Speaker
Description
Quality of water resources is a major global challenge and water pollution is a daily topic. Certain pollutants can kill bacteria and destroy cell walls depending on their concentration, leading to the release of cytoplasm cell ions to the medium by diffusion. Hence, studying the conductivity and permittivity of a bacterial solution is used to investigate bacterial behaviour with respect to the presence of a pollutant that can then be detected.
As a first step towards this pollutant biosensing method, we propose a study of Electrochemical Impedance Spectroscopy (EIS) in the 40 Hz - 20 MHz range for heat-killed and alive solutions of Escherichia coli at different concentrations. EIS is done with a planar electrode sensor. Within this experiment parameters, our copper-tin alloy electrodes have no impact on bacterial viability.
Two different data analysis methods are investigated. Firstly, we propose to study impedance magnitude data from EIS to discriminate alive from heat-killed bacteria at a given concentration. Secondly, we use Distribution of Relaxation Times (DRT) analysis on EIS data, which is equally useful for discriminating between different concentrations.
The use of single-bacteria simulations as a building brick provided a semi analytical model consistent with the measured electrical behaviour a bacteria population. Finally, the biosensor prototype was applied to detect the effect of anti-helminthic and antibiotic.
