Determination of the linear elastic regime in AFM nanoindentation experiments on cells

Kontomaris, Stylianos Vasileios; Stylianou, Andreas; Nikita, Konstantina S.; Malamou, Anna

doi:10.1088/2053-1591/ab4f42

Cited by 24 publications

(24 citation statements)

References 40 publications

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“…Thus, a load-indentation curve is created. This curve consists of two parts, the loading part in which the tip is moving towards the sample and the unloading part in which the motion of the tip is the opposite (figure 1) [9,10]. These curves can be processed using contact mechanics models for the determination of the Young's modulus value of the sample [7].…”

Section: Theorymentioning

confidence: 99%

“…the properties of the material are the same in all directions) and present a linear elastic response (i.e. stress is proportional to strain) [10]. However, biological samples at the nanoscale do not meet these requirements [15].…”

Section: The Hertz Modelmentioning

confidence: 99%

“…Nevertheless, equation (1) can be easily modified for big h R / ratios. The general equation (10) can easily provide the differences regarding the Young's modulus calculation when a parabolic approximation is used (since it was proved that the load-indentation data can be fitted to equation = P ah 3 2(b)). As a result, the Hertzian modification for big h R / ratios is the following:…”

Section: The Oliver and Pharr Analysismentioning

confidence: 99%

“…Despite the fact that these techniques are based on the same theoretical tools, there are significant differences regarding the data processing [7,9]. However, if the biological sample can be considered as homogeneous and isotropic the two techniques should theoretically provide the same results [7,10]. Nevertheless, as it has been previously reported, in case of biological samples (e.g.…”

Section: Introductionmentioning

confidence: 99%

“…The data processing is usually performed using basic models arising from the contact mechanics theory [7,9]. If the sample that is being tested can be characterized as an elastic half space, the Young's modulus of the sample can be calculated using the Hertz model or the Oliver & Pharr analysis [7,9,10]. Despite the fact that these techniques are based on the same theoretical tools, there are significant differences regarding the data processing [7,9].…”

Section: Introductionmentioning

confidence: 99%

See 4 more Smart Citations

Hertz model or Oliver & Pharr analysis? Tutorial regarding AFM nanoindentation experiments on biological samples

Kontomaris

Malamou

2020

Mater. Res. Express

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The data processing regarding AFM nanoindentation experiments on biological samples relies on the basic contact mechanics models like the Hertz model and the Oliver & Pharr analysis. Despite the fact that the two aforementioned techniques are assumed to provide equivalent results since they are based on the same underlying theory of contact mechanics, significant differences regarding the Young's modulus calculation even on the same tested sample have been presented in the literature. The differences can be even greater than 30% depending on the used model. In addition, when the Oliver & Pharr analysis is used, a systematic greater Young's modulus value is always calculated compared to the Hertzian analysis. In this paper, the two techniques are briefly described and two possible reasons that accurately explain the observed differences in the calculated value of the Young's modulus are presented.

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Section: Theorymentioning

confidence: 99%

Section: The Hertz Modelmentioning

confidence: 99%

Section: The Oliver and Pharr Analysismentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Hertz model or Oliver & Pharr analysis? Tutorial regarding AFM nanoindentation experiments on biological samples

Kontomaris

Malamou

2020

Mater. Res. Express

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A Magneto‐Responsive Hydrogel System for the Dynamic Mechano‐Modulation of Stem Cell Niche

Goodrich

Tai

Yin

et al. 2023

Adv Funct Materials

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The biophysical microenvironment of cells dynamically evolves during embryonic development, leading to defined tissue specification. A versatile and highly adaptive magneto‐responsive hydrogel system composed of magnetic nanorods (MNRs) and a stress‐responsive polymeric matrix is developed to dynamically regulate the physical stem cell niche. The anisotropic magnetic/shape factor of nanorods is utilized to maximize the strains on the polymeric network, thus regulating the hydrogel modulus in a physiologically relevant range under a minimal magnitude of the applied magnetic fields below 4.5 mT. More significantly, the pre‐alignment of MNRs induces greater collective strains on the polymeric network, resulting in a superior stiffening range, over a 500% increase as compared to that with randomly oriented nanorods. The pre‐alignment of nanorods also enables a fast and reversible response under a magnetic field of the opposite polarity as well as spatially controlled heterogeneity of modulus within the hydrogel by applying anisotropic magnetic fields. The mechano‐modulative capability of this system is validated by a mechanotransduction model with human‐induced pluripotent stem cells where the locally controlled hydrogel modulus regulates the activation of mechano‐sensitive signaling mediators and subsequent stem cell differentiation. Therefore, this magneto‐responsive hydrogel system provides a platform to investigate various cellular behaviors under dynamic mechanical microenvironments.

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Pancreatic Cancer Presents Distinct Nanomechanical Properties During Progression

et al. 2023

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Determination of the linear elastic regime in AFM nanoindentation experiments on cells

Cited by 24 publications

References 40 publications

Hertz model or Oliver & Pharr analysis? Tutorial regarding AFM nanoindentation experiments on biological samples

Hertz model or Oliver & Pharr analysis? Tutorial regarding AFM nanoindentation experiments on biological samples

A Magneto‐Responsive Hydrogel System for the Dynamic Mechano‐Modulation of Stem Cell Niche

Pancreatic Cancer Presents Distinct Nanomechanical Properties During Progression

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