Bionic ion skin multimodal system for advanced epidermal electronics

Bionic ion skin technology embodies a pivotal advancement in epidermal electronics, moving beyond elementary sensing functions to emulate the sophisticated multimodal perception of natural skin. Current research landscapes reveal a conspicuous disconnect: although ionic conduction mechanisms and general hydrogel properties have received considerable attention, the fundamental relationship between hierarchical structural configurations and their corresponding device-level performance lacks systematic investigation. This conceptual gap substantially restricts progress toward systems exhibiting tissue-like mechanical behavior, consistent signal interpretation, and prolonged bio-integration stability. This review addresses this void through an integrated framework based on Structure-Property-Function interrelationships. Comprehensive analysis introduces a structural taxonomy for hydrogel architectures, systematically organized into five categories: dual-phase composite networks, supramolecular assemblies, microphase-separated morphologies, ion-regulated conductive systems, and dynamic slide-ring topologies. Each structural paradigm receives detailed analysis regarding how specific architectural characteristics direct molecular organization, energy dissipation routes, and ion transport behavior to produce enhanced mechano-electrical performance. Further discussion investigates how these structural principles govern essential device parameters-encompassing fracture toughness, tissue-comparable elasticity, and so on. Particular focus centers on mechanisms through which specific hydrogel configurations concurrently improve mechanical robustness and sensing accuracy via customized molecular dynamics. Concluding sections identify emerging research pathways focusing on structurally engineered ionic interfaces, computationally guided material development, and self-regulating bio-electronic systems. These directions collectively outline a coherent progression strategy for next-generation bionic ion skins capable of surpassing current limitations in signal decoding precision and bio-interface reliability.