Energy transfer in spherical geometry. Application to micelles

Abstract

A model for long-range dipole–dipole energy transfer in spherical geometry is presented which, from steady-state or time-resolved fluorescence measurements, enables the determination of the relative positions of donor and acceptor inside the sphere. Its application to micelles (sodium dodecyl sulphate, SDS, and Triton X-100) did not lead to a quantitative determination of the position of the probes [n-(9-anthroyloxy) stearic acids, n-AS, (n= 2, 3, 6, 9, 12) and functional rhodamine and cyanine dyes], and this fact is attributed to probe-induced perturbations on the micellar structure. The results obtained lead to the following conclusions: (i) functional probes in micelles have specific radial positions and (ii) the perturbed region is a preferential solubilization site for a second probe.