After several months of work, little sleep, a lot of coffee, the biggest depreciation of Mexican peso since 1994, and TONS of fun (required for winning a medal), the LCG-UNAM-Mexico team eventually got over all its members’ crisis and was able to put together all the bits of information, carry out the experiments, measurements, and controls to finally sat down to analyze the results.
First of all, the measuring device (the one which measures resistivity), was calibrated with different but known nickel and cell concentrations. Then, measurements where performed with our modified cells and a proof principle was achieved, which shows that the idea is plausible although more replicates are needed. Sensitivity was detected as our main limiting step, and nickel specific electrodes are proposed as the obvious way to improve it.
Meanwhile, extensive literature search was carried out in order to implement a mathematical model to represent the dynamics of the system. After exhausting this approach, the role of remaining parameters was analyzed through extensive simulation and parameter scan, and byologically plausible parameters where used to analyze the general dynamics of the system.
The overall result is that the general behavior of the system is understood and formalized through a set of differential equations; it is also shown that resistivity can be readily related to nickel concentration even in the presence of living cells. More work is needed to fully implement an efflux pump as a transcriptional indicator, but we think that the potential benefits for the scientific community greatly outweight the much effort and time needed to take this idea to its ultimate practical implications.
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