Influence of the Membrane Dye R18 and of DMSO on Cell Penetration of Guanidinium‐Rich Peptides

A quantitative analysis by confocal fluorescence microscopy of the entry into HEK 293 and MCF ‐7 cells by fluorescein‐labeled octaarginine ( 1 ) and by three octa‐Adp derivatives ( 2 – 4 , octamers of the β ‐Asp‐Arg‐dipeptide, derived from the biopolymer cyanophycin) is described, including the effects of the membrane dye R18 and of DMSO on cell...