Preparation Of Fluorescent Nanocomposites And Its Application In Metal Enhanced Fluorescence And Biomimetic Imaging

In this article, we synthesized and studied two kinds of composites. One is preparation of pH-responsive AgNPs/polymer nanohybrids with controllable metalenhanced fluorescence behavior; the other is graphene oxide coated Fe3O4@mSiO2 NPs for magnetic controlled bioimaging.Fabrication of metal-enhanced fluorescence(MEF) system with stimuli responsive “soft” shells is an efficient means to achieve tunable MEF behaviour. In this article, pH responsive fluorophores modified polyacrylic acid(PAA) with tunable chain length was synthesized via reversible addition fragmentation chain transfer(RAFT) polymerization using a rhodamine B(RB) functionalized RAFT agent, followed by the immobilization onto silver nanoparticles(AgNPs) via Ag-S coordination interaction to afford core-shell nanohybrids with AgNPs core, PAA shell and RB fluorophores on the surface. These pH responsive AgNPs/polymer core-shell nanohybrids may envision potential applications in drug delivery, sensors and nanodevices.A novel GO coated porous magnetic nanoparticles(Fe3O4@mSiO2@GO NPs) for biomaging was synthesized. First, Fe3O4 magnetic NPs were prepared through a solvothermal reaction. Second, mesoporous SiO2 shell was attached on Fe3O4 NPs surfaces, and then the RB was loaded inside Fe3O4@mSiO2 NPs composites. Last, the magnetic NPs surfaces were then wrapped with graphene oxide(GO) nanosheets. Fe3O4@mSiO2@GO NPs could efficiently protect the loaded dye from releasing. MTT assay revealed that the RB loaded Fe3O4@mSiO2@GO NPs exhibited insignificant cytotoxicity at moderate concentrations and could undergo targetdirected move under the action of a magnetic field. The noncytotoxic magnetic hybrids presented significant potential for applications in cell imaging.