Read the full article here: Angew. Chem. Int. Ed. 2020, 60, 3619
by X. Fan and A. Walther
Transient signaling orchestrates complex spatiotemporal behaviour in living organisms via (bio)chemical reaction networks (CRNs). Compartmentalization of signal processing is an important aspect for controlling such networks. However, artificial CRNs mostly focus on homogeneous solutions to program autonomous self‐assembling systems, which limits their accessible behaviour and tuneability. Here, we introduce layered compartments housing antagonistic pH‐modulating enzymes and demonstrate that transient pH signals in a supernatant solution can be programmed based on spatial delays. This overcomes limitations of activity mismatches of antagonistic enzymes in solution and allows to flexibly program acidic and alkaline pH lifecycles beyond the possibilities of homogeneous solutions. Lag time, lifetime, and the pH minima and maxima can be precisely programmed by adjusting spatial and kinetic conditions. We integrate these spatially controlled pH flips with switchable peptides, furnishing time‐programmed self‐assemblies and hydrogel material system.