Preparation And Photothermal Conversion Performance Of CoWO_4-x Nanomaterials

With the continuous improvement of human living standards,environmental issues have received widespread attention.Problems such as the pollution of rivers and lakes and the lack of clean water in the world have emerged year by year.Solar-driven water evaporation is a new,green and effective way to solve the above-mentioned environmental problems.At the same time,the abuse of antibiotics makes it difficult to treat bacterial infectious diseases,and the high incidence of cancer also threatens human health.Photothermal antibacterial and photothermal antitumor are effective methods to solve the above problems.Solar-driven water evaporation,photothermal antibacterial and photothermal antitumor all rely on excellent photothermal conversion materials.However,most current photothermal conversion materials still have many disadvantages,such as low photothermal conversion efficiency and poor photothermal stability.The photothermal membrane used for solar-driven water evaporation has the disadvantages of complex preparation,high cost and low yield,and applying it to solve real problems is still facing huge challenges.In this thesis,CoWO_4-x nanoparticles have been synthesized by the hydrothermal method to overcome the above problems.Based on the excellent light-to-heat conversion performance of CoWO_4-x,CoWO_4-x@NF photothermal membrane,CoWO_4-x@CMC@SF hydrogels,and CoWO_4-x@PEO-b-MAA nanoparticles were designed,respectively.Three systems of hydrogel and CoWO_4-x@PEO-b-MAA nanoparticles are used for solar-driven water evaporation,photothermal antibacterial,and anti-tumor research.Applying the above three systems to solar-driven water evaporation,photothermal antibacterial and anti-tumor research.The specific research contents are as follows:（1）CoWO_4-x-deposited NF photothermal membrane(CoWO_4-x@NF)synthesized via a simple pouring method.Due to the excellent light-to-heat conversion performance of CoWO_4-x and the three-dimensional porous structure of foamed nickel,the CoWO_4-x@NF photothermal membrane has better water evaporation efficiency.The outdoor evaporation performance of the pure water group,the NF group and the CoWO_4-x@NF group was systematically investigated.The experimental results show that CoWO_4-x@NF exhibits a better water evaporation rate under sunlight.Through the phytoplankton quantify analyses,the CoWO_4-x@NF photothermal membrane can effectively reduce the cell density of Cyanophyta,Euglenophyta,and Bacillariophyta to achieve the purification of eutrophic lake water.（2）The CoWO_4-x@CMC@SF hydrogel was constructed by the method of physical stirring.The hydrogel exhibits excellent photothermal performance under irradiation with an 808 nm laser(0.75 W cm^-2),and the temperature can be increased by 45℃.The photothermal antibacterial properties of CoWO_4-x@CMC@SF hydrogel were detect Systematically in vivo and vitro.Experimental results show that the number of live bacteria is almost zero after hydrogel combined with 808 nm laser irradiation treatment,and the antibacterial rate is as high as 100%.In vivo antibacterial experiments also proved that the hydrogel has good photothermal antibacterial properties,can be used as a wound dressing to accelerate wound healing and achieve high-efficiency antibacterial.（3）CoWO_4-x was surface modified by PEO-b-PMAA to prepare CoWO_4-x@PEO-b-PMAA nanoparticles.The results of in vivo and in vitro photoacoustic（PA）and Computer Tomography（CT）imaging show that CoWO_4-x@PEO-b-PMAA has a good contrast effect.CoWO_4-x@PEO-b-PMAA can simultaneously generate hyperthermia and reactive oxygen species（ROS）under near-infrared light irradiation,illustrating that they can be used to realize photothermal therapy（PTT）and photodynamic therapy（PDT）on tumors.,realizing the integration of tumor diagnosis and treatment.This chapter systematically studied the relationship between phototherapy,immunogenic cell death（ICD）and immunoresistance,and enhanced phototherapy was achieved for the first time by injecting etoposide and ML385,which are two typical inhibitors for HSP60 and NRF2,respectively.Furthermore,the biocompatibility of materials in vivo was demonstrated through changes in mouse body weight and histological analysis of main organs.