Research progress on reactive oxygen species production mechanisms in tumor sonodynamic therapy

Figure 1 Schematic diagram of the different mechanisms of reactive oxygen species generation. A: Schematic diagram of the principle of sonodynamic therapy. Citation: Greenwald BD. Photodynamic therapy for esophageal cancer. Update. Chest Surg Clin N Am 2000; 10(3): 625-637. Copyright © 2011 American Cancer Society, Inc. Published by American Cancer Society, Inc; B: ROS generation by active piezoelectric catalysis. Piezoelectric materials in the electrostatic balance state release charge when under compressive stress and react with H₂O to produce •OH, and O₂ obtains negative charge to generate •O²⁻. Then Piezoelectric materials adsorb the charges from the surrounding electrolyte under reduced compressive stress, H₂O loses negative electrons to generate ·OH, and O₂ releases positive charge to generate •O²⁻. Citation: Wang Y, Wen X, Jia Y, Huang M, Wang F, Zhang X, Bai Y, Yuan G, Wang Y. Piezo-catalysis for nondestructive tooth whitening. Nat Commun 2020; 11(1): 1328. Copyright © The Author(s) 2020. Published by Springer Nature Limited.