Now more than ever we are all thinking about germs. Germs, microbes, bacteria, viruses – it’s a constant mind-loop. Well, scientists from the University of Arkansas have also had bacteria on their minds; bacteria, and more specifically, what kills bacteria: silver.
While the antimicrobial properties of silver are not a recent discovery, understanding exactly how silver kills bacteria is still somewhat of a secret. In order to crack that code, U of Arkansas researchers used an advanced imaging technique, called single-particle-tracking photoactivated localization microscopy.
Their findings, published in the journal Applied and Environmental Microbiology, describe how proteins in live bacteria interact with silver on a molecular level. "It is known that silver ions can suppress and kill bacteria; we thus expected that everything slowed down in the bacteria when treated with silver. But, surprisingly, we found that the dynamics of this protein became faster," commented said one of the authors of the study, Yong Wang, who is an assistant professor of physics.
In looking at the dynamic of proteins in E. coli bacteria, the researchers discovered that silver ions triggered the separation of the bacteria’s paired strands of DNA and weakened the binding between the protein and the DNA.
"Then the faster dynamics of the proteins caused by silver can be understood," said Wang. "When the protein is bound to the DNA, it moves slowly together with the DNA, which is a huge molecule in the bacteria. In contrast, when treated with silver, the proteins fall off from the DNA, moving by themselves and thus faster."
The knowledge garnered from this study can be applied in future efforts using silver nanoparticles to fight superbugs. "What we want to do eventually is to use the new knowledge generated from this project to make better antibiotics based on silver nanoparticles," concluded Wang.