As planned, we started measuring at 0.5 OD in LB medium with gold electrodes (gold was chosen because of its high conductivity). By this initial approach satisfactory results were obtained the first day of measurements. However, the second measurement day we detected there was not a constant behaviour after each measurement replicate. The cause seemed to be the LB usage. This medium contains yeast extract which may be full of divalent ions. We expected to solve this problem by using a buffer as TE pH 8 or isotonic saline solution, but anyone of them would cause an stress to the cell that could modify or measurements in an unpredicted way.
At the same time, we detected that one of the electrodes was stained(oxidation was performed), so we changed the electrodes metal, avoiding at the same time heating of the electrodes or medium and the noise that this could imply. Instead of gold we used chrome electrodes recovered by platinum.
The second approach was performing measurements in LB with chrome electrodes recovered by platinum. In this way obtained results were more consistent after each measurement.
Full sensing dispositive explanation here.
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