Interfacial Engineering of Printable MOF/MXene Heterostructured Inks for High-Performance Wearable Ammonia Sensors

Precise molecular recognition and efficient signal transduction are pivotal for next-generation wearable health-monitoring platforms, particularly for detecting breath biomarkers like ammonia (NH₃) that indicate renal or hepatic distress. However, achieving high-selectivity NH₃ sensing in complex, trace-level environments is often hindered by low sensitivity. Herein, we report a sustainable, low-temperature strategy for the synthesis of printable and textile-compatible MOF/MXene heterostructured inks tailored for high-performance NH₃ sensing. We demonstrate that precise interfacial engineering and functional group alignment between the MXene and MOF phases trigger a robust synergistic effect, significantly accelerating charge-transfer kinetics. The resulting sensor achieves an extraordinary detection limit of 3 ppb, markedly outperforming current state-of-the-art benchmarks. For practical application, the sensing unit was integrated into a custom wearable wristband equipped with real-time signal processing and wireless transmission modules, exhibiting sensing capabilities on par with commercial sensors. This tailored synthesis strategy, coupled with systematic platform integration, enables non-invasive monitoring of trace NH₃ in human breath. This synergy provides a viable approach for the early screening of chronic kidney disease (CKD) while expanding the horizons for functional material development in next-generation intelligent wearable diagnostics.