AVS 53rd International Symposium
    Nucleic Acids at Surfaces Topical Conference Monday Sessions
       Session DN-MoM

Paper DN-MoM3
Hybridization Behavior of DNA/Oligo(ethylene glycol) Functionalized Gold Surfaces in Complex Media

Monday, November 13, 2006, 8:40 am, Room 2014

Session: Nucleic Acids at Surfaces I
Presenter: C.-Y. Lee, University of Washington
Authors: C.-Y. Lee, University of Washington
L.J. Gamble, University of Washington
D.W. Grainger, Colorado State University
D.G. Castner, University of Washington
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Reliable, direct capture of nucleic acid targets from complex media would greatly improve existing capabilities of DNA microarrays and biosensors. This goal remains a challenge for many current nucleic acid detection technologies attempting to produce assay results directly from complex real-world samples. In this study, we investigate the performance of single-strand DNA (ssDNA) adlayers containing short thiolated oligo(ethylene glycol) (OEG) molecules on gold surfaces using DNA target capture from complete bovine serum and from salmon genomic DNA mixtures with varying target concentrations. The attachment chemistry and surface coverage of probe DNA molecules were studied by X-ray photoelectron spectroscopy (XPS). Target DNA hybridization on probe DNA surfaces was monitored by surface plasmon resonance (SPR). SPR measurements of target DNA hybridization from bovine serum and salmon genomic DNA mixtures demonstrated that OEG incorporation into the ssDNA adlayer improved surface resistance to both non-specific protein and DNA adsorption, allowing detection of small DNA target sequences from concentrated, complex biological mixtures. Target hybridization efficiency from serum decreases only slightly (by roughly 20%) as the serum concentration is increased to 50%. In undiluted serum (100%), target hybridization on the probe surface was reduced by approximately 80%. SPR DNA target detection signal in full-length genomic DNA competition is significantly reduced (by 50-80%) compared to DNA target in buffer. The influence of different probe immobilization chemistry and limit of target DNA detection on the ssDNA adlayers from these complex mixtures will be discussed.