RESUMO
Tracking of Hg2+ in solutions as well as in living cells was conducted with a fluorescent chemodosimeter by measuring the spectral shift of its fluorescence under single- or two-photon excitation. The spectral hypsochromic shifts of this chemodosimeter when reacting with Hg2+ were found to be about 50 nm in acetonitrile/water solutions and 32 nm in Euglena gracilis 277 living cells. This chemodosimeter shows high sensitivity and selectivity, and is not influenced by the pH values. It can signal Hg2+ in solutions down to the ppb range under either single-photon excitation (SPE) at 405 nm or two-photon excitation (TPE) at 800 nm. However, with low cellular chemodosimeter concentrations, the SPE spectra were disturbed by the auto-fluorescence from the native fluorophore in the cell, while the TPE spectra were still of high quality since the two-photon absorption cross section of this chemodosimeter is much larger than that of the native fluorophores in the cell.
Assuntos
Corantes Fluorescentes , Mercúrio/análise , Microscopia de Fluorescência/métodos , Fótons , Espectrometria de Fluorescência/métodos , Cátions Bivalentes/química , Linhagem Celular , Sobrevivência Celular/efeitos dos fármacos , Mercúrio/química , Mercúrio/farmacologia , Estrutura Molecular , Feniltioureia/análogos & derivados , SoluçõesRESUMO
Time-dependent photoluminescence (PL) enhancement, blue shift, and photobleach were observed from the thiol-capped CdTe quantum dots (QDs) ingested in mouse myoblast cells and human primary liver cancer cells. It was revealed that the PL blue shift resulted from the photooxidation of the QD core by singlet oxygen molecules formed on the QD core surface.
