An Optomechanical Instrument for Pericardial Tissue Selection in Bioprosthetic Heart Valves

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dc.contributor.advisor Taberner, A en
dc.contributor.advisor Nielsen, P en
dc.contributor.advisor Nash, M en
dc.contributor.author Dixon, Alexander en
dc.date.accessioned 2015-09-17T04:24:24Z en
dc.date.issued 2015 en
dc.identifier.citation 2015 en
dc.identifier.uri http://hdl.handle.net/2292/26991 en
dc.description Full text is available to authenticated members of The University of Auckland only. en
dc.description.abstract Bioprosthetic heart valves constructed from bovine pericardium are becoming an increasingly used treatment for valvular heart disease. The functional performance and durability of these valves has been somewhat limited, by a lack of understanding of the relationship between the mechanical and structural properties of pericardium. Pericardium is a biomembrane, with anisotropic and heterogeneous mechanical properties, that are thought to reflect its complex collagen fibre architecture. Development of an instrument that can simultaneously measure the mechanical and structural properties of pericardium, would offer an improved understanding of the relationship between them. This thesis documents the development of such an instrument. A quantitative polarised light imaging system that measures the birefringence of collagen, was upgraded and developed to provide automated measurements of the optical properties of thin collagenous membranes, such as pericardium. These optical properties are suggested to relate to the predominant fibre architecture of collagen. The polarised light imaging system was integrated with a prototype mechanical testing system. Following the implementation of phase-based cross-correlation techniques, that estimate strains in pericardium undergoing mechanical testing, a framework of data acquisition and control software was created for the integrated optomechanical instrument. A fully automated instrument that could simultaneously perform mechanical and optical measurements of collagenous membranes was established. A novel technique for laser cutting pericardium membranes, and attaching them to the optomechanical instrument for testing, was developed. An investigation into a novel, non-invasive method for estimating strains in pericardium, using the intrinsic features within its structure revealed by polarised light, showed promising results. Displacements up to 20 pixels with an accuracy better than 0.5 pixels could be measured in images of pericardium membrane deformation. Preliminary testing of adult bovine pericardium gave results in agreement with previous observations of its mechanical properties. The combined optical and mechanical measurements of the instrument also shed light on the relationship between the collagen architecture of pericardium, and its mechanical response to loading. en
dc.publisher ResearchSpace@Auckland en
dc.relation.ispartof Masters Thesis - University of Auckland en
dc.relation.isreferencedby UoA99264823400602091 en
dc.rights Items in ResearchSpace are protected by copyright, with all rights reserved, unless otherwise indicated. Previously published items are made available in accordance with the copyright policy of the publisher. en
dc.rights Restricted Item. Available to authenticated members of The University of Auckland. en
dc.rights.uri https://researchspace.auckland.ac.nz/docs/uoa-docs/rights.htm en
dc.rights.uri http://creativecommons.org/licenses/by-nc-sa/3.0/nz/ en
dc.title An Optomechanical Instrument for Pericardial Tissue Selection in Bioprosthetic Heart Valves en
dc.type Thesis en
thesis.degree.discipline Bioengineering en
thesis.degree.grantor The University of Auckland en
thesis.degree.level Masters en
dc.rights.holder Copyright: The Author en
pubs.elements-id 497815 en
pubs.record-created-at-source-date 2015-09-17 en


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