Treating metal surfaces to enhance bio-compatibility and/or physical characteristics

Abstract

A metal, glass or ceramics surface is treated to enhance its compatibility with biological material such as blood or blood related products. Treatment involves covalently bonding to the surface by means of a catalyst functional molecules each of has at least one alkoxysilane group which can form at least one first covalent bond by reaction with the oxide or hydroxide of said surface and at least one other group which can participate in free-radical polymerisation. Free-radical polymerisation from said functional molecules is then effected to build bio-compatible and/or hydrophilic polymer chains. The compatibility of the metal surface with biological material may be further improved by bonding bio-active molecules, such as heparin or heparin derived molecules to the polymer chains. Suitable metal surfaces are those of medical devices such as heat exchangers, coronary and peripheral stents and guide wires used in angioplasty. In the case of a stent, restenosis may be inhibited by incorporating into the coating a radio-labelled compound, foe example radio-labelled heparin and/or by incorporating a compound that inhibits cell proliferation e.g. mitoxantrone.