Microrheology with optical tweezers: data analysis

Tassieri, Manlio; Evans, R. M. L.; Warren, Rebecca; Bailey, Nicholas J.; Cooper, Jonathan M.

doi:10.1088/1367-2630/14/11/115032

Cited by 121 publications

(166 citation statements)

References 76 publications

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“…However, while the dðtÞ function is generally not an option, the stepfunction is well approximated with the exception of an initial nonlinear ramp of short duration (e). In addition, it has been shown [7] that the evaluation of the above mentioned Fourier transforms, given only a finite set of data points over a finite time domain, is nontrivial [8][9][10][11][12] since interpolation and extrapolation from those data can yield artefacts that lie within the bandwidth of interest.…”

Section: Introductionmentioning

confidence: 99%

i-Rheo: Measuring the materials' linear viscoelastic properties “in a step”!

Tassieri

Laurati

Curtis

et al. 2016

Journal of Rheology

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We present a simple new analytical method for educing the materials' linear viscoelastic properties, over the widest range of experimentally accessible frequencies, from a simple step-strain measurement, without the need of preconceived models nor the idealization of real measurements. This is achieved by evaluating the Fourier transforms of raw experimental data describing both the time-dependent stress and strain functions. The novel method has been implemented into an open access executable "i-Rheo," enabling its use to a broad scientific community. The effectiveness of the new rheological tool has been corroborated by direct comparison with conventional linear oscillatory measurements for a series of complex materials as diverse as a monodisperse linear polymer melt, a bimodal blend of linear polymer melts, an industrial styrene-butadiene rubber, an aqueous gelatin solution at the gel point and a highly concentrated suspension of colloidal particles. a)

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Section: Introductionmentioning

confidence: 99%

i-Rheo: Measuring the materials' linear viscoelastic properties “in a step”!

Tassieri

Laurati

Curtis

et al. 2016

Journal of Rheology

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“…Rheology has two main techniques, i.e., microrheology and macrorheology. Microrheology has advantages over macrorheology such as much smaller sample volume, a high-frequency bandwidth (0 to 100 kHz), in situ measurement, and higher sensitivity to intracellular dynamics (Mizuno et al 2008;Tassieri et al 2012). Microrheology can be classified as passive microrheology, measuring spontaneous thermally driven fluctuations of beads, or active microrheology, driving the beads by an external force (oscillatory optical tweezers or magnetic tweezers (Jones et al 2015;Wessel et al 2015)).…”

Section: Introductionmentioning

confidence: 99%

Fibrin network adaptation to cell-generated forces

et al. 2018

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Fibrin promotes wound healing by serving as provisional extracellular matrix for fibroblasts that realign and degrade fibrin fibers, and sense and respond to surrounding substrate in a mechanical-feedback loop. We aimed to study mechanical adaptation of fibrin networks due to cell-generated forces at the micron-scale. Fibroblasts were elongated-shaped in networks with ≤ 2 mg/ml fibrinogen, or cobblestone-shaped with 3 mg/ml fibrinogen at 24 h. At frequencies f < 10 2 Hz, G′ of fibroblast-seeded fibrin networks with ≥ 1 mg/ml fibrinogen increased compared to that of fibrin networks. At frequencies f > 10 3 Hz, G″ of fibrin networks decreased with increasing concentration following the power-law in frequency with exponents ranging from 0.75 ± 0.03 to 0.43 ± 0.03 at 3 h, and of fibroblast-seeded fibrin networks with exponents ranging from 0.56 ± 0.08 to 0.28 ± 0.06. In conclusion, fibroblasts actively contributed to a change in viscoelastic properties of fibrin networks at the micron-scale, suggesting that the cells and fibrin network mechanically interact. This provides better understanding of, e.g., cellular migration in wound healing.

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“…Microrheology techniques have the advantage of being applicable in confined volumes as well as requiring low quantities of the fluid under investigation. A typical microrheology experiment, using existing methods [16] would measure the thermal fluctuations of a bead trapped by OT and then apply statistical mechanics to those position data for determining the fluid viscoelastic properties.…”

Section: Introductionmentioning

confidence: 99%

Dynamic stereo microscopy for studying particle sedimentation

Lee¹,

Gibson²,

Phillips³

et al. 2014

Opt. Express

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We demonstrate a new method for measuring the sedimentation of a single colloidal bead by using a combination of optical tweezers and a stereo microscope based on a spatial light modulator. We use optical tweezers to raise a micron-sized silica bead to a fixed height and then release it to observe its 3D motion while it sediments under gravity. This experimental procedure provides two independent measurements of bead diameter and a measure of Faxén's correction, where the motion changes due to presence of the boundary.

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Microrheology with optical tweezers: data analysis

Cited by 121 publications

References 76 publications

i-Rheo: Measuring the materials' linear viscoelastic properties “in a step”!

i-Rheo: Measuring the materials' linear viscoelastic properties “in a step”!

Fibrin network adaptation to cell-generated forces

Dynamic stereo microscopy for studying particle sedimentation

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