Hygiene's Silver Bullet

By Unmesh Kher

We live in a dirty world. Microbes fill the air, crowd our pores and carpet everything we touch. Shake a hand or open a door, and you leave with a menagerie of hitchhikers and parasites--yeast, bacteria--clinging to your palms. As any hypochondriac will tell you, cleaning up is a quixotic quest. The only hygienic surface is one that sterilizes itself. And how many such surfaces exist?

Lots of them, if AgION Technologies has its way. The privately held firm produces an antimicrobial material that gives anything in which it is embedded an enduring resistance to bacteria, yeast, algae and mold. AgION, which has raised $40.5 million in capital, works with manufacturers up and down the supply chain to incorporate its bug-busting stuff into everything from water filters to doorknobs and even the casing of a cell phone, the Motorola i870.

AgION's microbicide is silver, a metal long known to have potent anti-infective properties yet lacking the tendency of many organic agents to generate resistance. Trouble is, silver atoms have to be in an ionic (charged) state--as they are in solutions of silver salts--to kill microbes. Pure silver doesn't release enough ions to pack much disinfecting punch. Its salts, on the other hand, wash away too easily.

AgION worked around those difficulties by encasing silver ions in a type of powdery ceramic called zeolite. Each grain of zeolite is riddled with submicroscopic tunnels that are stuffed with silver ions. It releases the ions only in exchange for others--say, sodium ions in a salty drop of sweat. So ion-rich liquids, in which bugs often thrive, activate AgION's microbicide. "The ceramic delivers enough silver to be effective," says AgION CTO Jeffrey Trogolo, "but not so much that it loses effect over its lifetime."

Though AgION did not invent the ceramic--a Japanese firm did that--the company has unleashed its power since licensing the technology in 1997. It has engineered 14 grades of the material to meet various needs, from coating frequently washed factory floors to shielding intravenous catheters. One AgION customer, Wellman International's polyester unit, has infused fibers with AgION's compound and is testing ideas like germ-resistant T shirts, air-conditioner filters and pillows. "We believe it fills a need that exists in the marketplace," says the unit's business manager, David Whitley. "It has value--and, bottom line, it works." AgION, for its part, is working with 60 companies, including DuPont and Reebok. "We're not introducing any new chemicals to the world," Trogolo points out. "We're just using silver contained in what is essentially sand." Only it's the sort of sand he'd like to see getting into everything.