The present work was carried out during the period of July 2004 to the present year. Several persons have directly or indirectly contributed in my work, and I would like to thank them all, with special acknowledgements to the following people: My academic supervisor, Associate Professor Daniel Lim Chu Sing, School of Chemical and Biomedical Engineering (SCBE), Nanyang Technological University (NTU), gave me the idea of combining both the areas of pharmaceutical sciences and biosensor work in my research. I particularly enjoyed our scientific discussions which provided me with insights and inspirations for new ideas in my research.