Organization of Inorganic Nanoparticles Using Biotin−Streptavidin Connectors

Organizing inorganic matter at the nanometer and mesoscopic length scale represents a new challenge for materials chemistry. One potential strategy involves the use of biomolecular recognition in the coupling of complementary connecting units preattached to the surfaces of inorganic nanoparticles. In this paper, superparamagnetic iron oxide nanoparticles, synthesized within the 8 nm cavity of the protein ferritin, are reversibly organized into networks by intermolecular cross-linking of biotinylated molecules using high-affinity streptavidin binding. The extent and kinetics of aggregation are dependent on the concentrations and stoichiometry of the conjugated system.