Antimicrobial coating using copper-doped diamond-like carbon film deposited by dual magnetron sputtering

Copper-doped diamond-like carbon (Cu-DLC) film was deposited using dual magnetron sputtering to develop an antimicrobial coating. The Cu content in the DLC film ranged from 0.3 at% to 40 at% by varying the duty ratio of the pulsed voltage applied to the copper target. The graphite structure (sp(2) bond) in the Cu-DLC film increased with increasing Cu content. The antimicrobial effect of Cu-DLC on Escherichia coli was examined by the colony-count method. E. coli was inactivated at a Cu content of 0.3 at% and the inactivation rate increased with increasing Cu content. This antimicrobial effect was obtained while maintaining hardness at a low Cu content using dual magnetron sputtering.