Fluorescence lifetime imaging of membrane voltage

Nair, A.G., M. Rodewald, H. Bae, P. Rühl, J. Popp, M. Schmitt, T. Meyer-Zedler, S.H. Heinemann (2025) Absolute membrane potential recording with ASAP-type genetically encoded voltage indicators using fluorescence lifetime imaging. ACS Chemical Neuroscience

Membrane voltage measured with FLIM

Abbildung: FSU Biophysik

The noninvasive measurement of the electrical membrane voltage (Vm) is needed for studying various physiological processes. While recording the fluorescence intensity from genetically encoded voltage indicators (GEVIs) permits the detection of Vm changes, determination of absolute Vm is still very challenging. Using fluorescence lifetime imaging microscopy (FLIM), we measured the fluorescence lifetime as an alternative physical parameter for various GEVIs of the ASAP family. rEstus-NI and ASAP3 proved to provide large (≈750 ps) changes in fluorescence lifetime in the physiological Vm range. Moreover, spontaneous Vm changes of resting cells as well as those induced by the overexpression of ion channels were reliably measured, thus demonstrating that the usefulness of FLIM for non-invasive Vm determination in living cells.