IC/IR820 NPs trigger ROS-dependent apoptosis in breast cancer cells. (A–D) Apoptosis of IR820, IC, and IC/IR820 NPs were evaluated by annexin V-FITC/PI staining in MDA-MB-231, MCF-7 and 4T1 cells, quantification of apoptotic cell ratio. (λ = 808 nm, P = 1.0 W/cm2; the irradiation time = 2 min). (E–G) Immunoblot analysis of apoptotic markers for MDA-MB-231, MCF-7 and 4T1 cells treated IC, IR820, IC/IR820 with or without NAC treatment. (λ = 808 nm, P = 1.0 W/cm2; irradiation time = 2 min). (H–J) Viability of specific groups with or without ZVAD treatment in MDA-MB-231, MCF-7 and 4T1 cells. (λ = 808 nm, P = 1.0 W/cm2; irradiation time = 20 s).