Abstract
Shape-morphing uses a single actuation source for complex-task-oriented multiple patterns generation, showing a more promising way than reconfiguration, especially for microrobots, where multiple actuators are typically hardly available. Environmental stimuli can induce additional causes of shape transformation to compensate the insufficient space for actuators and sensors, which enriches the shape-morphing and thereby enhances the function and intelligence as well. Here, making use of the ionic sensitivity of alginate hydrogel microstructures, we present a shape-morphing strategy for microrobotic end-effectors made from them to adapt to different physiochemical environments. Pre-programmed hydrogel crosslinks were embedded in different patterns within the alginate microstructures in an electric field using different electrode configurations. These microstructures were designed for accomplishing tasks such as targeting, releasing and sampling under the control of a magnetic field and environmental ionic stimuli. In addition to structural flexibility and environmental ion sensitivity, these end-effectors are also characterized by their complete biodegradability and versatile actuation modes. The latter includes global locomotion of the whole end-effector by self-trapping magnetic microspheres as a hitch-hiker and the local opening and closing of the jaws using encapsulated nanoparticles based on local ionic density or pH values. The versatility was demonstrated experimentally in both in vitro environments and ex vivo in a gastrointestinal tract. Global locomotion was programmable and the local opening and closing was achieved by changing the ionic density or pH values. This ‘structural intelligence’ will enable strategies for shape-morphing and functionalization, which have attracted growing interest for applications in minimally invasive medicine, soft robotics, and smart materials.
Highlights
Shape-morphing uses a single actuation source for complex-task-oriented multiple patterns generation, showing a more promising way than reconfiguration, especially for microrobots, where multiple actuators are typically hardly available
To create an intelligent shape-morphing microrobot, a heterogeneous architecture should be embedded into a single hydrogel so that the structure can undergo autonomous shape morphing under various physiochemical environments
The alginate hydrogel microstructures remaining on the electrodes were detached and collected by washing with N-2-hydroxyethylpiperazine-N-2ethane sulfonic acid (HEPES) buffer
Summary
Shape-morphing uses a single actuation source for complex-task-oriented multiple patterns generation, showing a more promising way than reconfiguration, especially for microrobots, where multiple actuators are typically hardly available. Pre-programmed hydrogel crosslinks were embedded in different patterns within the alginate microstructures in an electric field using different electrode configurations These microstructures were designed for accomplishing tasks such as targeting, releasing and sampling under the control of a magnetic field and environmental ionic stimuli. It can be foreseen that environmental sensing and shape adaptivity are hurdles for achieving intelligent untethered microrobots designed for conducting tasks autonomously[25,26] These methods can neither generate ion-induced shape morphing microrobotic end-effector using a single degradable biomaterial through integral forming technique, nor develop a multi-field-controlled robotic system which can conduct different locomotion patterns and accomplish automatic transformation in the respective physiochemical environments. We present an ionic shapemorphing strategy for microrobots to adapt in physiochemical environments using alginate hydrogel microstructures, in which programmable hydrogel networks are spatially pre-embedded using an electric field, for accomplishing tasks, such as targeting, releasing, and sampling. We believe that the developed ISMEs hold great potential for medical applications, such as targeted therapy, precise diagnostics, and tissue repair and regeneration
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
