Fluid-Phase Uptake. Representative live cell confocal images ofHEK293 cells treatedfor 2 h with rhodamine B-labeled peptides and fluid-phase uptake markerdextranFITC. (A) Cells treated with 5 μM cFΦR4-A5 and dextranFITC in the same Z section. (B) Same as panel A but with 5 μM cFΦR4-R5. Early endosomal escape of a cyclic cell-penetrating peptide allows effective cytosolic cargo delivery. Qian Z, LaRochelle JR, Jiang B, Lian W, Hard RL, Selner NG, Luechapanichkul R, Barrios AM, Pei D - Biochemistry (2014). Not Altered. CC.