Cellular uptake of liposomes monitored by confocal microscopy and flow cytometry

For several years, two advanced techniques, confocal laser scanning microscopy (CLSM) and flow cytometry, in particular fluorescence-activated cell sorting (FACS) have been used more and more to study the cellular uptake of liposomal drug delivery systems. These techniques provide new potential to localize carriers in cells and quantify the amount of liposomal uptake, leading to essential information on the interaction between the formulation and the target cell. A better understanding of the underlying mechanism behavior of liposomes in biological systems is essential when adapting the liposomal formulation in order to improve carrier effectiveness. The present review describes these two techniques and their use in liposomal research.