Fig. 3.

Antitumor efficacy in vitro. (A) Cell uptake analyzed by flow cytometry after different treatments with the nanoclusters. (B) Representative Z-stack confocal images of the 3D 4T1 tumor spheroids after different treatments with the nanoclusters for 12 h. (C) Cell viability and (D) apoptosis assay of 4T1 cells after different treatments with the nanoclusters. P values were calculated by Student’s t test, **P < 0.01, ***P < 0.001. (E) ROS generation detected by the flow cytometry assay after different treatments of the nanoclusters.