A model for DNA detection by metal-enhanced fluorescence from immobilized silver nanoparticles on solid substrate.
N-(2-Mercaptopropionyl)glycine (tiopronin)-coated silver nanoparticles (average diameter of metal core=5 nm) were prepared by a modified Brust method. Tiopronin ligands were partially displaced by thiolate single-stranded oligonucleotides via ligand exchange. These particles were immobilized onto a solid substrate through hybridization with target oligonucleotides in a layer-by-layer approach. The dye-labeled complementary oligonucleotides were bound to the particle layers through hybridization. Fluorescence intensity was enhanced with a simultaneous increase of plasmon absorbance from accumulated particles. A steady state was shown at the 10th particle layer and then the fluorescence enhancement showed a plateau. This result reveals that increasing the particle layer contributes to fluorescence enhancement. This novel method was used to detect DNA hybridization through both absorbance and emission spectral changes.
Center for Fluorescence Spectroscopy, University of Maryland School of Medicine, Department of Biochemistry and Molecular Biology, 725 West Lombard Street, Baltimore, Maryland 21201, USA.
Jian
J
Zhang
Joseph R
JR
Lakowicz
D004247:DNA / Q000032:analysis* / Q000737:chemistry; D005456:Fluorescent Dyes / Q000737:chemistry*; D008024:Ligands; D008954:Models, Biological; D008956:Models, Chemical; D049329:Nanostructures / Q000737:chemistry*; D009693:Nucleic Acid Hybridization / Q000379:methods; D009841:Oligonucleotides / Q000737:chemistry; D012834:Silver / Q000737:chemistry*; D013050:Spectrometry, Fluorescence / Q000379:methods; D008625:Tiopronin / Q000737:chemistry*
D005456:Fluorescent Dyes; D008024:Ligands; D009841:Oligonucleotides; D012834:Silver; D004247:DNA; D008625:Tiopronin