Synthesis And Characterization Of Multifunctional Fluorescent Oxides Composites

Inorganic-organic composite materials with versatility have received increasing attention owing to their optics, chemistry and biomedical applications. In this work, by using oxides (Fe3O4or SiO2), polymer and fluorescent dyes as the starting materials, three kinds of multifunctional fluorescent oxide composites are synthesized via one-pot or multistep method and their structure and performance are investigated. The main contents are as follows:1. Synthesis and characterization of the fluorescent oxides-doped PVP composites. Based on the ring-opening and cross-linking mechanism of PVP, the fluorescent oxides-doped PVP composites have been successfully prepared in one-pot through the incorporation of oxides (Fe3O4or SiO2) and dye molecules into the cross-linked PVP. By changing the stirring model and adjusting the PVP content and reaction time, the morphologies of fluorescent oxides-doped PVP composites can be tuned. The oxide nanoparticles (NPs) and the dye molecules are bound to the ring-opened PVP chains through chemical bonds, thus leading to the high optical stability of the composites. The facile method may open a new way for the preparation of multifunctional fluorescent PVP composites based on other oxide particles.2. Synthesis and characterization of the magnetic-fluorescent NPs. Two kinds of magnetic-fluorescent NPs have been synthesized by using amino-functional squarylium indocyanine dye (Cy5) and PDI-cored star polymers (PDI-PAA) as the fluorophore. The Fe3O4NPs synthesized by the facile chemical co-precipitation method are encapsulated with SiO2via the reverse microemulsion method and further coated by the fluorescent dyes via chemical reaction. The results show that the composite NPs retain magnetic and fluorescent properties. The cytotoxicity and cellular uptake of such NPs are investigated for potential biomedical applications.3. Synthesis and characterization of dye-doped fluorescent silica NPs. The Cy5-doped fluorescent silica NPs have been synthesized in one-pot via covalent bonding by adding y-glycidoxypropyltrimethoxysilane (GPTMS) and (3-aminopropyl) triethoxysilane (APTES) to the reverse microemulsion. The results show that the composite NPs can effectively avoid Cy5leakage and have high photostability. The cytotoxicity and cellular uptake of such NPs are investigated for potential biomedical applications. This facile preparation method can be extended to the fabrication of dye-doped fluorescent silica NPs based on other amino-functional positively charged and water-soluble organic dyes.