ABSTRACT
References ........................................................................................................ 582
The first method used in the discovery of cell-penetrating peptides (CPPs) was
microscopy on fixed cells and indirect labeling of biotinylated peptides.1 Since then,
a number of different methods have been developed for the study of these
versatile peptides. Furthermore, the initial method of detection in fixed cells has
been reevaluated and it was shown that, in some cases, the intracellular distribution
can be overestimated in fixed cells.2,3 The detection of intracellular CPPs poses
several other problems; for example, the difficulty of distinguishing membrane
bound CPP from cytoplasm localized CPP. In this chapter, the most widely used
methods in detecting and quantifying the translocation of CPPs will be reviewed, as
well as the quantification of a few cargoes delivered by CPPs.