Micro/Nanoparticle‐Augmented Sonodynamic Therapy (SDT): Breaking the Depth Shallow of Photoactivation

The fast development of photoactivation for cancer treatment provides an efficient photo‐therapeutic strategy for cancer treatment, but traditional photodynamic or photothermal therapy suffers from the critical issue of low in vivo penetration depth of tissues. As a non‐invasive therapeutic modality, sonodynamic therapy (SDT) can break the depth barrier of photoactivation because ultrasound has an intrinsically high tissue‐penetration performance. Micro/nanoparticles can efficiently augment the SDT efficiency based on nanobiotechnology. The state‐of‐art of the representative achievements on micro/nanoparticle‐enhanced SDT is summarized, and specific functions of micro/nanoparticles for SDT are discussed, from the different viewpoints of ultrasound medicine, material science and nanobiotechnology. Emphasis is put on the relationship of structure/composition‐SDT performance of micro/nanoparticle‐based sonosensitizers. Three types of micro/nanoparticle‐augmented SDT are discussed, including organic and inorganic sonosensitizers and micro/nanoparticle‐based but sonosensitizer‐free strategies to enhance the SDT outcome. SDT‐based synergistic cancer therapy augmented by micro/nanoparticles and their biosafety are also included. Some urgent critical issues and potential developments of micro/nanoparticle‐augmented SDT for efficient cancer treatment are addressed. It is highly expected that micro/nanoparticle‐augmented SDT will be quickly developed as a new and efficient therapeutic modality which will find practical applications in cancer treatment. At the same time, fundamental disciplines regarding materials science, chemistry, medicine and nanotechnology will be advanced.