Document Type

Thesis

Date of Degree

Fall 2014

Degree Name

MS (Master of Science)

Degree In

Industrial Engineering

First Advisor

Ibrahim T. Ozbolat

Abstract

Vascularization of thick engineered tissue and organ constructs like the heart, liver, pancreas or kidney remains a major challenge in tissue engineering. Vascularization is needed to supply oxygen and nutrients and remove waste in living tissues and organs through a network that should possess high perfusion ability and significant mechanical strength and elasticity. In this thesis, we introduce a fabrication process to print vascular conduits directly, where conduits were reinforced with carbon nanotubes (CNTs) to enhance their mechanical properties and bioprintability. The generation of vascular conduit with a natural polymer hydrogel such as alginate needs to have improved mechanical properties in order to biomimic the natural vascular system. Carbon nanotube (CNT) is one of the best candidates for this goal because it is known as the strongest material and possesses a simple structure.

In this thesis, multi-wall carbon nanotube (MWCNT) is dispersed homogenously in the hydrogel and fabricated through an extrusion-based system.In vitro evaluation of printed conduits encapsulated in human coronary artery smooth muscle cells was performed to characterize the effects of CNT reinforcement on the mechanical, perfusion and biological performance of the conduits. Perfusion and permeability, cell viability, extracellular matrix formation and tissue histology were assessed and discussed, and it was concluded that CNT-reinforced vascular conduits provided a foundation for mechanically appealing constructs where CNTs could be replaced with natural protein nanofibers for further integration of these conduits in large-scale tissue fabrication. It was concluded that MWCNT has a significant effect on mechanical properties, vascular conduit swelling ratio and biological characterization in short-term and long-term cellular viability.

Public Abstract

Tissue engineering is an existing area which offering the potential for regenerating almost every tissue and organ of the human body particularly to address the tremendous shortage of donor tissues for transplantation procedures. Tissue engineers Integrates a variety of engineering principals and biological science discipline to develop biological substitutes that can be used to replace diseased/ damaged tissues.

Cardiovascular diseases have remained one of the leading causes of death during the past decade, one in every five American die due to Coronary Heart disease, however fewer progress have been made in engineering small diameter vascular grafts. In addition, Shortage numbers of donors for tissue replacement (18 people die each day waiting for an organ) and risk of organ transplantation for patient are the main reasons to perform this study.

In this research, vascular conduits were fabricated through an extrusion based bioprinting system. The generation of vascular conduits with natural polymer such as alginate needs to have improved mechanical properties in order to biomimic the natural blood vessel. Carbon nanotube (CNT) is one of the best candidates for this goal because it is known as the strongest material and possesses a simple structure. In this work, multi-wall carbon nanotubes (MWCNT) were dispersed homogenously in alginate and printed using an extrusion-based system. The effects of using MWCNT as a reinforcement agent were investigated in mechanical, swelling and degradation tests. Cell viability studies were conducted to explore effects of MWCNT on short term biocompatibility as well as long-term tissue formation.

Keywords

publicabstract, 3D Printing, Artificial Vascular Conduits, Carbon Nanotube Reinforcement, Multi Wall Carbon Nanotube, Tissue Engineering, Tissue Histology

Pages

ix, 56 pages

Bibliography

Includes bibliographical references (pages 51-56).

Copyright

Copyright 2014 Farzaneh Dolati

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