Metal Oxide Nanorods-Based Sensor Array for Selective Detection of Biomarker Gases

The breath gas analysis through gas phase chemical analysis draws attention in terms of non-invasive and real time monitoring. The array-type sensors are one of the diagnostic methods with high sensitivity and selectivity towards the target gases. Herein, we presented a 2 × 4 sensor array with a micro-heater and ceramic chip. The device is designed in a small size for portability, including the internal eight-channel sensor array. In₂O₃ NRs and WO₃ NRs manufactured through the E-beam evaporator's glancing angle method were used as sensing materials. Pt, Pd, and Au metal catalysts were decorated for each channel to enhance functionality. The sensor array was measured for the exhaled gas biomarkers CH₃COCH₃, NO₂, and H₂S to confirm the respiratory diagnostic performance. Through this operation, the theoretical detection limit was calculated as 1.48 ppb for CH₃COCH₃, 1.9 ppt for NO₂, and 2.47 ppb for H₂S. This excellent detection performance indicates that our sensor array detected the CH₃COCH₃, NO₂, and H₂S as biomarkers, applying to the breath gas analysis. Our results showed the high potential of the gas sensor array as a non-invasive diagnostic tool that enables real-time monitoring.