Magnetic soft elastomers with spatially programmed magnetization profiles can generate complex shape-morphing and locomotion dynamics. Enabled by their unique locomotion capabilities, magnetically programmed soft robots have been proposed for various biomedical applications, including targeted and localized delivery of liquid cargos, such as therapeutic drugs. Current magnetic soft material designs for targeted cargo delivery employ dedicated chambers for loading and integrated valve mechanisms for releasing, which can severely affect the locomotion capabilities or necessitate complicated designs for actuation. Therefore, new strategies are required for incorporating liquid payloads into magnetic soft materials without affecting their locomotion modality, preserving these payloads during transport, and on-demand release via external stimuli once the target location is reached. In this paper, we present magnetic soft elastomers with an interconnected porous internal structure, enabling loading of liquid payloads into the material while preserving magnetic programmability. Furthermore, microcrystalline wax sealing on the outer surface allows locomotion at lower magnetic fields and on-demand seal breaking and releasing of cargos at greater magnetic fields. The cargo loading and on-demand release strategy introduced here enables magnetically co-encoding locomotion and cargo-release and establishes the groundwork for multifunctional magnetic soft materials with potential applications ranging from soft robotics to medical devices and bio interfaces.
Zhou et al. (Thu,) studied this question.