Extreme Mechanics of Hydrogels Toward In Situ Hydrogel Bioelectronics

In-situ bioelectronics, a rapidly evolving field focusing on the development of implantable/injectable/ingestible electronic devices that can operate within the body and seamlessly interact with biological systems, has the potential to revolutionize the field of medicine in a variety of ways such as real-time monitoring, personalized diagnosis, and targeted therapies. However, interfacing electronic components and biological systems is extremely challenging due to their fundamentally contradictory properties. Hydrogels, polymer networks infiltrated with water, share similar mechanical and physiological properties with biological tissues, and are therefore exploited as an ideal material candidate to form long-term, high-efficacy, multi-modal interfaces between electronic components and biological systems. An emerging class of in-situ bioelectronics that combines hydrogel technologies with electronic components to create devices that can interact with harsh environments within the body, which we define as in-situ hydrogel bioelectronics , holds great promise for potentially addressing the limitations faced by existing in-situ bioelectronics. This chapter aims to provide an overview of the design principles, implementation strategies, and manufacturing/fabrication techniques, particularly centering on extreme mechanics of hydrogels, for developing three key components of in-situ hydrogel bioelectronics: stretchable hydrogel conductors, electrochemical hydrogel biosensors, and flexible hydrogel biobatteries. We will conclude the chapter with a set of future opportunities enabled by in-situ hydrogel bioelectronics, transforming various industries.