A cyclodextrin-core star copolymer with Y-shaped ABC miktoarms and its unimolecular micelles

Abstract

A well-defined β-cyclodextrin-core star copolymer with Y-shaped ABC miktoarms, star poly(ethyl methacrylate(-b-poly(2-(diethylamino)ethyl methacrylate)-b-methoxypolyethylene glycols (CD-star-PEMA(-b-PDEA)-b-mPEG), was designed and synthesized via ATRP and click reactions. The copolymer could exhibit unimolecular micelles in aqueous solution. The micelles were characterized by means of DLS, 1H NMR and TEM measurements. In the micelles the PEMA blocks work as a container for storing hydrophobic guest molecules, the mPEG is used as a hydrophilic block, and the PDEA block can respond to change in environmental pH. By using Nile red, celecoxib, and ketoprofen as hydrophobic model drugs, encapsulation and release behaviors of the unimolecular micelles were investigated. It was found that the unimolecular container is a good platform for encapsulating hydrophobic guest molecules. Release of the payload from the unimolecular micelles exhibited pH-sensitivity.