Group members discussing experimental results in the lab. Source: Laurent MekulGroup members discussing experimental results in the lab. Source: Laurent Mekul

A plethora of plastics in hospital settings pose an insidious health risk to patients. Bacteria are capable of surviving long enough on plastic tubes, devices and other surfaces to become infectious agents.

A preventive measure developed by researchers at the Swedish Medical Nanoscience Center at Karolinska Institutet uses a small electric current and silver nanoparticles to stem bacterial growth on conducting plastics.

An antimicrobial coating composed of silver nanoparticles and an electrically conducting polymer layer were tested against Staphylococcus aureus, a major colonizer of medical implants.

Applying tiny electrical currents to a conducting plastic surface with no antimicrobial coating had no effect on bacterial growth. Bacterial growth was reduced on a similar surface exposing an attached layer of silver, and application of a tiny electrical current to this surface enhanced the effect of attached silver nanoparticles, and the bacteria were completely destroyed.

“It’s a phenomenon known as the bioelectric effect, whereby electrical fields weaken bacterial cells against external attacks,” says PhD student Salvador Gomez-Carretero at Karolinska Institutet's Department of Neuroscience. “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.”

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