New types of flexible microrobots are enabled by patterning discrete 3D magnetization.

Intelligent magnetic soft robots capable of programmable structural changes and multifunctionality modalities depend on material architectures and methods for controlling magnetization profiles. While some efforts have been made, there are still key challenges in achieving programmable magnetization profile and creating heterogeneous architectures. Here, we directly embed programmed magnetization patterns (magnetization modules) into the adhesive sticker layers to construct soft robots with programmable magnetization profiles and geometries and then integrate spatially distributed functional modules. Functional modules including temperature and ultraviolet light sensing particles, pH sensing sheets, oil sensing foams, positioning electronic component, circuit foils, and therapy patch films are integrated into soft robots. These test beds are used to explore multimodal robot locomotion and various applications related to environmental sensing and detection, circuit repairing, and gastric ulcer coating, respectively. This proposed approach to engineering modular soft material systems has the potential to expand the functionality, versatility, and adaptability of soft robots.

Complex 3D miniature wireless soft machines for biomedical applications were fabricated with a 3D heterogeneous integration approach.

Manipulation of micrometer to millimeter-scale objects is central to biotechnological and medical applications involving small-scale robotic devices. Mobile untethered microgrippers have been developed, which use magnetic fields for motion and activation of grasping. This letter extends the capabilities of such microgrippers by presenting the first example of reliable and autonomous three-dimensional (3-D) micrograsping and cargo delivery of a microgripper using simple control strategies. This endeavor will allow microgrippers to reliably grasp and transfer microobjects, such as cells, with minimal user input, which is ideal for cooperative tasks performed by multiple microgrippers in future work. The proposed controller autonomously manipulates a 3-D magnetic microgripper for pick-and-place tasks in the 3-D space. By regulating the remotely applied force on the microgripper, the 3-D position and velocity of the microgripper are controlled, and the microgripper grasping, i.e., opening and closing, is determined by the magnetic field strength. In experiments, the microgripper successfully grasps cargoes with cubic, irregular, triangular, and beam shapes using at most 5, 8 , 20, and 24 attempts, respectively. The microgripper shown here demonstrates fast grasping due to their complete magnetic actuation method. Moreover, a preliminary cell viability test suggests that the microgripper has no adverse effects on living cells. This study proves the proposed microgripper and controller to be agile and reliable tools for biomedical tasks.

Liquid crystal elastomers exhibit large reversible strain and programmable shape transformations, enabling various applications in soft robotics, dynamic optics, and programmable origami and kirigami. The morphing modes of these materials depend on both their geometries and director fields. In two dimensions, a pixel-by-pixel design has been accomplished to attain more flexibility over the spatial resolution of the liquid crystal response. Here we generalize this idea in two steps. First, we create independent, cubic light-responsive voxels, each with a predefined director field orientation. Second, these voxels are in turn assembled to form lines, grids, or skeletal structures that would be rather difficult to obtain from an initially connected material sample. In this way, the orientation of the director fields can be made to vary at voxel resolution to allow for programmable optically- or thermally-triggered anisotropic or heterogeneous material responses and morphology changes in three dimensions that would be impossible or hard to implement otherwise.

Soft materials that respond to wireless external stimuli are referred to as “smart” materials due to their promising potential in real‐world actuation and sensing applications in robotics, microfluidics, and bioengineering. Recent years have witnessed a burst of these stimuli‐responsive materials and their preliminary applications. However, their further advancement demands more versatility, configurability, and adaptability to deliver their promised benefits. Here, a dual‐stimuli‐responsive soft bimorph material with three configurations that enable complex programmable 3D shape‐morphing is presented. The material consists of liquid crystal elastomers (LCEs) and magnetic‐responsive elastomers (MREs) via facile fabrication that orthogonally integrates their respective stimuli‐responsiveness without detrimentally altering their properties. The material offers an unprecedented wide design space and abundant degree‐of‐freedoms (DoFs) due to the LCE's programmable director field, the MRE's programmable magnetization profile, and diverse geometric configurations. It responds to wireless stimuli of the controlled magnetic field and environmental temperature. Its dual‐responsiveness allows the independent control of different DoFs for complex shape‐morphing behaviors with anisotropic material properties. A diverse set of in situ reconfigurable shape‐morphing and an environment‐aware untethered miniature 12‐legged robot capable of locomotion and self‐gripping are demonstrated. Such material can provide solutions for the development of future soft robotic and other functional devices.