| Independent Control of Grafting Density and Conformation of Single-Stranded DNA Brushes |
02 JAN 2007 |
8 pages |
| Authors:
Aric Opdahl; Dmitri Y. Petrovykh; Hiromi Kimura-Suda; Michael J. Tarlov; Lloyd J. Whitman; NATIONAL INST OF STANDARDS AND TECHNOLOGY GAITHERSBURG MD
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 | We describe self-assembly of ssDNA brushes that exploits the intrinsic affinity of adenine nucleotides (dA) for gold surfaces. The grafting density and conformation of these brushes is deterministically controlled by the length of the anchoring dA sequences, even in the presence of thymine nucleotides (dT). We produce and characterize brushes of model block-oligonucleotides, d(Tm-An), with systematically varied lengths m and n of the thymine and adenine blocks [denoted d(Tm) and ... |
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| Alkanethiols on Platinum: Multicomponent Self-Assembled Monolayers |
2006 |
11 pages |
| Authors:
Dmitri Y. Petrovykh; Hiromi Kimura-Suda; Aric Opdahl; Lee J. Richter; Michael J. Tarlov; Lloyd J. Whitman; MARYLAND UNIV COLLEGE PARK DEPT OF PHYSICS
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| We have studied the formation of self-assembled monolayers (SAMs) of n-alkanethiols on platinum thin films using X-ray photoelectron spectroscopy (XPS), reflection-absorption infrared spectroscopy (RAIRS), spectroscopic ellipsometry (SE), and contact angle (CA) measurements. Specifically, SAMs of 1-hexanethiol, 1-dodecanethiol, and 1-octadecanethiol were grown on polycrystalline Pt films, and the effects of Pt surface preparation, deposition conditions, and solvent treatments on the initial quality and stability of the monolayer in air were investigated. ... |
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| Nucleobase Orientation and Ordering in Films of Single-Stranded DNA on Gold |
APR 2005 |
3 pages |
| Authors:
Dmitri Y. Petrovykh; V. Perez-Dieste; Aric Opdahl; Hiromi Kimura-Suda; J. M. Sullivan; Michael J. Tarlov; F. J. Himpsel; Lloyd J. Whitman; MARYLAND UNIV COLLEGE PARK DEPT OF PHYSICS
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| Understanding the structure of single-stranded DNA (ssDNA) immobilized on surfaces is critical for applications exploiting the molecular recognition function of nucleic acids. Here we show how the structure of ssDNA monolayers can be characterized using complementary spectroscopies that probe electronic and vibrational states of nucleobasessX-ray photoelectron (XPS), Fourier transform infrared (FTIR), and near-edge X-ray absorption fine structure (NEXAFS) spectroscopies. XPS reveals core-level shifts sensitive to DNA surface chemistry; NEXAFS probes ... |
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| Quantitative Characterization of DNA Films by X-ray Photoelectron Spectroscopy |
SEP 2003 |
13 pages |
| Authors:
Dmitri Y. Petrovykh; Hiromi Kimura-Suda; Michael J. Tarlov; Lloyd J. Whitman; MARYLAND UNIV COLLEGE PARK DEPT OF PHYSICS
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| We describe the use of self-assembled films of thiolated (dT)25 single-stranded DNA (ssDNA) on gold as a model system for quantitative characterization of DNA films by X-ray photoelectron spectroscopy (XPS). We evaluate the applicability of a uniform and homogeneous overlayer-substrate model for data analysis, examine model parameters used to describe DNA films (e.g., density and electron attenuation length), and validate the results. The model is used to obtain quantitative composition ... |
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| Base-Dependent Competitive Adsorption of Single-Stranded DNA on Gold |
2003 |
3 pages |
| Authors:
Hiromi Kimura-Suda; Dmitri Y. Petrovykh; Michael J. Tarlov; Llyod J. Whitman; NATIONAL INST OF STANDARDS AND TECHNOLOGY GAITHERSBURG MD
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| Single-stranded DNA probes (ssDNA) immobilized on gold surfaces are a common element in many biotechnology and nanotechnology applications. Although recent studies have shown that different DNA bases and homo-oligonucleotides interact differently with Au surfaces, competitive interactions among the bases, which will occur in most practical applications, have not been systematically addressed. Here, we examine room-temperature adsorption of homo-oligonucleotides onto polycrystalline Au films, including competitive adsorption between all possible pairs of ... |
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| Quantitative Analysis and Characterization of DNA Immobilized on Gold |
2003 |
9 pages |
| Authors:
Dmitri Y. Petrovykh; Hiromi Kimura-Suda; Lloyd J. Whitman; Michael J. Tarlov; MARYLAND UNIV COLLEGE PARK DEPT OF PHYSICS
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| We describe the complementary use of X-ray photoelectron spectroscopy (XPS) and Fourier transform infrared (FTIR) spectroscopy to quantitatively characterize the immobilization of thiolated (dT)25 single-stranded DNA (ssDNA) on gold. When electron attenuation effects are accurately accounted for in the XPS analysis, the relative coverage values obtained by the two methods are in excellent agreement, and the absolute coverage can be calculated on the basis of the XPS data. The evolution ... |
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