Prototype detector could identify anthrax in minutes

A prototype handheld detector under development at Sandia National Laboratories can identify the fatty acid methyl esters of anthrax in less than five minutes.

A prototype handheld detector under development at Sandia National Laboratories can identify 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 said to be a crucial step in alerting a building’s occupants to flee the deadly bacteria, as well as in activating defences such as anti-anthrax foam dispersal systems. The detector would also, according to Sandia Labs, 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 vaporises 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,’ said lead researcher Curtis Mowry of the microchemistry lab. ‘The wafted gases are distinctive to a detector.’

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

Pyrolisation is not only far faster than current suitcase-sized prototype devices but requires 150 milliwatts of power instead of 130 watts. The low power is made possible by microdevices fabricated at Sandia.

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 micro-organisms,’ said Mowry.

Standard techniques are said to require a lengthy extraction-derivatisation step followed by FAME chromatography. Sandia’s chemographic and surface acoustic wave analysis of gasses driven from the bacteria enables far more rapid 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.