Advances in sonodynamic therapy for metal complexes in biomedical research: challenges and future perspectives

Sonodynamic therapy (SDT) is a novel, non-invasive cancer treatment that uses sonosensitizers and very low-intensity ultrasound radiation. Inspired by photodynamic therapy, this rapidly emerging technique mitigates the severe drawbacks of PDT, PTT, and related techniques, such as simple mechanisms of action and limited deep-tissue penetration. Although mushrooming research has been undertaken by a score of investigators in the field of cancer therapy, it is still in its infancy. This review will focus on recent updates on the application of metal complexes (with special emphasis on transition-metal complexes of Ru, Ir, Re, Pt, and Mn), highlighting their unique use as sonosensitizers for targeted applications in cancer therapy, design principles, basic mechanisms of action, sprints during the application process, and future perspectives. We believe that this sustainable, innovative technique could be one of the best plausible alternatives in the near future, and this not-so-explored field will be one of the best choices for the treatment of the perilous disease, cancer, and will help future researchers to explore more about the sustained specific advantages and disadvantages of metal complexes relative to established organic sonosensitizers and previous research studies in terms of ROS yield, stability, hypoxia tolerance, imaging capability, toxicity, and clinical translatability.