Soft Sensory Robots based on Stimuli-Responsive Hydrogels for Electronic Implants

Living organisms with motor and sensor units integrated seamlessly exhibit effective adaptation to dynamically changing environments. Taking inspiration from coherent integration between skeletal muscles and sensory skins in human, we present a design strategy for soft robots, primarily consisting of an electronic skin (e-skin) and an artificial muscle, that naturally couples multifunctional sensing and on-demand actuation in a soft, biocompatible platform. here, we will describe an <i>in situ</i> solution-based method to create the e-skin layer with a series of sensing materials (e.g., silver nanowires, reduced graphene oxide, and poly(3,4-ethylenedioxythiophene) polystyrene sulfonate) incorporated within a polymer matrix (e.g., polyimide and polydimethylsiloxane), imitating human skin with complex receptors to perceive various stimuli. Biomimicry designs (e.g., starfish and chiral seedpods) of the soft robots enable various active motions (e.g., bending, expanding, and twisting) on demand and realize good fixation and stress-free contact with tissues. Furthermore, integration of a battery-free wireless module into these soft robots enables robotic operation and communication without tethering, thus enhancing safety and biocompatibility of the soft robots as minimally invasive implants. Demonstrated examples range from a robotic cuff enclosing around a blood vessel for precise detection of blood pressure, a robotic gripper holding onto a bladder for accurately tracking bladder volume, an ingestible robot residing inside stomach for pH sensing and on-site drug delivery, to a robotic patch wrapping onto a beating heart for quantifying cardiac contractility, temperature and applying cardiac pacing, highlighting the application versatilities and potentials of the bioinspired soft robots. Our designs of soft robots could establish a promising strategy to integrate a broad range of sensing and responsive materials, for forming highly integrated systems for medical technology and beyond.