Based on the mathematical model we developed in our paper in Metabolic Engineering, we designed a bacterium with the highest rate of AI-2 uptake to manipulate QS behaviors from inside a biocompatible capsule. While in our prior work, we showed that these controller cells could uptake AI-2 when interacting directly with the population, useful in many infections, these cells are retained within the capsule, while AI-2 is small enough to freely diffuse into the capsule and be consumed. By minimally interacting with the cell population, the device could not only quench QS, but could also tune the phenotypes of QS subpopulations. There would be tremendous advantages in controlling the signal intensity so that some cells could make one designed protein, and some cells could make another, thereby generating ‘quantized quorums’, a concept advanced in a previous study (ISME 2016). This was a major leap forward from our work published in the ISME journal, where quantized quorums were generated by knocking out the luxS gene and adding metabolites.
Now, we could guide one cell population to produce a product and another subpopulation to produce another, which is the major advantage of microbial consortias. Following up on this work, I described how discrete levels of molecules like AI-2 could be used to connect different cell populations together on a microfabricated chip as a ‘bioproduction breadboard’ (cover, Curr. Opin. 2016). By separating the populations but linking and coordinating them with discrete levels of AI-2, we could create microbial communities with balanced growth populations. This allows de novo biological pathways to be produced by leveraging the specialization of each cell type.