Alternating Interlayered Piezoelectric Self-Heterojunction Boosts Sono-Piezocatalytic Pyroptosis Oncotherapy

Recombination of sono-generated charge carriers is a major barrier hindering the effectiveness of piezocatalytic oncotherapy. Herein, ultrathin oxygen vacancy-engineered self-heterojunction bismuth oxysilicate (O_v-BOS) nanosheets with alternating hetero-layered nanostructure are constructed for enhanced sono-piezocatalytic tumor therapy. Benefiting from its out-of-plane asymmetry, O_v-BOS features an exceptional electromechanical strain coefficient (d^* ₃₃ = 203 pm/V), highlighting its outstanding capability as a piezoelectric heterojunction for energy conversion. Particularly, the oxygen vacancy engineering facilitates the spatial redistribution of bands across the alternating [Bi₂O₂] and [SiO₃] layers in O_v-BOS, promoting effective charge separation and stratified charge storage, thereby further suppressing recombination of sono-generated charge carriers in a manner analogous to heterojunctions. Leveraging this strategy, O_v-BOS demonstrates efficient reactive oxygen species production and exhibits superior peroxidase and catalase-like activities compared to the conventional piezoelectric nanocatalysts. Consequently, the enhanced radical generation induced the specific cancer-cell pyroptosis via caspase-3 mediated gasdermin E-dependent pathway. Therefore, the engineered interlayer self-heterojunction provides an efficient strategy for the design and engineering of high-performance piezoelectric nanocatalysts.