Synthesis And Biomimetic Application Of Phosphorescence / Upconversion Luminescent Nanomaterials

Fluorescence bioimaging has provided a facile and less cell-damaging means of visualizing analytes of biological by virtue of its highly sensitive and high-speed spatial analysis of cells. Phosphorescent heavy metal complex and Rear-earth upconversion luminescent nanophosphors (UCNPs) are two new kinds of biological luminescent labels. The low water-solubility of metal complex and low upconversion luminescent efficiency of UCNPs limited their bioimage application.This thesis is focused on the above-mentioned two problems, and composed of two parts as following:â… . Phosphorescent polymer nanoparticles and their application in cell imaging1) Polymer nanoparticles embedded with phosphorescent osmium(â…¡) complex for cell imagingA simple and effective emulsion polymerization method was developed for converting a hydrophobic Os(â…¡) complex into hydrophilic polymer nanoparticles so as to obtain a well water-dispersed phosphorescent polymer nanoparticles (PNPs). Upon incorporation into the PNPs the Os(â…¡) complex retains its original structure and emits intense phosphorescent emission. Moreover the PNPs show low cytotoxicity, good cellular uptake, and exclusive staining of the cytoplasm of living cells.2) Fluorophore-photochrome co-embedded polymer nanoparticles for photoswitchable fluorescence bioimagingOn the basis of effective FRET from the luminescence emission of an iridium(â…¢) complex to the colored state of a photochromic diarylethene, reversibly photoswitchable luminescent polymer nanoparticles (ps-PNPs) were synthesized by emulsion polymerization to co-embed the distinct fluorophore [Ir(bt)2(pic)] and the photochrome diarylethene DTE. Compared with the mixture of [Ir(bt)2(pic)] and DTE, the ps-PNPs exhibit reversible photoswitchable luminescence modulation through DTE switching in aqueous solution and even in living cells.â…¡. NaREF4based upconversion nanophosphors and their application in bioimaging in vivoWe synthesized Er3+or Tm3+and Yb3+co-doped cubic NaREF4nanoparticles with small size (<20nm) were synthesized by solvothermal process and well dispersed in nonpolar solvent. These upconversion nanophospers (UCNPs) display very strong emission under CW980nm excitation. Hydrophilic polyacrylic acid (PAA) coated UCNPs was prepared through ligand exchange. Furthermore, hydrophilic Tm3+and Yb3+co-doped UCNPs showing near-inrared to near-inrared (NIR-to-NIR) upconversion luminescence were used for high contrast upconversion luminescent imaging in vivo of Kunming rats and ordinary black rats. These facts indicate that NaREF4is an ideal host matrix to fabricate high effective upconversion nanophosphors.