Vinyl Sulfone-Terminated PEG−PLLA Diblock Copolymer for Thiol-Reactive Polymeric Micelle

Abstract

Vinyl sulfone-terminated polyethylene glycol-poly(l-lactide) (VS−PEG−PLLA) diblock copolymer was designed as an amphiphilic structure containing a VS group with high reactivity toward thiols. Prior to the copolymer synthesis, heterobifunctional PEG with a VS group at one terminus was prepared and then PLLA was introduced to the other end of PEG. The chemical structure and molecular weight of the resulting products was assigned by 1H NMR and GPC. As micellar properties of VS−PEG−PLLA under aqueous environment, the critical micelle concentration and mean size of VS−PEG−PLLA were found to be approximately 59.8 mg/L and 34 nm, respectively. Kinetic studies of the VS-functionalized PEG−PLLA micelle showed that the reaction rates were affected by various factors but most of cysteine-contained peptides reacted rapidly within 1 h via Michael-type addition. Therefore, this thiol-reactive polymeric micelle is expected to be very useful for a functional nanocarrier system through the effective conjugation of cystein...