A Finite Element Prediction of Cellular Strain in a GAG-Scaffold

Author(s):  
A. J. F. Stops ◽  
L. A. McMahon ◽  
D. O’Mahoney ◽  
P. E. McHugh ◽  
P. J. Prendergast

Tissue engineering is an emerging area in bioengineering engaging biomaterials, biology and biomechanics. Current in-vitro studies have shown mesenchymal differentiation into specific cellular lineages when using osteoinductive factors [1], though the quantitative understanding of the load transfer process within a cell-seeded scaffold is still relatively unknown. Here, this paper presents a finite element simulation of the cellular-scaffold interaction so that cellular strain and the corresponding strain mechanisms can be evaluated.

2008 ◽  
Vol 130 (6) ◽  
Author(s):  
A. J. F. Stops ◽  
L. A. McMahon ◽  
D. O’Mahoney ◽  
P. J. Prendergast ◽  
P. E. McHugh

Tissue engineering often involves seeding cells into porous scaffolds and subjecting the scaffold to mechanical stimulation. Current experimental techniques have provided a plethora of data regarding cell responses within scaffolds, but the quantitative understanding of the load transfer process within a cell-seeded scaffold is still relatively unknown. The objective of this work was to develop a finite element representation of the transient and heterogeneous nature of a cell-seeded collagen-GAG-scaffold. By undertaking experimental investigation, characteristics such as scaffold architecture and shrinkage, cellular attachment patterns, and cellular dimensions were used to create a finite element model of a cell-seeded porous scaffold. The results demonstrate that a very wide range of microscopic strains act at the cellular level when a sample value of macroscopic (apparent) strain is applied to the collagen-GAG-scaffold. An external uniaxial strain of 10% generated a cellular strain as high as 49%, although the majority experienced less than ∼5% strain. The finding that the strain on some cells could be higher than the macroscopic strain was unexpected and proves contrary to previous in vitro investigations. These findings indicate a complex system of biophysical stimuli created within the scaffolds and the difficulty of inducing the desired cellular responses from artificial environments. Future in vitro studies could also corroborate the results from this computational prediction to further explore mechanoregulatory mechanisms in tissue engineering.


Nanomedicine ◽  
2022 ◽  
Author(s):  
Jihye Baek ◽  
Kwang Il Lee ◽  
Ho Jong Ra ◽  
Martin K Lotz ◽  
Darryl D D'Lima

Aim: To mimic the ultrastructural morphology of the meniscus with nanofiber scaffolds coupled with controlled growth factor delivery to modulate cellular performance for tissue engineering of menisci. Methods: The authors functionalized collagen nanofibers by conjugating heparin to the following growth factors for sustained release: PDGF-BB, TGF-β1 and CTGF. Results: Incorporating growth factors increased human meniscal and synovial cell viability, proliferation and infiltration in vitro, ex vivo and in vivo; upregulated key genes involved in meniscal extracellular matrix synthesis; and enhanced generation of meniscus-like tissue. Conclusion: The authors' results indicate that functionalizing collagen nanofibers can create a cell-favorable micro- and nanoenvironment and can serve as a system for sustained release of bioactive factors.


2015 ◽  
Vol 76 (10) ◽  
Author(s):  
Nor Fazli Adull Manan ◽  
Jamaluddin Mahmud ◽  
Aidah Jumahat

This paper for the first time attempts to establish the biomechanical characteristics of bovine skin via experiment-theory integration and finite element simulation. 30 specimens prepared from fresh slaughtered bovine were uniaxially stretched in-vitro using tensile tests machine. The experimental raw data are then input into a Matlab programme, which quantified the hyperelastic parameters based on Ogden constitutive equation. It is found that the Ogden coefficient and exponent for bovine skin are μ = 0.017 MPa and α = 11.049 respectively. For comparison of results, the quantified Ogden parameters are then input into a simple but robust finite element model, which is developed to replicate the experimental setup and simulate the deformation of the bovine skin. Results from experiment-theory integration and finite element simulation are compared. It is found that the stress-stretch curves are close to one another. The results and finding prove that the current study is significant and has contributed to knowledge enhancement about the deformation behaviour of bovine skin.


1996 ◽  
Vol 24 (4) ◽  
pp. 321-338 ◽  
Author(s):  
J. Padovan

Abstract This paper investigates the cord-matrix load transfer problem in twisted cord-rubber composites. The central feature of the study is to ascertain the polarizing effects of twist-induced coupling of the axial loads and torque. Particular emphasis is given to the end problem, namely the transition between the axial-circumferential shear stress-dominated end region and the axial normal stress and torque-controlled far-from-end zone. This is achieved through the development of both a closed form analytic formulation and its corroboration by a detailed finite element simulation.


2020 ◽  
Vol 980 ◽  
pp. 58-69
Author(s):  
Wen Cheng Wang ◽  
Lisong Tang ◽  
Feng Wang

The paper first introduces the concept of inherent strain and the theory and method of predicting welding deformation by the inherent strain finite element method. Studies have shown that the inherent strain exists in the weld and the near seam area, and it is also related to factors such as welding heat input and plate thickness. Through the use of large-scale finite element simulation software ANSYS, the inherent strain finite element prediction method is applied to the welding deformation of the outer gantry assembly material of forklift, which provides effective reference data for future welding work of forklift gantry materials.


2010 ◽  
Vol 16 (3) ◽  
pp. 781-793 ◽  
Author(s):  
Claudio E. Pedraza ◽  
Benedetto Marelli ◽  
Florencia Chicatun ◽  
Marc D. McKee ◽  
Showan N. Nazhat

1982 ◽  
Vol 104 (2) ◽  
pp. 119-124 ◽  
Author(s):  
E. Rooz ◽  
D. F. Young ◽  
T. R. Rogge

A finite-element model for pulsatile flow in a straight flexible partially obstructed tube is developed. In the unobstructed sections of the tube the model considers the continuity equation, the one-dimensional momentum equation, and an equation of state relating tube cross-sectional area to pressure. For the obstructed region, a nonlinear relationship between the flow and the pressure drop across the stenosis is considered. The applicability of a model is checked by comparing predicted flow and pressure waveforms with corresponding in-vitro experimental measurements obtained on a mechanical system. These comparisons indicate that the model satisfactorily predicts pressures and flows under variety of frequencies of oscillation and stenosis severities.


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