Hydrogel‐Based Bioelectronics: From Therapy and Sensing to Neuromorphic Computation

ABSTRACT Bioelectronics establish bidirectional communication between living systems and electronic devices, providing an enabling platform for continuous health monitoring, tissue repair, personalized intervention, and intelligent human–machine interfaces. However, the mechanical rigidity, limited biological compatibility, and inefficient ionic–electronic coupling of conventional electronic materials restrict their stable integration with soft, wet, and dynamically moving tissues. Hydrogels offer a distinctive solution because their hydrated three‐dimensional networks can simultaneously accommodate tissue‐like mechanics, ionic and electronic transport, wet adhesion, biochemical exchange, and therapeutic functions. This review discusses recent progress in material systems, conduction mechanisms, properties and applications of hydrogel‐based bioelectronics. Natural, synthetic, and composite hydrogel matrices are first summarized, followed by a comparative discussion of ionic, electronic, and mixed ionic–electronic conduction and their implications for biological signal transduction. Key interfacial properties, including mechanical adaptability, bioadhesion, and biocompatibility, are then connected to three evolving application levels: hydrogel‐enabled therapy for wound, bone, and neural repair, sensing and feedback for closed‐loop intervention, and neuromorphic bioelectronics involving artificial synapses, memristive devices, physical reservoirs, and in‐sensor processing. Particular attention is given to the transition of hydrogels from passive hydrated contacts to active platforms capable of sensing, stimulation, therapy, and information processing. Finally, persistent challenges in biological integration, scalable manufacturing, long‐term stability and packaging, artificial‐intelligence integration, and standardized evaluation are discussed. By connecting materials design with device physics, biological functions, and system‐level intelligence, this review provides a roadmap toward adaptive and closed‐loop hydrogel bioelectronics.