Independent Control of Grafting Density and Conformation of Single-Stranded DNA Brushes

Abstract

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 d(An), respectively]. The hairpin conformation, dominant for self-complementary d(Tm-An) oligos in solution, is disrupted by the high preferential affinity of dA for gold surfaces. As a result, the d(Tm-An) oligos adsorb as a brush of d(T) strands immobilized via the d(A) blocks. Quantitative analysis by FTIR spectroscopy and x-ray photoelectron spectroscopy (XPS) reveals a unique feature of DNA immobilization via d(A) blocks: The surface density of dA nucleotides is close to saturation and is nearly independent of d(A) block length. Accordingly, the lateral spacing (grafting density) of the d(T) blocks is determined by the length of the d(A) blocks. The d(T) blocks extend away from the surface in a brush-like conformation at a lateral spacing 2 3 times larger (a grafting density 5 10 times lower) than in analogous films immobilized via standard thiol linkers. This combination of brushlike conformation and low saturation grafting density is expected to increase the efficiency of DNA hybridization at surfaces. Therefore, immobilization via d(A) blocks offers a method of producing DNA brushes with controlled properties for applications in biotechnology and nanotechnology.

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Document Details

Document Type
Technical Report
Publication Date
Jan 02, 2007
Accession Number
ADA480830

Entities

People

  • Aric Opdahl
  • Dmitri Y. Petrovykh
  • Hiromi Kimura-suda
  • Lloyd J. Whitman
  • Michael J. Tarlov

Organizations

  • National Institute of Standards and Technology

Tags

Communities of Interest

  • Energy and Power Technologies

DTIC Thesaurus Topics

  • Adsorption
  • Chemistry
  • Electrolytes
  • Electron Energy
  • Electronic Mail
  • Films
  • Materials
  • Measurement
  • Military Research
  • Nanotechnology
  • Self Assembled Monolayers
  • Self Assembly
  • Spectra
  • Spectroscopy
  • Standards
  • X Ray Photoelectron Spectroscopy
  • X Rays

Readers

  • Aerial Delivery - Logistics and Supply Chain Management.
  • Molecular Genetics
  • Nanocomposite Materials Science

Technology Areas

  • Biotechnology
  • Microelectronics
  • Space