Angew. Chem. Int. Ed.http://doi.org/fz679p (2012)

The use of surfactant molecules to stabilize aqueous–organic biphasic systems, including emulsions, is a dynamic process involving the interchange of surfactant molecules at the interface. If an emulsion is stabilized using colloidal nanoparticles, namely a Pickering emulsion, however, the nanoparticles are absorbed in a permanent manner at the interface. As a result of their high stability, Pickering emulsions have several practical advantages in enzymatic biphasic reactions. Now, Jan van Hest and colleagues have shown that polymersomes — vesicles formed from amphiphilic block copolymers — can be used to form Pickering emulsions in which enzymes can be either located in the aqueous phase or within the lumen of the polymersomes, and then used to catalyse esterification reactions. The enzyme's specific activity was highest when encapsulated within the polymersomes and was maintained at 89% following eight reaction cycles, when using toluene as the organic solvent. In future studies, the many distinct compartments within this polymersome-based Pickering emulsion could be exploited to load different enzymes and perform a cascade of organic reactions.