1. EC-Joint Research Centre-IHCP, Biomedical Materials and Systems Unit, 21020 Ispra, Varese, Italy, University of Toronto, Department of Chemical Engineering and Applied Chemistry, 200 College Street, Toronto, Ontario M5S 3E5, Canada, Innoval Technology, Beaumont Close, Banbury OX16 1TQ, U.K., and Laboratory of Biophysics and Surface Analysis, School of Pharmacy, University of Nottingham NG7 2RD, U.K.