Ultrasound-Triggering Carbon Monoxide Release from Rhodium Nanoparticles for Myocardial Infarction Treatment.

ST-segment elevation myocardial infarction (STEMI) represents the most severe clinical manifestation of coronary heart disease. Despite the availability of current treatments, their high cost and surgical complexity have limited their effectiveness in reducing the associated high rates of disability and mortality. Additionally, conventional nanoparticles face significant challenges in achieving precise and controlled drug release within the infarcted myocardium. In this study, we developed a carbon monoxide (CO)-releasing system based on rhodium nanodots. The resulting nanoparticles (Rh-PEG-CO NDs) enable site-specific CO release from infarcted cardiac tissue upon ultrasound stimulation. The combination of CO and rhodium nanodots effectively scavenges reactive oxygen species (ROS) and mitigates postinfarction myocardial fibrosis, thereby attenuating the inflammatory response in the infarcted region. Both in vitro and in vivo experiments demonstrated that these functional nanoparticles exhibit high efficacy in inhibiting cardiomyocyte apoptosis, reversing pathological cardiac remodeling, and improving overall cardiac function. This study presents a novel CO-releasing platform that advances the clinical potential of CO-based therapies and underscores the promise of metal-based nanomaterials in biomedical applications.