Fluorescence probes for membrane potentials based on mesoscopic electron transfer.

A new type of voltage-sensitive dye is proposed based on the electric-field dependence of electron transfer. These dyes contain an electron donor-acceptor pair in which intramolecular electron transfer competes with fluorescence emission, converting changes in electric field to those in fluorescence intensity. With electron-transfer distance of nanometers, theoretical analysis shows that these dyes can have high sensitivity to neuron action potentials with high fluorescence quantum yield, allowing for fast optical neuroimaging with large signal-to-noise ratio.