Bacteria are a huge problem in hospitals, where colonies can build up on instruments and cause potentially fatal infections in vulnerable patients. Now, researchers at Aston University have developed a new type of antimicrobial material that's made using a centuries-old stained glass technique.

The old phrase says that "prevention is better than a cure," and that counts double for bacterial infections. Once a colony builds a biofilm it's tough to get through it, and bugs are quickly evolving resistance to our best antibiotics. We might have more luck if we work to prevent them taking hold in the first place.

The Aston team's new antimicrobial material is built around a substance known as bioactive glass. This stuff is made up of glass laced with different metals, which release ions at a steady rate. Different bioactive glass mixtures have been found to help kill bacteria as well as promote new bone growth, with recent experiments showing they might be useful in dental fillings or bone implants that fight off infection.

There are several different forms of bioactive glass, and the Aston team developed a new recipe for this work. It's made using glass laced with cobalt, which is fired in a furnace to over 1,000° C (1,832° F), in a method that's similar to those used since the Middle Ages to produce stained glass. The glass is then cooled quickly enough that it doesn't crystallize, and finally ground up into a fine powder.

The team tested different mixtures of bioactive glass with varying cobalt concentrations, adding it to petri dishes full of bacteria. The bioglass with the highest amount of cobalt was found to completely wipe out a population of E. coli within six hours, and Candida alibicans in 24 hours. Similar effects were seen on Staphyloccus aureus, killing 99 percent of the bacteria within 24 hours.

The researchers found that the bacteria were killed by contact with the metal ions in the glass, which breaks down their cell walls. As an added bonus, these ions were found to leach out and kill bacteria that wasn't in direct contact with the material. This is the first study on bioactive glass made with cobalt, but similar antibacterial effects have been found with other versions of the material.

This bioactive glass is a potential weapon against antibiotic-resistant bacteria, and prevent the spread of further resistance. The researchers say it could be used to stave off infection directly at a surgical site, or even built into cartridges that are placed in catheters to prevent bacteria spreading upwards and causing urinary tract infections.

"These glasses provide localized delivery at the surgical site to stop infections from forming in the first place," says Richard Martin, lead researcher on the study. "Once an infection has had time to establish itself it is much harder to treat, because complex bacterial biofilms start to form which are much tougher to tackle. With the rise of antimicrobial resistance, these glasses have the potential to radically transform how we guard against common hospital infections, because if we can stop the bacteria from multiplying it negates the need for heavy doses of antibiotics."

The research was published in the journal ACS Biomaterials.