Therapeutic ultrasound enables rapid and robust activation of ROS-responsive prodrugs in vivo

Abstract Reactive oxygen species (ROS)-responsive prodrugs offer a route to disease-selective drug activation, but their in vivo performance is often constrained by heterogeneous ROS production, short ROS lifetimes and reductive quenching. Therapeutic ultrasound can generate reactive species locally and on demand in deep tissues, yet whether conventional ROS-responsive masking groups respond productively to sonochemical activation and enable efficient drug release remains unclear. Here we show that, among representative ROS-responsive triggers, boronic acid/boronate motifs emerge as the most productive ultrasound-responsive motifs for prodrug activation, enabling rapid, robust and programmable release. Mechanistic studies indicate that this performance arises from a mixed sonochemical oxidation regime, in which hydrogen peroxide serves as the longer-lived oxidant and sustains major boronate oxidation, while transient hydroxyl radicals provide additional contributions. We validate this strategy using fluorogenic probes, doxorubicin and monomethyl auristatin E (MMAE) prodrugs, and an albumin–MMAE conjugate. In tumour-bearing mice, localized ultrasound enables therapeutic activation of boronic acid/boronate-caged prodrugs within short irradiation windows, suppressing tumour growth while reducing systemic toxicity. These findings establish therapeutic ultrasound as an external trigger for spatiotemporally controlled prodrug activation in vivo and provide design principles for advancing ROS-responsive prodrug chemistry beyond the constraints of endogenous ROS activation.