Date of Award

2012

Document Type

Thesis

Degree Name

Master of Science (MS)

Department

Mechanical Engineering

First Advisor

Kumar, Dhananjay Dr.

Abstract

One-dimensional (1D) nanostructures, such as nanowire, nanorods, and nanotubes, have shown great promise in both fundamental and application studies due to their size, structure, and several other unique properties. In this study, magnesium oxide (MgO) nanowires (NWs) with varying diameter have been grown on magnesium oxide (100) single crystal substrates using a pulsed laser deposition (PLD) technique. Magnesium oxide was chosen due to its high melting point, high hardness, high tensile strength, excellence diffusion barrier, and good biocompatibility. In the fabrication of MgO nanowires, gold has been used as a catalyst. A systematic study has been carried out to identify critical parameters for the fabrication of single-crystalline MgO nanowires. These parameters included substrate temperature, ambient pressure, and catalyst size. The diameter of MgO-NWs was found to depend on the diameter of the gold catalyst. Using this finding, the diameter of nanowires w a s v a r i e d from 12-46 nm. T h e s i z e o f g old particles prior to MgO deposition was in the range of 3-12 nm. The diameter of MgO-NWs linearly depended on the number of pulses used to deposit the gold catalyst. To determine the biocompatibility of MgO-NWs, cultures of primary osteoblast cells and osteoblast cell lines were used to simulate in vitro response in various cell-based assays xvi to measure cytotoxicity. These tests included lactate dehydrogenases (LDH) assays, live/dead assays to determine cell viability, and proliferation assays. LDH released from all MgO nanowire samples were close to the LDH released from the low control and much lower than high control. The low LDH release from the samples indicated the low cytotoxicity of MgO nanowire. Future work is needed to explore the possibility of growing MgO nanowires in existing and future implant material surfaces. It is also be desirable to test these nanowires in biosensor applications.

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