Material can kill E. Coli bacteria in just 30 seconds

Professor Jackie Y. Ying, Executive Director, IBN, A*STAR, commented: "The global threat of drug-resistant bacteria has given rise to the urgent need for new materials that can kill and prevent the growth of harmful bacteria. Our new antimicrobial material could be used in consumer and personal care products to support good personal hygiene practices and prevent the spread of infectious diseases."

Triclosan, a common ingredient found in many products such as toothpastes, soaps and detergents to reduce or prevent bacterial infections, has been linked to making bacteria resistant to antibiotics and adverse health effects. The EU has restricted the use of triclosan in cosmetics (Scientific Committee on Consumer Safety of the European Commission: "Opinion on Triclosan Antimicrobial Resistance: 5.1 Triclosan in cosmetics") while the U.S. Food and Drug Administration is conducting an on-going review of this ingredient (U.S. Food and Drug Administration website: "Triclosan: What Consumers Should Know").

Driven by the need to find a more suitable alternative, IBN Group Leader Dr Yugen Zhang and his team synthesised a chemical compound made up of molecules linked together in a chain. Called imidazolium oligomers, this material can kill 99.7% of the E. coli bacteria within 30 seconds aided by its chain-like structure, which helps to penetrate the cell membrane and destroy the bacteria. In contrast, antibiotics only kill the bacteria without destroying the cell membrane. Leaving the cell structure intact allows new antibiotic-resistant bacteria to grow.

"Our unique material can kill bacteria rapidly and inhibit the development of antibiotic-resistant bacteria. Computational chemistry studies supported our experimental findings that the chain-like compound works by attacking the cell membrane. This material is also safe for use because it carries a positive charge that targets the more negatively charged bacteria, without destroying red blood cells," said Dr Zhang.

The imidazolium oligomers come in the form of a white powder that is soluble in water. The researchers also found that once this was dissolved in alcohol, it formed gels spontaneously. This material could be incorporated in alcoholic sprays that are used for sterilisation in hospitals or homes.

E. coli is a type of bacteria found in the intestines of humans and animals and some strains can cause severe diarrhea, abdominal pain and fever. Such infection is contagious and can spread through contaminated food or water, or from contact with people or animals. Good hygiene practices and proper food handling can prevent E. coli infections.

Besides E. coli, IBN's material was also tested against other common strains of antibiotic-resistant bacteria and fungi, such as Staphylococcus aureus, Pseudomonas aeruginosa and Candida albicans. These pathogens can cause conditions ranging from skin infections to pneumonia and toxic shock syndrome. The material was able to kill 99.9% of these microbes within two minutes.

The ultrafast bacteria-killing material could therefore be a potent new weapon against drug-resistant microbes.

The full paper can be read here.