Soft, Flexible, and Stretchable Platforms for Tissue‐Interfaced Bioelectronics

Seamless integration of electronic systems with living tissues requires not only biocompatibility but also careful matching of mechanical properties across heterogeneous organs. This review clarifies the often-conflated notions of "soft," "flexible," and "stretchable" electronics, and links these definitions to a tissue-mechanics framework spanning brain, nerve, skin, myocardium, and visceral organs. Based on this framework, we outline general mechanical design principles-ultrathin structures, stretchable architectures, and bioadhesive interfaces-that enable deformable devices to conform to moving, curved surfaces. Recent advances are then organized into tissue-targeted platforms, including imperceptible skin-mounted nanosheet and nanomesh electrodes, haptic and neural interfaces for bidirectional communication, and wet-organ adhesive systems for cardiac and gastrointestinal applications. We further highlight emerging material systems such as liquid metal-based conductors and biodegradable transient electronics, which respectively extend mechanical adaptability and introduce time-programmed disappearance to reduce surgical burden. Across these topics, the review distills unifying design rules for matching modulus, adhesion, and strain tolerance to specific biological environments, positioning soft, tissue-interfaced bioelectronics as a coherent toolbox that bridges wearable, implantable, and transient formats for future healthcare technologies.