Hollow CoP@N–Carbon Nanospheres: Heterostructure and Glucose-Enhanced Charge Separation for Sonodynamic/Starvation Therapy

Sonodynamic therapy (SDT) can be described as ultrasonic (US) catalysis. Adequate charge separation is considered as effective means to promote reactive oxygen species (ROS). Here, hollow CoP@N–carbon@PEG (CPCs@PEG) nanospheres (∼60 nm) are prepared as sonosensitizers, showing greater ROS generation than pure CoP@PEG under US irradiation. Both 1O2 and ·O2– are activation species that are determined by O2 and electrons. The great SDT performance of CPCs@PEG is ascribed to the heterostructure which promotes the separation and transfer for US-generated electrons and holes. In addition, holes can be further captured by endogenous glucose that is in favor of electron aggregation and ROS generation. Moreover, the consumption of glucose would decrease intracellular ATP for starvation therapy. Given the higher oxidation ability of Co3+, CPCs@PEG nanospheres possess catalase (CAT) activity to convert H2O2 into O2 for assisting ROS generation. Moreover, they also can oxidize glutathione (GSH) as a mimic GSH oxidase to break intratumor redox balance, facilitating oxidative stress. More importantly, the nanocomposites reveal good degradation ability dominated by the oxidation from insoluble phosphide into soluble phosphate, accelerating elimination via urine and feces within 14 days. CPCs@PEG nanospheres integrate the above effects not only to reveal great tumor inhibition ability but also to excite immune activation for anticancer.