Nanomaterial-Functionalized Fiber-Optic Biosensor for Label-Free Detection of <i>Vibrio parahaemolyticus</i>

Vibrio parahaemolyticus (V. parahaemolyticus) is a foodborne pathogen that can cause life-threatening illness after consuming raw or undercooked seafood; therefore, rapid and sensitive detection of this pathogen is crucial. In the present manuscript, a fiber-optic biosensor based on localized surface plasmon resonance (LSPR) has been developed for their application in the detection of V. parahaemolyticus. The developed sensor uses a multimode fiber (MMF) and nanoparticle-doped fiber (NDF) to construct a tapered fiber structure for quantitative detection of different concentrations of V. parahaemolyticus. Further, the LSPR phenomenon of the fiber has been enhanced by immobilizing gold nanoparticles (AuNPs), multiwalled carbon nanotubes (MWCNTs), and palladium nanocubes (PdNCs) on its surface. Nanoparticle coating also provides more attachment points for antibodies on the sensor surface due to the high surface-to-volume ratio. In addition, the specificity of the sensor was improved by functionalization with polyclonal antibodies on the probe surface. Subsequent research has verified that the proposed biosensor possesses reusability, repeatability, and stability, with a linear detection range of 1 × 100 to 1 × 107 CFU/mL and detection limit (LOD) of 2.71 CFU/mL. The proposed optical fiber sensor demonstrated potential for the detection of V. parahaemolyticus.