Precision in Uric Acid Detection: Unlocking Higher Sensitivity with Zinc Oxide-Coated Tapered No-Core Fibre-Based Sensor

In this paper, ZnO coated non tapered and tapered no-core fibre (NCF) were developed and experimentally demonstrated for the detection of changes in the uric acid (UA) concentrations. The fabricated main optical fibre-based sensor used non tapered and tapered NCF sandwiched in between SMF region. The tapered NCF by CO2 laser technique to achieve a waist diameter of 19.17 µm. The non tapered NCF was tested under the UA solutions for comparison purposes. The non tapered and tapered NCF sensing regions were then coated with ZnO solution using the dip-coating method. The ZnO was chosen as the coating due to its remarkable properties such as high transmittance, and good electrical conductivity. It is also known as effective in immobilizing with low isoelectric point (IEP) acidic proteins. Non-tapered UV-Vis spectroscopy was used to characterize the element of the thin composite film. The sensing performance test was performed by using different concentrations of UA solutions ranging from 100 µM to 800 µM for both non tapered and tapered NCF sensors. From the results, the tapered NCF biosensor with a coating of ZnO shows an excellent sensitivity than the non tapered NCF biosensor with the highest sensitivity of 0.00775 ± 0.00072 nm/µM. The reversibility, reproducibility, and reusability test of the designated optical fibre biosensor were also analysed and discussed in this paper.