Hydrophobic soft cone-assisted rolling robot inspired by sea urchins for gastrointestinal tract delivery

Miniature soft robots have evolved into various therapeutic materials because of their good adaptability. Nonetheless, complex terrains inside the body, especially soft wrinkled topographies with non-Newtonian viscous mucus in the gastrointestinal (GI) tract, pose a strict demand for the navigation of such robots. To address this challenge, a design inspired by sea urchins is proposed to fabricate a soft-cone-assisted rolling robot (SCARBot) by encapsulating blood coagulation gel, creating a hollow cylindrical structure for loading drugs inside. The arrangement of an array of soft cones with manually designed hydrophobicity allows for controlled locomotion of the robots under a low-frequency magnetic field, significantly reducing surface friction and improving environmental adaptability. This motion ability is further supported by ultrasound (US) imaging-guided navigation in the ex vivo and even in vivo GI tract. When a high-frequency magnetic field is applied, the drug-loaded blood coagulation gel inside the robot melts by a magnetothermal effect, thereby releasing drugs at the targeted location. The synergy of magnetothermal and pharmacological therapy enables this robot to exhibit enhanced antibacterial efficiency for ex vivo and in vivo bacterial infection and inflammation. Soft robots with exceptional adaptability and therapeutic functions offer high potential for targeted delivery and therapy through lumens inside the body.