Sandia LabNews

Prototype detector could I.D. anthrax

Some deadly things don’t deserve 15 minutes of FAME, let alone a few hours.

A prototype handheld detector under development at Sandia can recognize the fatty acid methyl esters (FAME) of anthrax in less than five minutes.

Identification of the bacillus in minutes, rather than the hours currently necessary, is a crucial step in alerting a building’s occupants to flee the deadly bacteria, as well as in activating defenses such as anti-anthrax foam dispersal systems. The patent-applied-for detector, in which commercial interest has been expressed, would also aid security people making their rounds to locate point sources of the disease.

The technique works by preconcentrating airborne particles on a tiny hotplate that acts like a skillet on a stove. The hotplate immediately vaporizes the fatty acids in anthrax’s cell walls to create the FAME that form a unique fingerprint of the bacteria.

"The process is a little like burning bacon," says lead researcher Curtis Mowry (1764) of the microchemlab. "The wafted gases are distinctive to a detector."

A small computer program correlates the amount of mass of each ester emitted in the analyzed gases at particular times — a process called elution — with already categorized elution peaks indicative of anthrax or other diseases.

The extremely low-power technique shrinks prototype suitcase-sized detectors to the size of a handheld device by using microdevices fabricated at Sandia. Pyrolization requires considerably less power — 150 milliwatts instead of 130 watts.

Components of the device have been individually tested, though not yet linked with a commercially available aerosol collector.

"The focus of the project is on increasing the speed of analysis in the microfabricated system while retaining enough information to distinguish between microorganisms," says Curtis.

Standard techniques require a lengthy extraction/derivatization step followed by FAME chromatography. Sandia’s chemographic and surface acoustic wave analysis of gases driven from the bacteria enables far faster identification of anthrax and other diseases.

Fatty acids are found in all living organisms with cell membranes. Analyses of gases driven from the bacteria have been used to identify bacteria and other pathogens at the genus level, and often at the species level.

Other researchers include Catherine Morgan (1738), Quentin Baca, Ronald Manginell, Richard Kottenstette, Patrick Lewis (all 1764), and Gregory Frye-Mason, a former Sandian, now an outside contractor.

Sandia’s Laboratory Directed Research and Development program supported the work. Initial results were reported at the SPIE conference in Boston in November.