Stereocomplexed micelle formation through enantiomeric PLA-based Y-shaped copolymer for targeted drug delivery

In this study, a novel stereocomplexed micelle system was prepared from the self-assembly of enantiomeric PLA-based Y-shaped copolymers, i.e. folic acid-adamantane/β-cyclodextrin-b-[poly(D-lactide)]2 (FA-AD/CD-b-(PDLA)2) and poly(2-dimethylaminoethyl methacrylate)-b-[poly(L-lactide)]2 (PDMAEMA-b-(PLLA)2) in aqueous solution. The newly designed Y-shaped copolymer FA-AD/CD-b-(PDLA)2 was prepared by a combination of “click” reaction and host guest interaction between FA-AD and CD-b-(PDLA)2. In addition, enantiomeric Y-shaped PDMAEMA-b-(PLLA)2 copolymer was synthesized through ring-opening polymerization (ROP) of L-lactide using three-head initiator with bromo and -OH at distal ends, followed by atom transfer radical polymerization (ATRP) of DMAEMA to obtain the desired macromolecular architecture. The resultant copolymers and their intermediates were characterized by 1H nuclear magnetic resonance (1H NMR) and gel permeation chromatography (GPC) techniques. Due to the strong stereocomplexation interaction, FA-AD/CD-b-(PDLA)2 and PDMAEMA-b-(PLLA)2 mixture could self-assemble into stable mixed micelles in aqueous solution. Further, the stereocomplexed micelles exhibited excellent biocompatibility as revealed in the cytotoxicity assay. Together with the intrinsic biodegradability of PLA, it is envisioned that the stereocomplexed micelles developed in this study can be used as a promising nanocarrier for targeting drug delivery.