Study on the AFM Force Curve Common Errors and Their Effects on the Calculated Nanomechanical Properties of Materials

Almasi, Davood; Sharifi, Roohollah; Kadir, Mohammed Rafiq Abdul; Krishnamurithy, G.; Kamarul, Tunku

doi:10.1155/2016/2456378

Cited by 6 publications

(4 citation statements)

References 36 publications

(53 reference statements)

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“…(4). This is normally translated to an empirical law that suggests to limit the indentation to about 10% of the smallest between the radius of the indenter and the thickness of the material [72,73]. Using ES, this limit can be experimentally identified, looking at the behavior, and avoiding large indentations for which the curve starts rising (see Additional file 1: Fig.…”

Section: Discussionmentioning

confidence: 99%

Elasticity spectra as a tool to investigate actin cortex mechanics

et al. 2020

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Background The mechanical properties of single living cells have proven to be a powerful marker of the cell physiological state. The use of nanoindentation-based single cell force spectroscopy provided a wealth of information on the elasticity of cells, which is still largely to be exploited. The simplest model to describe cell mechanics is to treat them as a homogeneous elastic material and describe it in terms of the Young’s modulus. Beside its simplicity, this approach proved to be extremely informative, allowing to assess the potential of this physical indicator towards high throughput phenotyping in diagnostic and prognostic applications. Results Here we propose an extension of this analysis to explicitly account for the properties of the actin cortex. We present a method, the Elasticity Spectra, to calculate the apparent stiffness of the cell as a function of the indentation depth and we suggest a simple phenomenological approach to measure the thickness and stiffness of the actin cortex, in addition to the standard Young’s modulus. Conclusions The Elasticity Spectra approach is tested and validated on a set of cells treated with cytoskeleton-affecting drugs, showing the potential to extend the current representation of cell mechanics, without introducing a detailed and complex description of the intracellular structure.

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Section: Discussionmentioning

confidence: 99%

Elasticity spectra as a tool to investigate actin cortex mechanics

et al. 2020

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“…Indentations falling out of the interval 2 nm < h max < 40 nm were also rejected, as they are considered out of the range of validity of the models used. Indentations with h max ~ 3 nm are often associated to reverse position of the approach-retract parts of the F-d curve [ 35 ], causing typically large errors in the calculated moduli and frequent rejection. All the invalid data were marked as “nan” (not a number) and left blank in the corresponding map.…”

Section: Methodsmentioning

confidence: 99%

Nanomechanical Mapping of Hard Tissues by Atomic Force Microscopy: An Application to Cortical Bone

et al. 2022

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Force mapping of biological tissues via atomic force microscopy (AFM) probes the mechanical properties of samples within a given topography, revealing the interplay between tissue organization and nanometer-level composition. Despite considerable attention to soft biological samples, constructing elasticity maps on hard tissues is not routine for standard AFM equipment due to the difficulty of interpreting nanoindentation data in light of the available models of surface deformation. To tackle this issue, we proposed a protocol to construct elasticity maps of surfaces up to several GPa in moduli by AFM nanoindentation using standard experimental conditions (air operation, nanometrically sharp spherical tips, and cantilever stiffness below 30 N/m). We showed how to process both elastic and inelastic sample deformations simultaneously and independently and quantify the degree of elasticity of the sample to decide which regime is more suitable for moduli calculation. Afterwards, we used the frequency distributions of Young’s moduli to quantitatively assess differences between sample regions different for structure and composition, and to evaluate the presence of mechanical inhomogeneities. We tested our method on histological sections of sheep cortical bone, measuring the mechanical response of different osseous districts, and mapped the surface down to the single collagen fibril level.

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“…4. This is normally translated to an empirical law that suggests to limit the indentation to about 10% of the smallest between the radius of the indenter and the thickness of the material [69,70]. Using ES, this limit can be experimentally identified, looking at the behavior, and avoiding large indentations for which the curve starts rising (see Additional file 1 Fig.…”

Section: Discussionmentioning

confidence: 99%

Elasticity Spectra as a Tool to Investigate Actin Cortex Mechanics

Lüchtefeld

Bartolozzi

Morales

et al. 2020

Preprint

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Background The mechanical properties of single living cells have proven to be a powerful marker of the cell physiological state. The use of nanoindentation-based single cell force spectroscopy provided a wealth of information on the elasticity of cells, which is still largely to be exploited. The simplest model to describe cell mechanics is to treat them as a homogeneous elastic material and describe it in terms of the Young's modulus. Beside its simplicity, this approach proved to be extremely informative, allowing to assess the potential of this physical indicator towards high throughput phenotyping in diagnostic and prognostic applications. Results Here we propose an extension of this analysis to explicitly account for the properties of the actin cortex. We present a method, the Elasticity Spectra, to calculate the apparent stiffness of the cell as a function of the indentation depth and we suggest a simple phenomenological approach to measure the thickness and stiffness of the actin cortex, in addition to the standard Young's modulus. Conclusions The Elasticity Spectra approach is tested and validated on a set of cells treated with cytoskeleton-affecting drugs, showing the potential to extend the current representation of cell mechanics, without introducing a detailed and complex description of the intracellular structure.

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Study on the AFM Force Curve Common Errors and Their Effects on the Calculated Nanomechanical Properties of Materials

Cited by 6 publications

References 36 publications

Elasticity spectra as a tool to investigate actin cortex mechanics

Elasticity spectra as a tool to investigate actin cortex mechanics

Nanomechanical Mapping of Hard Tissues by Atomic Force Microscopy: An Application to Cortical Bone

Elasticity Spectra as a Tool to Investigate Actin Cortex Mechanics

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