Low-intensity two-dimensional imaging of fluorescence lifetimes in living cells

The use of a time- and space-correlated single-photon counting detector enables us to perform fluorescence lifetime imaging microscopy in living cells with a temporal resolution of less than 100 ps and a spatial resolution of 500 nm. Two-dimensional (2D) maps of the fluorescence lifetimes and the corresponding prefactors are extracted by the use of a fitting program based on the Levenberg-Marquardt algorithm (Globals Unlimited). We applied this technique to extract 2D maps of protein localization in multilabeled living cells and to study protein-protein interaction by fluorescence resonance energy transfer. (C) 2003 American Institute of Physics.