The researchers from the Swedish Medical Nanoscience Center at Karolinska Institute reported that conducting plastics found in smartphone screens could be used to trick the pathogenic bacterial metabolism. The study was published in the scientific journal npj Biofilms and Microbiomes. Addition or removal of electrons from the plastic surface could trick the bacteria to grow more or less. The method could support to prevent bacterial infections in hospitals or improve effectiveness in wastewater management.

Bacterial growth rapidly increased when attached to a surface and formed a thick film known as a biofilm. The films were unsafe in hospitals where they could cause life-threatening infections. Scientists aimed to address the problem by producing coatings for medical devices made from a cheap conducting plastic called poly(3,4-ethylene dioxythiophene) PEDOT, which made smartphone screens respond to touch. When a small voltage was applied, the PEDOT surface was either flooded with electrons or left almost empty and turned affected the Salmonella bacterial growth.

The principal investigator of the study, Agneta Richter-Dahlfors said, "When the bacteria land on a surface full of electrons, they cannot replicate. They have nowhere to deposit their electrons which they need to do to respire. With the electrons being continually sucked out of the surface, bacteria could continually deposit their electrons, giving them the energy they needed to increase."

In contrast, when the bacteria encountered an empty surface they grew into a thick biofilm, she added.

Thus, the researchers could either abolish bacterial growth or let it continue more effectively, which could have many implications for both health and industry.

Richter-Dahlfors said that coating of medical devices with the material made them more resistant to colonization by bacteria. "However, if we look to industries like wastewater management that need a lot of beneficial biofilms to create clean water, we can produce surfaces that will promote biofilm production," she continued.

Further research would incorporate the technology into devices that could be implanted into patients to keep them safe when undergoing medical procedures or having devices implanted. Redox-active conducting polymers modulate Salmonella biofilm formation by controlling the availability of electron acceptors.