Modeling

Prior to the experiments a model of the molecular approach was built to predict the results. The CAD tool Tinkercell was used to produce the models (Chandran, Bergmann and Sauro, 2009).

Our novel biosensor approach Expression of the TEV protease is induced by 3-oxo-C12-HSL. The protease cleaves the GFP-REACh fusion protein to elicit a fluorescence response.

Model of the molecular approach and the output over time The molecular setup of the novel biosensor (left) yields results indicating a strong and fast fluorescence output after induction (right). A directly inducable system was modeled and added to the plot for comparison.

The novel biosensor approach was modeled as shown above. The plotted results also include a model of a direct expression of GFP as it appears in traditional biosensors. The strength of the promotor used for the traditional approach is twice as high as the strength of the promotor upstream of the TEV coding sequence in our novel approach. Despite the stronger promotor, a higher GFP concentration is generated in the model of the novel biosensor, proving the stronger and faster fluorescence response of our construct in theory.

Since the final construct could not be built in time, a new model was designed according to the existing and functional double plasmid system. This is inducible with IPTG instead of 3-oxo-C₁₂-HSL as it contains the lac operon and is therefore a negative regulatory system.

Revised model of the molecular approach and output over time. This model is for the IPTG-inducible double plasmid system.

References

• Chandran, D., Bergmann, F. T., & Sauro, H. M. (2009). TinkerCell: modular CAD tool for synthetic biology. Journal of biological engineering, 3(1), 19. doi: 10.1186/1754-1611-3-19