Coupling nanotechnology to optical affinity sensing: the case of surface plasmon resonance imaging for DNA detection

Surface Plasmon Resonance imaging (SPRi) is an advanced optical transducer for the DNA affinity biosensors. SPRi signal enhancement of a DNA biosensor is a goal in developing innovative devices, especially for clinical applications. Nanoparticles (NPs) play a forefront role in signal enhancement in biosensor-based analysis, using different transduction principles. This work focused on the use of NPs for gold chip surface nanostructuring with the aim to study influence of this modification on DNA-based sensing using SPRi transduction. In particular gold NPs of different size and materials were immobilized through dithiol layer on gold biochip surface and further functionalized with thiolated DNA probe. Plasmon curves were studied for assessing the presence of the nanostructure and the influence of the nanostructure in SPRi signal was evaluated for each structure in hybridization with complementary oligonucleotide.