| dc.description.abstract | Tissue engineering is a rapidly expanding field, with billions of dollars being invested each year. Despite all the attention and the resources expended, applications of tissue engineering technologies in a therapeutic setting is conspicuously limited. This could be because while the response of biological cells to biochemical stimuli has been well studied and understood, the effect of the mechanical environment on cell response has not been explored sufficiently. Cells are mechanotransducers i.e. they respond biochemically to mechanical stimuli. In order to improve the viability of tissue engineering technologies in a clinical setting, there is a need to understand the mechanical behavior of biological tissues and tissue engineering scaffolds as well as study cell response to physiological mechanical cues. This document details experimental validation of a novel theoretical framework for mechanical characterization of soft tissues, and the development of a bioreactor to study cell response to mechanical stimuli.
A QR decomposition of the deformation gradient allows for a novel decomposing any arbitrary deformation into three distinct modes: dilation, squeeze, and shear. The study of biological materials in simple shear is quite complex, and typically the boundary conditions in a rectilinear simple shear experiment are not fully measured. A novel device that produces a simple shear deformation while measuring the loads and the moments applied at the grips is detailed here, along with experimental validation. The three modes of deformation are then applied on silicone to get a sense of the experimental error inherent in the system. Rat skin was then studied in all three modes of deformation, and the resultant stress-strain curves were modelled with the 3 parameters Freed-Rajagopal model extended to 2D planar membranes, thus obtaining 9 material parameters for rat skin. Finally, the design and validation of a uniaxial bioreactor is presented, and its potential use in studying cell response with this novel framework is discussed. | |
