DNA Recognition Using Metal Fluorescence Interactions on Two-Dimensionally Assembled Gold Nanoparticles

摘要

We developed a novel DNA detection system using a probe DNA with a fluorophore immobilized on two-dimensionally assembled gold nanoparticles. This system enables quantitative and selective detection of DNAs without a labeling process. In the absence of a target DNA, fluorescence from cyanine dyes labeled at the distal end of the probe is quenched via energy transfer to the nanoparticles on which the dye moiety is adsorbed. However, once a complementary target DNA is hybridized with the probe, rigidity of the double stranded DNAs allows the dyes to desorb from the particles, and fluorescence is enhanced by the strong local electromagnetic field in the vicinity of the gold nanoparticles. The relative increase in fluorescence intensity after hybridization was maximized on gold nanoparticles of 10 nm where both quenching and enhancement factors were optimal.