Date of Award

Fall 2007

Document Type

Thesis

Degree Name

Master of Science in Biomedical Engineering - (M.S.)

Department

Biomedical Engineering

First Advisor

Bryan J. Pfister

Second Advisor

Cheul H. Cho

Third Advisor

Michael Jaffe

Abstract

Each year, there are approximately 11,000 new cases of spinal cord injury (SCI) in the United States [2]. There have been some success in pre-clinical studies to induce axonal generation, but the reconnection of axons over large distances remains the greatest challenge. Since the development of nerve conduit to facilitate general axonal regeneration, the primary focus has changed to directing the regeneration of axons while also promoting their outgrowth over very extensive lesions to ensure functional recovery of transected nerves during in vitro experiments by using natural materials such as type I collagen, which is the largest constituent of the extra- cellular matrix of living tissue. In this project, fabrication of novel constructs for nerve tissue guidance was carried out using homogenous hydrogels and multi-filament arrays of wet-spun fibers/hydrogel composites derived from extracted type I collagen. A comparison of axonal outgrowth on 2D and 3D environments revealed that dorsal root ganglia (DRGs) slightly favored 3D collagen gels compared to 2D collagen substrates after 9 days of culture. DRG neurites grown on 3D collagen gels exhibited optimal growth on a 0.8 mg/ml collagen gel concentration.

Extracted type I bovine collagen was wet spun at 2% and 5% wt bovine collagen in ethanol to yield fibers as small as 1.389 μm in diameter. BCA total protein assay and SDS-PAGE were used to validate the quantity and purity of extracted rat tail collagen. Doublet bands present at 235 kDa and 215 kDa and another pair of doublets at 130 kDa and 115 kDa characteristic of rat tail type I collagen were seen for both extracted and commercial rat tail collagen using SDS-PAGE. Low absorbance values from BCA total protein revealed that this technique is not suitable for quantifying rat tail type I collagen.

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