally and then antibacterial treatment can be performed under near-infrared light.

[0038] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions of the present invention. Obviously, the embodiments described are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0039] Example 1

[0040] Thiourea was dissolved in deionized water, and then 11 drops of 7 wt % ammonia water were added to obtain a thiourea solution with a pH of 7.4 and a concentration of 15 mg / mL; 9 mg of graphene oxide nanosheets were added to 5 mL of deionized water and ultrasonically dispersed to obtain a graphene oxide nanosheet dispersion; the obtained graphene oxide nanosheet dispersion was added to 10 mL of thiourea solution and magnetically stirred for 15 minutes to obtain a mixed solution.

[0041] A zinc sulfate solution with a concentration of 0.3 mol / L was prepared, and 10 mL of the zinc sulfate solution was slowly added dropwise to the above mixed solution using a pipette. The mixture was magnetically stirred at room temperature for 30 minutes, and then the resulting reaction solution was centrifuged (12000 rpm, 10 minutes) to collect the solid product. The solid product was alternately washed with deionized water and ethanol until the supernatant was colorless, and then vacuum dried at 60°C to obtain a zinc sulfide-graphene oxide composite material (denoted as ZnS / GO) with near-infrared photocatalytic effect.

[0042] Example 2

[0043] Other conditions were the same as those in Example 1, except that the amount of graphene oxide nanosheets was changed to 18 mg, to obtain a zinc sulfide-graphene oxide composite material with near-infrared photocatalytic effect.

[0044] Example 3

[0045] Other conditions were the same as those in Example 1, except that the amount of graphene oxide nanosheets was changed to 36 mg, to obtain a zinc sulfide-graphene oxide composite material with near-infrared photocatalytic effect.

[0046] The ZnS / GO prepared in Example 1 was used to carry out the experiments in Examples 4 to 6.

[0047] Example 4 Hydroxyl Radical Detection

[0048] (1) The principle of methylene blue changing color after being oxidized by hydroxyl radicals was used to detect the generation of active hydroxyl radicals in ZnS / GO under near-infrared light conditions. First, ZnS, GO and ZnS / GO solutions with a concentration of 200 μg / mL were prepared respectively. The solvents were all sterile deionized water. No material was added to the Con group. 1 mL of solution was taken from each group and added to a 1.5 mL centrifuge tube. The samples were illuminated by near-infrared light (NIR) at 1.5 W / cm 2 Irradiate for 5 minutes at a constant intensity. Prepare a 96-well plate and add 200 μL of 0.01% methylene blue solution to each well. Take 10 μL of the irradiated supernatant from each well and add it to the methylene blue solution. After a 5-minute reaction, measure the degree of fading of the methylene blue at a wavelength of 660 nm and calculate the concentration of methylene blue. Perform three parallel experiments for each group, and take the average methylene blue concentration.

[0049] The test results are as follows Figure 1 As shown, Figure 1 The left side shows the degree of fading of methylene blue, and the right side shows the concentration of methylene blue. Figure 1 From the test results, it can be seen that after 5 minutes of NIR irradiation, the methylene blue content of the ZnS / GO group was significantly reduced, while the degradation amounts of methylene blue in the ZnS group and the GO group were relatively small, indicating that ZnS / GO has a photocatalytic degradation effect and can produce hydroxyl radicals under NIR irradiation.

[0050] (2) The concentrations of ZnS / GO were controlled at 100 μg / mL, 200 μg / mL, and 400 μg / mL, respectively. The degradation test of methylene blue was carried out in the same manner as in (1). The results are shown in Figure 2. Figure 2 As shown, Figure 2 The left side shows the degree of fading of methylene blue, and the right side shows the concentration of methylene blue. Figure 2 It can be seen that the degradation amount of methylene blue is concentration-dependent. The higher the concentration of ZnS / GO, the greater the degradation amount of methylene blue.

[0051] Example 5 Antibacterial Performance Detection

[0052] Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus) were cultured overnight to the plateau phase, and the bacterial concentration was measured at 600 nm using a microplate reader. The bacterial solution was diluted with PBS to an appropriate concentration, and the material suspension (ZnS suspension, GO suspension, or ZnS / GO suspension) was added. The bacterial concentration in the resulting mixture was 1×10 6 CFU / mL, the material concentration was 100-400 μg / mL (the material concentration of the ZnS group was 200 μg / mL, the material concentration of the GO group was 200 μg / mL, the concentrations of the ZnS / GO group were 100 μg / mL, 200 μg / mL, and 400 μg / mL, respectively; no material was added to the Con group); the mixed solution (200 μL) was transferred to a 1.5 mL EP tube and irradiated with NIR for 5 min at a wavelength of 808 nm and an intensity of 1.5 W / cm 2 The liquid temperature was monitored in real time and maintained at ≤55°C. The irradiated bacterial mixture was plated and incubated overnight at 37°C to observe colony formation. An experiment was also conducted without NIR irradiation for comparison.

[0053] The test results are as follows Figure 3 and Figure 4 As shown, Figure 3 This is the antibacterial performance test result under non-near infrared light. Figure 4 The antibacterial performance test results under near-infrared light conditions. Figure 3 and Figure 4It can be seen that under non-near-infrared light conditions, ZnS, GO and ZnS / GO have no antibacterial properties, while under near-infrared light conditions, ZnS and GO still have no significant antibacterial properties, while the colony of the ZnS / GO group is significantly reduced, indicating that ZnS / GO has good antibacterial properties against Escherichia coli and Staphylococcus aureus under near-infrared stimulation.

[0054] Example 6 Detection of bacterial protein leakage

[0055] Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus) were cultured overnight to the plateau phase, and the bacterial concentration was measured at 600 nm using a microplate reader. The bacterial solution was diluted with PBS to an appropriate concentration, and the material suspension (ZnS suspension, GO suspension or ZnS / GO suspension) was added. The bacterial concentration in the resulting mixture was 1×10 6 CFU / mL, the material concentration was 200 μg / mL (no material in the Con group); the mixed solution (200 μL) was transferred to a 1.5 mL EP tube and irradiated with NIR for 5 min at a wavelength of 808 nm and an intensity of 1.5 W / cm 2 , and detect the liquid temperature in real time to control the liquid temperature to ≤55°C; the irradiated bacteria and material mixture was centrifuged at a centrifugal force of 10,000g for 5 minutes, 10 μL of the supernatant after centrifugation was added to 200 μL of Coomassie Brilliant Blue solution, and the protein concentration leaked by the bacteria was determined according to the Bradford test method. Three parallel experiments were set up for each group, and the protein concentration was averaged.

[0056] The test results are as follows Figure 5 As shown, Figure 5 The left side shows the protein concentration measured by Coomassie Brilliant Blue method, and the right side shows the protein concentration quantitative analysis results. Figure 5 It can be seen that after NIR stimulation, the bacteria in the ZnS / GO group ruptured and died, and the amount of protein leakage increased significantly, while neither the ZnS group nor the GO group had obvious antibacterial effect.

[0057] Example 7 Photothermal performance test

[0058] (1) Heating curve test: The vacuum-dried ZnS, GO, and ZnS / GO powders were prepared into a solution with a concentration of 200 μg / mL. The solvent was deionized water. No material was added to the Con group. 200 μL of the above solution was added to a 1.5 mL EP tube, and then vortexed and near-infrared light was used for excitation (808 nm, 1.5 W / cm 2 ), the temperature detector detects temperature changes in real time and records the sample temperature once a minute for a total of 10 minutes.

[0059] The test results are as follows Figure 6As shown in the figure, according to the temperature rise curve, there was no obvious temperature rise in the Con control group and the ZnS group, the temperature rise in the GO group was about 26°C, and the temperature rise in the ZnS / GO group was about 29°C, which proved that ZnS / GO had the same good photothermal conversion performance as GO.

[0060] (2) Thermal stability test: The vacuum-dried ZnS, GO, and ZnS / GO powders were prepared into solutions with a concentration of 200 μg / mL. The solvent was deionized water. No material was added to the Con group. 200 μL of the above solutions were added to 1.5 mL EP tubes, and then vortexed and near-infrared light was used for excitation (808 nm, 1.5 W / cm 2 ), the temperature detector detects the temperature change in real time for a total of 10 minutes, and the temperature of the sample is recorded every minute; then the light source is turned off for a total of 10 minutes, and the temperature of the sample is recorded every minute. 20 minutes is a cycle, and 5 cycles are performed.

[0061] The test results are as follows Figure 7 As shown in the figure, the photothermal cycle test results show that ZnS / GO has a significant temperature increase within 5 photothermal cycles. After removing the near-infrared light source, the temperature drops rapidly. The morphology of the 5 cycle curves is consistent, while the heating performance of GO gradually decreases in 4 to 5 cycles, indicating that the ZnS / GO material has better photothermal stability.

[0062] The ZnS / GO prepared in Examples 2 to 3 were tested according to the methods in Examples 4 to 7. The results were similar to those of the ZnS / GO prepared in Example 1, indicating that the ZnS / GO prepared in Examples 2 to 3 had photothermal / photodynamic conversion effects and had good antibacterial properties under NIR irradiation.

[0063] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present invention. These improvements and modifications should also be regarded as within the scope of protection of the present invention.

Claims

1. Application of zinc sulfide-graphene oxide composite material with near-infrared photocatalytic effect in the preparation of antibacterial agent, characterized in that: The antibacterial agent is an antibacterial agent with photothermal and photodynamic synergistic response, and the zinc sulfide-graphene oxide composite material is used as a photosensitive material in the antibacterial agent; the zinc sulfide-graphene oxide composite material performs photothermal and photodynamic conversion under near-infrared light irradiation; The preparation method of the zinc sulfide-graphene oxide composite material with near-infrared photocatalytic effect comprises the following steps: The thiourea solution, the graphene oxide nanosheet dispersion and the soluble zinc salt solution are mixed and reacted to obtain the zinc sulfide-graphene oxide composite material with near-infrared photocatalytic effect.

2. The use according to claim 1, characterized in that The concentration of thiourea in the thiourea solution is 10-20 mg / mL; and the pH value of the thiourea solution is 7.35-7.

45.

3. The use according to claim 2, characterized in that The preparation method of the thiourea solution comprises: dissolving thiourea in water, and then adjusting the pH value to 7.35-7.45 with ammonia water to obtain the thiourea solution.

4. The use according to claim 1, characterized in that The concentration of the graphene oxide nanosheet dispersion is 1.8-7.2 mg / mL; the mass ratio of the graphene oxide nanosheets in the graphene oxide nanosheet dispersion to the thiourea in the thiourea solution is 9-36:100-300.

5. The use according to claim 1, characterized in that The concentration of the soluble zinc salt solution is 0.3-0.4 mol / L; the soluble zinc salt includes one or more of zinc sulfate, zinc nitrate and zinc chloride.

6. The use according to claim 1 or 5, characterized in that The molar ratio of thiourea in the thiourea solution to zinc ions in the soluble zinc salt solution is 1:1 to 1.

6.

7. The use according to claim 1, characterized in that The reaction time is 20 to 30 minutes.

8. The use according to claim 1, characterized in that The zinc sulfide-graphene oxide composite material with near-infrared photocatalytic effect comprises graphene oxide and zinc sulfide modified on the surface of the graphene oxide.

9. The use according to claim 1, characterized in that The antibacterial agent comprises a photosensitive material and a drug-carrying matrix; the photosensitive material is the zinc sulfide-graphene oxide composite material with near-infrared photocatalytic effect.

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