SnO2/GO coated SPR optical fiber sensor for acetone detection in diabetes management: Experimental and theoretical studies.

Acetone in exhaled breath serves as a non-invasive biomarker of diabetes, with levels increasing in proportion to disease severity. We developed a surface plasmon resonance (SPR)-based fiber optic sensor to detect clinically relevant acetone concentrations. Theoretical optimization was carried out to determine the optimal thicknesses of functional layers and sensing parameters prior to fabrication. Two sensor designs were realized: one with a silver/tin oxide configuration (SP1), and another enhanced with a graphene oxide layer (SP2) for improved performance. SP2 demonstrated a higher sensitivity of 0.83 nm/ppm and a maximum resonance wavelength shift of 42 nm at 50 ppm acetone, compared to 0.44 nm/ppm and 22 nm for SP1. It also exhibited faster response/recovery times, as well as reliable detection down to 800 ppb. These proof-of-concept findings highlight the sensor's potential for real-time, non-invasive monitoring of diabetes.