Multifunctional Magnetic Origami Robots

Millimeter/centimeter-scale origami robots have recently been explored for biomedical applications due to their inherent shape-morphing capability. However, they mainly rely on passive or/and irreversible deformation that significantly hinders the clinic functions in an on-demand manner. Here, we report magnetically actuated crawling and swimming origami robots for effective locomotion and targeted drug delivery in severely confined spaces and aqueous environments. We design our robots based on the Kresling origami, whose thin shell structure 1) provides an internal cavity for drug storage, 2) permits torsion-induced contraction as the mechanism for crawling and controllable drug release, 3) serves as propellers that spin for propulsion to swim, 4) offers anisotropic stiffness to overcome the large resistance from the severely confined spaces in biomedical environments. These magnetic origami robots can potentially serve as minimally invasive devices for biomedical diagnoses and treatments.<br/><br/>Biomimetic soft robotic crawlers have attracted extensive attention in various engineering fields, owing to their inherent adaptivity to different terrains. Earthworm-like crawlers realize locomotion through in-plane contraction, while inchworm-like crawlers exhibit out-of-plane bending-based motions. The in-plane contractive crawling mechanism surpasses the bending-based one in confined spaces where out-of-plane motion is either constrained or unfeasible. Although in-plane contraction crawlers are more effective in confined spaces, miniaturization is challenging due to the limitations of actuation methods and complex structures. To address those challenges, we report a magnetically actuated small-scale origami crawler with in-plane contraction. The contraction mechanism is achieved through a four-unit Kresling origami assembly consisting of two Kresling dipoles with two-level symmetry designed for purely translational crawling motion. Magnetic actuation is utilized to provide appropriate torque distribution on the crawler, enabling a small-scale and untethered robot with both crawling and steering capabilities. Because the Kresling crawler exhibits anisotropic and magnetically tunable structure stiffness, it can overcome the large resistance from severely confined spaces during crawling. Finally, the multifunctionality of the crawler is explored by utilizing the internal cavity in the Kresling origami for drug storage and release. The magnetic origami crawler has the potential to serve as a minimally invasive device for biomedical diagnoses and treatments.