Date of Award

1-1-2017

Document Type

Masters Thesis

Degree Name

M.S.

Organizational Unit

Daniel Felix Ritchie School of Engineering and Computer Science, Center for Orthopaedic Biomechanics

First Advisor

Ali N. Azadani, Ph.D.

Second Advisor

Corinne Lengsfeld

Third Advisor

Matthew Rutherford

Keywords

3D Bioprinting, Bioreactor, Hydrogel, Scaffold, Tissue engineering, Vascular graft

Abstract

The gold standard in 2016 for thoracic aortic grafts is Dacron®, polyethylene terephthalate, due to the durability over time, the low immune response elicited and the propensity for endothelialization of the graft lumen over time. These synthetic grafts provide reliable materials that show remarkable long term patency. Despite the acceptable performance of Dacron® grafts, it is noted that autographs still outperform other types of vascular grafts when available due to recognition of the host's cells and adaptive mechanical properties of a living graft. 3-D bioprinting patient-specific scaffolds for tissue engineering (TE) brings the benefits of non-degrading synthetic grafts and autologous grafts together by constructing a synthetic scaffold that supports cell infiltration, adhesion, and development in order to promote the cells to build the native extracellular matrix in response to biochemical and physical cues. Using the BioBots 3-D bioprinter, scaffold materials we tested non-Newtonian photosensitive hydrogel that formed a crosslinked matrix under 365 nm UV light with appropriate water content and mechanical properties for cell infiltration and adhesion to the bioprinted scaffold. Viscometry data on the PEGDA-HPMC 15%-2% w/v hydrogel (non-Newtonian behavior) informed CFD simulation of the extrusion system in order to exact the pressure-flow rate relationship for every hydrogel and geometry combination. Surface tension data and mechanical properties were obtained from material testing and provide content to further characterize each hydrogel and resulting crosslinked scaffold. The goal of this work was to create a basis to build a database of hydrogels with corresponding print settings and resulting mechanical properties in order to progress the field of tissue engineered vascular grafts fabricated by nozzle-based rapid prototyping.

Publication Statement

Copyright is held by the author. User is responsible for all copyright compliance.

Rights Holder

Benjamin Stewart

Provenance

Received from ProQuest

File Format

application/pdf

Language

en

File Size

159 p.

Discipline

Biomedical Engineering, Industrial Engineering, Mechanical Engineering

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