Abstract: A method of reducing viability of a microbe is provided. An illustrative method comprises contacting a microbe with an antimicrobial surface comprising a copper-alloy steel comprising an iron matrix and copper nanoprecipitates distributed throughout the iron matrix, wherein the copper-alloy steel comprises: Cu in a range from 0.5 weight % to 5.0 weight %; C in a range from 0.03 weight % to 0.10 weight %; Mn in a range from 0.20 weight % to 5.0 weight %; Ni in a range from 0.0 weight % to 6.0 weight %; Al in a range from 0.0 weight % to 4.0 weight %; Nb in a range from 0.0 weight % to 0.10 weight %; Si in a range from 0.0 weight % to 2.0 weight %; Mo in a range from 0.0 weight % to 2.0 weight %; Ti in a range from 0.0 weight % to 2.0 weight %; V in a range from 0.0 weight % to 2.0 weight %; Cr in a range from 0.0 weight % to 8.0 weight %; and a balance of Fe. The antimicrobial surfaces are also provided.