Highly sensitive and real-time detection of acetone biomarker for diabetes using a ZnO-coated optical fiber sensor.

This work presents a ZnO-coated no-core optical fiber sensor (OFS) designed for the highly sensitive detection of acetone vapor. Acetone is a key biomarker for diabetes, which is linked to blood glucose levels and can be detected non-invasively through breath analysis. The OFS utilizes a no-core fiber (NCF) as the sensing region, coated with a thin layer of ZnO nanoparticles to enhance evanescent field interaction with the VOCs at the fiber interface. The NCF segment, optimized to 3.4 cm, maximizes coupling efficiency through multi-mode interference (MMI). The OFS was tested with six different VOCs including acetone, methanol, ethanol, isopropanol, toluene and xylene at concentrations ranging from 1 to 10 ppm, as they are commonly exhaled VOCs associated with diabetes. The fabricated OFS demonstrated high sensitivity to acetone (0.116 nm/ppm) and excellent selectivity compared to other VOCs. It exhibited a lower detection limit of 3.26 ppm, rapid response (26 s), and recovery times (32 s) for acetone, with minimal drift (0.2%) over 30 days. Operated at room temperature, this ZnO-coated no-core OFS offers a cost-effective and simple fabrication approach, showing promising potential for non-invasive acetone monitoring in diabetes.