Plasmon-Based Tapered-in-Tapered Fiber Structure for p-Cresol Detection: From Human Healthcare to Aquaculture Application

The development of a p-cresol biosensor for aquaculture, marine life, and healthcare applications is described in this study. The biosensor is based on localized surface plasmon resonance (LSPR) and employs a novel tapered-in-tapered fiber (TiTF) probe. Gold nanoparticles (AuNPs) and copper oxide nanoflowers (CuO-NFs) on TiTF structures are immobilized on this probe. The developed probe’s performance was evaluated by measuring the response to a variety of p-cresol solution concentrations. Combining AuNPs and CuO-NFs improves the sensitivity and anti-interference capability of the sensing probe. When the p-cresol solution reacts with the tyrosinase enzyme, the refractive index on the sensing region of the probe changes, and the resulting spectrum varies. The linear range, the limit of detection (LoD), and sensitivity of the proposed sensor are 0–1 mM, 0.14 mM, and 3.8 pm/mM, respectively. The probe is subjected to extensive testing, including LoD, repeatability, reusability, stability, selectivity, and pH testing, that all obtain satisfactory results.