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Portrait of Jonas Tegenfeldt. Photo: Kennet Ruona

Jonas Tegenfeldt

Professor, Coordinator Nanobiology & Neuronanoscience

Portrait of Jonas Tegenfeldt. Photo: Kennet Ruona

Single-molecule Detection and Mismatch Discrimination of Unlabeled DNA Targets

Author

  • Anders Gunnarsson
  • Peter Jönsson
  • Rodolphe Marie
  • Jonas Tegenfeldt
  • Fredrik Höök

Summary, in English

We report on a single-molecule readout scheme on total internal reflection fluorescence microscopy (TIRFM) demonstrating a detection limit in the low fM regime for short (30-mer) unlabeled DNA strands. Detection of unlabeled DNA targets is accomplished by letting them mediate the binding of suspended fluorescently labeled DNA-modified small unilamellar vesicles (Ø approximately 100 nm) to a DNA-modified substrate. On top of rapid and sensitive detection, the technique is also shown capable of extracting kinetics data from statistics of the residence time of the binding reaction in equilibrium, that is, without following neither the rate of binding upon injection nor release upon rinsing. The potential of this feature is demonstrated by discriminating a single mismatch from a fully complementary sequence. The success of the method is critically dependent on a surface modification that provides sufficiently low background. This was achieved through self-assembly of a biotinylated copolymer, Poly(L-lysine)-g-poly(ethylene glycol) (PLL-g-PEG) on a silicon dioxide surface, followed by subsequent addition of streptavidin and biotinylated DNA. The proposed detection scheme is particularly appealing due to the simplicity of the sensor, which relies on self-assembly principles and conventional TIRFM. Therefore, we foresee a great potential of the concept to serve as an important component in future multiplexed sensing schemes. This holds in particular true in cases when information about binding kinetics is valuable, such as in single nucleotide polymorphism diagnostics.

Department/s

  • Solid State Physics
  • Nanometer structure consortium (nmC)-lup-obsolete

Publishing year

2008

Language

English

Pages

183-188

Publication/Series

Nano Letters

Volume

8

Issue

1

Document type

Journal article

Publisher

The American Chemical Society (ACS)

Topic

  • Nano Technology

Status

Published

Research group

  • Nanometer structure consortium (nmC)-lup-obsolete

ISBN/ISSN/Other

  • ISSN: 1530-6992