The e-scaffold reduced the bacterial population to 1/10,000th of its original size in 24 hours (before on the left, after on the right, scale rule is 50 µm).
Image credit: Washington State University
The team from Washington State University (WSU) in Pullman describes their electrochemical scaffold or "e-scaffold" approach to wound healing and how they tested it in the journal Scientific Reports.
They note that when they used the e-scaffold on a biofilm of the highly multi-drug-resistant Acinetobacter baumannii, it killed nearly all of the microbes within 24 hours. The bacterial population was reduced to 1/10,000th of its original size.
Also, when they tested the e-scaffold on pig tissue infected with A. baumannii, it killed most of the bacteria without damaging surrounding tissue.
A. baumannii is often implicated in difficult-to-treat biofilm infections on wound surfaces. If biofilms are not promptly removed from wounds, they can delay healing and chronic infection can set in.
Due to the rising problem of antibiotic resistance, there is an urgent need for alternatives. According to the Centers for Disease Control and Prevention (CDC), every year at least 2 million Americans become infected with antibiotic-resistant bacteria, and at least 23,000 of them die as a direct result of these infections.
Hydrogen peroxide attacks the biofilm
The idea of using electrical stimulation to treat infected wounds has been around for over 100 years, but experiments have been met with mixed results. One reason, suggests co-author Haluk Beyenal, a professor in chemical engineering and bioengineering, was a poor understanding about how electricity affects biological systems.
Prof. Beyenal says they are very excited by the progress they have made in this area:
"We have been doing fundamental research on this for many years, and finally, we are able to transfer it to technology."
He and his colleagues discovered that applying electrical stimulation to biofilm reduces dissolved oxygen to hydrogen peroxide at the electrode surface.
Hydrogen peroxide is a disinfectant that attacks various essential cell components in bacteria and other microbes.
The team then developed the e-scaffold made of conductive carbon fabric. Running electrical current through the device - which acts as an electronic Band Aid - produces a low and constant concentration of hydrogen peroxide that kills bacteria.
The method works, says Prof. Beyenal, because of the way it controls the electrochemical reactions.
Other attempts to develop scaffolds for wound dressing have been met with mixed results. These have used a chemical approach - using antibacterial compounds like silver, zinc, iodine or honey, note the authors. But the problem with these is that they lose potency over time.
The e-scaffold appears to meet the need for continuous delivery of an antimicrobial effect at a constant concentration for a significant length of time. The authors conclude:
"This research establishes a novel foundation for an alternative antibiotic-free wound dressing to eliminate biofilms."
The researchers have applied for a patent for the e-scaffold and plan to investigate its effects on other species of bacteria.
Scientists are exploring a variety of methods to address the rising problem of antibiotic resistance. For example, Medical News Today recently learned how the MRSA superbug might be defeated using a drug commonly used to treat breast cancer. A study in Nature Communications shows how tamoxifen - a drug used to treat hormone receptor-positive breast cancer - boosted the immune system to fight MRSA (methicillin-resistant Staphylococcus aureus) infection in mice.