Date of Award

2013

Document Type

Thesis

First Advisor

Zhu, Dr. Donghui

Abstract

There are over 15 million people living in the United States with cardiovascular disease (CVD). The standard treatment for CVD is stent angioplasty, traditionally bare metal stents have been used for this procedure however they are permanent and can lead to in-stent restenosis. Biodegradable bare metal stents are a suggested solution to this problem because they will degrade over time. Magnesium alloys are the most clinically advanced materials for biodegradable bare metal stents. They have been tested in various clinical trials with promising biocompatibility results; however materials degrade before full healing has occurred. The alloying of magnesium with elements such as calcium and zinc should improve corrosion rate of materials and demonstrate good biocompatibility. This research compares the biocompatibility of four different ternary magnesium zinc calcium alloys and two magnesium-based rare earth alloys to high purity magnesium for cardiovascular applications. Biocompatibility was investigated through in vitro testing evaluating the hemocompatibility and cytocompatibility of materials. Tests for hemocompatibility included hemolysis and platelet adhesion and morphology characterization. Cytocompatibility tests were indirect in vitro examinations of toxicity measuring human aortic endothelial cell viability and characterizing cell morphology. Tests for hemocompatibility indicated a nonhemolytic response to material and mild platelet activation and aggregation. Cytocompatibility tests concluded that viability was concentration dependent for all materials; however, there was no difference between material types or exposure time. These results concluded that MgZnCa alloys and Mg-based rare earth alloys are promising candidates for cardiovascular stent applications.

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