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 immobilizing 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.