AFM Indentation on Highly Heterogeneous Materials Using Different Indenter Geometries

Hertzian mechanics is the most frequently used theory for data processing in Atomic Force Microscopy (AFM) indentation experiments on soft biological samples, due to its simplicity and significant scientific results previously published. For instance, using the Hertz model, it has been proven that t...

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Main Authors: Stylianos Vasileios Kontomaris, Andreas Stylianou, Georgios Chliveros, Anna Malamou
Format: Article
Language:English
Published: MDPI AG 2023-04-01
Series:Applied Mechanics
Subjects:
Online Access:https://www.mdpi.com/2673-3161/4/2/26
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author Stylianos Vasileios Kontomaris
Andreas Stylianou
Georgios Chliveros
Anna Malamou
author_facet Stylianos Vasileios Kontomaris
Andreas Stylianou
Georgios Chliveros
Anna Malamou
author_sort Stylianos Vasileios Kontomaris
collection DOAJ
description Hertzian mechanics is the most frequently used theory for data processing in Atomic Force Microscopy (AFM) indentation experiments on soft biological samples, due to its simplicity and significant scientific results previously published. For instance, using the Hertz model, it has been proven that there are significant differences in the mechanical properties of normal and cancerous tissues and that cancer cells’ invasive properties are correlated with their nanomechanical properties. However, many scientists are skeptical regarding the applicability of the Hertz theory to biological materials, as they are highly heterogeneous. The main critical question to be addressed is “what do we calculate” when fitting the force-indentation data to Hertz equations. Previous studies have shown that when using cylindrical, parabolic, or conical indenters, the fitting parameter is the average Young’s modulus. In this paper, it is demonstrated that it is also valid to fit equations derived from Hertzian mechanics to force-indentation data when testing soft, heterogeneous samples for any indenter geometry. The fitting factor calculated through this approach always represents the average Young’s modulus for a specific indentation depth. Therefore, Hertzian mechanics can be extended to soft heterogeneous materials, regardless of the indenter’s shape.
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spelling doaj.art-9ab54419662f41238e296a5f05f2fb462023-11-18T09:04:58ZengMDPI AGApplied Mechanics2673-31612023-04-014246047510.3390/applmech4020026AFM Indentation on Highly Heterogeneous Materials Using Different Indenter GeometriesStylianos Vasileios Kontomaris0Andreas Stylianou1Georgios Chliveros2Anna Malamou3BioNanoTec Ltd., 2043 Nicosia, CyprusSchool of Sciences, European University Cyprus, 2404 Nicosia, CyprusFaculty of Engineering and Architecture, Metropolitan College, 15125 Athens, GreeceIndependent Power Transmission Operator S.A. (IPTO), 10443 Athens, GreeceHertzian mechanics is the most frequently used theory for data processing in Atomic Force Microscopy (AFM) indentation experiments on soft biological samples, due to its simplicity and significant scientific results previously published. For instance, using the Hertz model, it has been proven that there are significant differences in the mechanical properties of normal and cancerous tissues and that cancer cells’ invasive properties are correlated with their nanomechanical properties. However, many scientists are skeptical regarding the applicability of the Hertz theory to biological materials, as they are highly heterogeneous. The main critical question to be addressed is “what do we calculate” when fitting the force-indentation data to Hertz equations. Previous studies have shown that when using cylindrical, parabolic, or conical indenters, the fitting parameter is the average Young’s modulus. In this paper, it is demonstrated that it is also valid to fit equations derived from Hertzian mechanics to force-indentation data when testing soft, heterogeneous samples for any indenter geometry. The fitting factor calculated through this approach always represents the average Young’s modulus for a specific indentation depth. Therefore, Hertzian mechanics can be extended to soft heterogeneous materials, regardless of the indenter’s shape.https://www.mdpi.com/2673-3161/4/2/26hertz modelheterogeneous samplesfittingdepth-dependent behaviorbiological materialsdeep spherical indentations
spellingShingle Stylianos Vasileios Kontomaris
Andreas Stylianou
Georgios Chliveros
Anna Malamou
AFM Indentation on Highly Heterogeneous Materials Using Different Indenter Geometries
Applied Mechanics
hertz model
heterogeneous samples
fitting
depth-dependent behavior
biological materials
deep spherical indentations
title AFM Indentation on Highly Heterogeneous Materials Using Different Indenter Geometries
title_full AFM Indentation on Highly Heterogeneous Materials Using Different Indenter Geometries
title_fullStr AFM Indentation on Highly Heterogeneous Materials Using Different Indenter Geometries
title_full_unstemmed AFM Indentation on Highly Heterogeneous Materials Using Different Indenter Geometries
title_short AFM Indentation on Highly Heterogeneous Materials Using Different Indenter Geometries
title_sort afm indentation on highly heterogeneous materials using different indenter geometries
topic hertz model
heterogeneous samples
fitting
depth-dependent behavior
biological materials
deep spherical indentations
url https://www.mdpi.com/2673-3161/4/2/26
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AT andreasstylianou afmindentationonhighlyheterogeneousmaterialsusingdifferentindentergeometries
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