Elaboration and Characterization of a New Heavy Metal Sensor Functionalized by Extracellular Polymeric Substances Isolated from a Tunisian Thermophilic Microalga Strain Graesiella sp.

Abstract

The present study aimed to develop and characterize new heavy metal sensors functionalized by extracellular polymeric substances (EPSs) isolated from a Tunisian thermophilic microalga strain Graesiella sp. The elaborated sensor showed a highly homogeneous character and revealed a microstructural lamellar arrangement, high crystalline nature, and several functional groups. Electrochemical impedance spectroscopy (EIS) and acoustic wave sensing were used as sensing techniques to explore the ability of microalgae-EPS-functionalized sensors to detect cadmium and mercury as heavy metals. For impedimetric measurements, a two-dipole circuit was adopted and showed good-fitted results with a low total error. The acoustic sensor platforms showed good compatibility with EPS in adjacent water. For both EPS-functionalized sensors, metal ions (Cd2+, Hg2+) were successfully detected in the concentration range from 10−10 M to 10−4 M. Impedimetric sensor was more sensitive to Cd2+ at low concentrations before saturation at 10−7 M, while the acoustic sensor exhibited more sensitivity to Hg2+ over the full range. The results highlight a new potential alternative to use microalgae EPSs as a sensitive coating material for the detection of heavy metals. However, its use in a real liquid medium requires further investigation of its selectivity in the presence of other compounds.

Electrochemical Sensors for Controlling Oxygen Content and Corrosion Processes in Lead-Bismuth Eutectic Coolant—State of the Art

“…The example of Nyquist plot taken from [ 85 ] together with fitted data is shown at Figure 3 below. Measured and fitted impedance agree one another fairly well.…”

FEM Modeling Strategies: Application to Mechanical and Dielectric Sensitivities of Love Wave Devices in Liquid Medium

“…This new design would be multiphysically optimized using the model for a selected bio-chemical target, improving the sensing performances. Extracellular polymeric substance (EPS) layers, isolated from a Tunisian thermophilic microalga strain Graesiella, are currently being investigated as promising candidates for such an application with heavy metals [29],…”

The Recent Development of Acoustic Sensors as Effective Chemical Detecting Tools for Biological Cells and Their Bioactivities

“…In addition, this technique has reached high sensitivity for the characterization of heavy metals at low concentrations (10 −12 M). Gongi et al [ 97 ] characterize the cadmium (Cd 2+ ) and mercury (Hg 2+ ) heavy metal ions based on the extracellular polymeric substances (EPSs) isolated from a Tunisian thermophilic microalga strain Graesiella sp. In that study, the authors used quartz-based AWS and a 1.2 × 1.2 cm 2 active area with an acoustic resonance of 118 MHz.…”