Label-free DNA detection on nanostructured Ag surfaces.
The dramatic local electric-field enhancement property of Ag nanoparticles was used as the basis to significantly increase the signal output of a novel label-free (or "self-labeled") fluorescence-based DNA detection system. In response to identical amounts of analyte, nanostructured Ag substrates provided a posthybridization fluorescent sensor response over 10-fold larger than the response from planar Au substrates. Detection performance strongly depended upon the Ag substrate roughness. Consistent with work by others on metal-enhanced fluorescence, fluorescence intensity also depended strongly on the distance between the fluorophore and the Ag substrate surface. Adjusting the surface roughness, amount of the Ag deposited on the surface, and the DNA probe length allowed for production of an optimized response. In addition to constituting a novel label-free DNA sensor, we anticipate that these structures will provide a unique platform for testing concepts in plasmonics.
Peng
Hsin-I
HI
Department of Biomedical Engineering, University of Rochester, Rochester, New York 14627, USA.
Strohsahl
Christopher M
CM
Leach
Kathryn E
KE
Krauss
Todd D
TD
Miller
Benjamin L
BL
D015374:Biosensing Techniques; D004247:DNA / Q000032:analysis* / Q000648:ultrastructure; D006046:Gold / Q000737:chemistry*; D053768:Metal Nanoparticles / Q000737:chemistry*; D018625:Microscopy, Atomic Force
D006046:Gold; D004247:DNA