Asymmetric nanocapsules via elongated liposome templated polymerization (ELTP) mediated by RAFT polymerization

Polymeric nanocapsules comprised of hydrophobic shells and hollow aqueous interiors are an extremely useful class of nanomaterial, particularly in the encapsulation and controlled delivery of hydrophilic cargo. Generally prepared via droplet or latex templation approaches, polymeric nanocapsules are mostly spherical. Controlling the morphology of hollow nanocapsules is an intriguing design challenge. Non-spherical, or elongated, templates are often inorganic materials which do not directly impart a hollow interior, and their post-polymerization removal is not straightforward. This study outlines a novel strategy for the preparation of elongated nanocapsules, wherein elongated liposomes are deployed as hollow templates. Initially, ciprofloxacin drug nanocrystals were utilized to facilitate the formation of elongated liposomes, followed by adsorption of reversible addition-fragmentation chain transfer (RAFT) oligomers. Subsequent chain-extension polymerization furnished the desired elongated nanocapsule morphology. This proof-of-concept study contributes towards the goal of elongated nanocapsule synthesis, a morphology which can impart improved circulation times in the field of drug delivery.