BioNEMS: Nanomechanical Systems for Single-Molecule Biophysics

Applied Physics Letters

Robbins

et al. 2012

mentioning

confidence: 99%

Correlations between the thermal vibrations of two cantilevers: Validation of deterministic analysis via the fluctuation-dissipation theorem

Honig

Applied Physics Letters

Robbins

et al. 2012

“…In principle, the main advantage of CFS over one cantilever AFM is that the thermal noise in the cross-correlation between two cantilevers is much smaller than the thermal noise in the autocorrelation for a single cantilever [43,47], so here I examine this prediction. The noise spectrum of a single cantilever and the cross-correlation noise spectrum of two cantilevers are shown in Figure stiffness and friction) is larger comparing to the larger autocorrelation noise spectrum.…”

Section: Correlation Force Spectroscopy Correlation Force Spectroscopmentioning

confidence: 99%

Correlation Force Spectroscopy for Single Molecule Measurements

2015

Springer Theses

This thesis addresses development of a new force spectroscopy tool, correlation force spectroscopy (CFS), for the measurement of the mechanical properties of very small volumes of material (molecular to µm 3 ) at kHz-MHz time-scales. CFS is based on atomic force microscopy (AFM) and the principles of CFS resemble those of dual-trap optical tweezers. CFS consists of was validated by comparison between experimental data and finite element modeling of the deterministic vibrations of the cantilevers using the known viscosity and density of fluids. Work in this thesis shows that the data can also be accurately fitted using a simple harmonic oscillator model, which can be used for rapid rheometric measurements, after calibration. The mechanical properties of biomolecules such as dextran and single stranded DNA (ssDNA) are also described. Working with this prominent scientist and researcher, and learning from him, were not only highlights of an academic life, but advent of a new lifestyle. This is due to his special character and charismatic behavior. His insights, ideas, perseverance and encouragements were great source of success in this project.

“…[1][2][3][4][5][6][7] In many situations, it is desirable for the oscillating objects to be strongly coupled through the fluid motion. For example, the coupled motion of cilia and flagella in microorganisms is essential for important biological processes such as transport and locomotion; [8][9][10] and the correlated motion of micron scale beads held in optical traps in a viscous fluid is central to current microrheological techniques that probe the material properties of complex fluids with unprecedented spatial and temporal precision.…”

Section: Introductionmentioning

confidence: 99%

“…5 In many sensing applications, it is desirable to minimize the coupling between the oscillating objects due to the fluid in order to probe quantitatively the effect of other interactions that are present. 4,[11][12][13] For example, the dynamics of the oscillating objects could also be correlated due to a direct tethering by a biomolecule or bulk material of interest. However, it has emerged in the literature that the coupling due to the viscous fluid can be quite complicated and subtle with the correlated dynamics depending upon the object's geometry, separation, amplitude of oscillation and oscillation frequency as well as the rheological properties of the surrounding fluid.…”

Section: Introductionmentioning

confidence: 99%

“…This approach achieved femtonewton force resolution on millisecond time scales and shed new physical insights into the complex elastic properties and internal hydrodynamic interactions of DNA. Extending this approach to a pair of micron or nanoscale cantilevers would provide access to piconewton forces on microsecond time scales 4,12 which is of significant biological relevance. [19][20][21] Recent experimental measurements used a pair of micron scale cantilevers to probe the mechanical properties of a single molecule of dextran tethered between the cantilever tips.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

The stochastic dynamics of tethered microcantilevers in a viscous fluid

Robbins

Journal of Applied Physics

Walz

et al. 2014

The stochastic dynamics of rectangular and V-shaped atomic force microscope cantilevers in a viscous fluid and near a solid boundary J. Appl. Phys. 103, 094910 (2008) We explore and quantify the coupled dynamics of a pair of micron scale cantilevers immersed in a viscous fluid that are also directly tethered to one another at their tips by a spring force. The spring force, for example, could represent the molecular stiffness or elasticity of a biomolecule or material tethered between the cantilevers. We use deterministic numerical simulations with the fluctuation-dissipation theorem to compute the stochastic dynamics of the cantilever pair for the conditions of experiment when driven only by Brownian motion. We validate our approach by comparing directly with experimental measurements in the absence of the tether which shows excellent agreement. Using numerical simulations, we quantify the correlated dynamics of the cantilever pair over a range of tether stiffness. Our results quantify the sensitivity of the auto-and cross-correlations of equilibrium fluctuations in cantilever displacement to the stiffness of the tether. We show that the tether affects the magnitude of the correlations which can be used in a measurement to probe the properties of an attached tethering substance. For the configurations of current interest using micron scale cantilevers in water, we show that the magnitude of the fluid coupling between the cantilevers is sufficiently small such that the influence of the tether can be significant. Our results show that the cross-correlation is more sensitive to tether stiffness than the auto-correlation indicating that a two-cantilever measurement has improved sensitivity when compared with a measurement using a single cantilever. V C 2014 AIP Publishing LLC.