Cascade‐amplified Oxidative Stress via Bandgap‐Tuned KBiO ₃ Perovskite for Cancer Therapy

Abstract Sonodynamic therapy (SDT) is a promising cancer treatment due to its ability to utilize ultrasound (US) to activate sonosensitizers, generating reactive oxygen species (ROS) for tumor suppression. High‐valence bismuth, known for its unique photoacoustic properties and biocompatibility, has shown great potential when combined with SDT. However, conventional sonosensitizers with large bandgaps and electron‐hole recombination have limited SDT's effectiveness. Herein, a bismuth‐based piezoelectric sonosensitizer is developed, DSPE‐PEG 2000‐modified KBiO ₃ (KBP), which features a reduced bandgap (1.9 eV). This facilitates electron transfer and depletes glutathione in the tumor microenvironment. Under the US, the piezoelectric sonosensitizer KBP generates a significant amount of ROS, leading to cancer cell pyroptosis via the ROS‐NLRP3‐Caspase‐1‐GSDMD pathway. Both in vitro and in vivo experiments demonstrated that the piezoelectric SDT treatment can effectively inhibit tumor growth. This research offers a novel approach to cancer treatment by leveraging the advantages of piezoelectric SDT, demonstrating promising clinical potential for tumor inhibition.