Open AccessSelective detection of cadmium ions using plasmonic optical fiber gratings functionalized with bacteria
Author(s) -
Shunshuo Cai,
Haixia Pan,
Álvaro González-Vila,
Tuan Guo,
David Gillan,
Ruddy Wattiez,
Christophe Caucheteur
Publication year - 2020
Publication title -
optics express
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.394
H-Index - 271
ISSN - 1094-4087
DOI - 10.1364/oe.397505
Subject(s) - materials science , fiber optic sensor , optical fiber , metal ions in aqueous solution , plasmon , detection limit , ion , fiber bragg grating , fiber , optics , cadmium , surface plasmon , optoelectronics , metal , chemistry , wavelength , composite material , chromatography , physics , organic chemistry , metallurgy
Environmental monitoring and potable water control are key applications where optical fiber sensing solutions can outperform other technologies. In this work, we report a highly sensitive plasmonic fiber-optic probe that has been developed to determine the concentration of cadmium ions (Cd 2+ ) in solution. This original sensor was fabricated by immobilizing the Acinetobacter sp. around gold-coated tilted fiber Bragg gratings (TFBGs). To this aim, the immobilization conditions of bacteria on the gold-coated optical fiber surface were first experimentally determined. Then, the coated sensors were tested in vitro. The relative intensity of the sensor response experienced a change of 1.1 dB for a Cd 2+ concentration increase from 0.1 to 1000 ppb. According to our test procedure, we estimate the experimental limit of detection to be close to 1 ppb. Cadmium ions strongly bind to the sensing surface, so the sensor exhibits a much higher sensitivity to Cd 2+ than to other heavy metal ions such as Pb 2+ , Zn 2+ and CrO 4 2- found in contaminated water, which ensures a good selectivity.