Figure 4

Extracellular pH affected penetration of poly-PR. (A) Peptides absorption assay using FITC-R12 or FITC-(PR)20. The pictures show the actual images of the absorbed peptides. The white arrowheads indicate octanol phase and white arrows show aqueous buffer phase. The bar graph shows the fluorescence of FITC-labeled peptides absorbed in the octanol fractions measured by a plate reader. (B) Hela cells were treated with PBS with different pH containing 2 μM FITC-R12 or FITC-(PR)20. Nucleus was visualized by Nucblue live dye. (C) Cell penetration rate of FITC-(PR)20 incubated at 37°C or 4°C or pH9 in HEK293 cells, measured by a plate reader. Asterisks indicate a significant difference analyzed by one-way ANOVA followed by Dunnett’s test (**p < 0.01, *p < 0.05). n.s.; not significant.