Researchers discover self-sterilizing polymer effective against drug-resistant pathogens

Researchers from North Carolina State University have found that an elastic polymer possesses broad-spectrum antimicrobial properties. This allows it to kill a range of viruses and drug-resistant bacteria in just minutes, including methicillin-resistant Staphylococcus aureus (MRSA).

The polymer’s antimicrobial properties stem from its unique molecular architecture, which attracts water to a sequence of repeat units that are chemically modified with sulfonic acid groups.

The polymer has been tested against six types of bacteria, including three antibiotic-resistant strains: MRSA, vancomycin-resistant Enterococcus faecium, and carbapenem-resistant Acinetobacter baumannii.

The polymer killed 99.9999 per cent of each strain of bacteria within five minutes, when 40 per cent or more of the relevant polymer units contain sulfonic acid groups.

Researchers also tested the polymer against three viruses which included an analog virus for rabies, a strain of influenza and a strain of human adenovirus.

“The polymer was able to fully destroy the influenza and the rabies analog within five minutes,” explained Frank Scholle, an associate professor of biological sciences at NC State and co-author of the paper.

“While the polymer with lower concentrations of the sulfonic acid groups had no practical effect against human adenovirus, it could destroy 99.997% of that virus at higher sulfonic acid levels.”

One concern of the researchers was that the polymer’s antimicrobial effect could progressively worsen over time, as sulfonic acid groups were neutralized when they interacted with positively charged ions in water.

However, they found that the polymer could be fully “recharged” by exposing it to an acid solution.

Reza Ghiladi, an associate professor of chemistry at NC State and co-corresponding author of the paper, said: “The work we’ve done here highlights a promising new approach to creating antimicrobial surfaces for use in the fight against drug-resistant pathogens – and hospital-acquired infections in particular.”

Rich Spontak, co-corresponding author of a paper on the work and Distinguished Professor of Chemical and Biomolecular Engineering at NC State, added: “What we found is extremely promising as an alternate weapon to existing materials-related approaches in the fight against drug-resistant pathogens. This could be particularly useful in clinical settings – such as hospitals or doctor’s offices – as well as senior-living facilities, where pathogen transmission can have dire consequences.”

“Functional block polymers like this are highly versatile and environmentally benign since they can be readily recycled and re-used.”

The paper, “Inherently self-sterilizing charged multiblock polymers that kill drug-resistant microbes in minutes,” appears in the journal Materials Horizons.