NASA's Jet Propulsion Laboratory (JPL) in Pasadena, California has developed a device capable of online monitoring of aerosolized spores, which can detect anthrax instantaneously and sound an alert before contamination reaches lethal levels. Dubbed the "anthrax smoke detector," its name metaphorically sums up the device's function, but details of how it works are quite different from a real smoke detector, and from the approach microbiologists' have been using to detect anthrax and other bacteria, according to the device's inventor, JPL chemist Adrian Ponce.

It's an excellent example of interdisciplinary cooperation, said Ponce. "The questions came from the microbiologists. We had the answers over on our side."

The device automates the detection of endospores, a dormant bacterial form so resilient that it is used to check the performance of autoclaves, Ponce explained. Endosphores are formed by Bacillus and Clostridium bacteria, which include the causative agents of anthrax, tetanus, botulism and gas gangrene.

Currently, endospores are only detectable by labor-and-time intensive methods like PCR (polymerase chain reaction) and colony counting, Ponce said. The "smoke detector" analogy refers to the new device's ability to automatically monitor for the presence of aerosolized spores for up to eight hours and sound an alert the moment spores are detected.

The prototype system designed by Ponce and Elizabeth Lester, an undergraduate microbiologist at Baylor University in Texas, USA, first detects Dipicolinic acid (DPA), which is unique to bacterial spores and thus serves as a "molecular fingerprint." Microwave radiation is used to release DPA from the spore into glycerol solution, which then binds to terbium ions. The rare earth element terbium, known primarily for its use in color TV tubes, triggers green luminescence under UV excitation, which is then monitored by a spectrometer. Intensity of the luminescence corresponds to spore concentration, and the device will automatically sound an alarm at set levels. "It's classic inorganic chemistry — it's a beautiful inorganic ligand, you just bind it to a metal," said Ponce.

Because the spore detector picks up Anthrax and botulism, Ponce thinks its primary uses will be in three types of location: mail rooms, hospitals and food preparation areas. The detector will be marketed by Universal Detection Technology of Beverly Hills, and may also be useful to those in the life science community concerned with contamination from toxic bacterial spores, said Ponce. However, because the detector picks up the "molecular fingerprint" of these particular types of bacterial spores, Ponce explained, "It is not amenable to molds or viruses or other protein-based toxins—the chemistry of detection is not present in fungal spores."

There is already one notable use for exo-biologists, Ponce noted. JPL may use the device in a space-craft assembling facility to detect microscopic stowaways, "because we're really worried about bio-load," he said.