MoS2 Functionalized Multicore Fiber Probes for Selective Detection of Shigella Bacteria Based on Localized Plasmon

Present study demonstrates the fiber-optic localized surface plasmon resonance (LSPR) based sensitive biosensor for detection of Shigella bacterial species. The proposed sensor is comprised of multi-core fiber (MCF) having seven cores arranged in a hexagonal shape and spliced with single-mode fiber (SMF) for efficient detection. An increase in evanescent waves (EWs) and coupling of modes between MCF cores was achieved by etching process in a controlled manner. The etching process also increases the refractive index sensitivity (RIS) of the proposed sensor. Further, coating with nanomaterials like gold nanoparticles (AuNPs) and molybdenum disulfide (MoS2) helps in the excitation of localized plasmons. Here, Shigella specific oligonucleotide probes are used as a recognition element. The results demonstrate that the proposed sensor can successfully and efficiently detect the Shigella bacterial species with high sensitivity. Shigella in the range of 10 - 100 CFU/ml (colony-forming unit/mL) can cause serious intestinal infection and therefore, its detection in this range is critical. The proposed sensor demonstrates a linearity range from 1 to 10(9) CFU/mL with a detection time of 5 min and a limit of detection (LoD) of 1.56 CFU/mL. The proposed sensing methodology can be a potential alternative to the commercially existing ones in the near future.

Automated summary

This study introduces a fiber-optic localized surface plasmon resonance (LSPR) based biosensor for sensitive detection of Shigella bacterial species. By controlled etching and coating with nanomaterials, the sensor achieves increased refractive index sensitivity and excitation of localized plasmons. Results show successful and efficient detection of Shigella with high sensitivity, making it potentially valuable in the future as an alternative to existing commercial methods.