Tumor Microenvironments-Adaptive Apoptotic Effects of Cytidine 5'-monophosphate-Capped Gold Nanoclusters.

In the present work, cytidine 5'-monophosphate capped gold nanoclusters (AuNCs@CMP) are reported as a catalyst for redox reactions, which show both oxidase- and excellent peroxidase-like activity. When employing 3,3',5,5'-tetramethylbenzidine (TMB) as a substrate in the presence of hydrogen peroxide (H 2 O 2 ), the maximum velocity ( V max ) was 175 × 10 -8 M s -1 in vitro . Besides, the AuNCs@CMP exhibited high catalytic activity for reactive oxygen species (ROS) generation with H 2 O 2 . Particularly, they also displayed excellent catalytic activity for ROS generation in tumor cells, being activated and promoted by the tumor microenvironment (TME). Consequently, the AuNCs@CMP show an excellent antitumor effect on HeLa and SW480 cells as assayed by flow cytometry. The antitumor mechanism of AuNCs@CMP was attributed to the high ROS generation based on the specific environments of the TME. Therefore, the present study provides TME-adaptive AuNCs@CMP with excellent mimetic peroxidase activity, producing significant ROS to kill the tumor cells in TME.