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Proceedings Paper

High-sensitivity immunoassay using a novel upconverting phosphor reporter
Author(s): William H. Wright; Naheed A. Mufti; N. Troy Tagg; Robert R. Webb; Luke V. Schneider
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Paper Abstract

A new class of reporter label, consisting of rare earth elements embedded in a crystalline particle, has been developed for in vitro diagnostic applications. These unique labels upconvert low energy (IR) radiation to high energy light by a multiphoton absorption process and subsequent phosphorescence emission. As a result, upconverting phosphors can be visualized with no biological background or autofluorescence signal. In addition, phosphors have narrow absorption and emission bands, making them ideal for simultaneous multianalyte test. The crystalline nature of the phosphors makes them insensitive to environmental conditions, with essentially infinite shelf life and no photobleaching at the irradiances used for excitation. We have covalently coupled (Y0.86Yb0.08Er0.06)6O2S phosphor labels to antibody probes to create a reporter reagent that can be excited by 980 nm radiation from a diode laser and detected by a modified spectrofluorimeter. Target analyte sensitivities of approximately 10 ng/mL to Staphylococcal enterotoxin B have been demonstrated using a sandwich assay in a magnetic bead or capillary wick formats in a non-optimized assay system. These results are directly applicable to the development of assays that can be performed on microfabricated biochips or in microflow channels.

Paper Details

Date Published: 22 May 1997
PDF: 8 pages
Proc. SPIE 2985, Ultrasensitive Biochemical Diagnostics II, (22 May 1997); doi: 10.1117/12.274357
Show Author Affiliations
William H. Wright, SRI International (United States)
Naheed A. Mufti, SRI International (United States)
N. Troy Tagg, SRI International (United States)
Robert R. Webb, SRI International (United States)
Luke V. Schneider, SRI International (United States)

Published in SPIE Proceedings Vol. 2985:
Ultrasensitive Biochemical Diagnostics II
Gerald E. Cohn; Gerald E. Cohn; Steven A. Soper, Editor(s)

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