Date of Award

Summer 2005

Document Type

Thesis

Degree Name

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

Department

Biomedical Engineering

First Advisor

Treena Livingston Arinzeh

Second Advisor

Michael Jaffe

Third Advisor

David S. Kristol

Abstract

Present spinal cord injury treatments cannot restore motor and sensory functions caused by the injury. These functions can return in the hopes of repairing the neural cells with a tissue engineered designed scaffold complex. The scaffold complex will include cells to repair and replace the damaged cells.

Mesenchymal stem cells (MSC) are multipotent adult stem ells that are capable of differentiating along several lineage pathways. Neural stem cell and MSC differentiating along the neural lineage bave been investigated both in vivo and in vitro depicting its feasibility. MSC for neural differentiation can be achieved by microenvironmental signaling. Substrate surface characteristics may influence both neuron and stem cell behavior and differentiation.

The effects of the polymer surface of tyrosine-derived polycarbonates and polyarylates on MSC differentiation along the neural lineage were investigated in this research. These polymers were developed by Dr. Joachim Kohn, where by altering the length of the alkyl ester pendent chain and the backbone composition, these polymers can have a gradual change in physicomechanical, chemical, and biological properties.

The MSC differentiated into neuron-like cell at 24 hours after induction. These cells express the presence of NSE which is a neuron marker. No systematic variation on cell proliferation among the polyarylate polymers was observed. The oxygen-contained diacid backbone stimulated cell growth on all the polyarylate polymers in this study. Cell proliferation increased as the substrate surface became less hydrophobic for all polymer surfaces. Wettability of polycarbonate polymers depicts high linear correlation with cell number and percentage of neural differentiation. The copolymer of tyrosine-derived poly DTE carbonate and 5% PEG was hydrophobic and did not stimulate cell growth and cells tend to aggregate on this substrate surface.

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