Measurement Platform Based on Fiber Optic SPR Sensor Using Exploding-Wire Generated Copper Nanoparticles for Ceftriaxone Detection

Antibiotics are one of the emerging groups of tenacious organic pollutants in aquatic environments. Their contamination with surface water is accountable for the occurrence of antibiotic resistance in micro-organisms, hindering the development of healthy gut microbiomes, and toxicity in humans and animals. Therefore, the rapid and accurate detection of antibiotics in water is an important aspect of environmental monitoring. In this study, we propose a measurement platform based on highly sensitive and selective fiber optic surface plasmon resonance (FOSPR) sensor modified with copper nanoparticles (CuNPs) to experimentally detect the ceftriaxone antibiotic having concentration ranging from 0 to 50 nM. CuNPs were produced by exploding wire method, which represents a more sustainable alternative compared to the traditional chemical methods used for producing nanoparticles (NPs). The FOSPR sensor was fabricated by coating a 40-nm silver (Ag)-layer over cladding-etched optical fiber exploiting thermal evaporation technique and then additionally modified with CuNPs. The measurement system was characterized in terms of sensitivity (0.68 nm/nM), limit of detection (LOD) (1.09 nM), and limit of quantification (LOQ) (1.05 nM). Selectivity was tested by performing experiments with potential interfering substances, such as ciprofloxacin and erythromycin (ERY). The outcome of the sensor was also evaluated in terms of repeatability, stability, and linearity. As a result, the platform is expected to be used as a portable device for simple, rapid, and effective detection of antibiotic pollutants in the water environment.