Coupling synthetic negative feedback loops

While coupled biochemical feedback loops are optimized over millions of years of evolution, the rational design of synthetic counterparts, not possessing the same advantage, is a challenging endeavor. The benefits of developing such loops, though, are immense, as they will pave the way for autonomous and self-regulating artificial systems. In this work, we demonstrate, through extensive structure-property analyses, how the modification of the building blocks of a synthetic negative feedback loop (NFL) allows for the design of NFLs that have varying onset thresholds. This fine control over the loops allows for the coupling of up to three of them, resulting in competition for resources, which establishes a strict operational hierarchy and leads to an emergent systems response.