This work investigates the fabrication, process optimization, and characterization of cobalt oxide-antimony doped tin oxide (CoO-ATO) nanofibersusing polystyrene (PS) solutions with toluene orD-limonene as solvents. These nanofibers are produced by anelectrospinning process. Nanofibers are fabricated using polymeric solutions of CoO doped ATO and mixtures of PS: D-limonene and PS:toluene. PSis a base aromatic organic polymer, a non-toxic material, and a versatile catalyst for fiber formation. PSsolutions are made by mixing polystyrene beads and D-limonene or toluene at specific weight percentages. These polymeric solutions of PS: D-limonene and PS:toluene are then mixed with CoO-ATO at various weight percentages. The two solutions are electrospun and the best process parameters optimized to obtain nanofibers with limited beading. Process optimization is completed by analyzing how changes in the electrospinningexperimental set up impact nanofiber formation and production efficiency (speed of formation). CoO-ATO nanofibers are characterizedby scanning electron microscopy, hydrophobicity via contact angle measurements, and viscosity measurements. Additional analysis is conducted to evaluate the environmental impact of using two different solvents to fabricate the CoO-ATO nanofibers. In this project, I was able to successfully produce novel nanofiber membranes of CoO-ATOusing two different solvents. These investigations were conducted and nanofiberprocess optimized to provide a technological contribution to future industrial scaleproductions of thermally reflective materials.

Bone defects caused by trauma, tumor resection or disease present a significant clinical problem. Failures in 'high risk' fractures and large bone defects have been reported to be as high as 30-50%. The drawbacks associated with current bone grafting procedures have stimulated the search for improved techniques for bone repair. Tissue engineering/regenerative medicine approaches promote tissue repair by providing a combination of physical and biological cues through structural scaffolds and bioactive agents. Though they have demonstrated significant promise for bone regeneration, very little has been translated to clinical practice. The goal of this thesis was to investigate the potential of electrospun nanofiber mesh scaffolds for bone regeneration. Nanofiber meshes were utilized in a three-pronged approach. First, we validated their ability to robustly support osteogenic cell functions, including proliferation and matrix mineralization. We also demonstrated their efficacy as a cell delivery vehicle. Second, we investigated the effects of modulating nanofiber bioactivity and orientation on stem cell programming. Our results indicate that functionalization of nanofiber meshes with a collagen-mimetic peptide enhanced the migration, proliferation and osteogenic differentiation of cells. Fiber alignment improved cell migration along the direction of fiber orientation. Finally, a nanofiber mesh based hybrid system for growth factor delivery was developed for bone repair and tested in a challenging animal model. The delivery of bone morphogenetic protein (BMP) via this system resulted in the functional restoration of limb function, and in fact proved more efficacious than the current clinical standard for BMP delivery. The studies performed in this thesis have suggested novel techniques for improving the repair of clinically challenging bone defects. They indicate that the delivery of BMP via the hybrid system may reduce the dose and side effects of BMP, thereby broadening the use of BMP based bone augmentation procedures. Therefore, this nanofiber mesh based system has the potential to become the standard of care for clinically challenging bone defects, including large bone defects, open tibial fractures, and nonunions.