Spontaneous Structuration in Coacervate‐Based Protocells by Polyoxometalate‐Mediated Membrane Assembly

Molecularly crowded, polyelectrolyte/ribonucleotide‐enriched membrane‐free coacervate droplets are transformed into membrane‐bounded sub‐divided vesicles by using a polyoxometalate‐mediated surface‐templating procedure. The coacervate to vesicle transition results in reconstruction of the coacervate micro‐droplets into novel three‐tiered micro‐compartments comprising a semi‐permeable negatively charged polyoxometalate/polyelectrolyte outer membrane, a sub‐membrane coacervate shell, and an internal aqueous lumen. We demonstrate that organic dyes, ssDNA, magnetic nanoparticles and enzymes can be concentrated into the interior of the micro‐compartments by sequestration into the coacervate micro‐droplets prior to vesicle formation. The vesicle‐encapsulated proteins are inaccessible to proteases in the external medium, and can be exploited for the spatial localization and coupling of two‐enzyme cascade reactions within single or between multiple populations of hybrid vesicles dispersed in aqueous media.