Modularity, context-dependence, and insulation in engineered biological circuits.

The ability to link systems together such that they behave as predicted once they interact with each other is an essential requirement for the forward-engineering of robust synthetic biological circuits. Unfortunately, because of context-dependencies, parts and functional modules often behave unpredictably once interacting in the cellular environment. This paper reviews recent advances toward establishing a rigorous engineering framework for insulating parts and modules from their context to improve modularity. Overall, a synergy between engineering better parts and higher-level circuit design will be important to resolve the problem of context-dependence.