Polymer-Modified Quartz Tuning Forks for Breath Biomarker Sensing

Volatile organic compounds (VOC) present in exhaled breath can serve as biological markers for human physiology. The change in levels of exhaled VOCs can be indicative of bodily disorders. Detection of such low levels of VOCs can allow early detection and diagnosis of diseases. A polymer- modified Quartz Tuning Fork (QTF) is a promising, cost-effective sensor that can detect a change in ppm levels of VOCs exhaled from the breath at room temperature. Acetone and acetaldehyde are biomarkers that are readily exhaled by human beings. Increased levels of these analytes can serve as indicators for toxicity or a wide array of diseases. The present work uses an array of QTFs modified separately using TiO₂ and WO₃­ nanostructures embedded in polystyrene to successfully detect low VOC concentrations present in simulated human breath. The frequency shift obtained after exposing the sensor array to breath is noted as the sensor response. The response shows a clear distinction between healthy human breath and breath spiked with varying VOC concentrations (5 – 400 ppm). The sensor response proves it can potentially serve as an economical and non-invasive tool for disease diagnostics.