Interfacial micro-compartmentalization by kinetic control of selective interfacial accumulation.

The spatial organisation of functional components is essential for numerous biological and technical processes. Here, we report a novel 2D, interfacial micro-compartmentalization strategy which is governed by 3D phase separation. In aqueous polyethylene glycol (PEG) solutions doped with biotinylated polymers, biotinylated polymers were serendipitously found to spontaneously accumulate in the interfacial layer between the oil-surfactant-water interface and the adjacent polymer phase. In aqueous two-phase systems, these biotinylated polymers first accumulated in the interfacial layer separating two polymer solutions and then selectively migrated to the oil-PEG interfacial layer. By equipping the different polymers with photopolymerizable groups and varying cross-linking rates, we have been able to kinetically control and capture the spatial organisation in a variety of compartmentalized macroscopic structures without the need of creating barrier layers. This new phenomenon of selective interfacial accumulation (SIA) provides an highly significant extension of current 3D phase separation towards synthetic compartmentalization, and may also be relevant for our understanding of intracellular organisation.