Dual‐Functional Laser‐Guided Magnetic Nanorobot Collectives against Gravity for On‐Demand Thermo‐Chemotherapy of Peritoneal Metastasis

Abstract Combining hyperthermic intraperitoneal chemotherapy with cytoreductive surgery is the main treatment modality for peritoneal metastatic (PM) carcinoma despite the off‐target effects of chemotherapy drugs and the ineluctable side effects of total abdominal heating. Herein, a laser‐integrated magnetic actuation system that actively delivers doxorubicin (DOX)‐grafted magnetic nanorobot collectives to the tumor site in model mice for local hyperthermia and chemotherapy is reported. With intraluminal movements controlled by a torque‐force hybrid magnetic field, these magnetic nanorobots gather at a fixed point coinciding with the position of the localization laser, moving upward against gravity over a long distance and targeting tumor sites under ultrasound imaging guidance. Because aggregation enhances the photothermal effect, controlled local DOX release is achieved under near‐infrared laser irradiation. The targeted on‐demand photothermal therapy of multiple PM carcinomas while minimizing off‐target tissue damage is demonstrated. Additionally, a localization/treatment dual‐functional laser‐integrated magnetic actuation system is developed and validated in vivo, offering a potentially clinically feasible drug delivery strategy for targeting PM and other intraluminal tumors.