Silver and electricity can kill bacteria: Here’s how

Swedish researchers have developed a way to use silver nanoparticles and electrical currents to prevent bacteria from growing on plastic surfaces – helping to prevent hospital infections in the process.

Large electric currents and high silver concentrations are known to kill bacteria but pose a risk to humans. Before the Swedish Medical Nanoscience Center at Karolinska Institutet’s development, both components were never used in hospitals. Led by professor Agneta Richter-Dahlfors in Karolinska’s department of neuroscience, researchers were able to prove that dangerous levels of silver and electricity don’t have to be used to be effective in killing bacteria.

“By targeting the bacteria on several fronts at the same time, the effect of different small attacks becomes larger than when each factor is acting on its own,” Richter-Dahlfors said in a press release.

The researchers tested their theory on the common hospital pathogen Staphylococcus aureus. When they applied tiny electrical current to conducting plastic surfaces, there was no effect on bacterial growth. On another plastic surface with a layer of silver nanoparticles, bacteria growth was reduced. When they combined the two processes, bacteria growth was completely destroyed.

“It’s a phenomenon known as the bioelectric effect, whereby electrical fields weaken bacterial cells against external attacks,” Salvador Gomez-Carretero, a PhD student in Karolinska Institutet’s department of neuroscience, said. “We use electrical signals to increase the antimicrobial activity of the silver nanoparticles. This reduces the amount of silver needed, which is beneficial for both the patient and the environment.”

The researchers hope that their discovery will help keep surfaces in hospitals free of the dangerous bacterias that cause infections.

“It has not yet been tested in the clinic, but we believe this technology could be a good approach to limiting the spread of infectious bacteria and the incidence of hospital-acquired infections,” Richter-Dahlfors said.

The research was funded by the Swedish Research Council, Vinnova, Carl Bennet AB and the Swedish Medical Nanoscience Center and was published in the Advanced Healthcare Materials journal.

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