Individual water-soluble dendrimer-encapsulated silver nanodot fluorescence.

Easily observed on the single molecule level, highly fluorescent and photostable silver nanoclusters have been photochemically prepared within poly(amidoamine) dendrimer hosts in aqueous solutions. The dendrimer cage stabilizes and solubilizes the nanoclusters to yield highly stable, photoactivated single nanodots ranging in size from 2 to 8 silver atoms. These multicolored, highly fluorescent species are extremely photostable and readily observed on the single molecule scale with weak mercury lamp excitation. Such easily created, bright, photoactivated water-soluble fluorophores are likely to greatly expand the impact of single molecule labeling studies in a wide variety of systems.