Until very recently, synthetic chemistry has focussed on the creation of chemical entities with desirable properties through the programmed application of isolated chemical reactions, either individually or in a cascade, that afford a target compound selectively. By contrast, biological systems operate using a plethora of complex interconnected signalling and metabolic networks with multiple checkpoint controls and feedback loops allowing biological systems to adapt and respond rapidly to external stimuli.
Systems chemistry attempts to capture the complexity and emergent phenomena prevalent in the life sciences within a wholly synthetic chemical framework. In this approach, complex dynamic phenomena are expressed by a group of synthetic chemical entities designed to interact and react with many partners within the ensemble in programmed ways. In this manner, it should be possible to create synthetic chemical systems whose properties are not simply the linear sum of the attributes of the individual components. These new system-level properties emerge through the interactions of chemical networks assembled from the many predesigned components.
Unlike traditional synthetic approaches, in which mixtures of compounds are treated as an unwanted feature that must be eliminated, systems chemistry demands the presence of a mixture of components and the interactions between these multiple components are a necessity for the emergence of properties at a whole system level.