Development of U-bent plastic optical fiber biosensor with plasmonic labels for detection of chikungunya non-structural protein 3

This study presents a novel plasmonic fiber optic sandwich immunobiosensor for the detection of chikungunya, an infectious mosquito-borne disease with chronic musculoskeletal pain and acute febrile illness, by exploiting non-structural protein 3 (CHIKV-nsP3) as a biomarker. A plasmonic sandwich immunoassay for CHIKV-nsP3 was realized on the surface of a compact U-bent plastic optical fiber (POF, 0.5 mm core diameter) with gold nanoparticles (AuNP) as labels. High evanescent wave absorbance (EWA) sensitivity of the U-bent probes allows absorption of the light passing through the fiber by the AuNP labels upon the formation of sandwich immunocomplex of CHIKV-nsP3 on the core surface of the U-bent probe region. A simple optical set-up with a low-cost green LED and a photodetector on its either end of the U-bent probe gave rise to a detection limit of 0.52 ng/ml (8.6 pM) and a linear range of 1 – 104 ng/ml with a sensitivity of 0.1043 A530 nm/log(CnsP3). In addition, the plasmonic POF biosensor shows strong specificity towards CHIKV-nsP3 analyte in comparison to HRP and HIgG proteins and Dengue whole virus. The results illustrate the potential of plasmonic POF biosensors for direct and sensitive point-of-care detection of chikungunya viral disease.