Date of Award

1-1-2013

Document Type

Open Access Thesis

Department

Biomedical Engineering

First Advisor

Susan M Lessner

Second Advisor

Michael A Sutton

Abstract

Mechanical characterization of biological soft tissues is essential in the field of biomedical engineering. In this study several loading experiments have been performed to efficiently characterize the passive mechanical response of both native porcine renal arteries and newly developed tissue constructs. The first aim of these studies is to determine whether there is a difference in mechanical response between the main renal artery and its first branch. After fitting the bi-axial data to a Holzapfel-type constitutive model, the results show that there is no statistical difference between the model parameters for renal artery and the first branch. The only significant differences between these two vessels were the geometric parameters. The second aim is to characterize the response of newly developed tissue constructs during their development, since recent studies [3] have shown that they vary in strength over time during the culture process. Specifically, mechanical characterization tests for the tissue constructs used in these studies show a significant increase in elastic modulus and failure strength as culture time is increased from 7 days to 17 days. The uniaxial mechanical test data was fitted to a simple single invariant constitutive model to determine appropriate material parameters that could be used in future studies to predict the 3-D response of tubular constructs. The test data was also used to obtain the low and high strain elastic modulus for elastin dominant and collagen dominant phases. The incremental elastic modulus data is useful for comparison to published values for other tissues.

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