Fig. 4

In vitro PTT effect study: (a) experimental design of in vitro PTT in the 4T1 breast cancer cell line. In vitro PTT effect (808 nm, 2 W cm⁻², 5 min) according to the concentration gradient (0, 2, 10, 20, 40, 100 μg 200 μL⁻¹) of (b) IBC, (c) PB NPs, and (d) IBC-PB composites (n = 3, mean ± s.d.). e Optical images of cell populations treated with the series of IBC-PB composites with and without PTT. *: P < 0.05, **: P < 0.01, ***: P < 0.001. The statistical analysis was conducted by means of student’s t test for b, c, and d