DNA hybridization using surface plasmon-coupled emission

摘要

We described a new approach to measuring DNA hybridization using surface plasmon-coupled emission (SPCE). This phenomenon occurs for fluorophores within few hundreds of nanometers of a thin metal film on a glass substrate, in our case a 50 nm thick silver film. Excited fluorophores coupled with the surface plasmons in the metal resulting in directional emission through the glass substrate. We studied the emission of Cy3-labeled DNA oligomers bound to complementary unlabeled biotinylated-oligomers, which were bound to the metal surface via a streptavidin-BSA monolayer. Hybridization resulted in directional emission of Cy3-DNA into the prism. Additionally, the use of SPCE resulted in suppression of interfering emission from non-complementary Cy5-DNA oligomers due to weaker coupling of the more distant fluorophores with the surface plasmons. A large fraction of the total potential emission can couple to the surface plasmon resulting in improved sensitivity. We expect SPCE to have numerous applications to nucleic acid analyses.