Viscoelastic Properties of Human Tracheal Tissues

The physiological performance of trachea is highly dependent on its mechanical behavior, and therefore, the mechanical properties of its components. Mechanical characterization of trachea is key to succeed in new treatments such as tissue engineering, which requires the utilization of scaffolds which are mechanically compatible with the native human trachea. In this study, after isolating human trachea samples from brain-dead cases and proper storage, we assessed the viscoelastic properties of tracheal cartilage, smooth muscle, and connective tissue based on stress relaxation tests (at 5% and 10% strains for cartilage and 20%, 30%, and 40% for smooth muscle and connective tissue). After investigation of viscoelastic linearity, constitutive models including Prony series for linear viscoelasticity and quasi-linear viscoelastic, modified superposition, and Schapery models for nonlinear viscoelasticity were fitted to the experimental data to find the best model for each tissue. We also investigated the effect of age on the viscoelastic behavior of tracheal tissues. Based on the results, all three tissues exhibited a (nonsignificant) decrease in relaxation rate with increasing the strain, indicating viscoelastic nonlinearity which was most evident for cartilage and with the least effect for connective tissue. The three-term Prony model was selected for describing the linear viscoelasticity. Among different models, the modified superposition model was best able to capture the relaxation behavior of the three tracheal components. We observed a general (but not significant) stiffening of tracheal cartilage and connective tissue with aging. No change in the stress relaxation percentage with aging was observed. The results of this study may be useful in the design and fabrication of tracheal tissue engineering scaffolds.

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UNDERSTANDING THE VISCOELASTIC PROPERTIES OF RABBIT CORNEA BASED ON STRESS RELAXATION TESTS AND CYCLIC UNIAXIAL TESTS

Journal of Mechanics in Medicine and Biology ◽

10.1142/s0219519417400358 ◽

2017 ◽

Vol 17 (07) ◽

pp. 1740035 ◽

Cited By ~ 2

Author(s):

HAIXIA ZHANG ◽

XIUQING QIAN ◽

LIN LI ◽

ZHICHENG LIU

Keyword(s):

Stress Relaxation ◽

Test Data ◽

Viscoelastic Properties ◽

Linear Optimization ◽

Constitutive Models ◽

Optimization Techniques ◽

Rabbit Cornea ◽

Uniaxial Test ◽

Material Parameters ◽

Biomechanical Behavior

Background: Determining the viscoelastic properties of cornea is important in the fields of understanding of the tissue’s response to mechanical actions and the accurate numerical simulation of corneal biomechanical behavior under the effects of keratoconus and refractive surgery. To address this need, we present an approach to model the viscoelastic response of rabbit cornea from uniaxial test data. Methods: The corneal strip samples from six rabbits were obtained to perform cyclic uniaxial tension tests and stress relaxation tests. We investigated the suitability of six constitutive models, including empirical models and hyperelastic models, by a quasi-linear viscoelastic law. Applying non-linear optimization techniques, we found material parameters for each different strip sample. Results and conclusions: The model gave a better fit to loading data with [Formula: see text], and predicted the unloading data in the cyclic uniaxial tests with errors-of-fit ranging from 0.03 to 0.06. The results indicate that the best model is the power of the first invariant of strain with Prony form relaxation model, and that the method to identify the material parameters are valid for modeling the visoelastic response of cornea from uniaxial test data.

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Viscoelastic properties of bovine orbital connective tissue and fat: constitutive models

Biomechanics and Modeling in Mechanobiology ◽

10.1007/s10237-010-0281-z ◽

2011 ◽

Vol 10 (6) ◽

pp. 901-914 ◽

Cited By ~ 17

Author(s):

Lawrence Yoo ◽

Vijay Gupta ◽

Choongyeop Lee ◽

Pirouz Kavehpore ◽

Joseph L. Demer

Keyword(s):

Connective Tissue ◽

Viscoelastic Properties ◽

Constitutive Models ◽

Orbital Connective Tissue

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An Experimental and Analytical Evaluation of the Nonlinear Viscoelastic Properties of the Healing Medial Collateral Ligament in a Goat Model

Advances in Bioengineering ◽

10.1115/imece2003-43075 ◽

2003 ◽

Author(s):

S. D. Abramowitch ◽

T. D. Clineff ◽

R. E. Debski ◽

S. L.-Y. Woo

Keyword(s):

Stress Relaxation ◽

Medial Collateral Ligament ◽

Viscoelastic Properties ◽

Soft Tissues ◽

Viscoelastic Behavior ◽

Collateral Ligament ◽

Relaxation Experiment ◽

Nonlinear Viscoelastic ◽

Linear Viscoelastic Behavior ◽

Linear Viscoelastic

The medial collateral ligament (MCL) is one of the most frequently injured ligaments in the knee. Although it can heal spontaneously after rupture, laboratory studies have shown that the mechanical properties of the healing MCL remain inferior to normal for up to two years after injury (1). Additionally, the healing MCL has been shown to display increased amounts of stress relaxation and creep (2). In order to more completely describe the viscoelastic properties of healing ligaments, we propose to use the Quasi-Linear Viscoelastic (QLV) theory formulated by Fung (1972). This theory has been used to successfully describe the viscoelastic properties of many soft-tissues (3). Recently, our research center has developed an improved approach to determine the constants describing the QLV theory based on data collected from a stress relaxation experiment that utilizes a slow strain rate during loading. This approach allows for experimental errors that commonly result from fast strain rates to be avoided (ex. overshoot) (4). Therefore, the objective of this study were to use this new approach to determine the constants describing the quasi-linear viscoelastic behavior of the healing goat MCL at 12 weeks after injury.

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Stress relaxation in tunable gels

Soft Matter ◽

10.1039/d1sm00091h ◽

2021 ◽

Author(s):

Chiara Raffaelli ◽

Wouter G Ellenbroek

Keyword(s):

Mechanical Properties ◽

Drug Delivery ◽

Tissue Engineering ◽

Stress Relaxation

Hydrogels are a staple of biomaterials development. Optimizing their use in e.g. drug delivery or tissue engineering requires a solid understanding of how to adjust their mechanical properties. Here, we...

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3D Plotting of Silica/Collagen Xerogel Granules in an Alginate Matrix for Tissue-Engineered Bone Implants

Materials ◽

10.3390/ma14040830 ◽

2021 ◽

Vol 14 (4) ◽

pp. 830

Author(s):

Sina Rößler ◽

Andreas Brückner ◽

Iris Kruppke ◽

Hans-Peter Wiesmann ◽

Thomas Hanke ◽

...

Keyword(s):

Additive Manufacturing ◽

Bone Regeneration ◽

Material Properties ◽

Viscoelastic Properties ◽

Viscoelastic Behavior ◽

Matrix Phase ◽

Patient Specific ◽

Active Player ◽

Alginate Concentration ◽

Alginate Matrix

Today, materials designed for bone regeneration are requested to be degradable and resorbable, bioactive, porous, and osteoconductive, as well as to be an active player in the bone-remodeling process. Multiphasic silica/collagen Xerogels were shown, earlier, to meet these requirements. The aim of the present study was to use these excellent material properties of silica/collagen Xerogels and to process them by additive manufacturing, in this case 3D plotting, to generate implants matching patient specific shapes of fractures or lesions. The concept is to have Xerogel granules as active major components embedded, to a large proportion, in a matrix that binds the granules in the scaffold. By using viscoelastic alginate as matrix, pastes of Xerogel granules were processed via 3D plotting. Moreover, alginate concentration was shown to be the key to a high content of irregularly shaped Xerogel granules embedded in a minimum of matrix phase. Both the alginate matrix and Xerogel granules were also shown to influence viscoelastic behavior of the paste, as well as the dimensionally stability of the scaffolds. In conclusion, 3D plotting of Xerogel granules was successfully established by using viscoelastic properties of alginate as matrix phase.

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