There is disclosed a substrate with an electron donating surface, characterized in having metal particles on said surface, said metal particles comprising palladium and at least one metal selected from the group consisting of gold, ruthenium, rhodium, osmium, iridium, and platinum, wherein the amount of said metal particles is from about 0.001 to about 8 μg/cm2. Examples of coated objects include contact lenses, pacemakers, pacemaker electrodes, stents, dental implants, rupture nets, rupture mesh, blood centrifuge equipment, surgical instruments, gloves, blood bags, artificial heart valves, central venous catheters, peripheral venous catheters, vascular ports, haemodialysis equipment, peritoneal dialysis equipment, plasmapheresis devices, inhalation drug delivery devices, vascular grafts, arterial grafts, cardiac assist devices, wound dressings, intermittent catheters, ECG electrodes, peripheral stents, bone replacing implants, orthopaedic implants, orthopaedic devices, tissue replacing implants, intraocular lenses, sutures, needles, drug delivery devices, endotracheal tubes, shunts, drains, suction devices, hearing aid devices, urethral medical devices, and artificial blood vessels.