Piezo-photodynamic therapy of Au@PEG-ZnO nanostructures enabled with a battery-free wireless cancer therapeutic dot

Cancer remains a global health concern, necessitating advanced therapeutic strategies to address its fatal challenges. Conventional treatments, such as radiotherapy and chemotherapy, often lack tumor specificity and may induce systemic toxicity. Photodynamic therapy (PDT) and sonodynamic therapy (SDT) have emerged as promising alternatives, demonstrating high specificity and minimal side effects. In this study, we propose a novel piezo-photodynamic therapy (PPDT) enabled with battery-free wireless cancer therapeutic dot, in which the nanocomposites of gold nanoparticles (Au NPs), zinc oxide nanorods (ZnO NRs) and hydrophilic polyethylene glycol (PEG) can enhance reactive oxygen species (ROS) generation and effectively inhibit tumor growth. The therapeutic dot is implanted directly inside the tissue around the tumor and wirelessly controlled by ultrasound (US), allowing dual activation of electron-hole pairs from the nanocomposites via US and ultraviolet light (UV). The internally generated piezoelectric field minimizes electron-hole recombination, maximizing ROS induction within tumor cells. This PPDT approach surpasses the efficacy of conventional PDT and SDT, showcasing a synergistic therapeutic effect. The study further elucidates the detailed mechanism of Au@PEG-ZnO NRs catalysts, providing insights into their piezoelectric-photocatalytic action. The battery-free wireless control and minimally invasive implantation of the therapeutic dot with inorganic piezo-photocatalyst open new perspectives in cancer therapy.