Fig. 4. Met bis-alkylation increases the peptides' cellular uptakes. (A) A schematic presentation of peptides. (B) Confocal microscopy images of HeLa cells after treatment for 4 h with 10 μM peptides 11a, 11c, 11i, and TAT. (C) Flow cytometry comparison of the cellular uptake efficiency of the FITC labelled peptides 11a–e, 11h, and 11i, thioether cyclic peptides 12c and 13c, and the cell penetrating peptide TAT (10 μM, 4 h) in Hela cells. (D) Flow cytometry comparison of the cellular uptake efficiency of the FAM labelled peptides 14, 14c, and 15, 15c (10 μM, 4 h) in T47D cells in the medium containing 10% fetal bovine serum.
