The research presented in this thesis investigates the potential for sputter deposited titanium and calcium phosphate thin films, singularly and in combination, to directly induce osteogenic differentiation in human bone marrow derived mesenchymal stem cells (MSCs). The nature and scale of these substrate driven effects have been compared with osteogenesis induced in MSCs by exposure to biochemical stimulants in the culture media. MSCs hold great promise for use in bone tissue engineering applications, therefore the provision of biomaterials that can direct the osteogenic differentiation of MSCs has significant implications for improving the repair or replacement of damaged or lost bone tissue. RF magnetron sputter deposition was used to create titanium and calcium phosphate thin films from titanium metal and hydroxyapatite powder targets respectively. The distinct chemical and topographical surface properties of each substrate were confirmed using XPS, FTIR, XRD, AFM and water contact angle analysis. The commercially obtained MSCs used for this work were characterised in detail to provide a benchmark data set for correlation with subsequent thin film substrate studies. To determine the previously unreported effects that these types of sputter deposited surfaces have on MSC behaviour, a range of relevant biological assays and detailed quantitative real time PCR gene expression studies were used. In this way, a comprehensive profile of MSC response to each type of surface condition was obtained over an in vitro culture period of up to 28 days. Early stage adhesion and morphology was also examined in order to attain a better understanding of the underlying mechanisms of the attendant MSC behaviour. All of the sputter deposited thin film surfaces directly promoted significant levels of osteogenic differentiation, to varying degrees, without the use of biochemical stimulants. This work shows for the first time, that the topography of the sputtered titanium coatings and the bioactive chemistry of the calcium phosphate coatings can individually direct the differentiation of MSCs towards an osteogenic lineage.
| Identifer | oai:union.ndltd.org:bl.uk/oai:ethos.bl.uk:558775 |
| Date | January 2012 |
| Creators | McCafferty, Mura |
| Publisher | University of Ulster |
| Source Sets | Ethos UK |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
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