ZnO nanoparticles coated optical fiber sensor for volatile organic compound biomarker detection

This study proposes an optical fiber sensor with a single mode - no-core - single mode (SNS) structure. The sensor employs zinc oxide (ZnO) as a sensing layer coated over the no-core fiber (NCF) region. ZnO is introduced to absorb volatile organic compound (VOC) biomarkers of diabetes, utilizing an evanescent sensing mechanism. The ZnO colloidal solution used for this purpose was synthesized through aqueous chemical growth. A cost-effective airbrush was used for coating a thin layer of ZnO over the NCF. Several material characterizations, including FE-SEM, UV-Vis, and XRD, were conducted to validate the presence of the ZnO layer over the NCF. The study investigates VOC biomarkers for diabetes, such as acetone, isopropanol, and ethanol, with 100-500 ppm concentrations. These VOCs were chosen because they belong to the same class of alcohol found in the exhaled breath of individuals with diabetes. Notably, the optical fiber sensor exhibited the highest sensitivity to acetone, with a sensitivity of 0.0028 nm/ppm. In addition, the sensor demonstrated selectivity to acetone, highlighting the significant role played by the morphology of the ZnO layer. The results presented in this study suggest that the proposed sensor has the potential for real-time and non-invasive monitoring of acetone vapor, a biomarker in exhaled breath for diabetes. Its advantages include cost-effectiveness and simple fabrication processes, making it a promising tool for diabetes management and diagnosis.