Advanced Uric Acid Detection by No-Core Fibre (NCF) and Single-Mode Fibre (SMF) Based Sensor Coated with Graphene Oxide

In this paper, optical fibre-based sensors incorporating with no-core fibre (NCF) and single-mode fibre (SMF) were developed for the detection of uric acid (UA). The primary sensor probe was fabricated by sandwiching NCF between two SMF segments, resulting in an SMF-NCF-SMF based structure. As for comparative analysis, a second sensor consisting solely of an SMF structure was developed. To enhance sensitivity, the sensing regions of both NCF and SMF were immobilized with a layer of graphene oxide (GO) coating. The functional groups of GO i.e., hydroxyl, carboxyl, and epoxy groups facilitated dispersion in polyvinyl alcohol (PVA) and increase the surface area available for biomolecule attachment, making it high effective for use in optical fibre sensor. The sensor performance was evaluated using UA concentrations ranging from 100 µM to 800 µM, respectively. The results demonstrated that the NCF-based biosensor with GO coating exhibited superior sensitivity compared to the SMF-based sensor, achieving a maximum sensitivity of 0.00420 ± 0.000118 nm/µM. The reproducibility and reusability of both the SMF and NCF biosensors were thoroughly assessed and discussed in this paper.