Toward the Detection and Identification of Single Bacteria by Electrochemical Collision Technique

Abstract

Fast and cost-efficient detection and identification of bacteria in food and water samples and biological fluids is an important challenge in bioanalytical chemistry. It was shown recently that bacteria can be detected by measuring the decrease in the diffusion current to the ultramicroelectrode caused by cell collisions with its surface. To add selectivity to the bacteria detection, herein we show the possibility of collision experiments with the signal produced by electrochemical activity of bacterial cells reducing (or oxidizing) redox species. The mediator oxidation/reduction rate can be used to identify different types of bacteria based on their specific redox activities. Here we report the analysis of electrochemical collision transients produced by two kinds of bacteria, Escherichia coli and Stenotrophomonas maltophilia. The effects of the charge and redox activity of bacterial cells on collision events are discussed. The current transients due to live cell collisions were compared to those produced by bacteria killed either by heavy metal ions (cobalt) or by an antibiotic (colistin). This approach is potentially useful for evaluating the effectiveness of antimicrobial agents. Finite-element simulations were carried out to model collision transients.

Detection of individual insulating entities by electrochemical blocking

“…Detection of phospholipids vesicles of 120 nm is shown by Lebègue et al [25]. Several groups report the detection of Escherichia Coli and B Subtilis bacteria [20,[26][27][28][29]. Figure 3A shows fluorescently labeled E Coli adsorbed on an electrode with the current-time trace recorded simultaneously.…”

Lipid Membrane Permeability of Synthetic Redox DMPC Liposomes Investigated by Single Electrochemical Collisions

“…Electrochemical discrete collisions at an ultramicroelectrode (UME) is a useful technique to detect one at a time single biological entities such as cells, [1][2][3] bacteria, [4][5][6][7] macromolecules, 8 viruses, [9][10][11] and synthetic or biological vesicles. [12][13][14][15] Especially, electrochemical detection of single liposome collisions by recording electron transfer from the UME to an encapsulated redox species is fully appropriate for studying their membrane permeability.…”

Electrochemical Analysis for Multiscale Single Entities on the Confined Interface†

“…To enhance the selectivity of the bacteria detection, Mirkin and co‐workers proved that bacterial cells could oxidize the electroactive substances in solutions, and according to the mediator oxidation/reduction rate, different kinds of bacteria can be identified. [ 64 ] To enhance the rate of response to the single bacteria detection, Compton and co‐workers proved that Escherichia coli bacterium was detected rapidly within seconds by impact electrochemistry (Figure 2c). [ 65 ]…”