Initating The Signal

We initiate the signal by pipetting 3OC6-HSL in a well of the first line.

Sensing

Diffused HSL molecules are identified via quorum sensing. This integration from a continuous variable, the concentration of HSL, to a discrete variable, the activation of a promoter, is prone to errors due to leakiness and crosstalk between HSL molecules, regulatory proteins and promoters (we characterized it for Lux promoter (BBa_R0062), Las promoter (BBa_R0079) and Rhl promoter (BBa_R0071)). To limit the risk of error propagation throughout the rows, we used a riboregulating system.

Computing

Integrases compute an XOR logic gate via single switching or double switching of a terminator. Their behavior depends on a set of parameters.

Postprocessing

The enzyme synthesizes the signaling molecule AHL.

Sending

The HSL produced diffuses then through the channels to the rows below. The speed of this directed diffusion determines the time needed from the pattern to emerge. You can find out more information about diffusion and chip design on our modeling page, our experimental results page and our chip page.

After initializing the signal, it propagates through the wells with directed diffusion. In each well, bacterial colonies have to be able to proceed in the information pathway: detecting (sensing), integrating (computing), producing and sending. These successive iterations leads to possible error propagation. Robustness is one major issue of our system.