Squid-Inspired Multifunctional Retainable Magnetic Soft Robot: Foreign Body Transport and Transmucosal Drug Delivery in Complex Gastrointestinal Environments.

Magnetically controlled soft microrobots, by virtue of their exceptional flexibility and noninvasiveness, exhibit immense potential in the field of minimally invasive diagnosis and treatment within complex physiological environments. However, existing microrobot research is largely limited to the integration of single functions, and often faces bottlenecks such as insufficient pinpointing ability and difficulty in transmucosal drug delivery when encountering slippery and dynamic biological barriers like the gastrointestinal tract. Here, inspired by the grasping, jetting, and adhesive characteristics of squid tentacles, we report an integrated, multifunctional Squid-Inspired Retainable Magnetic Robot (SRMR). By employing a spatially programmable magnetization distribution and a gradient magnetic powder loading strategy, the SRMR is capable of reconfiguring its locomotion modes according to topographical requirements, enabling cross-scale motion control and functional execution. Results demonstrate that the SRMR possesses the ability to move stably in unstructured environments, utilizing rotating, swinging, and conical magnetic fields to transition between multiple modes, including rolling, walking, and even jumping. By integrating a drug delivery module based on swellable materials and microneedle arrays, the SRMR can precisely penetrate mucosal barriers under the drive of instantaneous gradient magnetic forces, achieving the active delivery of macromolecular drugs. Furthermore, combined with a "dry-wet synergistic" retention strategy, the robot can not only dexterously encapsulate and transport foreign bodies within the digestive tract but also maintain robust positional stability under complex fluid flushing. This microrobotic system, which integrates multimodal locomotion, foreign body handling, and transmucosal drug delivery, holds great promise for future wireless medical intervention tasks within confined regions of the human body.