Long-Circulating Au-TiO₂ Nanocomposite as a Sonosensitizer for ROS-Mediated Eradication of Cancer

Although sonodynamic therapy (SDT) has emerged as a potential alternative to conventional photodynamic therapy, the low quantum yield of the sonosensitizer such as TiO₂ nanoparticles (NPs) is still a major concern. Here, we have developed hydrophilized Au-TiO₂ nanocomposites (HAu-TiO₂ NCs) as sonosensitizers for improved SDT. The physicochemical properties of HAu-TiO₂ NCs were thoroughly studied and compared with their counterparts without gold deposition. Upon exposure of HAu-TiO₂ NCs to ultrasound, a large quantity of reactive oxygen species (ROS) were generated, leading to complete suppression of tumor growth after their systemic administration in vivo. Overall, it was evident that the composites of gold with TiO₂ NPs significantly augmented the levels of ROS generation, implying their potential as SDT agents for cancer therapy.