Microwave sterilisation

Researchers at Glyndŵr University in Wrexham have developed technology for producing a portable device for sterilising medical equipment – using a £40 microwave oven.

The kitchen device provided the solution to efforts by a team of researchers, led by senior research scientist Dr Andy Wright, to come up with a low-cost, chemical-free solution to killing harmful bacteria on medical tools used in GP, dentist and veterinary surgeries.

Traditionally, steam at high temperatures has been used to sterilise medical instruments before being used on patients. However, with bacteria becoming more resistant to such treatments, aggressive chemicals have increasingly been used in recent years.

Now, researchers at the university’s Advanced Materials Unit have discovered that by attaching a vacuum vessel to a microwave oven, plasma discharges can be generated in the form of atomic oxygen and ozone – both aggressive gases that are highly effective in killing bacteria.

Dr Wright said that tests have shown the technology to be just as effective as existing steam-based methods of sterilisation – if not more – but at a fraction of the cost. The device is capable of sterilising equipment in five minutes or less with air.

He added: ’The oven we chose is the simplest type commercially available and with the modifications we made, the cost of the system comes to less than £2,000. The most reliable sterilisation systems currently cost around £70,000, making this very cost effective.’

The technology now exists for hospitals, surgeries and dentists to move away from steam-based sterilisation methods and take up a plasma-based approach that has been shown to be 100 per cent effective against the most difficult pathogens.

’However, one of the main advantages is its small size and low weight. It means it can also be easily used by military field hospitals when coupled with a small portable generator. Thus, instruments do not have to be sent away for treatment and the cost of using disposable items can be reduced,’ said Dr Wright.