Multimodal capsule micromotors with magnetic actuation, ultrasound imaging, and NIR-triggered drug release

Micro/nanomotors have gained substantial interest for their potential to enable precision therapy. However, achieving reliable in vivo control, particularly precise navigation, targeted accumulation within tumors, and spatiotemporally regulated drug release, remains a major challenge. In this study, we present a multifunctional capsule micromotor to overcome these barriers and enhance targeted therapy for bladder cancer. Using a microfluidic fabrication strategy, we engineered composite capsule micromotors that integrate magnetic nanoparticles, photothermal agents, and chemotherapeutic drugs. This design enables ultrasound-guided real-time imaging, magnetically directed locomotion, and near-infrared (NIR)-triggered drug release. In vitro studies revealed that the capsule micromotors rapidly accumulated on bladder tumor spheroids under magnetic field propulsion. Subsequent NIR irradiation induced pronounced local heating, resulting in capsule shell breakup and efficient drug release. The synergistic combination of magnetic navigation and photothermal activation significantly enhanced tumor cell killing. This system provides a promising strategy for achieving efficient, controllable, and minimally invasive tumor treatment within complex biological microenvironments.