Toxicity of hydrogen peroxide produced by electroplated coatings to pathogenic bacteria

The ability of various electroplated coatings (cobalt, zinc, copper, and cobalt-containing alloys of nickel, zinc, chromium, etc.) to inhibit the growth of pathogenic bacteria (Gram-positive bacteria Enterococcus faecalis and methicillin-resistant Staphylococcus aureus and Gram-negative bacteria Escherichia coli, Pseudomonas aeruginosa, and Klebsiella pneumoniae) was determined by a drop-method antibacterial experiment. The amounts of H₂O₂ produced and metal ions dissolved from the surfaces of various electroplated coatings were measured and it was found that the inhibitory ability of coatings corresponded to the amounts of H₂O₂ produced. The more significant the inhibition of the coating to bacterial growth, the greater the amount of H₂O₂ production. In addition, the bacterial survival rates on the surfaces of coatings were almost zero when H₂O₂ was produced in amounts greater than 10^-6 mmol/cm². However, the dominant concentrations of metal ions dissolved from coatings were outside of the bacterial lethal range.