A Fully Flexible Sensing Ionogel‐Based Transistor With Gate‐Induced Enhancement for Wearable Breath Monitoring

ABSTRACT Early screening of Helicobacter pylori ( H. pylori ) infection is crucial for reducing gastric cancer risk, yet current diagnostic methods are limited by invasiveness, bulky instrumentation, or delayed readouts. Exhaled ammonia (NH 3 ), a metabolic product of H. pylori , provides a promising noninvasive biomarker, but achieving sensitive, real‐time detection in wearable formats under mechanical deformation remains challenging. Here, we present a fully flexible and stretchable wearable bioelectronic mask based on a sensing ionogel‐based transistor for wireless monitoring of trace NH 3 in exhaled breath. The device employs a sensing ionogel dielectric with synergistic chemical and ionic synergistic, while transistor gating induces ion separation and an intrinsic electric field that accelerates gas diffusion and interfacial recognition. This gate‐induced enhancement enables rapid and amplified NH 3 sensing at room temperature. The sensing ionogel‐based transistor exhibits a fast response time of 2.6 s, a detection limit of 270 ppb—well below clinically relevant NH 3 levels, high linearity (R 2 = 0.978), together with excellent selectivity. Stable performance is maintained under 35% tensile strain, 180° bending, and 100 repeated folding. Integrated with a wireless system, this bioelectronic mask provides a wearable platform for noninvasive, real‐time NH 3 monitoring, highlighting its potential for future breath‐based health monitoring applications.