Nano-structured surface engineering for biomedical implants

Understanding of cell-substrate interaction will help us to gain insight into differences in cell behaviour in vivo and in vitro. It will help attain our ability to elicit specific cell responses and to control the formation of tissue in contact with the medical implants. In vivo cells react to many chemical, physical and geometric cues within the extracellular environment. Clinical and experimental investigations have reported that manufactured micro-scale surface topographies have significant effects on cell adhesion, contact guidance, apoptosis, macrophage activation, gene expression and tissue integration. Some recent researches with nano-scale features have demonstrated interesting preliminary changes in cell behaviour. However, the constraints of prevailing nanofabrication methods greatly hinder the progress of this kind of studies. In our study, a sophisticated nanofabrication which offers various uniform nano-sized features in large assemblies on different materials with adjustable feature size and spacing is employed. The easy accessibility and low cost of this approach are important advantages to the future commercial application of this manufacturing technique. Anodized aluminium oxide (AAO) templates with a highly-ordered nanoporous surface structure have been employed to determine the influence of nanoengineered surface structures on cellular adhesion. The AAO templates were coated with alkanethiol based (terminal groups -CH3, -OH, and -COOH) self-assembled monolayers (SAMs). The results show changes in surface property of the nanostructured SAMs from that of similar studies conducted on planar samples. In addition, templates were also coated with calcium phosphate. This calcium phosphate mixture was created to replicate hydroyapatite, a calcium-phosphate mineral found in large quantities in bone. Osteoblasts adhesion and proliferation on those nanoengineered surfaces will be examined