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PubMed · 16285685

Homogeneous assay technology based on upconverting phosphors.

Katri Kuningas·Terhi Rantanen·Telle Ukonaho·Timo Lövgren·Tero Soukka
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Abstract

Upconversion photoluminescence can eliminate problems associated with autofluorescence and scattered excitation light in homogeneous luminescence-based assays without need for temporal resolution. We have demonstrated a luminescence resonance energy-transfer-based assay utilizing inorganic upconverting (UPC) lanthanide phosphor as a donor and fluorescent protein as an acceptor. UPC phosphors are excited at near-infrared and they have narrow-banded anti-Stokes emission at visible wavelengths enabling measurement of the proximity-dependent sensitized emission with minimal background. The acceptor alone does not generate any direct emission at shorter wavelengths under near-infrared excitation. A competitive model assay for biotin was constructed using streptavidin-conjugated Er3+,Yb3+-doped UPC phosphor as a donor and biotinylated phycobiliprotein as an acceptor. UPC phosphor was excited at near-infrared (980 nm) and sensitized acceptor emission was measured at red wavelength (600 nm) by using a microtitration plate fluorometer equipped with an infrared laser diode and suitable excitation and emission filters. Lower limit of detection was in the subnanomolar concentration range. Compared to time-resolved fluorometry, the developed assay technology enabled simplified instrumentation. Excitation at near-infrared and emission at red wavelengths render the technology also suitable to analysis of strongly colored and fluorescent samples, which are often of concern in clinical immunoassays and in high-throughput screening.

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Biosensing TechniquesBiotinPhosphorusPhycobiliproteinsTitrimetryJournal ArticleResearch Support, Non-U.S. Gov't

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Katri Kuningas, Terhi Rantanen, Telle Ukonaho, Timo Lövgren, Tero Soukka. 2005-11-15. Homogeneous assay technology based on upconverting phosphors.. https://doi.org/10.1021/ac0510944

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