Selective detection of cadmium ions using plasmonic optical fiber gratings functionalized with bacteria

Abstract

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 (Cd2+) 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 Cd2+ 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 Cd2+ than to other heavy metal ions such as Pb2+, Zn2+ and CrO42− found in contaminated water, which ensures a good selectivity.

High Quality Factor Silicon Membrane Metasurface for Intensity-Based Refractive Index Sensing

“…Hence, the nature of the analyte placed in proximity of the metallic NP can be disclosed by analyzing the sensor optical response. Recently, a plethora of sensors based on plasmonic structures have been presented [4,6,7] and proved to selectively detect cadmium ions and bacteria when jointly operated with optical fibers [8][9][10]. Although plasmonic sensors can offer a very good performance in terms of sensitivity, analyte selectivity and versatility, they may be plagued by strong ohmic losses due to light absorption in the metallic parts.…”

A Novel Ultra-Miniaturized THz Refractive Index-Based Material Sensor

“…This technique offers high quality of data and high throughput with the help of a lesser quantity of the analyte. Thus, it also offers good repeatability, reproducibility, the limit of detection, and best suits for real-time sensing [24][25]. Therefore, the THz sensor is designed for high sensitivity which operates at 7.16 THz with 99.9% absorptivity.…”

Roadmap on Universal Photonic Biosensors for Real-Time Detection of Emerging Pathogens

“…These sensing structures can be implemented in prism configurations or in waveguides, such as optical fibers (Figure 2c). Optical fiber-based sensors have been implemented for a variety of applications, including antibody [39], bacteria [40], and environmental sensing [41,42]. Fiber optic sensors offer many potential advantages over conventional planar structures, including their simplicity, low cost, and potential for multiplexing [43].…”