Synthesis, self-assembly and recognition properties of biomimetic star-shaped poly(ε-caprolactone)-b-glycopolymer block copolymers

Biomimetic star-shaped poly(epsilon-caprolactone)-b-poly(gluconamidoethyl methacrylate) block copolymers (SPCL-PGAMA) were synthesized from the atom transfer radical polymerization (ATRP) of unprotected GAMA glycomonomer using a tetra(2-bromo-2-methylpropionyl)-terminated star-shaped poly(epsilon-caprolactone) (SPCL-Br) as a macroinitiator in NMP solution at room temperature. The block length of PGAMA glycopolymer within as-synthesized SPCL-PGAMA copolymers could be adjusted linearly by controlling the molar ratio of GAMA glycomonomer to SPCL-Br macroinitiator, and the molecular weight distribution was reasonably narrow. The degree of crystallization of PCL block within copolymers decreased with the increasing block length ratio of outer PGAMA to inner PCL. Moreover, the self-assembly properties of the SPCL-PGAMA copolymers were investigated by NMR, UV-vis, DLS, and ITEM, respectively. The self-assembled glucose-installed aggregates changed from spherical micelles to worm-like aggregates, then to vesicles with the decreasing weight fraction of hydrophilic PGAMA block. Furthermore, the biomolecular binding of SPCL-PGAMA with Concanavalin A (Con A) was studied by means of UV-vis, fluorescence spectroscopy, and DLS, which demonstrated that these SPCL-PGAMA copolymers had specific recognition with Con A. Consequently, this will not only provide biomimetic star-shaped SPCL-PGAMA block copolymers for targeted drug delivery, but also improve the compatibility and drug release properties of PCL-based biomaterials for hydrophilic peptide drugs. (C) 2007 Wiley Periodicals, Inc.