Prospects for applications of lanthanide-based upconverting surfaces to bioassay and detection

Morgan, CG and Mitchell, A 2007, 'Prospects for applications of lanthanide-based upconverting surfaces to bioassay and detection' , Biosensors and Bioelectronics, 22 (8) , pp. 1769-1775.

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Biological assays to detect binding interactions are often conducted using fluorescence resonance energy transfer (FRET) but this has several disadvantages that markedly reduce the dynamic range of measurements. The very short range of FRET interactions also causes difficulties when large analytes such as viruses or spores are to be detected. Conventional FRET-based assays can in principle be improved using infrared-excited upconverting lanthanide-based energy donors but this does not address the short range of the FRET process. Here we investigate an alternative mode of energy transfer based on evanescent wave coupling from an erbium-doped waveguide to an absorbed fluorophore and characterise the luminescence from the dopant. The upconverted erbium emission is highly structured with well-separated bands in the violet, green and red spectral regions and very little detectable signal between the peaks. The relative intensity of these bands depends on power-density of infrared excitation. Green emission predominates at low power-density and red emission increases more rapidly as power-density increases, with a smaller violet peak also emerging. The temporal response of the upconverting material to pulsed infrared excitation was investigated and was shown to vary markedly with emission wavelength with the red component being particularly sensitive to the duration of the excitation pulse. A surface monolayer of the fluorescent protein R-phycoerythrin was very easily detected on binding to an upconverting waveguide. The potential advantages and limitations of the evanescent wave excitation technique for fluorescence detection are discussed and avenues for further development are considered.

Item Type: Article
Themes: Subjects / Themes > Q Science > Q Science (General)
Subjects outside of the University Themes
Schools: Schools > School of Environment and Life Sciences
Schools > School of Environment and Life Sciences > Biomedical Research Centre
Journal or Publication Title: Biosensors and Bioelectronics
Publisher: Elsevier
Refereed: Yes
ISSN: 09565663
Depositing User: H Kenna
Date Deposited: 08 Aug 2007 09:21
Last Modified: 27 Aug 2021 21:58

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