PhD student Tate Shannon successfully defends dissertation

September 23, 2026 — University of Minnesota Biomedical Engineering PhD student Tate Shannon successfully defended his dissertation, "Novel Methods for Characterizing and Simulating Vein Valve Devices and Methods to Endothelialize them in Vitro" last month. He was advised by Professor Robert Tranquillo.

Following is an abstract of his dissertation:

Cardiovascular disease is the leading cause of death worldwide and in the United States. It takes many forms, but several common treatments involve placing engineered devices and materials into the bloodstream. Such devices and materials must be well-behaved both mechanically, allowing proper bloodflow, and biologically, by resisting the formation of occlusive blood clots. In the cases of chronic venous insufficiency and coronary artery bypass grafting, there are no such devices that do not require the recipient to spend their life on anticoagulation therapy. This thesis explores how to address both the hemodynamic and thrombogenic difficulties by using our biologically engineered matrix platform to demonstrate a novel design and characterization of a tissue-engineered vein valve prototype and cell treatments based on adipose-derived microvascular endothelial cells. Along the way, it presents a novel computational model for venous flow and characterizes the cells planned for use in future cell-based treatments. The results show that a sinused vein valve design meets or exceeds current industry trends used for vein-valve characterization under new, physiologically derived flow conditions, that a proposed lumped-parameter model of venous flow can be fitted to experimental data and used to make predictions about best valve placement (though no best computational valve model was identified with the model), and that adipose-derived microvascular cells can form a confluent, shear-resistant layer on biological matrix within a clinically useful timeframe.