Loop to linear: exploring the impact of corona topology on the properties of self-assembled polymer nanoparticles

Abstract

Macromolecular architecture plays a pivotal role in endowing distinct properties to polymer nanomaterials. We introduce a synthesis approach to produce cyclic polystyrene-b-poly(acrylic acid) block copolymers featuring UV-cleavable motifs by combining atom transfer radical polymerisation and copper-catalyzed azide–alkyne cycloaddition. The resulting cyclic copolymers could self-assemble into discrete nanoparticles. Their coronal topology could be altered from looped to linear poly(acrylic acid) chains upon UV irradiation while maintaining the original nanoparticle morphology, therefore achieving the post-assembly modification of polymer nanoparticles. Small molecule release profiles were markedly different for self-assemblies with looped or linear corona, as was their interaction with model cell membranes in electrochemical impedance spectroscopy assays. Compared to their linear counterparts, cyclic copolymer assemblies exhibited slower release and weakened membrane interactions.