Defense Date

2009

Document Type

Dissertation

Degree Name

Doctor of Philosophy

Department

Biomedical Engineering

First Advisor

Gary Bowlin

Abstract

The resurgence, and eventual rise to prominence in the field of tissue engineering, that electrospinning has experienced over the last decade speaks to the simplicity and adaptability of the process. Electrospinning has been used for the fabrication of tissue engineering scaffolds intended for use in nearly every part of the human body: blood vessel, cartilage, bone, skin, nerve, connective tissue, etc. Diverse as the aforementioned tissues are in both form and function, electrospinning has found a niche in the repair of each due to its capacity to consistently create non-woven structures of fibers ranging from nano-to-micron size in diameter. These structures have had success in tissue engineering applications because of their ability to mimic the body’s natural structural framework, the extracellular matrix. In this study we examine a number of different techniques for altering scaffold properties (i.e. mechanical strength, degradation rate, permeability, and bioactivity) to create electrospun structures tailored to unique tissue specific applications; the end goal being the creation of a cellularized tissue engineering ligament analogue. To alter the mechanical properties of electrospun structures while maintaining high levels of bioactivity, synthetic polymers such as polydioxanone were blended in solution with naturally occurring proteins like elastin and fibrinogen prior to electrospinning. Cross-linking of electrospun structures, using glutaraldehyde, carbodiimide hydrochloride, and genipin, was also investigated as a means to both improve the mechanical stability and slow the rate of degradation of the structures. Fiber orientation and scaffold anisotropy were controlled through varying fabrication parameters, and proved effective in altering the mechanical properties of the structures. Finally, major changes in the structure of electrospun scaffolds were achieved through the implementation of air-gap electrospinning. Scaffolds created through air-gap electrospinning exhibited higher porosity’s than their traditionally fabricated counterparts, allowing for greater cell penetration into the scaffold. Overall, this collection of results provides insight into the diversity of electrospinning and reveals innumerous options, both pre and post fabrication, for the tissue engineer to create site-specific engineering scaffolds capable of mimicking both the form and function of native tissue.

Rights

© The Author

Is Part Of

VCU University Archives

Is Part Of

VCU Theses and Dissertations

Date of Submission

July 2009

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