An ultrasmall theranostic nanozyme for abdominal aortic aneurysm management and therapeutic efficacy monitoring.

Abdominal aortic aneurysm (AAA) is a life-threatening condition lacking effective drug interventions, and its progression is difficult to predict, complicating early clinical management. Here, we present a reactive oxygen species-responsive theranostic nanozyme for AAA early intervention and efficacy monitoring, establishing a feedback loop between treatment and diagnostics. OZn, designed by encapsulating ultrasmall Prussian blue (SPBZn) within oxidation-sensitive dextran, targets aneurysm sites, where it responds to inflammatory microenvironments by releasing SPBZn. In vivo, SPBZn not only mitigated CaCl2-induced aneurysm expansion and AAA progression in rat models but also enabled noninvasive diagnostic monitoring via urinalysis due to its enzymatic activities and renal metabolism. This theranostic nanozyme dynamically regulated therapeutic efficacy and provided feedback on disease progression. By preventing vascular rupture through early intervention and enabling precise drug administration, this work highlights a transformative strategy for integrating diagnostics and therapy to improve AAA management and clinical outcomes.