Thiol-Functionalized Block Copolymer Vesicles

Thiol-functionalized block copolymer vesicles are readily prepared via RAFT-mediated polymerization-induced self-assembly (PISA). More specifically, a disulfide-functionalized poly(glycerol monomethacrylate) macro-CTA is chain-extended using 2-hydroxypropyl methacrylate): the growing water-insoluble poly(2-hydroxypropyl methacrylate) chains drive in situ self-assembly to produce diblock copolymer vesicles in concentrated aqueous solution. The disulfide bonds in the poly(glycerol monomethacrylate) stabilizer chains are reductively cleaved in situ using either tributyl phosphine or tris(2-carboxyethyl)phosphine to generate thiol groups, which react immediately with either a quaternary acrylate to introduce cationic character or with rhodamine B acrylate or rhodamine B isothiocyanate to confer a convenient fluorescent tag. In addition to such facile derivatization, such thiol-functionalized vesicles may offer some potential for drug delivery applications, because enhanced muco-adhesion is anticipated for these nano-objects.