Fig. 5.

Triazole polypeptides mediate cancer cell-targeted internalization and acid-induced endosomal escape. a Scheme showing pH-dependent membrane penetration of P1. b Cell uptake of P1(L)-FITC and folic acid (FA)-modified polypeptide P1(L)-FA-FITC in HeLa cells at pH 7.2 and 5.2. Results represent the means ± s.e.m. of three replicates. c Uptake level of FITC-Tris in HeLa cells after co-incubation with P1 at pH 7.2 and 5.2. Results represent the means ± s.e.m.of three replicates. d, e Merged CLSM images of HeLa cells following incubation with P1(L)-FA-FITC (d) or P1(DL)-FA-FITC (e) at 37 °C for 4 h. Cell nuclei were stained with Hoechst 33258 (blue) and endosomes/lysosomes were stained with Lysotracker Red (red). Scale bar represents 10 μm. Col% represents the colocalization ratio of P1(L)-FA-FITC or P1(DL)-FA-FITC (green) with Lysotracker Red (red) (n = 50)