New Synthesis Methods Of Water-soluble Quantum Dots And Magnetic Nanoparticles

Functional nanomaterials have been widely applied to nanoteclnology and biotechnology for their extraordinary properties.Especially for those nanomaterials which can be used for biolabeling,bioimaging,separation in the nanobiomedical research,such as Quantum Dots and magnetic nanoparticles.Because of their small radius,strong coercive force,superparamagnetism and excellent dirigibility,magnetic nanoparticles have been successfully used in the diagnosis and treatment of disease,separation and purification of biosubstances. Quantum Dots are superior to traditional organic fluorescent dyes for their exceptional fluorescence characteristics,and have been extensively used in the preparation of fluorescent probes,biolabeling and bioimaging.However,many kinds of present ways to synthesize Quantum Dots and magnetic nanoparticles used organic passivators are toxic,which will pollute the environment if large-scale nanoparticles are produced Thus,one of the main research directions of nanomaterials and analytical chemistry is to establish a new environmentally friendly synthesis nanotechnology of quantum dots and magnetic nanoparticles.In this thesis,chapter 1 is the review about synthesis and applications of QDs and magnetic nanomaterial,and chapter 2-4 are some original research works during the study of master's degree.Chapter 1,the basic knowledge and characters,synthesis and modification route, recent progress and prospect of QDs and magnetic nanomaterial in biomedical science were introduced.Chapter 2,CdTe QDs have been successfully synthesized by a simple and "green" route using starch as a capping agent at room temperature.XRD pattern and TEM images confirmed the formation of cubic structural CdTe nanocrystals(4-9 nm). The capped CdTe QDs showed absorption peaks locating within the visible range of 450-550 nm.This method is a mild,simple,cheap and efficient "green" route for producing nanoparticles.Chapter 3,we report a novel one-pot aqueous synthesis method of highly fluorescent citric acid capped CdSe QDs using Na₂SeO₃ as the Se source.It can avoid a pretreatment to synthesize the unstable Se precursors and require equipping with the Schlenk line.Furthermore,the CdSe QDs have high photoluminescence intensity.It is a simple,cheap and with low toxicity method that is potential for large-scale production of semiconductor nanoparticles.Chapter 4,high quality alumina-coated Fe₃O₄ nanoparticle was prepared from simple inorganic salt,TEM and XRD results show that the product is in good crystal structure,monodispersed,uniform in radius.This method is cheap,with low toxicity,safe,repeatable and convenient to produce.