Su Ryon Shin1
Harvard Medical School1
Engineered living-synthetic systems possess functions to dynamically control their shape and movements in biological environments that are pertinent to various biomedical applications, such as building biorobots and artificial muscles. To create functional bio-hybrid systems, in vivo-like living natural components such as 2D and 3D muscle tissue constructs, and their contractile function are required to be integrated into artificial platforms. Among various biomaterials, electrically conductive nanoparticles-incorporated hydrogels, which can improve the nanofibrous morphology and electrical and mechanical properties of conventional hydrogels while maintaining the hydrogels’ beneficial properties, such as high porosity, biocompatibility, and biodegradability, are required to develop scaffolds mimicking biological and physical properties of native extracellular matrices (ECMs). These nanofibrous and electrically conductive scaffolds showed excellent myofiber maturation and organization along with cell-cell junction formation, providing self-actuating motions. Also, these nano-biomaterials can be engineered by various microfabrication techniques (i.e., bioprinting) to create 3D complex architectures, such as accordion-inspired hydrogel-based scaffolds which replicated the native myofiber architecture together with its function in terms of robustness and enhanced contractibility after culturing with cardiomyocytes. Recently, the maneuvering of bio-hybrid soft robots has been controlled by various strategies, such as by electrical and optical stimulations. We have developed advanced technologies to control the biohybrid soft robots by integrating flexible microelectrodes into soft and deformable engineered scaffolds to stimulate muscle actuators locally. Harnessing wireless power transfer technology without requiring batteries and wires, we developed untethered biohybrid soft robots that could swim; whereby, the steering of this swimming motion could be remotely controlled by transmitting electrical power into a cell simulator wirelessly. To this end, wirelessly powered, stretchable, and lightweight cell stimulators were successfully integrated into self-actuating soft muscle bodies without impeding the robot’s underwater swimming ability. Wirelessly modulated electrical frequencies enabled us to control the speed and direction of the biohybrid soft robots. This innovative approach should provide a platform for building untethered biohybrid systems for various biomedical applications.