Wireless Modular Millirobots With Magnetic Actuation for Targeted Cardiac Drug Delivery

ABSTRACT Infective endocarditis remains difficult to treat due to limited drug accumulation at infection sites via systemic delivery and reliance on invasive, high‐risk surgery. To address this, we present a wireless, modular millirobotic system actuated by external magnetic fields for targeted cardiac drug delivery. We validate the system in vitro using an agarose heart phantom under physiologically relevant pulsatile flow and ex vivo by demonstrating tissue penetration and module undocking in excised porcine heart tissue. The system comprises two cooperative millirobots: a barbed needle module that reduces tissue penetration force by 66.7% in cardiac tissue‐mimicking gels, and a drug module capable of delivering 22 microliter liquid doses over 180 min. AI‐assisted vision guidance enables autonomous navigation with root‐mean‐square tracking errors of 0.23 and 0.26 body lengths for the needle and drug modules, respectively. The modules support on‐demand magnetic docking and undocking, achieving success rates of 100% and 93%, respectively. These results highlight the potential of modular millirobots for precise, repeatable, and minimally invasive cardiac therapies.