Date of Award

2006

Degree Type

Thesis

Degree Name

Master of Engineering Science

Program

Biomedical Engineering

Supervisor

Dr. Amin Rizkalla

Second Advisor

Dr. Harvey Goldberg

Third Advisor

Dr. Graeme Hunter

Abstract

The biomaterial surface plays a critical role in determining cell-biomaterial compatibility, and in regulating cellular events such as attachment, proliferation, and differentiation. This is important in tissue engineering, where synthetic materials such as polymers and ceramics are often used to fabricate scaffolds for seeding of cells. One strategy of modifying surfaces for tissue engineering scaffolds to elicit a particular cellular response is mimicking the in-vivo environment in which cells naturally exist. The goal of this study was to create a biomimetic material by immobilizing bone sialoprotein (BSP), an extracellular matrix protein important in regulating osseous tissue formation, for eventual use as a scaffold in skeletal tissue engineering. 1,1’-Carbonyldiimidazole (CDI) was chosen to immobilize BSP through primary amines onto surface hydroxyl groups of polycaprolactone∕poly(2- hydroxyethyl methacrylate) (PCL∕pHEMA) polymer networks or PCL∕pHEMA bioactive glass (BG) composites. Unmodified and modified surfaces were characterized on their ability to support MC-3T3-E1 cell attachment and proliferation. BSP-conjugated surfaces supported the highest amount of cell attachment compared to control surfaces. Qualitatively, cells on these surfaces appeared more spread, with extension of pseudopodia from the cell body. When grown over a 5 day period, cell proliferation was not significantly different on BSP-conjugated surfaces compared to controls. The effects of incorporating the experimental bioactive glass filler on mechanical properties, and cell attachment and proliferation were also determined. 111 When dry, silane-treated BG composites improved the Young’s Modulus over unfilled PCL∕pHEMA controls. In terms of the cellular events of attachment and proliferation, there was no significant difference compared to unfilled PCL∕pHEMA materials. The cell attachment and proliferation results suggest that BSP immobilization may be a useful biomimetic strategy for skeletal tissue engineering scaffolds to support cell interaction and eventual extracellular matrix deposition and mineralization.

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