Flow microfluorometric monitoring of the interaction of lipid vesicles with cells.

Flow microfluorometric techniques have been applied to experiments concerned with the penetration of cells by lipid vesicles. The high sensitivity of laser flow systems enables to measure the weak fluorescence emitted by individiual liposomes tagged with perylene, inserted into their multilamellar layer. The total fluorescence of cells which habe incorporated such perylene-loaded liposomes could be measured and well separated from that unbound liposomes. Significant differences in the incorporation rates of cationic and anionic liposomes were shown by means of time-course analyses of cellular fluorescence spectra. The advantages of the rapid data analysis by flow fluorescence techniques is discussed in comparison with conventional radio-isotopic methods.