Afiqah Yaacob, Nor Hafizah Ngajikin, Nurfatihah Che Abd Rashid, Maslina Yaacob, Siti Hajar Aminal Ali, Ian Yulianti, Noran Azizan Cholan
This study presents the first application of a balloon-like bent polymer optical fiber (POF) sensor in uric acid detection. The sensor head was fabricated by integrating an unclad region with macrobending, creating a balloon-like structure that enhances evanescent wave interaction and improves sensing performance. The effect of bending radius on sensor response was systematically investigated, with radii varied from 1.5 to 2.5 cm, to identify optimal conditions. Experimental results revealed a strong linear relationship between transmitted intensity and uric acid concentration of 15–90 mg dl−1. Optimal performance was achieved at a bending radius of 1.5 cm and an operating wavelength of 770 nm, delivering a sensitivity of 0.0028 (mg dl)−1, linearity of 0.8843, and a resolution of 3.61 mg dl−1. Compared to other unclad and coated optical fiber designs, the proposed configuration offers a competitive combination of sensitivity, linearity, and detection range while maintaining simple fabrication and robust mechanical properties. These findings highlight the potential of bending geometry optimization as a practical approach to advancing low-cost, high-performance optical fiber biosensors for biomedical and environmental applications. © 2026 IOP Publishing Ltd. All rights, including for text and data mining, AI training, and similar technologies, are reserved.
Faculty of Electrical and Electronics Engineering, Universiti Tun Hussein Onn Malaysia (UTHM), Parit Raja, Johor, Batu Pahat, 86400, Malaysia; Physics Department, Faculty of Mathematics and Natural Sciences, Universitas Negeri Semarang, Indonesia
