Plasma treatment used to heal chronic wounds

An international team of scientists has developed new treatment for chronic wounds that does not involve antibiotics or silver-based dressings, but instead utilises an ionised gas called plasma.

Described in the journal Advanced Functional Materials, the treatment involves boosting the plasma activation of hydrogel dressings with a unique mix of different chemical oxidants that decontaminate and help heal chronic wounds. According to study leader Dr Endre Szili, from the University of South Australia (UniSA), the new method is “a significant breakthrough” that could revolutionise the treatment of diabetic foot ulcers and internal wounds.

“Antibiotics and silver dressings are commonly used to treat chronic wounds, but both have drawbacks,” Szili said. “Growing resistance to antibiotics is a global challenge and there are also major concerns over silver-induced toxicity. In Europe, silver dressings are being phased out for this reason.

“It is imperative that we find alternative treatments to antibiotics and silver dressings, because when these treatments don’t work, amputations often occur.”

The benefits of cold plasma ionised gas have already been proven in clinical trials, showing it not only controls infection but also stimulates healing. This is due to the potent chemical cocktail of oxidants — namely reactive oxygen and nitrogen species (RONS) — produced when it mixes and activates the oxygen and nitrogen molecules in the ambient air.

Szili and his colleagues have now shown that plasma-activating hydrogel dressings with RONS makes the gel far more powerful, killing common bacteria such as E. coli and P. aeruginosa that cause wounds to become infected. The researchers noted that the plasma-activated hydrogels might also help trigger the body’s immune system, which can help fight infections.

“Despite recent encouraging results in the use of plasma-activated hydrogel therapy (PAHT), we faced the challenge of loading hydrogels with sufficient concentrations of RONS required for clinical use,” Szili said. “We have overcome this hurdle by employing a new electrochemical method that enhances the hydrogel activation.”

While diabetic foot ulcers were the focus of the study, Szili said the PAHT technology could be used for treating all chronic wounds and internal infections. He added that, in future, plasma could even be used to treat cancerous tumours by activating drugs contained within gels injected into the body.

“The active ingredients could be delivered over a lengthy period, improving treatment, with a better chance of penetrating a tumour,” he said.

A final advantage of PAHT technology, according to Szili, is that it is “an environmentally safe treatment that uses the natural components in air and water to make its active ingredients, which degrade to non-toxic and biocompatible components”. The next step in its development will involve clinical trials to optimise the electrochemical technology for treatment in human patients.

“Plasma has massive potential in the medical world, and this is just the tip of the iceberg,” Szili said.

Image caption: A demonstration of how the plasma is administered to a hydrogel dressing to decontaminate and heal wounds. Image credit: University of South Australia.