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Preparation, characterization and application of fluorescent terbium complex-doped zirconia nanoparticles

Abstract:

Novel zirconia-based fluorescent terbium nanoparticles have been prepared as a fluorescent nanoprobe for time-resolved fluorescence bioassay. The nanoparticles were prepared in a water-in-oil (W/O) microemulsion consisting of a strongly fluorescent Tb3+ complex, N,N,N 1, N 1-[2,6-bis(3′-aminomethyl-1′-pyrazolyl)-phenylpyridine] tetrakis(acetate)-Tb3+(BPTA-Tb3+), Triton X-100, hexanol, and cyclohexane by controlling co-condensation of Zr(OCH2CH 3)4 and ZrOCl2. The characterizations by transmission electron microscopy and fluorometric methods indicate that the nanoparticles are uniform in size, 33± 4 nm in diameter, and have a fluorescence quantum yield of 8.9% and a long fluorescence lifetime of 2.0 ms. The zirconia-based fluorescent terbium nanoparticles show high stability against basic dissolution in a high pH aqueous buffer compared to the silica-based nanoparticles. A surface modification and bioconjugation method for the fluorescent nanoparticles was developed, and the nanoparticle-conjugated streptavidin (SA) was used for time-resolved floroimmunoassy (TR-FIA) of human prostate specific antigen (PSA). The result shows that the zirconia-based fluorescent terbium nanoparticles are useful as a fluorescent nanoprobe for time-resolved fluorescence bioassay. © 2005 Springer Science + Business Media, Inc.