Engineers Kill Superbugs with Star-Shaped Polymers

Peptide polymers used to destroy antibiotic-resistant bacteria.

A bacteria cell before (left) and after (right) treatment with the star-shaped polymers. (Image courtesy of University of Melbourne.)

A bacteria cell before (left) and after (right) treatment with the star-shaped polymers. (Image courtesy of University of Melbourne.)

A team of engineers has demonstrated that tiny, star-shaped molecules are effective at killing bacteria that can no longer be killed by current antibiotics.

The research, published in Nature Microbiology, holds promise for a new treatment method against antibiotic-resistant bacteria, more commonly known as superbugs. The star-shaped structures are short chains of proteins called ‘peptide polymers’, and were created by a team from the Melbourne School of Engineering.

“It is estimated that the rise of superbugs will cause up to ten million deaths a year by 2050. In addition, there have only been one or two new antibiotics developed in the last 30 years,” said professor Greg Giao of the department of chemical and biomolecular engineering.

Professor Qiao and his team have been working with peptide polymers in the past few years. Recently, the team created a star-shaped peptide polymer that was extremely effective at killing Gram-negative bacteria – a major class of bacteria known to be highly prone to antibiotic resistance – while being non-toxic to the body.

The star-shaped polymer (green) surrounding and ripping apart bacterial cells. (Image courtesy of the University of Melbourne.)

The star-shaped polymer (green) surrounding and ripping apart bacterial cells. (Image courtesy of the University of Melbourne.)

Moreover, tests undertaken on red blood cells showed that the star-shaped polymer dosage rate would need to be increased by a factor of greater than 100 to become toxic. The star-shaped peptide polymer is also effective in killing superbugs when tested in animal models. Superbugs showed no signs of resistance against these peptide polymers.

The team discovered that their star-shaped peptide polymers can kill bacteria with multiple pathways, unlike most antibiotics which kill with a single pathway. They believe that this accounts for the superior performance of the star-shaped peptide polymers over antibiotics.

One of these pathways includes ‘ripping apart’ the bacteria cell wall. While more research is needed, Professor Qiao and his team believe that their discovery is the beginning of unlocking a new treatment for antibiotic-resistant pathogens.

For more from the world of biomolecular engineering, find out how engineers target cancerous tumors with nanobots.