Hollow magnetic nanosystem-boosting synergistic effect between magnetic hyperthermia and sonodynamic therapy via modulating reactive oxygen species and heat shock proteins

As a promising treatment modality with spatial and temporal control, alternating magnetic field (AMF) triggered magnetic hyperthermal therapy (MHT) shows broad and promising applications to overcome the drawbacks of traditional focal therapies in combating cancer. However, the MHT efficacy is still not satisfactory with the presence of heat shock proteins (HSPs). In addition, sustained tumor hypoxia haunts practical implications for the treatment of solid tumors. Herein, a novel magnetic nanosystem composed of hollow iron oxide nanoparticles (HIONs), Fe3O4, and sonosensitizers, hematoporphyrin (HP) was rationally designed and successfully synthesized. The hollow HIONs show a large inner cavity for loading sonosensitizer molecules and possess nanozyme activity for catalyzing decomposition of endogenous overexpressed hydrogen peroxide (H2O2) to produce molecular oxygen (O2) that can overcome tumor hypoxia, thus augmenting the sonodynamic therapy (SDT)-induced highly toxic reactive oxygen species (ROS) production for efficient cancer cell apoptosis. Importantly, the generated ROS can also activates the cleavage of HSPs that further eliminate themotolerance and facilitates MHT efficacy. The synergistic catalysis-enhanced SDT efficiency and MHT effect realized most potent tumor suppression efficacy. This work develops a versatile nanoplatform for a multifunctional strategy and broadens the biological applications by rationally designing their structure.