Autonomously adhesive and anti-freezing MXene-organohydrogel bionic sensor for wearable interfaces and silent speech recognition

Abstract

Conductive hydrogels are widely used in bionic sensors and wearable electronics due to their similarity to biological tissues, biocompatibility, and flexibility. However, their practical applications are limited by their low mechanical strength, lack of adhesion, insufficient conductivity, and poor freeze-resistance. To address these challenges, we developed MXene-supported acrylamide (AAm) and 2-(dimethylamino)ethyl acrylate methochloride (DMAEAMC) organohydrogels (OHGs) using a binary solvent system of dimethyl sulfoxide (DMSO) and water. The binary solvent endows the OHGs with anti-freezing properties, enabling their operation at subzero temperatures. MXene reinforces their mechanical properties through physical interaction with their polymer chains, which further enhances their autonomous adhesion to diverse substrates, KCl and MXene synergistically provide ionic and electronic conductivity across a wide temperature range. These features make the OHGs ideal candidates for bionic sensors in harsh environments, offering high conductivity, stable signals, and fast response times. The sensor was successfully tested for monitoring human physiological activities, including finger movements, drinking, coughing, and speaking. Notably, it accurately tracked silent speeches in multiple languages (English, Urdu, and Pushto), demonstrating potential for treating speech impediments such as aphasia and dysarthria. OGH-based sensors successfully transduced mechanical stimuli into Morse code signals, enabling real-time SOS communication under extreme conditions. Consequently, this multipurpose sensor has enormous potential for next-generation wearable electronics, especially in healthcare monitoring of real-time voice recognition for patients with vocal impairments, human–machine interfaces, and extreme-environment sensors.