2003 Volume 52 Issue 8 Pages 428-435
In order to make the clean antimicrobial surface using metals on which bacteria are too hard to cling and multiply, antimicrobial activity against Saccharomyces cerevisiae, Escherichia coli and Staphylococcus aureus placed on the plate surface of copper, silver and gold which belong to 1B family transition metals has been investigated. The results obtained are summarized as follows: The order of antimicrobial activity was copper>silver>>gold. Copper had the excelent antimicrobial activity against E. coli and S. cerevisiae. Silver had a strong antimicrobial activity against E. coli and a weak one against S. aureus. Gold had a scarce antimicrobial activity. The antimicrobial activity of copper ion against E. coli and S. aureus was weakly found but 640ppm copper ion of a large quantity caused the antimicrobial activity against except S. cerevisiae. 10ppm silver ion caused the antimicrobial activity against all bacteria tested. Contact of copper with E. coli produced a little amount of H2O2 which caused the antimicrobial activity as an oxidizing stress. The mechanism of antimicrobial activity of the surface of 1B family transition metal plates was supposed as following. The synergistic effects of both sterilization ability due to H2O2 produced in very short time from contact of bacteria with the surface of copper plate and oxidizing ability due to copper ion dissolved from the surface of copper plate caused the great antimicrobial activity of the surface of copper plate. Since the quantity of both H2O2 produced and silver ion dissolved from the surface of silver plate was a little, the sterilization ability and oxidizing ability due to silver ion were not so strong as copper's. Consequently, the antimicrobial activity of silver became weaker than copper's. H2O2 produced scarcely from the surface of gold plate and gold did not dissolve at all, so that the sterilization ability and the oxidizing ability did not generate.