[9YearLurker]

Looks like gold is antibacterial, at least, too:

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3405418/

[unread]

"Looks like gold is antibacterial, at least, too:"

"In conclusion, we have demonstrated that gold and silver nanoparticles display excellent antibacterial potential for the Gram negative bacteria E. coli and the Gram positive bacteria BCG. These NPs display their best performance when aggregation is not observed at high levels. By changing surface modifications agents, gold NPs with the same shape and size exhibited different inhibitory effects. Our mechanistic analyses indicated that PAH capped gold NPs caused cell lysis, while citrate capped gold NPs did not. Strong antibacterial activities were observed for silver NPs due to their inherent elemental properties. In terms of anti-TB drug development, this study suggests that NPs may represent useful candidates, but will require significant development to ensure optimal bactericidal activity and low host toxicity."

Well, it would certainly seem so... :)

[Ozark Tom]

Any material reduced to the nanoparticle scale has different properties than a larger sample. If in bulk form it does not chemically react in ambient conditions (tarnish, patina, oxidation) it is less likely to be antimicrobial. Oxygen interaction with a metal may be the key.