Pipette aspiration applied to the characterization of nonhomogeneous, transversely isotropic materials used for vocal fold modeling

Weiß, Sandra; Thomson, Scott L.; Lerch, Reinhard; Döllinger, Michael; Sutor, Alexander

doi:10.1016/j.jmbbm.2012.08.005

Cited by 13 publications

(8 citation statements)

References 57 publications

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“…To characterize whether the investigated material is isotropic or exhibits anisotropic properties, the nu-merical parameter A * describing the deviation from profile axisymmetry was introduced. The value tends to 1 for isotropic materials whereas anisotropic materials lead to a value smaller or greater than 1, as has been previously demonstrated (Weiss et al, 2013).…”

Section: Discussionsupporting

confidence: 68%

“…As a result, by choosing an appropriate pipette geometry, anisotropic regions can be characterized. Moreover, the suitability of the pipette aspiration technique for the characterization of inhomogeneous transversely isotropic silicone samples was recently demonstrated by (Weiss et al, 2013). All these studies show the potential of the pipette aspiration technique for determining the material properties of synthetic materials and real tissue.…”

Section: Introductionmentioning

confidence: 81%

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Influence of Pipette Geometry on the Displacement Profile of Isotropic Materials used for Vocal Fold Modeling

Weiß¹,

Thomson

Sutor

et al. 2013

Proceedings of the International Conference on Biomedical Electronics and Devices

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Due to limited access to human vocal folds, synthetic vocal folds are used to study periodic phonation. With respect to a realistic replica, the properties of the synthetic material should be to those of as real tissue. Silicone rubber is a commonly used material for vocal fold models. A suitable method to analyze the material parameters of both artificial and real vocal folds is the pipette aspiration technique. In the present study, the displacement profiles of an isotropic silicone specimen were measured with three different pipette geometries. The experimental results were compared to finite element simulations of the setup based on frequency dependent material parameters extracted from a previous study. The results demonstrate the potential of the pipette aspiration technique for material characterization and validate the determination of material parameters by means of an Inverse Method. Furthermore, a possible parameter for the classification of anisotropic materials is proposed and the suitability of the different pipette geometries for material characterization is discussed.

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Section: Discussionsupporting

confidence: 68%

Section: Introductionmentioning

confidence: 81%

Influence of Pipette Geometry on the Displacement Profile of Isotropic Materials used for Vocal Fold Modeling

Weiß¹,

Thomson

Sutor

et al. 2013

Proceedings of the International Conference on Biomedical Electronics and Devices

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“…Conventional testing methods along with a transversely isotropic model were used to determine the anisotropic mechanical properties of porcine VFs (Miri et al, 2012b). Pipette aspiration method is another technique for characterization of the local, anisotropic properties of the VFs (Weiß et al, 2012). …”

Section: Introductionmentioning

confidence: 99%

Indentation of poroviscoelastic vocal fold tissue using an atomic force microscope

Heris

Miri

Tripathy

et al. 2013

Journal of the Mechanical Behavior of Biomedical Materials

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The elastic properties of the vocal folds (VFs) vary as a function of depth relative to the epithelial surface. The poroelastic anisotropic properties of porcine VFs, at various depths, were measured using atomic force microscopy (AFM)-based indentation. The minimum tip diameter to effectively capture the local properties was found to be 25 µm, based on nonlinear laser scanning microscopy data and image analysis. The effects of AFM tip dimensions and AFM cantilever stiffness were systematically investigated. The indentation tests were performed along the sagittal and coronal planes for an evaluation of the VF anisotropy. Hertzian contact theory was used along with the governing equations of linear poroelasticity to calculate the diffusivity coefficient of the tissue from AFM indentation creep testing. The permeability coefficient of the porcine VF was found to be 1.80 ± 0.32 × 10−15 m4/N s.

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“…The out-of-plane velocity at the centre of the specimen's surface within the pipette was measured by a laser scanning vibrometer. Weiss et al [40][41][42] enhanced the setup of Zörner et al [39] to suggest a reliable pipette aspiration method for spatially-resolved material characterization of synthetic vocal folds over a frequency range of 50 Hz to 700 Hz. Unlike the Aoki et al [33] method to counteract the pipette wall force on the sample surface, Weiss et al [40] limited the force to 0.1 N for all the mixtures in the frequency range.…”

Section: Introductionmentioning

confidence: 99%

Acoustic Pressure Pipette Aspiration Method Combined with Finite Element Analysis for Isotropic Materials

2019

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A measurement setup combined with a numerical simulation by a linear finite element analysis is presented as a method to determine the elastic modulus of both artificial and real tissue as a function of frequency. At the end, the future goal is to develop and validate the method to measure the elastic modulus of in-vivo human vocal folds over the human phonation frequency range. In the present study, a miniaturized acoustic pressure pipette aspiration technique is developed to measure the material characteristics of an isotropic silicone specimen with similar characteristics as human vocal folds. In previous studies, friction and compression force effects of the pipette tip wall on the surface of the sample and the radius of the pipette were not investigated. Moreover, the large scale of the measurement setups made them impossible to use for clinical applications. Therefore, two different pipette sample cross-section boundary conditions and two different pipette radii were used. With the aim of ensuring reliable results, we tested our method with pipettes of two different radii on four silicone samples with different consistencies over a frequency range of 50–500 Hz. The simulation verified the measurement results in which the strong dependency of the elastic modulus on the excitation frequency, radius of the pipette, the pipette tip compression force and friction was revealed. By the simulation results, two different frequency dependent equations were developed for calculating elastic modulus of the silicone mixtures in the two cross-section boundary conditions. It was concluded that using a very small gap in between the pipette tip and the specimen can cancel the impact of the pipette tip force and friction which are the major cause of uncertainty. However, if a connection between the pipette and the surface is unpreventable, the contact force should be restricted to be absolutely zero.

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Pipette aspiration applied to the characterization of nonhomogeneous, transversely isotropic materials used for vocal fold modeling

Cited by 13 publications

References 57 publications

Influence of Pipette Geometry on the Displacement Profile of Isotropic Materials used for Vocal Fold Modeling

Influence of Pipette Geometry on the Displacement Profile of Isotropic Materials used for Vocal Fold Modeling

Indentation of poroviscoelastic vocal fold tissue using an atomic force microscope

Acoustic Pressure Pipette Aspiration Method Combined with Finite Element Analysis for Isotropic Materials

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