SMS Fiber Structure-Based Enzymatic Sensor Probe for Uric Acid Detection Using Gold Nanoparticles and Graphene Oxide

A consequence of human purine metabolism is uric acid (UA). An abnormal amount of UA in serum and human urine have substantial clinical repercussions in the majority of individuals. Normal readings for the human body range from 3.5 to 7.2 mg/dL. In this work, single-mode fiber–multimode fiber–single-mode fiber (SMS) structure-based probe has been developed for sensing UA levels. The fabricated probe is immobilized using synthesized gold nanoparticles (AuNPs) to improve the sensitivity. The surface plasmon (SP) excitation was induced at the surface of the fiber using AuNPs, which eventually produced the localized SP resonance (LSPR) phenomenon. Its sensitivity was further improved by coating with graphene oxide (GO). Thereafter, uricase enzyme functionalization further improved the detection of the sensor probe. A detailed analysis for the developed SMS probes was performed on parameters, such as sensitivity, linearity, response time, selectivity, reproducibility, and reusability.