Biological Effect And Biological Application Of Near-Infrared Fluorescent Ag₂Se Quantum Dots

Since the 21st century,the rapid development of nanotechnology has led to the rapid development of a series of disciplines such as medicine,biology,chemistry,and physics and so on.As the basis of the development of nanotechnology,the research and development of nanomaterials has earned worldly extensive attention.The physical and chemical properties,such as mechanical,electrical,magnetic,optical,catalytic,superconductivity,thermology and sensing,etc.,of nanomaterials are different from the corresponding bulk materials,and also from molecule and atom.Thus nanomaterials have more superior performance,such as large specific surface area,high susceptibility,strong hardness,electrical conductivity,good catalytic activity and chemical activity,etc.And due to the massive excellent optical properties,fluorescent quantum dot has been widely used in fields of biomedical research including bioinstrumentation,bio-labeling and in vivo imaging,etc.The near-infrared fluorescence quantum dots has the deep tissue penetration depth,minimal autofluorescence and negligible tissue scattering.Therefore,near-infrared fluorescence quantum dot is superior in the application of imaging research in terms of living body.Ag₂Se quantum dots,which is a kind of near-infrared fluorescence with low-toxicity,has been popular in recent years.Research and development on Ag₂Se quantum dot has roused public interest of nanotechnology researchers.At present,the research on biosecurity and living imaging application of Ag₂Se quantum dots is still on the initial stage.In our previous work,we artificially construct a "quasi-biological" system to synthesis the ultrasmall,less cytotoxic Ag₂Se quantum dots with tunable fluorescence.However the biological effect and biological application of the Ag₂Se quantum dots is still less reported.The main work in this thesis is as follow:1.This text is intended to systematically evaluate biological effect based on the preparation of near-infrared fluorescence quantum dots,and apply it to living tumor diagnosis and treatment research.The goal of this text is to get hold of the distribution of these external materials on living body,and to know their ultimately whereabouts?for exemple,degradation,biogenic accumulation,out of the body as wastes,etc?.These researches in a certain degree hold a lot of value for reference and guidance significance in terms of further discussing biological distribution of other nanoparticles in living body.2.An Ag₂Se QDs-based probe has been constructed by modifying glucosamine molecule on the surface of the near-infrared Ag₂Se quantum dots.The glucosamine-functionalized Ag₂Se QDs can be used to perform targeting human breast cancer cells imaging not only in vitro but also in vivo.The cytotoxicity in vitro,the acute toxicity in vivo and the tissue distribution were demonstrated in this work.These results indicated that Glc-Ag₂Se QDs has been a promising general tool for intravital long term observation of tumor evolution.