High-power Ultrasound KO’s Bacteria

Currently used for applications such as cell disruption and particle size reduction, high-power ultrasound has been shown to be 99.99% effective in killing bacterial spores after only 30 seconds of non-contact exposure.

Researchers at Penn State University and Ultran Labs, Boalsburg, Pa., say that their experiments are the first to show that non-contact ultrasound (NCU) can knock out bacterial spores. Their findings are especially significant, coming at a time of increased security concerns. The researchers suggest that it would be an ideal way to decontaminate mail packages, because ultrasound waves can penetrate cardboard and other wrappings, just as they do layers of skin and tissue when used to image internal body organs.

Researchers suggest another use that will come readily to the minds of mechanical engineers — building air duct sterilization.

In the experiments, bacterial spores contained in a paper envelope were placed 3 mm above the active area of a specially equipped source of inaudible, high-frequency sound waves and hit for 30 seconds. There was no contact medium, such as water or gel, between the ultrasound source and spores, as is typically the case with low-power medical ultrasound.

Team member Dr. Kelli Hoover, assistant professor of entomology, explains that the team used bacillus thuringiensis (Bt) spores rather than deadly anthrax. Bt is a commercial insecticide and a close cousin of anthrax. “They differ by only a few genes,” she says.

A patent, “Gas Contact Ultrasound Germicide and Therapeutic Treatment,” is pending on the technique.

Do you have experience and expertise with the topics mentioned in this content? You should consider contributing to our CFE Media editorial team and getting the recognition you and your company deserve. Click here to start this process.