Photosensitization of extracellular TMR-TAT causes plasma membrane blebbing, plasma membrane permeabilization, and cell shrinkage.

A) HeLa cells were incubated with TMR-TAT (3 µM) at 4°C to block endocytosis of the peptide. Images represent the bright field image and the fluorescence image of SYTOX® Blue (inverted monochrome). B) The effects of photosensitization of hematoporphyrin (HP) on cell morphology are similar to those obtained by photosensitization of TMR-TAT. HP was incubated with HeLa cells for 1 hour, washed with fresh L-15 media, and irradiated at 560 nm. Black arrows in A) and B) highlight the membrane blebbing observed during light exposure.