MnO 2 -Based Nanomotors with Active Fenton-like Mn 2+ Delivery for Enhanced Chemodynamic Therapy.

Chemodynamic therapy (CDT) is an emerging strategy for cancer treatment based on Fenton chemistry, which can convert endogenous H ₂ O ₂ into toxic ·OH. However, the limited endocytosis of passive CDT nanoagents with low penetrating capability resulted in unsatisfactory anticancer efficacy. Herein, we propose the successful fabrication of a self-propelled biodegradable nanomotor system based on hollow MnO ₂ nanoparticles with catalytic activity for active Fenton-like Mn ²⁺ delivery and enhanced CDT. Compared with the passive counterparts, the significantly improved penetration of nanomotors with enhanced diffusion is demonstrated in both the 2D cell culture system and 3D tumor multicellular spheroids. After the intracellular uptake of nanomotors, toxic Fenton-like Mn ²⁺ is massively produced by consuming overexpressed intracellular glutathione (GSH), which has a strong scavenging effect on ·OH, thereby leading to enhanced cancer CDT. The as-developed MnO ₂ -based nanomotor system with enhanced penetration and endogenous GSH scavenging capability shows much promise as a potential platform for cancer treatment in the near future.