Future Experiments

We still have three experiments to perform in order to complete of our project:

Voigt Plasmid and degradation tag

To test the light-sensitive promoters for the expression and degradation of KillerRed and to show that the KillerRed concentration can be controlled both positively and negatively.

Control with the fluorescence alone

To demonstrate that the bacterial concentration can be stabilized without any other variable measurable than KillerRed fluorescence. This is essentially the same experiment as the one described in the proof of concept experiment but the correction on the light intensity will be calculated with only KillerRed fluorescence as a guide.

Test of the Device

To test the device, and to show that a model predictive control algorithm is able to automatically run the experiment. A Java program will be written to automatize the manual procedure that we employed for the proof of concept experiment .

Perspectives

Studying bacterial resistance to oxidative stress

The possibility to independently control the amount of KillerRed expressed in the cells and its phototoxic activity will allow us to obtain cell suspension growing at a precisely defined oxidative stress. Our device indeed allows controlling the ROS production rate in living bacteria. In the frame of our model, this means making the quantity $\frac{IK}{C}$ constant. Assuming that ROS disappear at a rate proportional to the ROS concentration, the ROS concentration per living cell will thus remain constant. Our bio-electronic system can thus be useful to study the influence of ROS on cell growth, and to investigate how different genes and molecule affect bacterial resistance to oxidative stress. Practically, one would first determine the specific parameters of the bacterial suspension as explained before, then the light intensity time profile will be calculated with our model and applied to the bacterial suspension.