Fluorescence Lifetime Imaging of Propranolol Uptake in Living Glial C6 Cells
Fluorescence of propranolol in solution and after uptake into C6 glial cells. (a) Effect of pH on the fluorescence lifetime of propranolol in aqueous solution; (b) Stern-Volmer plots at pH 7 for the self-quenching of the fluorescence lifetime of propranolol (□) and quenching by phosphate (■). Images (c) through (f) show results obtained on incubation of C6 glial cells with SR-propranolol (100 μM) at 37°C for 10 minutes. Fluorescence at 340 nm was observed following 2PE at 630 nm. The results show the fluorescence intensity (d) and lifetime (e) images (field 76 μm square) together with the lifetime distribution within the image (c). Image (f) shows the intracellular propranolol concentration profile calculated from (d) and (e) as described in the text.