Photo-Cross-Linking Polymersome Nanoreactors with Size-Selective Permeability

The design of stable, inert, and permeable nanoreactors remains a challenge due to the additives required to create a cross-linked network, limiting their potential for catalysis. Polymersomes are nanovesicles self-assembled from amphiphilic block copolymers that can act as nanoreactors by encapsulating catalysts. A major restriction toward their use is their stability and reduced permeability. In order to overcome this, polymersome membranes can be cross-linked to retain their shape and function. Here, we report the synthesis of a PEG-b-P(S-co-4-VBA) polymer, which can self-assemble into polymersomes and subsequently be cross-linked using UV light. We demonstrate that these polymersomes are stable over a long period of time in various organic solvents, that incorporation of functional handles on their surface is possible, and that they are able to undergo reactions. Additionally, we show that co-assembly with up to 40% PEG-b-PS present results in the formation of pores in the membrane structure, which allows for the structure to be used as a nanoreactor. By encapsulating a platinum nanocatalyst, we are able to catalyze the depropargylation of a small coumarin substrate, which was able to enter and leave the porous nanoreactor.