Treating surfaces to enhance bio-compatibility

A metal, glass or ceramics article, for example a stent, having at its surface oxide or hydroxide is treated to enhance the biocompatibility and/or physical characteristics of the surface. The surface is de-greased and primed by contact with an alkoxysilane in a aprotic organic solvent in the presence of an acid catalyst so that the alkoxysilane molecules react with the oxide or hydroxide of said surface to form covalent bonds, the alkoxysilane further comprising one or more amino, hydroxyl, carboxylic acid or acid anhydride groups. A polymer, e.g. carbodymethyl cellulose, is then covalently coupled to said surface via said amino, hydroxyl, carboxylic acid or acid anhydride groups, after which biologically active materials may be coupled to the polymer. Such materials may include an anti-coagulating agent or anti-platelet agent and an agent that inhibits smooth cell proliferation and restenosis.