Impact and contact stress analysis in multilayer media

Chen, W.T.; Engel, Peter A.

doi:10.1016/0020-7683(72)90079-0

Cited by 136 publications

(61 citation statements)

References 30 publications

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“…The Hertz model relates the force exerted by the SFM cantilever and the indentation of the probe with the elastic constant K 5 E/(1 2 m) 2 defined by the Young's modulus E and Poisson ratio m. Extensions of the Hertz model consider the fact that the stiffness of the underlying substrate can significantly affect the results when measuring the elasticity at thin cell regions. The models from Chen [1971;Chen and Engel, 1972] and Tu and Grazis [1964] were transformed to correction factors for the Hertz model as described previously [Mahaffy et al, 2004]. Therefore, our calculation includes these factors and corrects our results for thin layers.…”

Section: Elasticity Measurements With Sfmmentioning

confidence: 99%

Compaction of cell shape occurs before decrease of elasticity in CHO‐K1 cells treated with actin cytoskeleton disrupting drug cytochalasin D

Schulze

Müller

Käs

et al. 2009

Cell Motil. Cytoskeleton

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The actin filaments of the cytoskeleton form a highly dynamic polymer scaffold which is actively involved in many essential mechanisms such as cell migration, transport, mitosis, and mechanosensitivity. We treated CHO-K1 cells with different concentrations of the actin cytoskeleton disrupting drug cytochalasin D. Then investigating the cells' elastic behaviour by scanning force microscopy-based rheology we confirmed for high cytochalasin D concentrations (> or =1.5 microM) a significant decrease of mechanical stability. At lower concentrations we measured no significant softening, but flattening and a horizontal contraction was observable even at low concentrations (> or =0.3 microM) of cytochalasin D. The observed changes in cell shape resulted in a lower cell volume, showing that there is compensation by volume for small decreases in cytoskeletal strength resulting from reduced numbers or lengths of actin filaments. These results suggest that the characteristic functions defining a cell's mechanical stability such as mechanosensitivity can be maintained via small changes in cell volume in order to counter fluctuations in cytoskeletal composition.

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Section: Elasticity Measurements With Sfmmentioning

confidence: 99%

Compaction of cell shape occurs before decrease of elasticity in CHO‐K1 cells treated with actin cytoskeleton disrupting drug cytochalasin D

Schulze

Müller

Käs

et al. 2009

Cell Motil. Cytoskeleton

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show abstract

“…elastic parameters pyramid [100] flat punch (average radius 0.53 mm) [105] E 0.53 + 0.11 kPa 0.5 kPa It needs to be pointed out that depending on where the indentation is located, one needs to use different thin-layer models (i.e. non-adhered thin-layer model [110] or adhered thin-layer model [111,112]). For example, it was found that when indentation was made at a thin region relatively near the edge of the fibroblast, the adhered thin-layer model is more appropriate [37].…”

Section: Cell Morphology On Cell Mechanicsmentioning

confidence: 99%

Nanobiomechanics of living cells: a review

Chen

2014

Interface Focus.

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Nanobiomechanics of living cells is very important to understand cellmaterials interactions. This would potentially help to optimize the surface design of the implanted materials and scaffold materials for tissue engineering. The nanoindentation techniques enable quantifying nanobiomechanics of living cells, with flexibility of using indenters of different geometries. However, the data interpretation for nanoindentation of living cells is often difficult. Despite abundant experimental data reported on nanobiomechanics of living cells, there is a lack of comprehensive discussion on testing with different tip geometries, and the associated mechanical models that enable extracting the mechanical properties of living cells. Therefore, this paper discusses the strategy of selecting the right type of indenter tips and the corresponding mechanical models at given test conditions.

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“…Historically, analytical expressions using integral transforms were derived to find the stress and displacement fields (Bufler 1971;Fretigny and Chateauminois 2000;Chen 1971). However, these methods still generally require sophisticated mathematical manipulations or extensive numerical computations (Tu and Gazis 1964;Dhaliwal and Rau 1970;Chen and Engel 1972). The inconvenience of using these solutions has largely precluded their use by experimentalists who need a simple solution to compare experiments to.…”

mentioning

confidence: 99%

Spherical indentation analysis of stress relaxation for thin film viscoelastic materials

Cheneler¹,

Mehrban²,

Bowen³

2013

Rheol Acta

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The mechanical testing of thin layers of soft materials is an important but difficult task. Spherical indentation provides a convenient method to ascertain material properties whilst minimising damage to the material by allowing testing to take place in situ. However, measurement of the viscoelastic properties of these soft materials is hindered by the absence of a convenient yet accurate model which takes into account the thickness of the material and the effects of the underlying substrate. To this end, the spherical indentation of a thin layer of viscoelastic solid material is analysed. It is assumed that the transient mechanical properties of the material can be described by the generalised standard linear solid model. This model is incorporated into the theory and then solved for the special case of a stress relaxation experiment taking into account the finite ramp time experienced in real experiments. An expression for the force as a function of the viscoelastic properties, layer thickness and indentation depth is given. The theory is then fitted to experimental data for the spherical indentation of poly(dimethyl)siloxane mixed with its curing agent to the ratios of 5:1, 10:1 and 20:1 in order to ascertain its transient shear moduli and relaxation time constants. It is shown that the theory correctly accounts for the effect of the underlying substrate and allows for the accurate measurement of the viscoelastic properties of thin layers of soft materials.

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Impact and contact stress analysis in multilayer media

Cited by 136 publications

References 30 publications

Compaction of cell shape occurs before decrease of elasticity in CHO‐K1 cells treated with actin cytoskeleton disrupting drug cytochalasin D

Compaction of cell shape occurs before decrease of elasticity in CHO‐K1 cells treated with actin cytoskeleton disrupting drug cytochalasin D

Nanobiomechanics of living cells: a review

Spherical indentation analysis of stress relaxation for thin film viscoelastic materials

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