European Biophysics Journal

, Volume 27, Issue 1, pp 75–81

Thermal noise limitations on micromechanical experiments

Authors

  • Frederick Gittes
    • Department of Physics, and Biophysics Research Division, University of Michigan, 930 N. University, Ann Arbor, MI 48109-1055, USA
  • C. F. Schmidt
    • Department of Physics, and Biophysics Research Division, University of Michigan, 930 N. University, Ann Arbor, MI 48109-1055, USA
BIOPHYSICS LETTER

DOI: 10.1007/s002490050113

Cite this article as:
Gittes, F. & Schmidt, C. Eur Biophys J (1998) 27: 75. doi:10.1007/s002490050113

Abstract

Thermal motions of microscopic probes limit the possibilities of experiments that are designed to resolve single-macromolecule dynamics in aqueous conditions. We investigate theoretical strategies for maximizing signal-to-noise ratios or resolution in typical situations, illustratin+g our discussion with examples from optical tweezers and atomic force microscopy experiments. A central result is that the viscous drag on a micromechanical probe is more important than the compliance of the probe. Within limits, increased stiffness of an AFM cantilever or of an optical trap does not increase resolution, and decreased stiffness does not provide the possibility of less invasive measurements.

Key words Thermal noiseOptical tweezersAtomic force microscopySingle moleculesMicromechanics

Copyright information

© Springer-Verlag Berlin Heidelberg 1998