Sounds Hot Enough to Zap Anthrax
High-frequency sound kills microscopic bugs. Now scientists have found a way to transmit ultrasound through air, which could lead to news ways to sterilize food, air ducts and suspected bio-weapons.

Scientists have long known that in addition to their other uses, high-frequency sound waves (i.e. notes with an extremely high pitch), also known as ultrasound, can tear apart the tiny pathogens that cause disease.

However, ultrasound spreads out too fast in gasses, so sending ultrasound through the air has been ineffective. Until now, all ultrasound applications have required the use of some kind of "contact medium," a gel or liquid, to let the sound waves pass through without dissipating.

The May issue of Discover magazine reports that M. Bhardwaj, a scientist at ultrasound company Ultran Laboratories, has discovered a simple way to transmit ultrasound without messy goops: simply place a layer of compressed fibers (cotton or paper, for example) between the transducer and the item being bombarded. Bhardwaj reports killing 99.9% of BT spores (a cousin of anthrax harmless to humans) in the lab.

Commercial development is now underway.

Link to complete Discover article (search site using keywords: sterilized sound)

Link to Ultran Laboratories company site