Effect of Silver Nanoparticles on Common Bacteria in Hospital Surfaces
In this clinical study, published in June 2013 and titled “Effect of Silver Nanoparticles on Common Bacteria in Hospital Surfaces,” researchers from the Infectious and Tropical Diseases Research Center, University of Medical Sciences, Ahvaz, Iran, tested three different concentrations of silver nanoparticles – 100 ppm, 200 ppm and 300 ppm – on surface colonies of infectious microbes including MRSA, Pseudomonas aeuroginosa and Bacillus cereus.
According to the study authors, each of the three dilutions of silver nanoparticles were able to produce “more than a 99 percent reduction” in bacterial surface contamination. While it took longer for the more dilute preparations to work, there were “no remarkable differences” between the three “when tested at 5,15, 30 and 60 minute disinfection intervals.” The researchers concluded: “Silver nanoparticles had appropriate effects in all three types of dilutions…After five minutes all disinfectants reduced the S. aureus colony count significantly (more than 99%), but none of them could bring the S. aureus colony count to zero. This rate was achieved following 30 minutes of disinfection with 300 ppm silver nanoparticles…For two other dilutions of silver nanoparticles, this rate was possible after 60 minutes of disinfection.”
In short, whereas other clinical studies have demonstrated lower concentrations of silver nanoparticles to reduce bacterial count on hospital surfaces to zero after 24 to 48 hours, this study demonstrated that concentrations of 100 ppm, 200 ppm and 300 ppm silver nanoparticles could reduce the bacterial count by 99% after just five minutes of application, with a full 100% reduction in bacterial count being achieved within 30 minutes when using the 300 ppm nanosilver, and after one hour when using the 100 ppm and 200 ppm nanosilver.
