Soft Ionic and Electronic Triboelectric Nanogenerators: Toward Attachable and Implantable Biomedical Applications.

The growing societal demand for convenient and personalized healthcare solutions has driven significant progress in human-interactive technologies. Soft electronics, with their extrinsic deformability, have sparked innovations in the design of stretchable and highly adaptable biomedical devices that enhance wearability. Despite these advancements, portable power sources remain a key limitation, constrained by short operating times and the inconvenience of frequent recharging or battery replacement. To overcome this hurdle, triboelectric nanogenerators (TENGs), which convert mechanical energy into electricity, have emerged as promising sustainable power sources, offering high efficiency, lightweight design, and self-sustaining operation. Recent developments in integrating TENGs with ionic materials have enabled their use on or beneath the skin, allowing the harvesting of biomechanical energy that would otherwise be wasted to power healthcare devices. This review provides a comprehensive overview of attachable and implantable TENGs, classified by electronic and ionic materials, and examines their material choices, device structures, and operational mechanisms. This review further explores various sustainable biomedical applications, assessing the performance of these devices in both sustainable power sources and self-powered physiological signal sensing. Finally, key future research directions are outlined, including sweat tolerance, skin compliance, AI-enabled TENG biointerfaces, acoustic transparency, minimally invasive implantation strategies, and regulatory considerations for clinical translation.