Fig. 4

The fluorescence intensity of Cou-6-Sol, Cou-6 labeled NLC and CPP modified Cou-6 labeled NLC (Cou-6 at the concentration of 0.05 μg/mL) at different incubation time interval (4 h, 8 h, and 12 h) (a: MDA-MB-231 cells, b: 4T1 cells, c: MCF-7 cells). *P < 0.05; **P < 0.01; ***P < 0.001; n.s., not significant. Results are expressed as mean ± SD, n = 3.