Ultrathin-FeOOH-Coated MnO2 Sonosensitizers with Boosted Reactive Oxygen Species Yield and Remodeled Tumor Microenvironment for Efficient Cancer Therapy

Sonodynamic therapy (SDT) typically suffers from compromised anticancer efficacy owing to the low reactive oxygen species (ROS) yield and complicated tumor microenvironment (TME) which can consume ROS and support the occurrence and development of tumors. Herein, ultrathin-FeOOH-coated MnO2 nanospheres (denoted as MO@FHO) as sonosensitizers which can not only facilitate ultrasound (US)-triggered ROS but also tune the TME by hypoxia alleviation, H2O2 consumption as well as glutathione (GSH) depletion are designed. The FeOOH coating will boost the production yield of singlet oxygen (O-1(2)) and hydroxyl radicals ((OH)-O-center dot) by inhibiting the recombination of US-initiated electron-hole pairs and Fenton-like reaction, respectively. Additionally, the catalase-like and GSH peroxidase-like activities of MO@FHO nanospheres enable them to break the TME equilibrium via hypoxia alleviation and GSH depletion. The combination of high ROS yield and fundamental destruction of TME equilibrium results in satisfactory antitumor outcomes, as demonstrated by the high tumor suppression efficacy of MO@FHO on MDA-MB-231-tumor-bearing mice. No obvious toxicity is detected to normal tissues at therapeutic doses in vivo. The capability to modulate the ROS production and TME simultaneously can afford new probability for the development of advanced sonosensitizers for synergistic comprehensive cancer therapy.

Automated summary

This study designs ultrathin-FeOOH-coated MnO2 nanospheres as sonosensitizers to enhance the anticancer efficacy of sonodynamic therapy. The nanospheres facilitate ultrasound-triggered reactive oxygen species (ROS) production and modulate the tumor microenvironment. The results show that MO@FHO exhibits high tumor suppression efficacy without obvious toxicity to normal tissues.