Materials and methods for studying and modulating the interaction of carbohydrate-containing moieties with other species are described, in particular, small particles, e.g. clusters of metal or semiconductor atoms, which can be employed as a substrate for immobilising a plurality of ligands comprising carbohydrate groups. These “nanoparticles” can then be used to study carbohydrate mediated interactions, e.g. with other carbohydrates or proteins, and as therapeutics and diagnostic reagents.
1. A method of vaccinating a patient with an antigen, the method comprising vaccinating the patient with nanoparticles comprising a core of metal atoms covalently linked to at least one species of ligand, wherein (a) at least one of the species of ligand comprises a carbohydrate group and (b) the core of the nanoparticle is covalently linked to at least 20 ligands, wherein at least one of the ligands linked to the core of the nanoparticle comprises the antigen.