Glycopolymer decoration of gold nanoparticles using a LbL approach

Two different copolymers, i.e., poly(tert-BuA-co-chloromethylstyrene) and poly(terr-BuA-coHEA), were synthesized by reversible addition- fragmentation (RAFT) polymerization. A poly(tert-BuA-cochloromethylstyrene) copolymer was subsequently modified by thioglucosc using a thio-halogen click nucleophilic substitution reaction. A poly(tert-BuA-co-HEA) copolymer was subsequently modified by p-toluenesulfonyl chloride, followed by sugar functionalization (galactose) via a nucleophilic substitution reaction. The resultant glycopolymers were characterized by NMR, FTIR, and GPC analyses. Both glyco-modification procedures were shown to be highly efficient, with yields close to 100 . After deprotection of the tert-butyl groups to form carboxylic acid functionality, the copolymers were assembled onto positively charged gold nanoparticlc (GNPs) surfaces using a layer-by-layer (LbL) methodology to yield sugar-functional GNPs. The glycopolymer-coated nanoparticles were characterized by transmission electron microscopy (TEM), UV-vis spectroscopy, dynamic light scattering (DLS), zeta-potcntial, and X-ray photoelectron spectroscopy (XPS). Finally, the presence of accessible sugar moieties on the surface of the GNPs was confirmed, by a. binding assay with Con A.