All-weather antibacterial and anti-biofilm photo-thermal material and preparation method thereof

Abstract

The invention discloses an all-weather antibacterial and anti-biofilm photo-thermal material and a preparation method thereof, and belongs to the technical field of photo-thermal materials.The preparation method comprises the steps that S1, MXene nanosheets are dispersed in a mixed solvent, and uniform dispersion liquid is obtained; respectively dissolving trimesic acid and copper nitrate trihydrate in a mixed solvent to obtain a solution A and a solution B, uniformly mixing the solution A and the solution B with the dispersion liquid, carrying out hydrothermal reaction, washing, and freeze-drying under a vacuum condition to obtain an intermediate product; and S2, adding the intermediate product and thioacetamide into ethanol, stirring while carrying out vulcanization reaction for 2-4 hours, washing, and freeze-drying under a vacuum condition to obtain the antibacterial and anti-biofilm photo-thermal material, the prepared photo-thermal material not only has high photo-thermal conversion efficiency and excellent antibacterial performance, but also can show antibacterial activity under the condition of no light, so that bacterial biofilms loaded on an interface are effectively removed, and the overall performance of a solar-driven water evaporation system is improved.

Description

Technical Field

[0001] This invention belongs to the field of photothermal materials technology, specifically relating to an all-weather antibacterial and anti-biofilm photothermal material and its preparation method. Background Technology

[0002] Solar-driven interfacial water evaporation technology offers an effective strategy for extracting clean water from seawater and wastewater, thereby alleviating the global water shortage problem. Solar-driven interfacial water evaporation systems require multifunctional characteristics to adapt to complex application environments, including high evaporation efficiency, pollutant removal capacity, antibacterial properties, and anti-biofilm properties. However, biofilms loaded on the system surface reduce photothermal conversion efficiency. Bacterial biofilms are communities formed by the excessive growth of bacteria, encapsulated by extracellular polymers, including proteins, polysaccharides, and extracellular DNA. Bacteria in mature biofilms typically exhibit stronger antibiotic resistance than planktonic bacteria. Therefore, finding photothermal materials that can inhibit planktonic bacteria and prevent biofilm accumulation on the surface of the evaporation system is crucial for improving solar photothermal conversion efficiency.

[0003] Current photothermal materials primarily achieve their sterilization effects through light-driven processes, mainly via two mechanisms: photodynamic therapy (PDT) and photothermal therapy (PTT). PDT relies on the presence of oxygen, and its effectiveness is limited in anaerobic environments; while PTT struggles to maintain the necessary temperatures for complete sterilization in water. However, both methods are highly dependent on light conditions, exhibiting insufficient antibacterial performance in the absence of light. Therefore, developing a photothermal material capable of inhibiting planktonic bacteria and preventing biofilm accumulation on the surface of evaporation systems under all-weather conditions is of great significance. Summary of the Invention

[0004] The purpose of this invention is to provide an all-weather antibacterial and anti-biofilm photothermal material and its preparation method, so as to solve the problems in the background art.

[0005] The objective of this invention can be achieved through the following technical solutions: A method for preparing an all-weather antibacterial and anti-biofilm photothermal material includes the following steps: Step S1: Disperse MXene nanosheets in a mixed solvent to obtain a uniform dispersion; then dissolve pyromellitic acid in the mixed solvent to obtain solution A; dissolve copper nitrate trihydrate in the mixed solvent to obtain solution B; stir and mix solutions A, B and the dispersion at room temperature, then transfer them to a hydrothermal autoclave reactor for hydrothermal reaction; centrifuge and wash the product with deionized water until the supernatant is neutral, then freeze-dry under vacuum to obtain an intermediate product; Step S2: Add the intermediate product and thioacetamide to ethanol and carry out a sulfidation reaction for 2-4 hours while stirring. Wash the product with a mixture of deionized water and ethanol, and freeze-dry under vacuum to obtain an antibacterial and anti-biofilm photothermal material.

[0006] Furthermore, the ratio of MXene nanosheets to the mixed solvent in the dispersion is 0.1 g: 12 mL; the ratio of trimesic acid to the mixed solvent in solution A is 0.07 g: 12 mL; the ratio of copper nitrate trihydrate to the mixed solvent in solution B is 0.1 g: 12 mL; the mixed solvent is composed of N,N-dimethylformamide, ethanol, and deionized water in a volume ratio of 1:1:1.

[0007] Furthermore, the hydrothermal reaction temperature is 110°C, and the hydrothermal reaction time is 18 hours.

[0008] Furthermore, the ratio of the intermediate product, thioacetamide, and ethanol is 0.1 g: 0.075 g: 40 mL.

[0009] Furthermore, the temperature of the sulfidation reaction is 20-40°C.

[0010] A weather-resistant, antibacterial, and anti-biofilm photothermal material, prepared by the above method, comprises MXene nanosheets, a copper-based metal-organic framework (HKUST-1) in situ modified on the surface of the MXene nanosheets, and a CuS nanostructure introduced into the HKUST-1 framework through a sulfidation reaction. The MXene nanosheets, as the substrate material, possess high electrical conductivity and excellent photothermal conversion performance; the porous structure of HKUST-1 enhances the specific surface area of ​​the material and can release free copper ions, achieving continuous antibacterial activity under light-free conditions; the unique semiconductor properties of the CuS nanostructure enable it to generate electron-hole pairs under near-infrared light irradiation, further improving the material's photothermal conversion performance.

[0011] The beneficial effects of this invention are: This invention uses MXene nanosheets as the substrate material and modifies the surface of MXene nanosheets with HKUST-1 metal-organic framework structures in situ via a hydrothermal method. The high thermal conductivity of the MXene nanosheet substrate rapidly transfers the heat generated by the photothermal effect to the water interface, improving water evaporation efficiency. Meanwhile, the high specific surface area of ​​the HKUST-1 metal-organic framework structure enhances the contact area between the material and water molecules, further improving evaporation efficiency. During the sulfidation process, copper ions on the HKUST framework react with thioacetamide to generate CuS nanostructures. The growth degree of the CuS nanostructures and the Cu... 2+ The release rate is controlled by the sulfidation time to construct an all-weather antibacterial and anti-biofilm photothermal material with triple antibacterial capabilities; the triple antibacterial mechanism is mainly manifested in: (1) Photothermal antibacterial mechanism: Through the synergistic effect of MXene nanosheets and CuS nanostructures, light energy is converted into heat energy under near-infrared light irradiation, and the local temperature rises to 50 to 60°C, reaching the threshold required for sterilization; (2) Photodynamic antibacterial mechanism: The electron-hole pairs generated by CuS nanostructure under near-infrared light irradiation react with water molecules to generate reactive oxygen species, which inactivate planktonic bacteria and biofilms. (3) Antibacterial mechanism under no-light conditions: Incompletely sulfurized Cu 2+ Slowly released from the material surface, it enters the water and binds to phospholipid molecules in the bacterial cell membrane, disrupting the bacterial metabolic process and inhibiting its reproduction; This photothermal material not only possesses high photothermal conversion efficiency and excellent photothermal and photodynamic antibacterial properties, but also exhibits the ability to inhibit bacterial growth under no-light conditions. This effectively removes bacterial biofilms loaded on the surface of the interfacial water evaporation system, improves the overall performance of the solar-driven water evaporation system, and solves the problem of insufficient antibacterial performance of photothermal materials in complex aquatic environments in existing technologies. Attached Figure Description

[0012] The invention will now be further described with reference to the accompanying drawings.

[0013] Figure 1 This is a SEM image of the photothermal material MX / HK@CuS-3 prepared in Example 2 of this invention at 200 μm. Figure 2 This is a SEM image of the MXene nanosheets of Comparative Example 1 of this invention at 200 μm. Figure 3 This is a SEM image of the intermediate product MX / HK obtained in Comparative Example 2 of this invention at 200 μm. Figure 4 The photothermal materials prepared in Examples 1-3 and Comparative Examples 1-3 were used in 808nm laser (2W / cm²) experiments. 2 The graph shows the change in surface temperature of a photothermal material over time under irradiation. Figure 5 This is a schematic diagram of the photothermal evaporator used in the water evaporation efficiency test. Detailed Implementation

[0014] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0015] Example 1 This embodiment provides an all-weather antibacterial and anti-biofilm photothermal material, which is prepared by the following steps: Step S1: N,N-dimethylformamide, ethanol, and deionized water are mixed in a volume ratio of 1:1:1 to obtain a mixed solvent; 0.1g of MXene nanosheets are dispersed in 12mL of the mixed solvent to obtain a uniform dispersion; then 0.07g of trimesic acid is dissolved in 12mL of the mixed solvent to obtain solution A; 0.1g of copper nitrate trihydrate is dissolved in 12mL of the mixed solvent to obtain solution B; solutions A, B, and the dispersion are stirred and mixed evenly at room temperature, then transferred to a hydrothermal autoclave reactor and subjected to a hydrothermal reaction at 110℃ for 18h. The product is centrifuged and washed with deionized water until the supernatant is neutral, and then freeze-dried under vacuum to obtain the intermediate product MX / HK. Step S2: Add 0.1g of intermediate product and 0.075g of thioacetamide to 40mL of ethanol, and carry out the sulfidation reaction at 20℃ with stirring for 4h. Wash the product with a mixture of deionized water and ethanol, and freeze dry under vacuum to obtain antibacterial and anti-biofilm photothermal material, named MX / HK@CuS-2 according to the sulfidation reaction time.

[0016] Example 2 This embodiment provides an all-weather antibacterial and anti-biofilm photothermal material, which is prepared by the following steps: Step S1: N,N-dimethylformamide, ethanol, and deionized water are mixed in a volume ratio of 1:1:1 to obtain a mixed solvent; 0.1g of MXene nanosheets are dispersed in 12mL of the mixed solvent to obtain a uniform dispersion; then 0.07g of trimesic acid is dissolved in 12mL of the mixed solvent to obtain solution A; 0.1g of copper nitrate trihydrate is dissolved in 12mL of the mixed solvent to obtain solution B; solutions A, B, and the dispersion are stirred and mixed evenly at room temperature, then transferred to a hydrothermal autoclave reactor and subjected to a hydrothermal reaction at 110℃ for 18h. The product is centrifuged and washed with deionized water until the supernatant is neutral, and then freeze-dried under vacuum to obtain the intermediate product MX / HK. Step S2: Add 0.1g of intermediate product and 0.075g of thioacetamide to 40mL of ethanol, and carry out a sulfidation reaction at 30℃ with stirring for 3h. Wash the product with a mixture of deionized water and ethanol, and freeze-dry under vacuum to obtain an antibacterial, anti-biofilm photothermal material, named MX / HK@CuS-3 based on the sulfidation reaction time. Figure 1 It can be seen that the surface morphology of MX / HK@CuS-3 is rough. This is because the surface structure of MX / HK changes after sulfidation, forming CuS nanostructures.

[0017] Example 3 This embodiment provides an all-weather antibacterial and anti-biofilm photothermal material, which is prepared by the following steps: Step S1: N,N-dimethylformamide, ethanol, and deionized water are mixed in a volume ratio of 1:1:1 to obtain a mixed solvent; 0.1g of MXene nanosheets are dispersed in 12mL of the mixed solvent to obtain a uniform dispersion; then 0.07g of trimesic acid is dissolved in 12mL of the mixed solvent to obtain solution A; 0.1g of copper nitrate trihydrate is dissolved in 12mL of the mixed solvent to obtain solution B; solutions A, B, and the dispersion are stirred and mixed evenly at room temperature, then transferred to a hydrothermal autoclave reactor and subjected to a hydrothermal reaction at 110℃ for 18h. The product is centrifuged and washed with deionized water until the supernatant is neutral, and then freeze-dried under vacuum to obtain the intermediate product MX / HK. Step S2: Add 0.1g of intermediate product and 0.075g of thioacetamide to 40mL of ethanol, and carry out the sulfidation reaction at 40℃ with stirring for 2h. Wash the product with a mixture of deionized water and ethanol, and freeze dry under vacuum to obtain antibacterial and anti-biofilm photothermal material, named MX / HK@CuS-4 according to the sulfidation reaction time.

[0018] Comparative Example 1 Compared to Example 2, this comparative example directly uses MXene nanosheets as the photothermal material. Figure 2 As can be seen, MXene nanosheets are single-layer sheet structures with smooth and flat surfaces.

[0019] Comparative Example 2 Compared to Example 2, this comparative example omits step S2 and directly uses the intermediate product MX / HK as the photothermal material. Figure 3 It can be seen that the surface of MX / HK is covered with a large number of regular polyhedra, which corresponds to the structure of HKUST-1.

[0020] Comparative Example 3 The difference between this comparative example and Example 2 is that the vulcanization time in step S2 is 1 hour, while the other raw materials and steps are the same. It is named MX / HK@CuS-1 based on the vulcanization reaction time.

[0021] The performance of the photothermal material samples prepared in Examples 1-3 and Comparative Examples 1-3 was tested: (1) Photothermal performance test: The photothermal material sample was mixed with deionized water to obtain a sample mixture with a concentration of 500 μg / mL; an 808 nm laser (2 W / cm²) was used at room temperature. 2Irradiate 1 mL of the sample mixture for 20 min, measure and record the temperature change of the sample mixture, calculate and record the photothermal conversion efficiency of the photothermal material sample; deionized water without the photothermal material sample is used as a blank control. (2) Water evaporation efficiency test: Apply a pressure of 18 MPa to press 0.6 g of photothermal material sample powder into a circular sheet with a diameter of 20 mm, and place the circular sheet in a container such as Figure 5 The photothermal evaporator shown consists of a cotton core, polyethylene foam, and a beaker. A xenon lamp was used to simulate sunlight for irradiation. The sample's performance at 1 kW / m² was calculated and recorded. 2 Water evaporation efficiency under sunlight intensity; (3) Antibacterial performance test: Using Escherichia coli and Staphylococcus aureus, 0.1 mL of a 10... 6 A bacterial suspension of CFU / mL was mixed with 0.4 mL of sample / PBS solution (500 μg / mL), incubated at 37 °C for 2 h, and then subjected to a simulated light source (100 mW / cm²). 2 UV filter), 808nm near-infrared laser (2W / cm²) 2 The mixture was treated for 20 min under conditions of no light source and then incubated at 37°C for 2 h. Serial dilutions were performed with PBS, and 100 μL of each dilution was plated onto agar plates. After 24 h of incubation, bacterial colony counts were performed, and the inhibition rate was calculated. Bacterial suspensions from samples without photothermal materials served as blank controls. (4) Anti-biofilm performance test: Using Escherichia coli and Staphylococcus aureus, a silicon wafer with a diameter of 12 mm was immersed in 3 mL of fresh broth, and 100 μL of a 10% concentration was added. 6 CFU / mL activated bacterial suspension was cultured at 37°C for 72 h, with the broth changed every 24 h; after washing several times with PBS, silicon wafers with biofilm were collected; the biofilm-containing silicon wafers were then immersed in 2 mL of sample / PBS suspension (500 μg / mL) under a simulated light source (1 kW / m²). 2 After irradiation with UV filtration and placement under no light source for 20 min, the silicon wafer was sonicated in 2 mL PBS to disperse bacteria. The resulting bacterial solution was serially diluted and inoculated onto agar plates. The biofilm removal rate was calculated by colony counting.

[0022] The test results are shown in Table 1: Table 1 As shown in Table 1, the photothermal materials prepared by this invention not only possess excellent photothermal performance but also exhibit all-weather antibacterial and biofilm removal properties. Among them, the photothermal material obtained by sulfidation reaction for 3 hours has the best comprehensive performance. Although the MXene nanosheets of Comparative Example 1 have a higher photothermal conversion efficiency, they have the lowest water evaporation efficiency and the worst antibacterial and biofilm removal performance. The surfaces of MX / HK in Comparative Example 2 and MX / HK@CuS-1 in Comparative Example 3 do not form or form very few CuS nanostructures, thus their photothermal conversion efficiency is relatively low. However, due to the ability to release high concentrations of Cu... 2+ Therefore, it exhibits stronger antibacterial properties; however, the excessive release of copper ions may pose a potential risk to human health and the environment, while high concentrations of Cu... 2+ The release of [something] can induce the secretion of extracellular polysaccharides by biomembranes, which in turn can hinder the removal of biomembranes.

[0023] Depend on Figure 4 As can be seen, under 808nm laser irradiation, as the irradiation time increases, the MXene nanosheets of Comparative Example 1 can reach a maximum temperature of about 62°C, and the maximum temperature of Example 2 of this application can reach about 60°C, which is much higher than the maximum temperature that Comparative Example 2 and Comparative Example 3 can reach, showing excellent photothermal conversion performance.

[0024] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article, or apparatus.

[0025] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A method for preparing an all-weather antibacterial and anti-biofilm photothermal material, characterized in that, Includes the following steps: Step S1: Disperse MXene nanosheets in a mixed solvent to obtain a uniform dispersion; then dissolve pyromellitic acid in the mixed solvent to obtain solution A; dissolve copper nitrate trihydrate in the mixed solvent to obtain solution B; stir and mix solutions A, B and the dispersion at room temperature, then transfer them to a hydrothermal autoclave reactor for hydrothermal reaction; centrifuge and wash the product with deionized water until the supernatant is neutral, then freeze-dry under vacuum to obtain an intermediate product; Step S2: Add the intermediate product and thioacetamide to ethanol and carry out a sulfidation reaction for 2-4 hours while stirring. Wash the product with a mixture of deionized water and ethanol, and freeze-dry under vacuum to obtain an antibacterial and anti-biofilm photothermal material.

2. The method for preparing an all-weather antibacterial and anti-biofilm photothermal material according to claim 1, characterized in that, The ratio of MXene nanosheets to the mixed solvent in the dispersion is 0.1 g: 12 mL; the ratio of trimesic acid to the mixed solvent in solution A is 0.07 g: 12 mL; the ratio of copper nitrate trihydrate to the mixed solvent in solution B is 0.1 g: 12 mL; the mixed solvent is composed of N,N-dimethylformamide, ethanol and deionized water in a volume ratio of 1:1:

1.

3. The method for preparing an all-weather antibacterial and anti-biofilm photothermal material according to claim 1, characterized in that, The hydrothermal reaction was carried out at a temperature of 110°C for 18 hours.

4. The method for preparing an all-weather antibacterial and anti-biofilm photothermal material according to claim 1, characterized in that, The ratio of the intermediate product, thioacetamide, and ethanol is 0.1 g: 0.075 g: 40 mL.

5. The method for preparing an all-weather antibacterial and anti-biofilm photothermal material according to claim 1, characterized in that, The temperature of the sulfidation reaction is 20-40℃.

6. A photothermal material with all-weather antibacterial and anti-biofilm properties, characterized in that, Prepared by the preparation method according to any one of claims 1-5.

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