Hanbat National University study details dual-mode ammonia detection on skin
Iain Hoey
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Ammonia sensor combines visual and electronic detection
A skin-worn wearable sensor has been presented that detects ammonia gas through both colour change and an electronic signal.
Hanbat National University (HBNU) researchers described the device in a study made available online on 18 August 2025 and published in Advanced Fiber Materials on 1 December 2025.
The study describes a flexible, stretchable sensor designed to work when attached to human skin and exposed to high humidity.
The platform combines a colourimetric readout with quantitative chemiresistive detection in a polymer nanofiber structure described as highly gas-permeable.
The study reports ppm-level sensitivity and stable performance under humidity and mechanical deformation.
How the dual-mode platform is intended to function
The study describes ammonia as widely used in fertilizers, refrigerants, biomarkers and next-generation fuel.
It states that ammonia is highly toxic and can cause respiratory irritation, chest pain, pulmonary edema and death.
The researchers describe a dual-mode approach that integrates chemiresistive sensing and colourimetric sensing in one device.
Professor Hyun Il Kang said: “Our device provides flexibility and facilitates efficient transport of NH3 between the bromocresol-green-based colorimetric and poly(3,4-ethylene dioxythiophene):poly(styrene sulfonate)-based chemiresistive sensing layers.
“This innovative dual-mode design enables reliable NH3 detection.”
The study states that each individual sensing layer performs on par with the dual-mode platform, with the device intended to remain accurate if one sensing mode fails.
It also describes operation while attached to human skin and in humid conditions.
Applications described in the study
The study lists potential uses including personal safety monitoring for workers in ammonia-handling facilities and industrial refrigeration and cold-chain environments.
It also lists agriculture and livestock operations where ammonia buildup occurs and noninvasive health screening via breath-NH3.
The study also cites vehicle energy systems using NH3 as another potential application.
The researchers describe the work as a basis for further development of the platform across biomedical, environmental monitoring and industrial use cases described in the paper.