CAT and cancer: Unlike ROS-mediated PDT, which is limited by the penetration depth and damage to normal tissue, SDT could treat deep-seated tumors safely with sonosensitizer-loaded exosomes.164 For example, owing to the BBB and hypoxic TME, conventional SDT generally leads to poor outcomes.165,166 However, AS1411 aptamer-modified macrophage exosomes possess efficient BBB penetration and precise cancer cell-targeting capability,167 which consists of catalase (CAT)-loaded silica nanoparticles (CAT@SiO2) and the sonosensitizer ICG.