Tumbler-Inspired Microneedle Containing Robots: Achieving Rapid Self-Orientation and Peristalsis-Resistant Adhesion for Colonic Administration

Microneedle containing miniature robots offer a promising route for gastrointestinal administration since their capability of transmucosal delivery and controllable drug release. However, many challenges still lie ahead such as the intricate control modes, destitute systematic theory of the locomotion and adhesion behaviors, failure due to peristalsis and fluid flow, and risk of ileus. Herein, an untethered microneedle containing robots is designed for specific colonic administration, which can dispense with control systems, achieve fast self-orientation and adhesion onto the mucosa (<0.6 s), against physiology of peristalsis, and show low risks of obstruction. Further, the detachable layer between the microneedle and the robots can degrade under a time of 6 min, which ensures safely discharge under a small, excreted force of 20 mN induced by fluid flow. Through the optimism of microneedles, different drug release times can be achieved including 14 min, 2 days, 4 days, and 30 days, respectively. The in vivo experiments also demonstrate the effectiveness and feasibility of the robots. These robots can serve as a versatile platform to treat diseases such as chronic inflammation and cancer of the colon to minimize invasive surgical intervention and patient suffering.