Dynamic Compartmentalisation of Chemical Reactivity in Droplet Microreactors

Abstract

Selective fusion and transport of reactive compartments is fundamental to biological processes. For examples biomolecular condensates dynamically concentrate resources required to initiate reactions. Whilst synthetic systems have been shown to mimic the autonomous mobility of biological compartments, they have seen limited use as reaction compartments. Complex chemical synthesis in autonomous droplets has yet to be reported. Here we show that two component droplets of propylene glycol (PG) and water can be used to deliver chemical reagents to a precise location without external inputs or user intervention. By exploiting surface tension mediated interactions between populations of two component droplets, compartments can be combined in > 90% selectivity and transported to a set location, enabling parallel reaction sequences to occur that would otherwise be incompatible in solution. Furthermore, the system is shown to respond to changes in droplet composition, allowing multiple reaction pathways to occur from the same initial starting point. Finally, the system can be made to respond to external inputs using a photoswitchable surfactant, enabling dynamic switching of chemical reactivity by raising the surface tension of a droplet. These results demonstrate that droplet compartments can autonomously regulate chemical systems using inputs both internal and external to the droplet, providing a platform for the development of complex responsive systems.