Modelling

Modelling took a large place in the project; it was not only used for the characterization of KillerRed and the Voigt plasmids, it was needed for the control of the bacteria’s population. With our device, we cannot control a population of living cells with a simple closed-loop transfer function. First, this is because optical measurements (OD 600 nm or fluorescence) originate from all cells, whether they are alive or not. This fluorescence intensity gives clues about living cell activity and therefore its temporal evolution permits to find the number of living cells, but there is no simple relation between them. Second, there is a large delay between an action and its effect: there are about one or two hours between the onset of illumination and the deceleration of fluorescence. In those conditions, a simple closed-loop transfer function is predictably unstable, and a model predictive control is needed to stabilize the population of living cells.

Come, sit, and listen to the story of the model's construction ! You will hear about the journey of this model, from its genesis to its fulfilment ! Going through the reasons that drove it to consider the time of maturation of KillerRed or the resilence of bacteria.

Here, you traveler, will read about the way the parameters were chosen to fit best the experiments, and so make the model to predict properly the evolution of the bacterial concentration. You will see how a genetic algorithm can be used to understand a genetic network. And of course will appreciate the final results.

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