Direct optical visualization of DNA-DNA interaction by nanoparticle-capture on resonant PET-films

Based on the understanding of the absorption behavior of metal nanoparticles we aimed at the direct detection of sub-monomolecular layers of DNA with the naked eye. This extremely sensitive detection needs optical amplification techniques to be used in replacement of nanoparticle-aggregates applied e.g., in agglutination assays. We focus on the nanolayer-coated metallized-PET-chip setup and on the synthesis of DNA-nanoparticle conjugates suitable for 'resonance enhanced absorption'-point of care-tests and the application of those particles in the direct visualization of DNA-DNA binding events. Stabilization of nanoparticles and their sequence specific binding was proven with direct optical visibility of sub-monolayers of colored nanoclusters. Synthetic routes leading to suitable conjugates as well as stability tests and a biorecognition test are described in detail adding to the repertoire of tools that contribute to the application of nanoparticles in novel nano-enhanced devices.