Experimental Evolution of Silver Nanoparticle Resistance in Escherichi

The recent exponential increase in the use of engineered nanoparticles (eNPs) means both greater intentional and unintentional exposure of eNPs to microbes. Intentional use includes the use of eNPs as biocides; unintentional exposure results from the fact that eNPs are included in a variety of commercial products (paints, sunscreens, cosmetics.) Many of these eNPs include heavy metals or metal oxides such as titanium dioxide, silver, gold, zinc and zinc oxide. The fact that early studies of the impact of metallic nanoparticles achieved approximately 90% lethality to Ag, Cu eNPs, suggests that genetic variants are already circulating in bacteria that can be co-opted to provide heavy metal eNP resistance.