Turning on fluorescence by plasmonic assembly with large tunable spacing: a new observation and its biosensing application.

Assembling nanoparticle-film metallic junctions with a spacing of up to tens of nanometers efficiently turned on fluorophores attached to the film from the quenching status to an intense surface plasmon-coupled emission. Benefiting from this new finding, a fluorescence biosensor was created based on the use of a biomolecule-linked plasmonic assembly as the trigger.