Biotin chain-terminated glycopolymers were generated by cyanoxyl-mediated free-radical polymerization using a biotin-derivatized arylamine initiator with high conversion (75%) and low polydispersity (1.30). Streptavidin-biotinylated glycopolymer binding was verified by SDS-PAGE gel shift assay and patterned glycocalyx-mimetic surfaces successfully fabricated.

A stabilized, phosphatidylcholine-containing polymeric surface was produced by in-situ polymerization of a self-assembled lipid monolayer on an alkylated substrate. The phospholipid monomer 1-palmitoyl-2-[12-(acryloyloxy)dodecanoyl]-sn-glycero-3-phosphorylcholine was synthesized, prepared as unilamellar vesicles, and fused onto alkylated glass. Free-radical polymerization was carried out in aqueous solution at 70 °C and characterized using either the water-soluble initiator 2,2‘-azobis(2-methylpropionamidine) dihydrochloride (AAPD) or an oil-soluble initiator 2,2‘-azobis(isobutyronitrile) (AIBN). Under optimized conditions, the supported monolayer displayed advancing and receding water contact angles of 64 and 44°, respectively. Angle-dependent ESCA results confirmed the presence of phosphorus and nitrogen and were consistent with theoretical predictions for close-packed monolayer formation with near-normal alignment of lipid chains. In the absence of network formation, polymeric films demonstrated acceptable stability under static conditions in water and air, as well as in the presence of a high shear flow environment. Blood compatibility was assessed in a baboon arteriovenous shunt model, which revealed miminal platelet deposition over a 2 h observation period.

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-beta-d-galactopyranosyl)-(1-4)-2,3,6-tri-O-acetyl-beta-d-glucopyranoside (AEL) by ATRP with a dibromoxylene (DBX)/CuBr/bipy complex system was used to generate a central glycopolymer block. Telechelic glycopolymers with diamino end groups were obtained by end group transformation and subsequently used as macroinitiators for ROP of l-alanine N-carboxyanhydride monomers (Ala-NCA). Gel permeation chromatography (GPC) and nuclear magnetic resonance (NMR) spectroscopy analysis demonstrated that copolymer molecular weight and composition were controlled by both the molar ratios of the Ala-NCA monomer to macroinitiator and monomer conversion and exhibited a narrow distribution (Mw/Mn = 1.06-1.26). FT-IR spectroscopy of triblock copolymers revealed that the ratio of alpha-helix/beta-sheet increased with poly(l-alanine) block length. Of note, transmission electron microscopy (TEM) demonstrated that selected amphiphilic glycopolymer-polypeptide triblock copolymers self-assemble in aqueous 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 triblock copolymers with a central glycopolymer block and flanking polypeptide blocks of defined architecture, controlled molecular weight, and low polydispersity.