Electronic Thesis and Dissertation Repository

Thesis Format

Integrated Article

Degree

Master of Engineering Science

Program

Biomedical Engineering

Supervisor

Hamilton, Douglas W.

2nd Supervisor

Rizkalla, Amin S.

Co-Supervisor

Abstract

Synthetic bone graft materials have become an increasingly popular choice for bone augmentation. Ceramic-based and polymer-based bone graft materials constitute the two main classes of synthetic bone graft materials. This study investigated the synthesis of novel bioactive composites for their potential use as bone graft biomaterials. Poly(diethyl fumarate-co-triethoxyvinylsilane)/bioceramic class II organic/inorganic hybrid biomaterials were synthesized via a sol gel process. These biomaterials were then reacted with an ammonium phosphate solution to prepare their respective composites. For the first time, we successfully synthesized sol-gel derived bioceramic poly(diethyl fumarate-co-triethoxyvinylsilane) composites. In vitro bioactivity evaluation of poly(diethyl fumarate-co-triethoxyvinylsilane)/bioceramic composites in simulated body fluid exhibited hydroxyapatite surface formation. Mechanical testing revealed that these composites exhibit elastic moduli comparable to trabecular bone. Degradation of poly(diethyl fumarate-co-triethoxyvinylsilane)/bioceramic composites in phosphate buffer solution was controlled. It is necessary to conduct further research investigating cytotoxicity, cell attachment, proliferation and differentiation characteristics of these composites.

Summary for Lay Audience

The aging population calls for the development of novel bone graft materials. Although aging results in bone loss, other causes of bone loss include periodontal disease, fractures/bony defects, cancer tumor removal and congenital disease. There are many factors that play a role in bone healing and determine whether an intervention is required or not. Some of these factors include age, medical history, size of bony defect and location. Defects that require intervention call for use of bone substitutes. The current clinical standard involves harvesting bone from the patient themselves (i.e., autograft) or from another human donors (i.e., allograft). Some disadvantages with these methods include the risk of host rejection and the limited availability of healthy bone.

Synthetic bone graft materials have become an increasingly popular choice for bone augmentation. Ceramic-based and polymer-based bone graft materials constitute the two main classes of synthetic bone graft materials. The most frequently used bone cements are bioactive glass variants and poly(methyl methacrylate) (PMMA). These materials have disadvantages that limit their usefulness as ideal bone graft materials. Some of these disadvantages include their brittle nature, low degradation rate, lack of integration/bonding, polymerization shrinkage, heat generation and toxicity. There is a requirement for the development of a novel osteoconductive, osteoinductive and osteogenic material suitable for bone augmentation that will facilitate healing and remodeling of the bone.

In this work, for the first time, we were able to successfully copolymerize diethyl fumarate with triethoxyvinylsilane, synthesize poly(diethyl-co-triethoxyvinylsilane)/bioceramic class II hybrid biomaterials and prepare their respective composites to be used as a potential bone graft. Composites were incubated in simulated body fluid to study bioactivity, incubated in phosphate buffer saline to study degradation behavior, and tested with an Instron machine for mechanical properties. The preliminary work presented in this thesis shows the potential of these composites to be used for next generation bone graft biomaterials to meet the increasing demand.

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