Figure 5.

Viability of HeLa cells after incubation with 10 µM of FAM-labeled CPPs for 90 min at 37 °C. (A–F) En face microscopic analysis of cell layers after incubation with: (A) medium only; (B) WLRRIKAWLRRIKALNRQLGVAA; (C) VKRKKKPALWKTLLKKVLKA; (D) KTVLLRKLLKLLVRKI; (E) KKKKKKKKKKKKKKKKKKK; and (F) KLALKLALKALKKAALK. Dark shadows are caused by proximity to well walls. Bar 100 µm. (G) Cell viability, analyzed by MTT-test, after incubation with top 20 CPP in our setup (see Table 1; 1–20 from left to right). Bars indicate mean values and standard deviations of quadruplicate measurements. HeLa cells incubated in cell growth medium without CPP were defined as 100% viable.