An Anti-Dehydration Hydrogel Based on Zwitterionic Oligomers for Bioelectronic Interfacing.

Hydrogels are ideal interfacing materials for on-skin healthcare devices, yet their susceptibility to dehydration hinders their practical use. While incorporating hygroscopic metal salts can prevent dehydration and maintain ionic conductivity, concerns arise regarding metal toxicity due to the passage of small ions through the skin barrier. Herein, we report an anti-dehydration hydrogel enabled by the incorporation of zwitterionic oligomers into its network. This hydrogel exhibits exceptional water retention properties, maintaining approximately 88% of its weight at 40% relative humidity, 25°C for 50 days and about 84% after being heated at 50°C for 3 hours. Crucially, the molecular weight design of the embedded oligomers prevents their penetration into the epidermis, as evidenced by experimental and molecular simulation results. Our hydrogel allows stable signal acquisition in electrophysiological monitoring of humans and plants under low-humidity conditions. This research provides a promising strategy for the development of epidermis-safe and biocompatible anti-dehydration hydrogel interfaces for on-skin devices. This article is protected by copyright. All rights reserved.