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Proceedings Paper

Reversible quenching of a europium complex by a photochromic spiropyran in a lipid bilayer host
Author(s): B. Z. Nadolski; Christopher G. Morgan
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Paper Abstract

The ability to reversibly control fluorescence quenching by processes such as resonance energy transfer to a photochromic acceptor is of potential interest in mechanistic fluorescence studies, and might also find practical application. In this paper we report on studies of a model system comprising a europium chelate (europium tetrakis (2-naphthoyltrifluoroacetone) piperidine) and a photochromic spiropyran(SP) (1-hexadecyl-6-methoxy-3, 3'-dimethyl-8-nitro-2H-chromene-2-spiro-2'-(2,3-dihydroindole) codissolved in a bilayer of the phospholipid Dipalmitoyl-phosphatidylcholine in aqueous dispersion. Reversible quenching of the fluorescence of the europium complex is observed when the system is irradiated with long wave UV light, resulting in transient conversion of the SP into a strongly coloured merocyanine dye (MC) , which has spectral overlap with the europium emission. There are several possible modes of fluorescence quenching in this system. One possibility is formation of a ground state complex, wherein europium dissociates from its ligand and binds to the charged merocyanine. The most likely alternatives are resonance energy transfer, collisional deactivation of the long lived excited state of europium or energy transfer from the ligand on europium to the SP triplet state. It has been shown using analysis of UV absorption spectra that ground state complex formation does not occur. Both isomers of SP and merocyanine are involved in the overall quenching of europium emission, and both collisional- and resonance energy transfer are involved.

Paper Details

Date Published: 1 May 1990
PDF: 12 pages
Proc. SPIE 1204, Time-Resolved Laser Spectroscopy in Biochemistry II, (1 May 1990); doi: 10.1117/12.17772
Show Author Affiliations
B. Z. Nadolski, Univ. of Salford (United Kingdom)
Christopher G. Morgan, Univ. of Salford (United Kingdom)

Published in SPIE Proceedings Vol. 1204:
Time-Resolved Laser Spectroscopy in Biochemistry II
Joseph R. Lakowicz, Editor(s)

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