Active microgel particle swarms for intrabronchial targeted delivery.

Intrabronchial delivery of therapeutic agents is critical to the treatment of respiratory diseases. Targeted delivery is demanded because of the off-target accumulation of drugs in normal lung tissues caused by inhalation and the limited motion dexterity of clinical bronchoscopes in tortuous bronchial trees. Herein, we developed microrobotic swarms consisting of magnetic hydrogel microparticles to achieve intrabronchial targeted delivery. Under programmed magnetic fields, the microgel particle swarms performed controllable locomotion and adaptative structure reconfiguration in tortuous and air-filled environments. The swarms were further integrated with imaging contrast agents for precise tracking under x-ray fluoroscopy and computed tomography imaging. Magnetic navigation of the swarms in an ex vivo lung phantom and in vivo delivery into deep branches of the bronchial trees were achieved. The on-demand reconfiguration of swarms for avoiding the microgel particles from entering nontarget bronchi and the precise delivery into tilted bronchi through climbing motion were validated.