Tethered particle motion mediated by scattering from gold nanoparticles and darkfield microscopy

Heidelinde R.C. Dietrich, Bernd Rieger, Frank G.M. Wiertz, Frederik H. De Groote, Hendrik A. Heering, Ian T. Young, Yuval Garini

Research output: Contribution to journalArticlepeer-review

9 Scopus citations

Abstract

We measured light scattered from gold nanoparticles with darkfield microscopy in order to perform single molecule detection based on tethered particle motion (TPM). This combination results in a signal to noise ratio of about 40 dB, which allowed us to use 80 nm diameter gold particles as reporters instead of the typically used polystyrene particles whose sizes are up to 1 μm. The particle size is crucial in TPM experiments as it can induce a volume-exclusion effect, which results in a stretching force acting on the DNA tether. This affects both the biophysical and statistical properties of the anchored DNA and hence the interpretation of the experimental data. We demonstrated that the gold nanoparticles and darkfield microscopy can be used to characterize the confined Brownian motion of dsDNA-tethered gold particles with a spatial precision of 3 nm. Physical parameters such as the spring constant of the tethered DNA fragment and the persistence length can be derived from the two dimensional (2D) (x, y) projected image data. We have applied this method to various MgCl2 and glycerol concentrations as a proof of principle.

Original languageEnglish
Article number031795
JournalJournal of Nanophotonics
Volume3
Issue number1
DOIs
StatePublished - 2009
Externally publishedYes

Bibliographical note

Funding Information:
We thank Wim van Oel and Guus Liqui Lung for their technical support. We thank Prof. Dr. Hans Tanke and Prof. Dr. Simon de Vries for their support on biochemical issues. We further thank Prof. Dr. Theo Odijk for his theoretical calculation of the tethered particle’s position probability distribution. We thank Sanneke Brinkers for her input on the image analysis and data fitting. We thank Bart Vermolen for his support in the use of Matlab. HAH and FGMW are financially supported by the Netherlands Organization for Scientific Research (NWO). This work was supported by the BSIK programs Cyttron and Microned (2F), and the Delft Interdisciplinary Research program (DIOC): Molecular Recognition of Biomacromolecules in Life Science and Technology.

Keywords

  • Tethered particle motion
  • darkfield microscopy
  • gold nanoparticles
  • scattering

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