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.
Zhang
Jian
J
Center for Fluorescence Spectroscopy, University of Maryland School of Medicine, Department of Biochemistry and Molecular Biology, 725 West Lombard Street, Baltimore, Maryland 21201, USA.
Lakowicz
Joseph R
JR
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