Preparations And Characteristics Of TiO₂ Nanoparticles And The Studies On Its Interaction With BSA

Part1:Microwave method has been widely used in many chemistry field such as inorganic chemistry, organic chemistry, macromolecule, metal-organic chemistry, material chemistry. The precursor of TiOCl2 is prepared by easily obtained TiCl4 at low temperature .The nanocrystalline TiO2 is prepared by easily prepared by microwave radiation .With Transmission Electron Microscopy (TEM),the diameter of TiO2 nanopartiles has been measured.The result shows that the diameter of TiO2 is about 4～5nm. The characteristics of TiO2 nanopartiles have been analyzed by Transmission Electron Microscopy (TEM),Raman spectra , X-ray powder diffraction method(XRD), infra-red spectrum(IR) and Vis-UV spectra.The influences of concentration of precursor,pH of precursor,the kind of catalyst and the timeof microwave radiation to the dimetres of of TiO2 nanopartiles also have been discussed.Part2:The colloid of TiO2 nanopartiles is prepared by easily obtained TiCl4 at low temperature .With Transmission Electron Microscopy (TEM),the diameter of TiO2 nanopartiles has been measured.The result shows that the diameter of TiO2 is about 20～30nm.The factors of The colloid of TiO2 nanopartiles of Vis-UV Spectra and Resonance Scattering Spectra (RSS). have been discussed.Part3:At physiological pH,interaction of TiO2 nanoparticles with Bovine Serum Albumin(BSA) is studied by fluorescence spectrum.The Quenching of fluorescence spectrum is determined by the competition between the enhancement of local electromagnetic field around TiO2 nanoparticles and the lost of non-radiant energy transfer of BSA.The calculated binding constants for TiO2 nanoparticles and HSA at different temperature are k27℃=3.52×106,k37℃=9.31×106,ΔH=75.2kJ·mol-1, ΔS27℃=-376.0J·mol-1·K-1, ΔS37℃=-375.9J·mol-1·K-1.The possible quenching mechanism is discussed.The overlapping spectrum of BSA and absorption spectrum of TiO2 nanoparticles shows: the distance between the Trp-212resiidue of BSA and TiO2 nanoparticles are suitable for the condition of non-radiant energy transfer.Synchronous fluorescence shows that as the intensity of TiO2 nanoparticles increases,the synchronous fluorescence spectrum peak of tryptophan is red-shifed from 340nm to 342nm,the synchronous fluorescence peak of tyrosine from 299nm to 301nm. It can be inferred that TiO2 induced conformational of BSA changes slightly and the environmental polarity of amino acid increases.The fluorescence spectrum outcome is effectively proved by the result of Raman spectrum..