Metal-based inorganic nanocrystals for biological sonodynamic therapy applications: recent progress and perspectives

With the fast development of technology for the treatment of tumor and bacteria, photo-therapeutic strategies emerge as a kind of highly effective and common treatment, but the low tissue penetration depth of light limits their development. Sonodynamic therapy (SDT), as an efficient and non-invasive treatment, attracts more people's attention due to the inherent property of high tissue penetration. The soft tissue penetration depth of ultrasound (US) can even reach more than 10 cm, which has great advantage over that of light. Therefore, many sonosensitizers are studied and applied to SDT-based therapy. Metal-based inorganic nanocrystals are able to generate more reactive oxygen species (ROS) due to the special composition and band structure. The representative achievements and the specific functions of the nanocrystals sonosensitizers are summarized in this work, and the relationship of structure/composition-SDT performance and the internally regulated composite is revealed. Synergistic effects of SDT in combination with other therapeutic modalities are mainly highlighted. At the same time, the critical and potential issues and future perspectives are addressed.