Electronic Thesis and Dissertation Repository

Degree

Doctor of Philosophy

Program

Biomedical Engineering

Supervisor

Wan, Wankei

Abstract

Tissue engineering aims to regenerate damaged and deceased tissue by combining cells with scaffold made from an appropriate biomaterial and providing a conducive environment to guide cell growth and the formation or regeneration of new tissue or organ. While collagen, an important material of the extracellular matrix (ECM), is a natural choice as a scaffold biomaterial, the conducive environment can only be created by having the ability to control the geometry, organization, structural and mechanical properties of the scaffold. Moreover, degradability and degradation rate control of the scaffold has to be taken into consideration too. In this work, we aim at developing a scaffold that possess the geometry, organization, structural and mechanical properties of the ECM, that is also degradable with degradation rate control. We accomplish this through fabrication of scaffolds composed of collagen fibers with diameters of ~ 50 to 500 nm using electrospinning. These fibers can be organized and provide structural and mechanical support for the cells populating it. The versatile electrospinning setup not only allows mimicking the define architecture of the native ECM environment containing collagen fibers but, in the core-shell or porous structure, can also enable bioactive molecule encapsulation and their controlled release into the cell culture environment. Post fabrication processing for fiber stability via chemical or photochemical crosslinking as well as ion implantation resulted in fibers with controlled degradation rate and enhanced mechanical properties. Chemical structure characterization demonstrated close resemblance of fiber surface and native collagen. Favorable cell adhesion and proliferation demonstrated good cell compatibility using the human fetal lung (IMR-90) cells. By implementing the strategy developed in this thesis to construct scaffolds using electrospun collagen fiber that possess appropriate organization and properties to mimic the natural environment, scaffolds can be custom designed for specific tissue engineering applications with potentially improved outcome.

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