Measuring the viscoelastic properties of human platelets with the atomic force microscope

Radmacher, Manfred; Fritz, Monika; Kacher, Claudia M.; Cleveland, J. P.; Hansma, Paul K.

doi:10.1016/s0006-3495(96)79602-9

Cited by 777 publications

(586 citation statements)

References 42 publications

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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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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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“…SPM can also be used to evaluate mechanical properties, because its probe is in physical contact with the samples during measurement. To obtain cellular stiffness with SPM, two methods have been proposed, namely, a force modulation mode [22,23] and a force mapping mode [24]. According to experiments performed by using these methods, the local stiffness of fibroblasts is not homogeneous on the cellular surface, but varies largely from point to point [25,26].…”

Section: Introductionmentioning

confidence: 99%

Contribution of cellular contractility to spatial and temporal variations in cellular stiffness

Nagayama

Haga

Takahashi

et al. 2004

Experimental Cell Research

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Scanning probe microscopy and immunofluorescence observations indicated that cellular stiffness was attributed to a contractile network structure consisting of stress fibers. We measured temporal variations in cellular stiffness when cellular contractility was regulated by dosing with lysophosphatidic acid or Y-27632. This experiment reveals a clear relation between cellular stiffness and contractility: Increases in contractility cause cells to stiffen. On the other hand, decreases in contractility reduce cellular stiffness. In both cases, not only the stiffness of the stress fibers but also that of the whole of the cell varies. Immunofluorescence observations of myosin II and vinculin indicated that the stiffness variations induced by the regulation of cellular contractility were mainly due to rearrangements of the contractile actin network on the dorsal surface. Taken together, our findings provide evidence that the actin cytoskeletal network and its contractility features provide and modulate the mechanical stability of adherent cells.

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“…In 1996, Radmacher et al [74] applied AFM in the force-mapping mode to monitor the mechanical properties of human platelets. The pseudonucleus, which comprises the cytosol and small vesicles, was found to be the softest part of these bodies (Young's modulus, 1.5-4 kPa), whereas the outer filamentous zone, which consists of bundles of actin filaments and microtubules, was up to tenfold stiffer (Young's modulus, 10-40 kPa).…”

Section: Eukaryotesmentioning

confidence: 99%

Probing nanomechanical properties from biomolecules to living cells

Kasas

Dietler

2008

Pflugers Arch - Eur J Physiol

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Atomic force microscopy is being increasingly used to explore the physical properties of biological structures. This technique involves the application of a force to the sample and a monitoring of the ensuing deformation process. The available experimental setups can be broadly divided into two categories, one of which involves a stretching and the other an indentation of the organic materials. In this review, we will focus on the indentation technique and will illustrate its application to biological materials with examples that range from single molecules to living cells.

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Measuring the viscoelastic properties of human platelets with the atomic force microscope

Cited by 777 publications

References 42 publications

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

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

Contribution of cellular contractility to spatial and temporal variations in cellular stiffness

Probing nanomechanical properties from biomolecules to living cells

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