Plasmon enhanced catalysis-driven nanomotors with autonomous navigation for deep cancer imaging and enhanced radiotherapy

Abstract

Radiosensitizers potentiate the radiotherapy effect while effectively reducing the damage to healthy tissues. However, limited sample accumulation efficiency and low radiation energy deposition in the tumor significantly reduce the therapeutic effect. Herein, we developed multifunctional photocatalysis-powered dandelion-like nanomotors composed of amorphous TiO₂ components and Au nanorods (∼93 nm in length and ∼16 nm in outer diameter) by a ligand-mediated interface regulation strategy for NIR-II photoacoustic imaging-guided synergistically enhanced cancer radiotherapy. The non-centrosymmetric nanostructure generates stronger local plasmonic near-fields close to the Au–TiO₂ interface. Moreover, the Au–TiO₂ Schottky heterojunction greatly facilitates the separation of photogenerated electron–hole pairs, enabling hot electron injection, finally leading to highly efficient plasmon-enhanced photocatalytic activity. The nanomotors exhibit superior motility both in vitro and in vivo, propelled by H₂ generated via NIR-catalysis on one side of the Au nanorod, which prevents them from returning to circulation and effectively improves the sample accumulation in the tumor. Additionally, a high radiation dose deposition in the form of more hydroxyl radical generation and glutathione depletion is authenticated. Thus, synergistically enhanced radiotherapeutic efficacy is achieved in both a subcutaneous tumor model and an orthotopic model.