Mechanical integrity is one of the most important goals which biological tissues and biomaterials aim to achieve in order to support the life processes inside a living organism. A variety of mechanical structures and mechanisms are adopted from the nanoscale to the level of organisms, and mechanics plays an essential role. In this thesis, we first show that the epicardial layer of porcine ventricle exhibits a pre-strain, inducing a non-trivial residual stress, to protect the mechanical integrity of the ventricular system against over-filling. We construct a finite-element (FE) model of the porcine left ventricle and show that the cavity volume and the myocardial stress reduce significantly due to the pre-strain. Next, we focus on how to design the material properties of an epicardial patch to preserve the mechanical integrity of human heart after myocardial infarction. With FE modeling, we identify a gel-point property which optimizes the patch performance. Later we investigate how the limpet teeth utilize their highly heterogeneous and anisotropic microscopic structure to acquire a negative Poisson’s ratio without introducing any void, a common constituent in artificial auxetic engineering structures which can deteriorate the mechanical integrity. Finally, we study the mechanism by which the aggregated membrane-active nanoagents in lipid bilayers can degrade the mechanical integrity of bacterial membrane. Overall this thesis is aimed to provide some theoretical insights towards the mechanical interactions inside or between different biological materials and tissues, and how they affect the overall mechanical performance of the organism.
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Citation
Liu, Yue,
"Mechanics of Biological Materials, Structures and Tissues at Multiple Scales"
(2020).
Engineering Theses and Dissertations.
Brown Digital Repository. Brown University Library.
https://repository.library.brown.edu/studio/item/bdr:1129384/
