Double interference fluorescence enhancement from reflective slides: Application to bicolor microarrays

A technique for enhancing fluorescence from species close to a substrate is described, based on a multilayer dielectric mirror coating. For proper design, interferences bring improvements to both fluorescence excitation and collection, each about four fold. The overall improvement reaches 10 to 15 fold as compared to a standard glass slide. We apply this to so-called deoxyribonucleic acid (DNA) chips, that is to DNA hybridization assays on microarray platforms, for which two fluorophores most commonly used are cyanine dyes (Cy3 (TM) and Cy5 (TM)). Impact of the two-color scheme is discussed. A validation method based on spin-coated fluorescent ultrathin layers is shown to accurately determine the amplification factors of the different tagging dyes. (c) 2005 American Institute of Physics.