Ultralow-Cost Hydrogel Electrolytes Based on Agricultural Byproducts for Distributed Electrophysiological Recording in Resource-Limited Settings

Global access to quality healthcare remains one of the most pressing issues for modern society. Despite advances in wearable and point-of-care biomedical devices, the dissemination of these technologies to resource-limited populations remains challenging, partially due to limitations imposed by cost. One of the largest cost drivers in the adoption of wearable devices for electrophysiological (ExG) monitoring, for instance, is the consumable overhead (electrolytes, adhesives, and electrodes) necessary to support patient use. Herein, we report the development and optimization of ultralow-cost (<0.03 USD per electrode), stable, and resource-available ExG electrolytes fabricated from agricultural byproducts widely available in local settings, thereby negating the dependency on importation. We show that composite hydrogels can be prepared from a variety of starch precursors via a facile one-pot sol-gel method to yield ionically conductive, mechanically compliant gel electrolytes. We further demonstrate that food starch materials for these purposes are resistant to dehydration and, when coupled with a wireless recording platform, can facilitate long-term (8 h) signal recording without significant loss in signal quality. Together, these characteristics mark starch-based electrolytes as possible alternatives to commercial formulations for skin-interfaced measurement electrodes, compatible with mobile sensing apparatus in resource-limited settings with cost, sustainability, and supply chain advantages without sacrificing clinical performance.