In view of a pharmacological test system with living cells we examined Forster Resonance
Energy Transfer (FRET) between fluorescent proteins upon Total Internal Reflection
(TIR) of a laser beam. We measured in particular HeLa cells expressing membrane associated
EGFR-CFP and Grb2-YFP prior to and subsequent to stimulation with the epidermal growth
factor EGF. In addition, HeLa cells expressing a membrane associated Green Fluorescent
Protein (HeLa hFR-GPI-GFP) were incubated with the energy acceptor Nile Red for further
validation. Measurements range from fluorescence microscopy to Fluorescence Lifetime
Imaging (FLIM) of a larger number of samples in a TIR reader.
