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Proceedings Paper

Long-wavelength emitting nanocrystals for bioassay applications
Author(s): Valerie J. Leppert; Ashley S. Harvey; Geoff D. McCool; Forest T. Quinlan; Jun Feng; Guomin Shan; Pieter Stroeve; Subhash H. Risbud; Bruce D. Hammock; Ian M. Kennedy
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Paper Abstract

New fluorophores that can be excited using visible or near-infrared radiation are of considerable interest for application in environmental and complex bioassays, where background fluorescence is exacerbated by ultra-violet or blue excitation. Useful labels for biomolecules include infrared emitting semiconductor nanoparticles that can be blue-shifted into the near-infrared and visible through quantum confinement effects, oxides of iron, and rare earth oxides. In this work, the synthesis of 6 nm average diameter lead selenide nanocrystals (well below the Bohr exciton diameter of 92 nm) through a reverse micelle technique; and the synthesis of iron and europium oxides with particles less than 5 nm in diameter by pulsed laser ablation is reported. The europium oxide nanoparticles' emission showed a large Stokes shift (144 nm or 216 nm, depending on excitation wavelength); a narrow, symmetric emission line at 610 nm (FWHM of 8 nm); and long lifetime (300 μs). The Eu2O3 nanoparticles, which were coated with silica for functionalization, displayed a greatly enhanced sensitivity over a conventional ELISA (0.025 ng ml-1 vs. 0.1 ng ml-1) when run in an atrazine immunoassay.

Paper Details

Date Published: 4 November 2002
PDF: 12 pages
Proc. SPIE 4809, Nanoscale Optics and Applications, (4 November 2002); doi: 10.1117/12.451573
Show Author Affiliations
Valerie J. Leppert, Univ. of California/Davis (United States)
Ashley S. Harvey, Univ. of California/Davis (United States)
Geoff D. McCool, Univ. of California/Davis (United States)
Forest T. Quinlan, Univ. of California/Davis (United States)
Jun Feng, Univ. of California/Davis (United States)
Guomin Shan, Univ. of California/Davis (United States)
Pieter Stroeve, Univ. of California/Davis (United States)
Subhash H. Risbud, Univ. of California/Davis (United States)
Bruce D. Hammock, Univ. of California/Davis (United States)
Ian M. Kennedy, Univ. of California/Davis (United States)

Published in SPIE Proceedings Vol. 4809:
Nanoscale Optics and Applications
Guozhong Cao; Wiley P. Kirk, Editor(s)

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