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

Abstract

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.

Breath Analysis: A Promising Tool for Disease Diagnosis—The Role of Sensors

“…More recently, a 2 × 4 array of sensors based on pristine Pt, Pd, or Au NPs decorated In 2 O 3 and WO 3 nano-rods (NRs), was investigated for the detection of acetone, NO, and H 2 S as diabetes, asthma, and halitosis biomarkers. This achieved low LOD and visual discrimination between the three analytes using polar plots ( Figure 5 ); however, further statistical analysis is required [ 99 ]. The same group has also developed a 3 × 3 sensor array based on WO 3 , SnO 2 , or In 2 O 3 -based thin films, Au NPs-decorated thin films and Au NP-decorated villi-like structures; the array efficiently discriminated ppt levels of H 2 S and ppb levels of NH 3 and NO in 80% of RH, being potentially applicable to halitosis, renal disorder, and asthma diagnosis, respectively [ 100 ].…”

Temperature‐Modulated Selective Detection of Part‐per‐Trillion NO2 Using Platinum Nanocluster Sensitized 3D Metal Oxide Nanotube Arrays

“…In addition, NO 2 can also be recognized as an important endogenous gas (parts per billion [ppb]/parts per trillion [ppt] level) for potential disease diagnoses (e.g., asthma and inflammatory bowel identification). [8][9][10][11] However, NO 2 always exists under the presence of other interfering gases, such as formaldehyde (FA), toluene, acetone, and SO 2 , and the sensitive and selective detection trace amount of NO 2 among the interfering gases remains a bottleneck challenge. Chemiresistive gas sensors made of metal-oxide semiconductors, such as tin oxide (SnO 2 ) [12][13][14] and zinc oxide (ZnO), [15][16][17][18] possess a number of highly attractive merits, including small formfactor and being integratable with other semiconductor devices, long life-time, and low cost.…”

“…In addition, NO 2 can also be recognized as an important endogenous gas (parts per billion [ppb]/parts per trillion [ppt] level) for potential disease diagnoses (e.g., asthma and inflammatory bowel identification). [ 8–11 ] However, NO 2 always exists under the presence of other interfering gases, such as formaldehyde (FA), toluene, acetone, and SO 2 , and the sensitive and selective detection trace amount of NO 2 among the interfering gases remains a bottleneck challenge.…”

Vortex-Induced Vibrations of an Elastic Micro-Beam with Gas Modeled by DSMC

“…Another trend is using sensors based on micro- and nanostructures. Such sensors have been developed to monitor harmful gases in the environment or breath gas analysis as part of health diagnostics [ 14 , 15 ]. Oosthuizena, Motaung, and Swart [ 14 ] evaluated CO gas sensing at room temperature (20 °C) in the presence of dry air and various relative humidity levels, using undoped p-type CuO nanoplatelets synthesized by hydrothermal reactions, without any surfactants.…”

“…Oosthuizena, Motaung, and Swart [ 14 ] evaluated CO gas sensing at room temperature (20 °C) in the presence of dry air and various relative humidity levels, using undoped p-type CuO nanoplatelets synthesized by hydrothermal reactions, without any surfactants. Kim et al [ 15 ] presented a 2 × 4 sensor array with a micro-heater and ceramic chip. The sensor array detected CH 3 COCH 3 , NO 2 , and H 2 S as biomarkers for breath gas analysis.…”