The superbug-destroying coating was developed by researchers at RMIT University in Melbourne, Australia.
The material is reportedly one of the thinnest antimicrobial coatings developed to-date, and is effective against a broad range of drug-resistant bacteria and fungal cells while leaving human cells unharmed.
Antibiotic resistance is a major global health threat, causing at least 700,000 deaths a year. Without the development of new antibacterial therapies the death toll could rise to 10m people a year by 2050, the researchers said, equating to $100tn in healthcare costs.
While the health burden of fungal infections is less recognised, globally they kill about 1.5m people each year and the death toll is growing. An emerging threat to hospitalised Covid-19 patients, for example, is the common fungus Aspergillus, which can cause deadly secondary infections.
The new coating is based on an ultra-thin ‘2D’ material that until now has mainly been of interest for next-generation electronics. Studies on black phosphorus (BP) indicated it has some antibacterial and antifungal properties, but the material was not previously methodically examined for potential clinical use.
The research, published in the American Chemical Society's journal Applied Materials & Interfaces, revealed that BP is effective at killing microbes when spread in ‘nanothin’ layers on surfaces like titanium and cotton, used to make implants and wound dressings.
Co-lead researcher Dr Aaron Elbourne said finding one material that could prevent both bacterial and fungal infections was a significant advance.
“These pathogens are responsible for massive health burdens and as drug-resistance continues to grow, our ability to treat these infections becomes increasingly difficult,” said Elbourne.
“We need smart new weapons… which don't contribute to the problem of antimicrobial resistance. Our nanothin coating is a dual bug killer that works by tearing bacteria and fungal cells apart, something microbes will struggle to adapt to. It would take millions of years to naturally evolve new defences to such a lethal physical attack.
“While we need further research to be able to apply this technology in clinical settings, it's an exciting new direction in the search for more effective ways to tackle this serious health challenge.”
As BP breaks down, it oxidises the surface of bacteria and fungal cells. This process, known as cellular oxidisation, ultimately works to rip them apart.
In the new study, first author and PhD researcher Zo Shaw tested the effectiveness of nanothin layers of BP against five common bacteria strains, including E. coli and drug-resistant MRSA, as well as five types of fungus, including Candida auris.
In just two hours, up to 99% of bacterial and fungal cells were destroyed. The BP also began to self-degrade in that time and was entirely disintegrated within 24 hours – “an important feature that shows the material would not accumulate in the body,” a research announcement said.
The study identified the optimum levels of BP for destroying microbes while leaving human cells healthy and whole.
The researchers are now experimenting with different formulations to test the efficacy on a range of medical surfaces.
The team is keen to collaborate with potential industry partners to further develop the technology, for which a provisional patent application has been filed.
Researchers at RMIT University have previously studied and mimicked the surface of insect wings,
which can also destroy bacterial cells.
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