A method of reducing or preventing bacterial growth on a substrate, wherein the method comprises the following steps: a. providing a substrate base, wherein said substrate base comprises an electron donating surface and b. depositing metal particles from a suspension of metal particles, at an amount of about 0.001 to about 8 µg/cnr on said surface wherein said metal particles comprise palladium and at least one non-palladium metal selected from the group consisting of gold, ruthenium, rhodium, osmium, iridium, and platinum, wherein said metal particles have an average size of about 100 to about 10,000 A, wherein said particles are distributed particles or clusters on said surface, and wherein the metal particles do not form a covering layer.
