Electronic Thesis and Dissertation Repository

Degree

Doctor of Philosophy

Program

Biomedical Engineering

Supervisor

Dr. Wankie Wan

2nd Supervisor

Dr. Derek Boughner

Joint Supervisor

Abstract

Design and fabrication of the scaffold is an important part of the tissue engineering process. Nanofibrous scaffolds based on proteins are gaining increasing acceptance due to its structural similarity to the extracellular matrix. Making use of the electrospinning technique, rat tail collagen type I nanofibers were produced using a collagen in hexafluoroisopropanol (HFIP) solution. In addition to optimizing the electrospinning process parameters, the effect of humidity on fiber morphology and diameter was investigated for fiber size control for particular tissue engineering applications. A generalized humidity effect on polymer fiber diameter of the polymer solution electrospinning process was developed. The as spun collagen type I fibers were unstable in aqueous solutions. To impart stability these fibers, the technique of ion implantation was used. Both helium (He+) and nitrogen (N+) ions were used. Polychromatic ion beam of energies of 0 – 100 MeV (He+) and 0 – 300 MeV (N+) with doses varied from 4*1015 ions /cm2 - 1.2*1016 ions/cm2 were used. The effect of the ion implantation process on collagen fiber stability was investigated as a function of ion dosages. While all implantation conditions gave stable fibers, their swelling characteristics vary. The structural and chemical compositional changes in the stabilized collagen type I fibers were investigated using the X-ray photoelectron spectroscopy (XPS). The results indicated that the lowest dose of both the ion species implanted had the highest degree of crosslinking and retained the largest amount of nitrogen which is essential for cell adhesion and important for tissue engineering.

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