Micro/nano optical fibers for label-free detection of abrin with high sensitivity

The recognition of abrin is of great civil and military importance. As an alternative to general detecting techniques, such as enzyme-linked immunosorbent assay (ELISA) and electrochemiluminescence (ECL)-based assay, micro/nano optical fibers (MNFs) for the label-free detection of abrin have been investigated for the first time in this paper. The MNFs fabricated through chemical etching are robust and have excellent mechanical strength for practical applications. This MNF-based biosensors feature fast response, high sensitivity, and low cost. A limit of detection of 10 pg/mL was obtained using a MNF with a waist diameter of circa 1.0 μm, and the typical measurement time was less than 10 min. By taking advantage of the label-free detection, Langmuir kinetics fitting for the dynamic reaction curve suggested a large affinity constant between the antibody and abrin. Regeneration ability of the sensor was also demonstrated by the maintenance of high sensitivity and selectivity after releasing experiments.