WaveFlex Biosensor: A Flexible-Shaped Plasmonic Optical Fiber Sensor for Histamine Detection

In this work, a combination of simulation and experiment is used to analyze the distribution of the evanescent field in a W-shaped optical fiber. A novel flexible W-shaped optical fiber (FWOF) biosensor based on the localized surface plasmon resonance (LSPR) effect (also known as a WaveFlex biosensor) is designed and fabricated for detecting histamine in food. First, gold nanoparticles (AuNPs) are immobilized on the FWOF probe’s surface to excite the LSPR effect. Second, niobium carbide (Nb
$_{{{2}}}$
CT
$_{\mathrm {x}}$
) MXene and molybdenum disulfide nanoparticles (MoS
$_{{{2}}}$
-NPs) are immobilized on the sensing area of the FWOF probe to improve the reaction area. A larger surface area can offer more immobilization sites for biomolecules. Meanwhile, to enhance the specificity of the sensing probe, the diamine oxidase (DAO) enzyme is functionalized on the nanomaterials (NMs)-immobilized probe. The absorption spectrum and microscopic distribution of the nanoparticles are characterized and measured using an ultraviolet-visible (UV-Vis) spectrophotometer and a high-resolution transmission electron microscope. The immobilization results of NMs on the probe surface are verified by scanning electron microscopy. In order to further explore the performance of the sensor, pH testing, stability testing, reproducibility, repeatability, and probe specificity testing are also carried out. The proposed sensor has a linear detection range of 0–
$1000 ~\mu \text{M}$
, a detection limit of
$52.5 ~\mu \text{M}$
, and a sensitivity of 4.4 pm/
$\mu \text{M}$
.