Biotin a-End-Functionalized Gradient Glycopolymers Synthesized by RAFT Copolymerization a Guillaume Gody, Paul Boullanger, Catherine Ladavie `re, Marie-The ´re `se Charreyre, * Thierry Delair Introduction Among the various synthetic polymers, glycopolymers (polymer chains bearing saccharidic pendant groups) have attracted increasing attention for applications in many fields such as detergence, compatibilization, diagnosis, therapeutics, and surface engineering. [1] Carbohydrate-based monomers have long been poly- merized by all kinds of polymerization techniques, simple ones such as conventional free radical polymerization to controlled ones such as living ionic polymerizations. [2] However, these last ones are carried out under stringent experimental conditions and are often limited to a few monomer families. The discovery of controlled radical polymerization (CRP) techniques has given a new interest to glycopolymers since such techniques can be performed in smooth conditions and apply to most monomer families. The main CRP techniques, namely nitroxide- mediated polymerization (NMP), [3] atom transfer radical polymerization (ATRP), [4] and reversible addition- fragmentation chain transfer (RAFT) [5] have been success- fully applied to the synthesis of carbohydrate-based polymers, [6] mostly homopolymers, block copolymers, and hyperbranched polymers. Copolymerization of a carbohydrate-based monomer with another kind of monomer has numerous advantages. The presence of a comonomer can modulate the polymer Communication Biotinylated gradient glycopolymers have been synthesized via RAFT copolymerization of an acrylamide derivative of galactose with N-acryloylmorpholine in the presence of a biotin CTA. The polymerization was controlled with a linear increase in molecular weights up to 80% conversion. Copolymer chains have a gradient microstructure with an increasing proportion of galactose units towards the v chain end. The presence of the biotin ligand at the a end of the chains was confirmed by 1 H NMR and MALDI-ToF MS. This strategy based on the use of a biotin-CTA instead of a post-polymerization labelling of the chains resulted in a high percentage of a- functionalized chains (92–95%). Such a-end-functionalized glyco- polymer chains may interact with streptavidin-modified surfaces. G. Gody, C. Ladavie `re, M.-T. Charreyre, T. Delair Unite ´ Mixte CNRS-bioMe ´rieux, E ´ cole Normale Supe ´rieure de Lyon, 69364 Lyon Cedex 07, France E-mail: mtcharrre@ens-lyon.fr G. Gody, P. Boullanger Laboratoire de Chimie Organique II, UMR 5622 CNRS/UCBL, 69616 Villeurbanne Cedex, France a : Supporting information for this article is available at the bottom of the article’s abstract page, which can be accessed from the journal’s homepage at http://www.mrc-journal.de, or from the author. Macromol. Rapid Commun. 2008, 29, 511–519 ß 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim DOI: 10.1002/marc.200700768 511