Two-dimensional Nanomaterials For Photothermal Therapy And Fluorescence Lifetime Imaging Monitoring

Cancer,as one of the diseases that poses a major threat to human health,has not been an effective and safe treatment for a long time.In recent years,nano-photothermal therapy has attracted a lot of attention because of its remarkable curative effect in the treatment of cancer,small toxic and side effects,and small trauma to human body.Compared with traditional photothermal therapy,nano-photothermal therapy is based on the photothermal conversion performance of nano-photothermal materials,using its characteristics of rapid temperature rise induced by near infrared（NIR）laser,local temperature rise,thereby killing heat-sensitive tumor cells.It is known from the principle of nano-photothermal therapy that the key to achieving a good therapeutic effect lies in the nano-photothermal material.Nano-photothermal materials should have excellent biocompatibility,high photothermal conversion efficiency,low toxicity and can be discharged from the body after treatment.In addition to the requirements of the material itself,nano-photothermal therapy also needs appropriate imaging technology to accurately monitor the entire treatment process,so as to grasp the useful information such as tumor position,size and shape.In this dissertation,fluorescence life-time imaging microscopy（FLIM）was used to monitor the treatment process in real time.Fluorescence life-time imaging is a non-invasive imaging method with high temporal resolution and spatial resolution,which uses the life-time information of the fluorescent signal to produce image contrast.The fluorescence life-time value depends only on the interaction of the intracellular fluorescent probe with the cellular micro-environment,so it can comprehensively reflect the physiological state information of the cell at this time.In this paper,we selected and obtained 3 types nano-photothermal,materials,ReS₂,BP and MoS₂,by using the liquid exfoliation method.Morphological characterization and spectral characterization were carried for this three types of nano-photothermal materials.The cytotoxicity of three types of nanomaterials was examined by CCK-8 method.The results show that the three types of materials have low cytotoxicity and meet the requirements of nano-photothermal treatment for good biocompatibility of nanomaterials.By measuring the in vitro temperature rise of the three types of nanomaterials,it is shown that this materials have high photothermal conversion efficiency.Then the photothermal therapy experiment of the nano-photothermal material on the tumor cells is carried out,and the results show that the three types of nano-photothermal material has excellent therapy effect of the tumor cells.Finally,Fluorescence life-time imaging was used to detect the morphological changes of cells during nano-photothermal therapy,and the fluorescence lifetime information of cells was used to quantitatively analyze the death of tumor cells.The academic innovations of this paper are as follows:（1）Layered ReS₂ nanomaterials with uniform morphology by combining probe ultrasound and water bath ultrasound in liquid exfoliation method.The cytotoxicity of layered ReS₂ nanomaterials was reduced by PEG modification.（2）The real-time and accurate monitoring of cells in photothermal process of nanomaterials is realized by using fluorescence lifetime imaging method.The cell death rate in photothermal treatment can be judged from two aspects,cell image and fluorescence lifetime numerical analysis...