Reporters are molecules that allow the detection of a range of processes or molecules in a system. Reporter systems currently used in biology are proteins or enzymes whose expression is typically based on visual assessment. While techniques exist to get quantitative data from these reporters, they often require sophisticated equipment and are prone to large background noise. Furthermore, such optical reporter systems are frequently imposing a burden on the cell as the quantity of reporter molecules and thus energy associated to their expression is considerable. Synthetic biology is a new field that hold great promise to revolutionise biotechnology by applying engineering concepts to biology. However, currently some of the most powerful engineering tools such as Fourier and Laplace transforms are not widely being applied to reporter systems.
We report the construction of a novel type of reporter mechanism based on programmable in vivo potassium efflux in Escherichia coli. We have successfully assembled the custom genetic circuit driving the expression of the mutated potassium efflux pump KefC and have built liquid phase potassium ion sensors capable of translating the change in extracellular potassium concentration into an electronic digital signal. This creates a bio-electronic interface in synthetic biology facilitating the application of strong analytical techniques to biological signals.
Furthermore, we have built hardware and software tools to enable automatic collection of experimental data. Wireless coordinated sensors were constructed and linked with the potassium sensor, incubator, spectrophotometer and an ambient light sensor. Web-based graphing software was developed to federate the data.