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Indexed by:期刊论文

Date of Publication:2009-01-01

Journal:JOURNAL OF MATERIALS CHEMISTRY

Included Journals:SCIE、EI、Scopus

Volume:19

Issue:9

Page Number:1258-1264

ISSN No.:0959-9428

Abstract:Time-gated luminescence bioimaging based on microsecond-lifetime luminescent biolabels can provide complete background-free conditions for detecting target cells in an autofluorescence biosample matrix. However, a major drawback of the current lanthanide biolabels is the requirement for UV excitation (<370 nm), which leads to damage to many biological systems and greatly affects the improvement of time-gated luminescence instruments. Herein we describe luminescent europium nanoparticles that have an excitation peak around 406 nm with high quantum yield (similar to 66%) and fine monodispersity in aqueous solutions. The nanoparticles were prepared by copolymerization of a visible-light-sensitized Eu(3+) complex 4,4'-bis(1 '',1 '',1 '',2 '',2 '',3 '',3 ''-heptafluoro-4 '',6 ''-hexanedion-6 ''-yl) chlorosulfo-o-terphenyl-Eu(3+)-2-(N,N-diethylanilin-4-yl)-4,6-bis(3,5-dimethylpyrazol-1-yl)-1,3,5-triazine conjugated with 3-aminopropyl(triethoxy) silane, free 3-aminopropyl(triethoxy) silane and tetraethyl orthosilicate in a water-in-oil reverse microemulsion. Characterization by transmission electron microscopy and luminescence spectroscopy indicates that the nanoparticles are monodisperse, spherical and uniform in size, <50 nm in diameter, and show strong visible-light-sensitized luminescence with a large quantum yield and a long luminescence lifetime. The new nanoparticles were successfully applied to distinguish an environmental pathogen, Giardia lamblia, within a concentrate of environmental water sample using a time-gated luminescence microscope with pulsed visible light excitation. The method resulted in highly specific and sensitive imaging for Giardia lamblia. These results suggest a broad range of potential bioimaging applications where both long time microscopy observation and high signal-to-background ratio are required for samples containing high concentrations of autofluorescence background.