Nanotech Layer Placed On Wound Dressings Kills Antibiotic-Resistant Bacteria With 99% Effectiveness

Despite stark warnings from microbiologists for the last decade, the world is still far too reliant on antibiotics. From prescribing them for diseases that aren’t bacterial, to pumping livestock to increase survival rates, antibiotic misuse and overuse is resulting in the emergence of bacterial species that can shrug off most current drugs we have. These "superbugs", or antibiotic-resistant bacteria, require intense monitoring to combat, and scientists are scrambling to create new drugs and therapies that can reliably kill them.

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In a new study released by RMIT University, Australia, researchers have created an innovative new nanotech coating that can fight off resistant strains of bacterial and fungal infection whilst leaving the human cells healthy. They believe their new material could be used on wound dressings and implants to protect against infection, and it may even self-degrade without the need to remove the coating once healed.

The new technology could provide a new tool in hospitals’ arsenal to stave off resistant infections, without creating new resistant strains in the process. Their findings were published in the journal Biological and Medical Applications of Materials and Interfaces.

"We need smart new weapons for the war on superbugs, which don't contribute to the problem of antimicrobial resistance,” Aaron Elbourne, a Postdoctoral Fellow in the School of Science at RMIT, explained in a statement.

"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 defenses to such a lethal physical attack.”

The nanotech layer comprises a few layers of wafer-thin black phosphorus, a stable allotrope of phosphorus that has previously been shown to have antibiotic properties. However, working with black phosphorus is no easy feat – it breaks down in the presence of oxygen. As it does so, it generates something called reactive oxygen species (ROS), which are bad news for bacteria. When a bacterial cell contacts a ROS, it rips electrons from the molecules in the bacteria’s cellular structures, disrupting its protective shell and essentially ripping apart the bacteria. This is called cellular oxidation, and is a rapidly emerging method of destroying bacteria.

A fungal cell (green) interacting with a nanothin layer of black phosphorous (red).​

In this study, the researchers demonstrated black phosphorus, which has never been used in a medical setting, is capable of being made into a thin layer that kills resistant infections, including the most well-known strain, MRSA. In just 2 hours, the layer killed 99 percent of all bacterial and fungal cells, and fully degraded in 24 hours.

This is very promising, but currently still purely a proof-of-concept, with many refining stages and clinical tests before it could be rolled out to patients. It is currently unknown exactly how much black phosphorus is required, and it is only in recent literature that large-scale nanothin production of the material is described. The researchers now aim to further their work and look for opportunities to bring it to industry.

"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," said Elbourne.

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