Characterization of Single- and Double-Stranded DNA on Gold Surfaces
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- 作者：Selina Moses ; Scott H. Brewer ; Lisa B. Lowe ; Simon E. Lappi ; Lauren B. G. Gilvey ; Marc Sauthier ; Robert C. Tenent ; Daniel L. Feldheim ; and Stefan Franzen
- 刊名：Langmuir
- 出版年：2004
- 出版时间：December 7, 2004
- 年：2004
- 卷：20
- 期：25
- 页码：11134 - 11140
- 全文大小：272K
- 年卷期：v.20,no.25(December 7, 2004)
- ISSN：1520-5827
文摘
Single- and double-stranded deoxy ribonucleic acid (DNA) molecules attached to self-assembled monolayers(SAMs) on gold surfaces were characterized by a number of optical and electronic spectroscopic techniques.The DNA-modified gold surfaces were prepared through the self-assembly of 6-mercapto-1-hexanol and5'-C6H12SH -modified single-stranded DNA (ssDNA). Upon hybridization of the surface-bound probe ssDNAwith its complimentary target, formation of double-stranded DNA (dsDNA) on the gold surface is observedand in a competing process, probe ssDNA is desorbed from the gold surface. The competition betweenhybridization of ssDNA with its complimentary target and ssDNA probe desorption from the gold surfacehas been investigated in this paper using X-ray photoelectron spectroscopy, chronocoulometry, fluorescence,and polarization modulation-infrared reflection absorption spectroscopy (PM-IRRAS). The formation ofdsDNA on the surface was identified by PM-IRRAS by a dsDNA IR signature at ~1678 cm-1 that wasconfirmed by density functional theory calculations of the nucleotides and the nucleotides' base pairs. Thepresence of dsDNA through the specific DNA hybridization was additionally confirmed by atomic forcemicroscopy through colloidal gold nanoparticle labeling of the target ssDNA. Using these methods, strandloss was observed even for DNA hybridization performed at 25 
ges/entities/deg.gif">C for the DNA monolayers studied hereconsisting of attachment to the gold surfaces by single Au-S bonds. This finding has significant consequencefor the application of SAM technology in the detection of oligonucleotide hybridization on gold surfaces.