Nanoparticle-structured thin film sensor arrays for breath sensing

Chemiresistor sensor arrays with nanoparticle-structured thin films and coupled with pattern recognition engine could enable chemical sensing of biomarker molecules such as acetone in human breath samples with high sensitivity and selectivity, which serves as an intriguing approach to developing potential medical device for noninvasive monitoring of diabetes. This report describes the results of a proof-of-concept investigation to demonstrate the viability of such sensor arrays with the nanostructured sensing films for the detection of human breath and acetone vapor (a volatile biomarker in diabetics' breath). The nanostructured sensing films were prepared by self-assembly of monolayer-capped gold nanoparticles on an array of chemiresistors using functionalized alkyl thiols as linking molecules. In addition to showing the viability for quantitative detection of acetone, the investigation focused on the understanding of how differences in human breaths could impact the sensor array recognition characteristics. The results have revealed that the difference in data scattering between male and female's breath samples was relatively small. The data distribution between breath samples obtained under controlled fasting and food conditions depends on the design parameters of the sensor arrays. The results have demonstrated the potential of the sensor arrays coupled with pattern recognition for the detection of acetone in diabetic breath, which upon further refinements and testing could lead to a useful portable sensor device for human breath recognition.