Effect of Branching Density on Avidity of Hyperbranched Glycomimetics for Mannose Binding Lectin

Hyperbranched glycopolymers containing mannose units in the branch point were synthesized through the copolymerization of a mannose inimer and mannose acrylate via atom transfer radical polymerization (ATRP). Incorporating a saccharide residue at the branch point results in a closer analogue to natural branched polysaccharides. Gel permeation chromatography characterization of the polymers qualitatively indicates branching in samples from polymerizations utilizing the mannose inimer. Deprotection of the acetate protecting groups from the hyperbranched mannose polymers yields water-soluble polymers that interact with mannose binding lectin (MBL), a key protein of the innate immunity complement system. MBL interaction increases with increasing polymer molecular weight and increasing branching density. Notably, incorporating mannose into the branching repeat unit also increases the interaction of the glycopolymers with MBL compared with glycopolymers with the same branching density but with no mannose at the branch point.