Determination of Strain-Rate-Dependent Mechanical Behavior of Living and Fixed Osteocytes and Chondrocytes Using Atomic Force Microscopy and Inverse Finite Element Analysis

2014 ◽  
Vol 136 (10) ◽  
Author(s):  
Trung Dung Nguyen ◽  
YuanTong Gu

The aim of this paper is to determine the strain-rate-dependent mechanical behavior of living and fixed osteocytes and chondrocytes, in vitro. First, atomic force microscopy (AFM) was used to obtain the force–indentation curves of these single cells at four different strain-rates. These results were then employed in inverse finite element analysis (FEA) using modified standard neo-Hookean solid (MSnHS) idealization of these cells to determine their mechanical properties. In addition, a FEA model with a newly developed spring element was employed to accurately simulate AFM evaluation in this study. We report that both cytoskeleton (CSK) and intracellular fluid govern the strain-rate-dependent mechanical property of living cells whereas intracellular fluid plays a predominant role on fixed cells' behavior. In addition, through the comparisons, it can be concluded that osteocytes are stiffer than chondrocytes at all strain-rates tested indicating that the cells could be the biomarker of their tissue origin. Finally, we report that MSnHS is able to capture the strain-rate-dependent mechanical behavior of osteocyte and chondrocyte for both living and fixed cells. Therefore, we concluded that the MSnHS is a good model for exploration of mechanical deformation responses of single osteocytes and chondrocytes. This study could open a new avenue for analysis of mechanical behavior of osteocytes and chondrocytes as well as other similar types of cells.

Author(s):  
Rafiul Shihab ◽  
Tasmirul Jalil ◽  
Burak Gulsacan ◽  
Matteo Aureli ◽  
Ryan C. Tung

Abstract In this study, we propose a novel plate-like sensor which utilizes curvature-based stiffening effects for enhanced nanometrology. In the proposed concept, the stiffness and natural frequencies of the sensor can be arbitrarily adjusted by applying a transverse curvature via piezoelectric actuators, thereby enabling resonance amplification over a broad range of frequencies. The concept is validated using a macroscale experiment. Then, a microscale finite element analysis is used to study the effect of applied curvature on the microplate static stiffness and natural frequencies. We show that imposed transverse curvature is an effective way to tune the in-situ static stiffness and natural frequencies of the plate sensor system. These findings will form the basis of future curvature-based stiffening microscale studies for novel scenarios in atomic force microscopy.


2006 ◽  
Vol 38 (6) ◽  
pp. 1090-1095 ◽  
Author(s):  
Matthias Müller ◽  
Thomas Schimmel ◽  
Pascal Häußler ◽  
Heiko Fettig ◽  
Ottmar Müller ◽  
...  

Langmuir ◽  
2006 ◽  
Vol 22 (15) ◽  
pp. 6578-6586 ◽  
Author(s):  
David Gasperino ◽  
Andrew Yeckel ◽  
Brian K. Olmsted ◽  
Michael D. Ward ◽  
Jeffrey J. Derby

2017 ◽  
Vol 19 (9.1) ◽  
pp. 177-190
Author(s):  
Yu.S. Nagornov ◽  
I.V. Zhilyaev

The paper presents a model for the calculation of morphofunctional erythrocyte properties. The model represents the erythrocyte as a homogeneous elastic body with elastic depending on the distance to the center of symmetry of the erythrocyte. The data for modeling were taken from the experimental study, which were used by atomic force microscopy (measuring the elasticity of the membrane of erythrocytes and morphology) and the Coulter method. In the developed model, the elasticity of the membrane to change depending on the distance to the center within 1-1,6 kPa. The calculation of the elastic properties is made by two methods - finite element analysis and optimization methods. In the model the dependence of erythrocyte morphology on the membrane pressure was obtained. Pressure difference across the erythrocyte membrane varied in the range of 0,5-2 kPa.


2020 ◽  
Author(s):  
Chuang Liu ◽  
Dongzhi Sun ◽  
Xianfeng Zhang ◽  
Florence Andrieux ◽  
Tobias Gerster

Abstract Cast iron alloys with low production cost and quite good mechanical properties are widely used in the automotive industry. To study the mechanical behavior of a typical ductile cast iron (GJS-450) with nodular graphite, uni-axial quasi-static and dynamic tensile tests at strain rates of 10− 4, 1, 10, 100, and 250 s− 1 were carried out. In order to investigate the effects of stress state, specimens with various geometries were used in the experiments. Stress–strain curves and fracture strains of the GJS-450 alloy in the strain-rate range of 10− 4 to 250 s− 1 were obtained. A strain rate-dependent plastic flow law based on the Voce model is proposed to describe the mechanical behavior in the corresponding strain-rate range. The deformation behavior at various strain rates is observed and analyzed through simulations with the proposed strain rate-dependent constitutive model. The available damage model from Bai and Wierzbicki is extended to take the strain rate into account and calibrated based on the analysis of local fracture strains. The validity of the proposed constitutive model including the damage model was verified by the corresponding experimental results. The results show that the strain rate has obviously nonlinear effects on the yield stress and fracture strain of GJS-450 alloys. The predictions with the proposed constitutive model and damage models at various strain rates agree well with the experimental results, which illustrates that the rate-dependent flow rule and damage models can be used to describe the mechanical behavior of cast iron alloys at elevated strain rates.


2021 ◽  
pp. 1-23
Author(s):  
Rafiul Shihab ◽  
Tasmirul Jalil ◽  
Burak Gulsacan ◽  
Matteo Aureli ◽  
Ryan Tung

Abstract Numerous nanometrology techniques concerned with probing a wide range of frequency dependent properties would benefit from a cantilevered sensor with tunable natural frequencies. In this work, we propose a method to arbitrarily tune the stiffness and natural frequencies of a microplate sensor for atomic force microscope applications, thereby allowing resonance amplification at a broad range of frequencies. This method is predicated on the principle of curvature-based stiffening. A macroscale experiment is conducted to verify the feasibility of the method. Next, a microscale finite element analysis is conducted on a proof-of-concept device. We show that both the stiffness and various natural frequencies of the device can be highly controlled through applied transverse curvature. Dynamic phenomena encountered in the method, such as eigenvalue curve veering, are discussed and methods are presented to accommodate these phenomena. We believe that this study will facilitate the development of future curvature-based microscale sensors for atomic force microscopy applications.


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