(A) The fluorescence time profiles of interaction between peptides and membranes. HeLa cells were incubated with different concentrations of FITC-labeled HPRP-A1 and HPRP-A1-TAT at concentrations of 2, 4, and 8 μM. Images (400× magnification) were captured by laser scanning confocal microscopy every 30 s from 0 to 180 s. Green, FITC peptides; blue, 4,6-diamidino-2-phenylindile-stained nuclei. (B) LDH leakage assay. HeLa cells were incubated with HPRP-A1 and HPRP-A1-TAT at 2, 4, and 8 μM for 1 h and LDH assayed. (C) Cellular uptake of peptides, measured by flow cytometry. After incubation for 1 h at 4°C, HeLa cells were incubated with FITC-HPRP-A1 or FITC-HPRP-A1-TAT peptides for 1 h. The cells were those cultured and treated with peptides at 37°C were used as controls. Data are presented as the mean ± SD of three independent experiments. LDH, lactate dehydrogenase.