Preparation And Application Of Novel Fluorescence Nanomaterials

Actively seeking for a photoluminescence materials with excellent properties become the key point of the development of highly sensitive biosensor and high-resolution biological imaging that based on light enhanced chemiluminescence (CL) technology. In this thesis, the new preparation technologies and the corresponding biomedical applications of the two kinds of materials including upconversion luminescence of rare earths and carbon quantum dots, were investigated. Results are as follows:(1) To achieve highly sensitive detection of biological molecules, it is necessary to make the upconversion luminescent nanomaterials have multi-functional that including good water solubility, appropriate biocompatibility, high fluorescence quantum yield and emission characteristics of polychromatic light. In this case, an amino acid was used as organic capping agent, and the straw-superstructure YF3:Yb3+, Er3+ nanoparticles self-assembled with the average size of about 30nm were synthesized. The roles of amino acids and fluorine source during the formation of the straw-superstructure YF3:Yb3+, Er3+ nanoparticles were discussed. In addition,β-phase copper-doped hexagonal NaYF4:Yb3+, Er3+ upconversion nanoparticles with straw-superstructure were obtained by doping technique. Results showed that the intensity of rare earth upconversion fluorescence increased with the increase of doping ratio of copper. The maximum fluorescence intensity of the materialwas achieved while 40% doping ratio of copper. The above prepared Cu-NaYF4:Yb3+, Er3+ upconversion fluorescent nanoparticles were applied to the detection of glutathione with a detection limit of 40 nM.(2) In this thesis, different amino acids were chosen as carbon source. The carbon quantum dots with good water solubility and high fluorescence quantum yield were obtained by hydrothermal method. The products were characterized by X-ray diffraction and Raman spectroscopy, X-ray photoelectron spectroscopy and Fourier transform infrared spectroscopy. The emission peak position of the carbon quantum dot solution changed following different excitation light. It was called "Excitation-Dependent". The maximum value of fluorescence was achieved by using 396 nm light as excitation sourceThe low cytotoxicity of carbon quantum dots we prepared was proved by cytotoxicity test. Moreover, after 24 h cultured with these carbon quantum dots, Hela cells can remain good form and emit green fluorescence under the corresponding excitation. It means that the carbon quantum dots we proposed have the potential to be applied to biological imaging and fluorescent security area.