Glycopolymer-polypeptide triblock copolymers of the structure, poly(
L-alanine)-
b-poly(2-acryloyloxyethyl-lactoside)-
b-poly(
L-alanine) (
AGA), have been synthesized by sequential atom transfer radical polymerization(ATRP)
and ring-opening polymerization (ROP). Controlled free radical polymerization of 2-
O-acryloyl-oxyethoxyl-(2,3,4,6-
tetra-
O-acetyl-
![](/images/gifchars/beta2.gif)
-
D-galactopyranosyl)-(1-4)-2,3,6-
tri-
O-acetyl-
![](/images/gifchars/beta2.gif)
-
D-glucopyranoside (AEL)by ATRP with a dibromoxylene (DBX)/CuBr/bipy complex system was used to generate a centralglycopolymer block. Telechelic glycopolymers with diamino end groups were obtained by end grouptransformation
and subsequently used as macroinitiators for ROP of
L-alanine
N-carboxyanhydride monomers(Ala-NCA). Gel permeation chromatography (GPC)
and nuclear magnetic resonance (NMR) spectroscopyanalysis demonstrated that copolymer molecular weight
and composition were controlled by both the molarratios of the Ala-NCA monomer to macroinitiator
and monomer conversion
and exhibited a narrowdistribution (
Mw/
Mn = 1.06-1.26). FT-IR spectroscopy of triblock copolymers revealed that the ratio of
![](/images/gifchars/alpha.gif)
-helix/
![](/images/gifchars/beta2.gif)
-sheet increased with poly(
L-alanine) block length. Of note, transmission electron microscopy (TEM)demonstrated that selected amphiphilic glycopolymer-polypeptide triblock copolymers self-assemble inaqueous solution to form nearly spherical aggregates of several hundreds nanometer in diameter. Significantly,the sequential application of ATRP
and ROP techniques provides an effective method for producing triblockcopolymers with a central glycopolymer block
and flanking polypeptide blocks of defined architecture,controlled molecular weight,
and low polydispersity.