Colocalization of gold nanoparticle-conjugated DNA hybridization for enhanced surface plasmon detection using nanograting antennas

We have investigated enhanced surface plasmon resonance detection through colocalization of gold nanoparticle (GNP)-conjugated target molecules and near-fields established by nanograting-based antennas. The target coloca-lization was implemented by angled dielectric thin-film deposition on the nanograting structure. The concept was testedby detecting DNA hybridization and shows that the colocalization produces an additional 60%-80% increase of resonance shifts. The colocalization involves a much smaller number of target molecules, so that the measured enhancement per molecule by the colocalization of GNP-conjugated DNA oligomers was estimated to be by more than 2 orders of magnitude relative to that of thin-film-based conventional detection.