Thesis (Ph. D.)--Medical College of Georgia, 1997. / eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references.

Thesis (Ph. D.)--Medical College of Georgia, 1997. / eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references.

Thesis (M.S.)--University of Louisville, 1998. / eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references.

Thesis (Ph. D.)--University of Lund, 1995. / Published dissertation.

Thesis (M.S.)--University of Louisville, 1998. / Includes bibliographical references.

Thesis (Ph. D.)--University of Lund, 1995. / Published dissertation.

published_or_final_version / Orthopaedic Surgery / Doctoral / Doctor of Philosophy

The addition of silicon ions (10-500 μM) to the culture medium of MG63 osteoblast-like cells showed no changes in cell viability, metabolic activity, proliferation or morphology. Silicon ions resulted in a concentration-dependent increase in the expression of vascular endothelial growth factor (VEGF) by the MG63 cells. Addition of magnesium ions (1-50 mM) to the culture medium of MG63 cells caused a dose-dependent decrease in cell viability, metabolic activity and proliferation at each time point. In general, silicon and magnesium ions had no effect on the viability of a human endothelial cell line (HUVEC). A slight decreasing trend to the metabolic activity of the HUVECs was observed with increasing concentrations of silicon ions at all time points, but this decreasing trend was more pronounced with the addition of magnesium ions. The highest magnesium ion concentration studied (50 mM) caused a change in HUVEC morphology from a typical cobblestone appearance to a fibroblast-like shape. Lastly, the effect of silicon ions on angiogenesis <i>in vitro</i> was studied using two different <i>in vitro</i> assays. The first, using Matrigel as an extracellular matrix coating for the guidance of endothelial cells to form tube-like structures (an indicator of angiogenesis), proved unreliable for studying the promotion of angiogenesis. Additionally, tube-like structures were also observed with osteoblasts cells, raising questions about the efficiency of this assay. The second assay, AngioKit, was a suitable model for studying stimulation and inhibition of tube-like formation. Results obtained using this assay showed that silicon ions alone (500 μM) did not stimulate tube-like formation, but a significant increase in tube-like formation was observed with MG63 cell-conditioned media, with (500 μM) and without silicon ions, when compared to the control medium.

The development of bone regeneration materials to support new bone formation is an active field of research. This report describes the development and characterization of a novel composite scaffold made of a chitosan-alginate co-polymer hydrogel matrix and eggshell (ES) particles. Scaffolds with ES particles or with nanotextured ES (NTES) particles following treatment with phosphoric acid were compared to scaffolds without particles. The scaffolds with particles exhibited a higher porosity and a larger median pore size. Their mechanical strength remained low, but both scaffold types were more resistant to deformation following compression than the scaffolds without particles. The osteogenic potential of the scaffolds was then evaluated with human bone-marrow derived mesenchymal stem cells (MSCs) from four different donors. Results showed that the inclusion of ES or NTES particles significantly increased MSC adherence and viability, as well as alkaline phosphatase activity in the scaffolds. A change of cell morphology and a small, although not statistically significant, increase of osteogenic protein expression (RUNX2 and osteopontin) were also observed at later time points (days 14 and 21). Overall, this research highlights the potential of ES for bone regeneration applications, opening the door for a high-value repurposing of a current industrial waste product.

Thesis (Ph. D.)--University of Hong Kong, 2001. / Includes bibliographical references (leaves 179-213).