Synthesis of well-defined glycopolymers and some studies of their aqueous solution behaviour Neil R. Cameron, * a Sebastian G. Spain, a James A. Kingham, a Stefan Weck, a Luca Albertin, a Carl A. Barker, a Giuseppe Battaglia, b Thomas Smart b and Adam Blanazs c Received 7th November 2007, Accepted 7th December 2007 First published as an Advance Article on the web 9th April 2008 DOI: 10.1039/b717177c Well-defined polymers with carbohydrate residues pendant to the main chain (glycopolymers) were prepared by reversible addition fragmentation chain transfer (RAFT) polymerisation. Excellent control over molecular weight and narrow polydispersities (1.1–1.2) were achieved over a range of molecular weights. In addition, efficient synthesis of block copolymers by sequential monomer addition with both hydrophilic and hydrophobic non-carbohydrate blocks was demonstrated. The aqueous solution behaviour of amphiphilic block glycopolymers was investigated, revealing the formation of multivalent carbohydrate-bearing aggregates in solution with the capability for the solubilisation of hydrophobic species (a water-insoluble dye). One such amphiphilic glycopolymer shows by TEM the formation of a worm-like micelle phase. Further investigations of these novel bioactive macromolecular assemblies are underway. Introduction It is now widely recognized that carbohydrates play a key role in a range of biologi- cal processes, including (but not limited to) fertilisation, the inflammatory cascade, viral particle docking and entry and signal transduction. These processes are initiated by carbohydrates (glycans), which are attached to cell surface lipids and proteins, binding noncovalently to receptor proteins known as lectins. The pattern of carbohydrates on cell surfaces is often referred to as the ‘glycocode’; decoding this language and elucidating the role of carbohydrates in biological processes is a thriving new discipline known as ‘glycomics’. Interactions between individual sugars and lectins are unusually weak; association constants (K A ) being of the order of 10 3 M 1 . The high specificity of a lectin for a given carbohydrate is brought about through a multivalent binding process known as the ‘cluster glycoside’ effect, 1 where many copies of the same sugar are presented to the lectin in the correct orientation, leading to much higher apparent K A values (10 9 –10 12 M 1 ). High avidity synthetic multivalent ligands such as glycodendrimers 2 and glycopolymers 3 have been prepared in order to exploit the cluster glycoside effect and study the glycocode. A number of studies of the binding of such multi- valent ligands to receptors have been carried out, 4–6 however, a clear picture of the nature of multivalent binding is still lacking. While all studies indicate enhanced a Department of Chemistry, Durham University, South Road, Durham, U.K. DH1 3LE b The Kroto Research Institute, North Campus, University of Sheffield, Broad Lane, Sheffield, U.K. S3 7HQ c Department of Chemistry, University of Sheffield, Brook Hill, Sheffield, U.K. S3 7HF PAPER www.rsc.org/faraday_d | Faraday Discussions This journal is ª The Royal Society of Chemistry 2008 Faraday Discuss., 2008, 139, 359–368 | 359 Published on 09 April 2008. Downloaded by University of Nottingham on 22/08/2013 10:47:17. View Article Online / Journal Homepage / Table of Contents for this issue