Magnetic glyconanoparticles for selective lectin separation and purification†
A modular platform for the separation and purification of lectins using polymer coated iron oxide nanoparticles is developed. Supramolecular host–guest interactions based on an adamantane beta-cyclodextrin (β-CD) dyad are utilized to modify the polymeric interface. Poly(ethylene glycol) based hydrophilic polymer-coated magnetic iron oxide nanoparticles are fabricated using reversible addition–fragmentation chain transfer polymerization, followed by their chain-end modification to install adamantane groups on the nanoparticle surface. These adamantyl containing nanoparticles could be surface modified using β-CDs appended with appropriate ligands for intended applications. In this study, we exploit this supramolecular system for the purpose of separation and purification of lectins. Therefore, a polymer-coated magnetic nanoparticle interface was decorated with two types of mannose-containing β-CD constructs, a monodisperse heptamannose conjugated CD and a CD-based 7-arm star shaped glycopolymer for selective binding towards the concanavalin A (ConA) lectin. The monodisperse and polydisperse CD derivatives were compared in terms of their efficiency for binding to ConA. It was demonstrated that the polymeric CD construct significantly improved the binding of magnetic nanoparticles and provided an effective system for the separation and purification of ConA from a mixture of ConA and peanut agglutinin (PNA). Moreover, the surface bound isolated protein could be simply regenerated by the addition of competitive ligands such as mannose. Specificity to bind a particular lectin can be tailored by choosing the appropriate sugar based ligand, as demonstrated by the specific capture of PNA using a galactose-containing polymer. The modular nature of functionalization of the nanoparticle interface that is tunable by host–guest chemistry affords a universal system that can be easily tailored for the purification of specific proteins from mixtures.