A Finite Element Study of Micropipette Aspiration of Single Cells: Effect of Compressibility

Bidhendi, Amir J.; Korhonen, Rami K.

doi:10.1155/2012/192618

Cited by 25 publications

(17 citation statements)

References 41 publications

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“…To compute the resultant mechanical strain in the cell/ECM, the FSI approach was applied to the micro model. The cell/ECM was modelled as a hyperelastic (Neo‐Hookean) material with strain energy density function according to previous cellular mechanics model: 28

W = C_{1} ((), \overset{I_{1}}{true} - 3) + \frac{1}{D_{1}} {(\det (boldF) - 1)}^{2},

where W and F are the strain energy density and deformation gradient, respectively; Ī 1 is the first invariant of the right Cauchy‐Green deformation tensor, which can be derived from:

\overset{I_{1}}{true} = {(\det (boldF))}^{- \frac{2}{3}} I_{1} = {(λ_{1} λ_{2} λ_{3})}^{- \frac{2}{3}} ((), λ_{1}^{2} + λ_{2}^{2} + λ_{3}^{2}),

where λ 1 , λ 2 and λ 3 are the principal stretches.…”

Section: Methodsmentioning

confidence: 99%

Fluid flow‐induced cell stimulation in bone tissue engineering changes due to interstitial tissue formation in vitro

Zhao

Rietbergen

Ito

et al. 2020

Numer Methods Biomed Eng

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In tissue engineering experiments in vitro, bioreactors have been used for applying wall shear stress (WSS) on cells to regulate cellular activities. To determine the loading conditions within bioreactors and to design tissue engineering products, in silico models are used. Previous in silico studies in bone tissue engineering (BTE) focused on quantifying the WSS on cells and the influence on appositional tissue growth. However, many BTE experiments also show interstitial tissue formation (i.e., tissue infiltrated in the pores rather than growing on the struts ‐ appositional growth), which has not been considered in previous in silico studies. We hereby used a multiscale fluid‐solid interaction model to quantify the WSS and mechanical strain on cells with interstitial tissue formation, taken from a reported BTE experiment. The WSS showed a high variation among different interstitial tissue morphologies. This is different to the situation under appositional tissue growth. It is found that a 35% filling of the pores results (by mineralised bone tissue) when the average WSS increases from 1.530 (day 0) to 5.735 mPa (day 28). Furthermore, the mechanical strain on cells caused by the fluid flow was extremely low (at the level of 10−14‐10−15), comparing to the threshold in a previous mechanobiological theory of osteogenesis (eg, 10−2). The output from this study offers a significant insight of the WSS changes during interstitial tissue growth under a constant perfusion flow rate in a BTE experiment. It has paved the way for optimising the local micro‐fluidic environment for interstitial tissue mineralisation.

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W = C_{1} ((), \overset{I_{1}}{true} - 3) + \frac{1}{D_{1}} {(\det (boldF) - 1)}^{2},

where W and F are the strain energy density and deformation gradient, respectively; Ī 1 is the first invariant of the right Cauchy‐Green deformation tensor, which can be derived from:

\overset{I_{1}}{true} = {(\det (boldF))}^{- \frac{2}{3}} I_{1} = {(λ_{1} λ_{2} λ_{3})}^{- \frac{2}{3}} ((), λ_{1}^{2} + λ_{2}^{2} + λ_{3}^{2}),

where λ 1 , λ 2 and λ 3 are the principal stretches.…”

Section: Methodsmentioning

confidence: 99%

Fluid flow‐induced cell stimulation in bone tissue engineering changes due to interstitial tissue formation in vitro

Zhao

Rietbergen

Ito

et al. 2020

Numer Methods Biomed Eng

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“…To address the limitations of applying all of the forms of Laplace's law to calculate membrane tension in membrane patches, FE models of pure azolectin liposomes for both cell-attached (MA technique) and excised patch (patchclamp experiment) configurations based on their related patch fluorometry data were developed. This approach has been widely used to model micropipette aspiration for several different cell types (46)(47)(48)(49)(50).…”

Section: Methodsmentioning

confidence: 99%

Biophysical implications of lipid bilayer rheometry for mechanosensitive channels

Bavi

Nakayama

Bavi

et al. 2014

Proc. Natl. Acad. Sci. U.S.A.

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The lipid bilayer plays a crucial role in gating of mechanosensitive (MS) channels. Hence it is imperative to elucidate the rheological properties of lipid membranes. Herein we introduce a framework to characterize the mechanical properties of lipid bilayers by combining micropipette aspiration (MA) with theoretical modeling. Our results reveal that excised liposome patch fluorometry is superior to traditional cell-attached MA for measuring the intrinsic mechanical properties of lipid bilayers. The computational results also indicate that unlike the uniform bilayer tension estimated by Laplace's law, bilayer tension is not uniform across the membrane patch area. Instead, the highest tension is seen at the apex of the patch and the lowest tension is encountered near the pipette wall. More importantly, there is only a negligible difference between the stress profiles of the outer and inner monolayers in the cellattached configuration, whereas a substantial difference (∼30%) is observed in the excised configuration. Our results have farreaching consequences for the biophysical studies of MS channels and ion channels in general, using the patch-clamp technique, and begin to unravel the difference in activity seen between MS channels in different experimental paradigms.MscL | azolectin | electrophysiology | finite element modeling L iposome reconstitution has been used for both functional and structural studies of bacterial mechanosensitive (MS) channels (MscL and MscS) for many years (1-4) and also more recently for the study of eukaryotic MS channels (5-8). Most frequently azolectin, a crude extract of phospholipids from animal and plant tissue consisting mainly of phosphatidylcholine (PC), phosphatidylethanolamine (PE), and phosphatidylinositol (PI) (9), has been used for liposome preparations. Given the frequent use of azolectin bilayers for the study of MS channels and the importance of protein-lipid interactions in MS channel gating it is imperative to consider the best way to accurately calculate and assess its material properties. This is also essential for studies of voltage-and ligand-gated ion channels as the activity of these proteins can also be modulated by membrane tension (6-8, 10-12).The mechanical properties of different types of lipids have been studied extensively using the micropipette aspiration (MA) approach (13-18). These experiments have shown that the mechanical properties of lipids differ considerably and that lipid bilayers exhibit elastic behavior (14,15,18,19). The MA technique is versatile and has the advantage of exerting a wide range of aspiration pressures on a specific portion of a bilayer (20-23).Here we use this technique in combination with finite-element (FE) simulation to examine in depth the mechanical properties of azolectin bilayers in both cell-attached and excised patch configurations (SI Materials and Methods). It is widely known that lipid behavior is vastly different at low (<0.5 mN/m) compared with high tensions, due to thermal shape fluctuations (24). Given that the m...

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“…When the fluid is allowed to flow freely, it is easy to see that the frame is highly compressible, and the drained bulk modulus is usually very low. Combining experimentally measured physical properties from a variety of sources, we have established that the bulk modulus of the bulk medium, K b , is on the order of 0.5 kPa (Baaijens et al 2005; Bidhendi and Korhonen 2012; Darling et al 2008; Leipzig and Athanasiou 2005; Shieh and Athanasiou 2006), and Poisson's ratio ν ≈ 0.38. However, the nucleus is known to be around four times stiffer than the cytoplasm (Guilak et al 2000), and we used the value K b ≈ 2 kPa.…”

Section: Mathematical Modelingmentioning

confidence: 99%

“…These characteristics warrant a biphasic approach: the cell is modeled as being composed of an elastic solid phase and a fluid phase. Biphasic models have been used successfully to predict the time-dependent response of cells to micropipet aspiration (Bidhendi and Korhonen 2012; Trickey et al 2006) and unconfined creep compression (Leipzig and Athanasiou 2005). Failure to incorporate biphasic effects will result in the incorrect prediction of mechanical responses.…”

Section: Introductionmentioning

confidence: 99%

Mechanotransduction of Ultrasound is Frequency Dependent Below the Cavitation Threshold

Louw

Budhiraja

Viljoen

et al. 2013

Ultrasound in Medicine & Biology

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This study provides evidence that low-intensity ultrasound directly affects nuclear processes, and the magnitude of the effect varies with frequency. In particular, we show that the transcriptional induction of first load-inducible genes, which is independent of new protein synthesis, is frequency dependent. Bovine chondrocytes were exposed to low-intensity below the cavitational threshold) ultrasound at 2,5 and 8 MHz. Ultrasound elevated the expression of early response genes c-Fos, c-Jun and c-Myc, maximized at 5 MHz. The phosphorylated ERK inhibitor PD98059 abrogated any increase in c-series gene expression, suggesting that signaling occurs via the MAPPK/ERK pathway. However, phosphorylated ERK levels did not change with ultrasound frequency, indicating that processes downstream of ERK phosphorylation (such as nuclear transport and chromatin reorganization) respond to ultrasound with frequency dependence. A quantitative, biphasic mathematical model based on Biot theory predicted that cytoplasmic and nuclear stress is maximized at 5.2 ± 0.8 MHz for a chondrocyte, confirming experimental measurements.

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A Finite Element Study of Micropipette Aspiration of Single Cells: Effect of Compressibility

Cited by 25 publications

References 41 publications

Fluid flow‐induced cell stimulation in bone tissue engineering changes due to interstitial tissue formation in vitro

Fluid flow‐induced cell stimulation in bone tissue engineering changes due to interstitial tissue formation in vitro

Biophysical implications of lipid bilayer rheometry for mechanosensitive channels

Mechanotransduction of Ultrasound is Frequency Dependent Below the Cavitation Threshold

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