Study on synthesis of glycopeptide-based triblock copolymers and their aggregation behavior in water

This paper describes a preliminary study on the synthesis of glycopeptide-based triblock copolymers and their aggregate behavior in water. Initially, a polypeptide-based triblock copolymer, poly(L-lysine)-b-poly(tetrahydrofuran)-b-poly(L-lysine) (PLL₃₀-b-PTHF-b-PLL₃₀), was synthesized by the ring-opening polymerization of ɛ-benzyloxycarbonyl-L-lysine N-carboxyanhydride using amine-terminated poly(tetrahydrofuran) as a macroinitiator in the fixed feed ratio, followed by the removal of the protecting group. The resulting copolymer then reacted with a varying amount of D-gluconolactone in the presence of dipropylethylamine to give the corresponding glycopeptide-based copolymers with high yields. This kind of amphiphilic sugar-containing triblock copolymer can self-assemble into nano-sized aggregates in water. The critical aggregation concentration (CAC) was determined in the range of around 10⁻⁶ M by fluorescence measurement. The spherical morphologies in 100–150 nm scale were also evidenced by transmission electron microscopy (TEM) measurements. They show potential as carriers for drug controlled delivery and templates for biomimetic mineralization.