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

Miniature soft robots have evolved into various therapeutic applications due to good adaptability. Nonetheless, complex terrains inside body, especially soft wrinkled topography with non-Newtonian viscous mucus in the gastrointestinal tract, pose a strict demand on the navigation of such robots. To address the challenge, here a design inspiration derived from sea urchin is proposed to fabricate the 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 low-frequency magnetic field, significantly reducing surface friction and improving environmental adaptability. This motion ability is further supported by US-imaging-guided navigation in an ex vivo and even in vivo gastrointestinal tract. When the high-frequency magnetic field is exerted, the drug-loaded blood coagulation gel sealed inside the robot melts by magnetothermal effect, thereby releasing drugs at the targeted location. The synergy of magnetothermal and pharmacological therapy enable this robot to exhibit enhanced antibacterial efficiency for ex vivo and in vivo bacterial infection and inflammation. Such soft robots with exceptional adaptability and therapeutic functions offer high potential for targeted delivery and therapy through lumens inside body.