Liquid metal takes on bacteria

Australian researchers are using liquid metals to develop a “bacteria-destroying” technology they hope will be the answer to antibiotic resistance.

It works by shredding bacteria and the bacterial biofilm in which they thrive without harming good cells, the team from RMIT University reports in a paper in the journal ACS Nano.

When exposed to a low-intensity magnetic field, tiny droplets of liquid metal change shape and develop sharp edges. When placed in contact with a bacterial biofilm, these edges break down the biofilm and physically rupture the bacterial cells.

In their study, the researchers tested the effectiveness of the approach against two types of bacterial biofilms (Gram-positive and Gram-negative).

After 90 minutes of exposure, both were destroyed and 99% of the bacteria were dead, they report. Importantly, laboratory tests showed the droplets did not affect human cells.

Co-author Aaron Elbourne, from RMIT’s Nanotechnology Laboratory, says the spread of drug-resistant superbugs and the growth of bacterial biofilm infections that can no longer be treated with existing antibiotics is a global health issue.

As such, we need to rethink how we fight bacterial infections.

“Bacteria are incredibly adaptable and over time they develop defences to the chemicals used in antibiotics, but they have no way of dealing with a physical attack,” he says.

“Our method uses precision-engineered liquid metals to physically rip bacteria to shreds and smash through the biofilm where bacteria live and multiply.”

Colleague Vi Khanh Truong says the technology is versatile and potentially could be used in a range of ways to treat infections.

“It could be used as a spray coating for implants, to make them powerfully antibacterial and reduce the high rates of infection for procedures like hip and knee replacements,” he says.

“There’s also potential to develop this into an injectable treatment that could be used at the site of infection.”

The next stage for the research – testing the effectiveness of the technology in pre-clinical animal trials – is underway.

The team also plans to explore how it could be adapted for other uses, such as treating fungal infections, breaking through cholesterol plaques or being injected directly into cancer cells.

The work involves collaboration with researchers from the CSIRO and the ARC Centre of Excellence in Convergent Bio-Nano Science and Technology in Australia, and North Carolina State University in the US.

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