Scanning Probe-Based Frequency-Dependent Microrheology of Polymer Gels and Biological Cells

Mahaffy, Rachel; Shih, Chih‐Kang; MacKintosh, F. C.; Käs, Josef A.

doi:10.1103/physrevlett.85.880

Cited by 448 publications

(391 citation statements)

References 17 publications

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“…Such a sharp tip induces high local strains that can exceed the linear regime, thus introducing artifacts in the determination of the cell's mechanical properties (14,15). To avoid such artifacts, an alternative technique is often used where a micrometric bead is attached to the tip of the AFM cantilever (16)(17)(18). In AFM, the applied force is deduced from the deformation of the cantilever, whose measurement requires the use of an optical sensor, most commonly a system of photodiodes collecting a laser beam reflected by the cantilever.…”

Section: Introductionmentioning

confidence: 99%

Mechanical Criterion for the Rupture of a Cell Membrane under Compression

Gonzalez‐Rodriguez

Guillou

Cornat

et al. 2016

Biophysical Journal

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We investigate the mechanical conditions leading to the rupture of the plasma membrane of an endothelial cell subjected to a local, compressive force. Membrane rupture is induced by tilted microindentation, a technique used to perform mechanical measurements on adherent cells. In this technique, the applied force can be deduced from the measured horizontal displacement of a microindenter's tip, as imaged with an inverted microscope and without the need for optical sensors to measure the microindenter's deflection. We show that plasma membrane rupture of endothelial cells occurs at a well-defined value of the applied compressive stress. As a point of reference, we use numerical simulations to estimate the magnitude of the compressive stresses exerted on endothelial cells during the deployment of a stent.

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Section: Introductionmentioning

confidence: 99%

Mechanical Criterion for the Rupture of a Cell Membrane under Compression

Gonzalez‐Rodriguez

Guillou

Cornat

et al. 2016

Biophysical Journal

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“…This research confirmed that the hydrodynamic drag force exhibits a locally pure viscous behavior and that the drag factor is dependent upon distance between the tip and the substrate. The authors pointed out that previous attempts to correct AFM measurements for hydrodynamic drag effects consisted of estimating the drag force at some distance above the specimen and then using this value to correct the measurements taken on contact [21][22][23]. However, it is expected that this approach will lead to an underestimation of the actual hydrodynamic drag at contact and the authors noted that applying corrective drag force measurements taken at even a few microns above the sample can lead to significant errors in the measured forces.…”

Section: Introductionmentioning

confidence: 99%

Numerical study of the hydrodynamic drag force in atomic force microscopy measurements undertaken in fluids

Méndez-Méndez

Alonso-Rasgado

Faria

et al. 2014

Micron

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When atomic force microscopy (AFM) is employed for in vivo study of immersed biological samples, the fluid medium presents additional complexities, not least of which is the hydrodynamic drag force due to viscous friction of the cantilever with the liquid. This force should be considered when interpreting experimental results and any calculated material properties. In this paper, a numerical model is presented to study the influence of the drag force on experimental data obtained from AFM measurements using computational fluid dynamics (CFD) simulation. The model provides quantification of the drag force in AFM measurements of soft specimens in fluids.The numerical predictions were compared with experimental data obtained using AFM with a V-shaped cantilever fitted with a pyramidal tip. Tip velocities ranging from 1.05 to 105 µm/s were employed in water, polyethylene glycol and glycerol with the platform approaching from a distance of 6000 nm. The model was also compared with an existing analytical model. Good agreement was observed between numerical results, experiments and analytical predictions. Accurate predictions were obtained without the need for extrapolation of experimental data. In addition, the model can be employed over the range of tip geometries and velocities typically utilized in AFM measurements.

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“…However, the rheological properties of in vitro F-actin networks are quite different from those of cells: the magnitude of the elastic modulus typically underestimates that measured in cells, often by several orders of magnitude. In addition, unlike the linear behavior assumed for cells [1][2][3]10], the viscoelasticity of F-actin networks is linear only for very small deformations; like most semiflexible biopolymers [11], it rapidly becomes strongly nonlinear with increasing deformation [5,9,12,13]. One possible cause for this discrepancy is the fact that, in vivo, F-actin is cross-linked with a variety of actin-binding proteins (ABP's), which are essential in determining the elastic properties of the cytoskeleton.…”

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confidence: 95%

“…The importance of such forces has inspired in vivo studies of the mechanical behavior of cells [1][2][3][4]. These have revealed an intriguing observation: a wide variety of cells exhibits properties well described by soft glassy rheology (SGR), a theory of linear viscoelasticity developed to characterize soft solids with glasslike behavior [3].…”

mentioning

confidence: 99%