Metal-sensitized Au-Bi2O3 nanoheterojunction for immunogenic cell death-boosted sono-immuno cancer therapy

Sonodynamic tumor therapy is limited by inefficient sonosensitizers and complex tumor microenvironments. Given this, a concept of metal-sensitized sonocatalyst is proposed and defined as a catalyst based on the metal sensitization effect of noble metals to advance semiconductor sonocatalytic activity. We load Au nanorods onto wide-bandgap semiconductor bismuth oxide to favor its sonocatalytic properties for supporting the concept's practicality. In the catalytic nano-system, Au nanorods improve the ability of bismuth oxide to separate electrons and holes under ultrasound, promoting multifarious reactive oxygen species (ROS) generation and enhancing the photothermal effect. Synergistically, bismuth oxide can consume intratumoral overexpressed glutathione, further disrupting the redox balance. Thus, ROS and heat can directly induce immunogenic cell death, reversing tumor immunosuppressive microenvironment in concert and promoting dendritic cell maturation and CD8 + T cell infiltration. The proposed metal-sensitized sonocatalyst will open up new avenues for sonocatalytic therapy.