DNA detection by dye labeled oligonucleotides using surface enhanced Raman spectroscopy

Dye labeled oligonucleotides have been applied to detection of DNA with high sensitivity using surface enhanced Raman spectroscopy (SERS). Duplex formation of dye labelled oligonucleotides with DNA targets, followed by selective conjugation with silver nanoparticles, made it possible to determine the optimal distance between the SERS label and the silver surface, which was necessary for strong signal enhancement. For all Rh6G labeled oligonucleotides the limits of detection were 3 fmol dm^–3, while for Cy3 labeled oligonucleotides the signal enhancement depended on the distance between Cy3 dye and silver nanoparticles.