Fractional order viscoelasticity in characterization for atrial tissue

“…However, a single fractional element is often insufficient to describe the experimentally found differences in the power-law exponents of the storage and the loss modulus. [14][15][16][17] One key finding of the work presented here is that microrheology of ECs can be well modelled by the generalized Kelvin-Voigt model comprised of two fractional elements in parallel.…”

Section: Introductionmentioning

confidence: 86%

Microchip based microrheology via Acoustic Force Spectroscopy shows that endothelial cell mechanics follows a fractional viscoelastic model

Nguyen

Brandt

Betz

2020

Preprint

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AbstractActive microrheology is one of the main methods to determine the mechanical properties of cells and tissue, and the modelling of the viscoelastic properties of cells and tissue is under heavy debate with many competing approaches. Most experimental methods of active microrheology such as optical tweezers or atomic force microscopy based approaches rely on single cell measurements, and thus suffer from a low throughput. Here, we present a novel method for cell based microrheology using acoustic forces which allows multiplexed measurements of several cells in parallel. Acoustic Force Spectroscopy (AFS) is used to generate multi-oscillatory forces in the range of pN-nN on particles attached to primary human umbilical vein endothelial cells (HUVEC) cultivated inside a microfluidic chip. While the AFS was introduced as a single-molecule technique to measure mechanochemical properties of biomolecules, we exploit the AFS to measure the dynamic viscoelastic properties of cells exposed to different conditions, such as flow shear stresses or drug injections. By controlling the force and measuring the position of the particle, the complex shear modulus G*(ω) can be measured continuously over several hours. The resulting power-law shear moduli are consistent with fractional viscoelastic models. In our experiments we confirm a decrease in shear modulus after perturbing the actin cytoskeleton via cytochalasin B. This effect was reversible after washing out the drug. Although these measurements are possible, we provide critical information regarding the AFS as a measurement tool showing its capabilities and limitations. A key result is that for performing viscoelastic measurements with the AFS, a thorough calibration and careful data analysis is crucial, for which we provide protocols and guidelines.

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“…The coefficients of fractional Maxwell element are denoted by K, c and a . The expression for the force in a fractional Maxwell chain is given by [16,52,53],…”

Section: Modelling Magnetic Field Frequency and Amplitude Dependent Behavior Of Mrementioning

confidence: 99%

Material modeling of frequency, magnetic field and strain dependent response of magnetorheological elastomer

Poojary

Gangadharan

2021

J Mater Sci

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Accurate modeling of material behavior is very critical for the success of magnetorheological elastomer-based semi-active control device. The material property of magnetorheological elastomer is sensitive to the frequency, magnetic field and the input strain. Additionally, these properties are unique for a particular combination of matrix and the filler loading. An experimental-based characterization approach is costly and time consuming as it demands a large amount of experimental data. This process can be simplified by adopting material modeling approach. The material modeling of magnetorheological elastomer is an extension of conventional viscoelastic constitutive relations coupled with hysteresis and magnetic field sensitive attributes. In the present study, a mathematical relation to represent the frequency, magnetic field and strain dependent behavior of magnetorheological elastomer is presented. The viscoelastic behavior is represented by a fractional zener element and the magnetic field and strain dependent attributes incorporated in the model by a magnetic spring and linearized Bouc-–Wen element, respectively. The proposed model comprised of a total of eight parameters, which are identified by minimizing the least square error between the model predicted and the experimental response. The variations of each parameter with respect to the operating conditions are represented by a generalized expression. The parameters estimated from the generalized expression are used to assess the ability of the model in describing the dynamic response of magnetorheological elastomer. The proposed model effectively predicted the stiffness characteristics with an accuracy, more than 94.3% and the corresponding accuracy in predicting the damping properties is above 90.1%. This model is capable of fitting the experimental value with a fitness value of more than 93.22%.

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Fractional order viscoelasticity in characterization for atrial tissue

Cited by 32 publications

References 25 publications

Fractional viscoelastic models for power-law materials

Fractional viscoelastic models for power-law materials

Microchip based microrheology via Acoustic Force Spectroscopy shows that endothelial cell mechanics follows a fractional viscoelastic model

Material modeling of frequency, magnetic field and strain dependent response of magnetorheological elastomer

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