New Fluorescence Molecular Tools of Bio-imaging to Monitor Membrane Potential in Multiphoton Mode

Fluorescent Resonant Energy Transfer (FRET) is a powerful technique for measuring intermolecular distances. Combined intensity (spectral) and Lifetime (FLIM) Imaging was used to discriminate the FRET signal of molecules on their different lifetimes whereas their emission spectra overlap. In this work, a twocomponent FRET sensor has been designed by using fluorescent phospholipids acceptor (DHPE-TRITC) bound on one side of the membrane and donor molecules (oxonol) which are sensitive to membrane potential. We used multiphoton excitation and FLIM to deliver contrast lifetimes to monitor membrane potential on cancerous cell in culture (HT-29 and fibroblasts).