Super vs star - Killing superbugs with star-shaped polymers
It is estimated that antibiotic resistance will cause up to ten million deaths a year by 2050. In addition, there have only been one or two new antibiotics developed since 30 years ago.
But researchers from the Melbourne School of Engineering have discovered a way to use chemistry to mimic biology to create new structures inspired by small
protein molecules produced by the body to fight against bacterial invasion.
Professor Greg Qiao and PhD candidate Shu Lam, from the Department of Chemical and Biomolecular Engineering have been working with Associate Professor
Neil O’Brien-Simpson and Professor Eric Reynolds from the Melbourne Dental School and Bio21 to build small protein molecules or Peptide polymers to
fight against bacterial infections.
Published today in Nature Microbiology, Professor Qiao said that currently the only treatment for infections caused by bacteria and superbugs
“The problem with this is that over time bacteria mutate to protect themselves against antibiotics, making treatment ineffective,” he said.
Professor Qiao and his team have been working with antimicrobial peptide polymers made from amino acids. Through this work, the team discovered an unexpected
property of the polypeptides they have been working with.
The team created a star-shaped polypeptide that was extremely effective at killing Gram-negative bacteria – a major class of bacteria known to be highly
prone to antibiotic resistance.
Traditional antimicrobial peptides (AMPs) are made from linear, short sequenced amino acids. While most AMPs kill bacteria, they are also very toxic to the body and will kill the host as well.
In vitro studies were undertaken and the star-shaped peptide polymer’s ability to kill superbugs was found to be better than that of antibiotics and linear
AMPs, with the added benefit of being non-toxic to human cells.
In fact, tests undertaken on red blood cells showed that the star-shaped polymer dosage rate would need to be increased by a factor of > 100 to become
In vivo tests using animal models have also shown that the star-shaped polymer is not only as effective in killing bacteria as antibiotics, but after bugs were mutated and antibiotics stopped working, they were still highly effective.
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
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