Fluorescence quenching by metal ions in lipid bilayers

Abstract

Fluorescence quenching of perylene by Co 2+ and Ni 2+ ions has been investigated both below and above the phase transition temperature in small unilamellar DPPC vesicles. Classic Förster type energy transfer was observed for perylene quenched by Co 2+ ions below the phase transition when the effects of donor-donor energy transfer are taken into account. In the liquid crystalline phase a simple diffusion theory incorporating energy transfer was found to model the system well. For quenching by Ni 2+ ions both above and below the phase transition temperature in lipid bilayers and in glycerol the data did not follow classic Förster type energy transfer but indicated that an additional quenching mechanism was present. A mechanism other than Förster behaviour was also observed for the quenching by Cr 3+ ions in glycerol.