Synthesis, Functionalization And Biological Effects Of Fluorescent Silica-based Nanoparticles

Due to its unique optical properties and ease of surface modifications, fluorescent silica-based nanoparticles are widely used in biological analysis and detection applications; on the other hand, magnetic nanoparticles can be used for hyperthermia treatment, taking advantage of their magnetic properties and energy transfer schema. Thus, silica coated magnetic nanoparticles, combining features of both nanoparticles, not only with improved chemical stability than magnetic nanoparticles, having less aggregation in liquid, but also can fulfill the goal of dual targeting or thermochemotherapy of cancer cells. But there are still limited research on their effects on cell growth, influences on surface structure and micro-structure of cancer cells, so this is one important topic of this study.At present, the traditional detection method of trace heavy metal ions, has many defects, such as expensive equipments, low selectivity for ions and low sensitivity. Till now there is no fluorescent nano-sensors detection of Hg2+has been studied, therefore, to develop anultra-sensitive and rapid mercury-sensing method is another topic of this study, and next step is to apply this method to detect intracellular HgA series of research have been performed in this study: (1) Synthesized iron magnetic nanoparticles (FeNPs) by coprecipitation, and prepared silica nanoparticles(SiNPs), silica coated magnetic nanoparticles(Si/FeNPs), amino group modified silica nanoparticles (NH2NPs) with Ru(bpy)32+fluorescent by W/O microemulsion method. Improvements made on the post-process of FeNPs, making it more suitable for Si/FeNPs preparation. Changed the reactant addition methods and resolved the problems encountered in the past, such as harsh synthetic conditions, high cost of nanoparticles preparation.(2) Si/FeNPs, SiNPs, NH2NPs, FeNPs were characterized by TEM, XRD, UV-Vis, FTIR, fluorescence spectroscopy and hysteresis analysis. Si/FeNPs, SiNPs, NH2NPs, were all spherical structure, had uniform particle size, single-well dispersed, and they were all successfully embedded with Ru(bpy)32-, retaining its optical properties; Si/FeNPs was superparamagnetic, amorphous material, and successfully embedded with FeNPs, although had relatively lower magnetic field than FeNPs; FeNPs amorphous nano-particles were spherical structure, single-well dispersed, and superparamagnetic.(3) Studied the biological effects of Si/FeNPs with different concentrations on HepG2 hepatoma cells, using FeNPs with same magnetic property and SiNPs with same silicon content as reference. Si/FeNPs, SiNPs could promote proliferation of HepG2 cells, could enter cells by endocytosis and had no harmful effects on cell morphology and micro-structure.(4) Successfully synthesized thymine-rich nucleic acid sequences modified silica-based fluorescent nanoparticles. As Hg2+can specific bind with thymidine, this nanoparticle-DNA sequence probe could be used to fast detect Hg2+ with high sensitivity. Further, this method could be applied to detection of intracellular Hg2+...