Researchers at NASA's Jet Propulsion Laboratory, Pasadena, Calif., have demonstrated a prototype device that automatically and continuously monitors the air for the presence of bacterial spores. The result is a novel alarm capability reminiscent of smoke detectors.

Current methods for detecting bacterial spores, such as anthrax, require a trained operator. The large number of trained monitors required, with associated costs, limits widespread implementation of these methods.

"Having a technician continuously monitor the air for spores is like having the fire department live at your house to ensure that there is no fire," said Dr. Adrian Ponce, a chemist and senior member of the technical staff at JPL. "What you want is a smoke detector, a device that continuously monitors the air for smoke, or in our case, bacterial spores," he said.

Ponce is co-author of a paper titled "An Anthrax 'Smoke' Detector: Online Monitoring of Aerosolized Bacterial Spores," which recently appeared in Engineering in Medicine and Biology magazine, published by the Institute of Electrical and Electronics Engineering. The paper details recent tests to detect airborne bacterial spores.

In a related development, JPL recently entered into an agreement with Universal Detection Technology, Beverly Hills, Calif., a public company specializing in environmental monitoring technologies. The agreement, to mutually develop a commercially available anthrax 'smoke' detector, will combine JPL spore detection technology with Universal's aerosol capture device. The partnership with Universal Detection Technology is possible through the Technology Affiliates Program, one of many Commercial Technology Programs aimed at transferring JPL knowledge to the private sector to improve public quality of life.

Ponce and Elizabeth D. Lester, a senior in microbiology at Baylor University, Waco, Texas, performed the tests on the anthrax detector last summer. Their paper details test results using harmless Bacillus subtilis spores that were aerosolized to simulate an anthrax attack. Bacillus subtilis is found worldwide in soils and on root vegetables.

During the tests, aerosolized spores were captured with an aerosol sampler and suspended in a solution. Suspended spores were ruptured with microwaves to release a chemical from inside the spores called dipicolinic acid, which is unique to bacterial spores. This dipicolinic acid instantaneously reacts with the chemical sensor in the solution. The sensor triggers an intense green luminescence when viewed under ultraviolet light. The intensity of the luminescence corresponds to the concentration of bacterial spores in the sample.

If an increase in spore concentration is detected, an alarm sounds. A technician would respond to confirm the presence of anthrax spores using traditional sampling and analysis, such as colony counting and polymerase chain reaction, which amplifies DNA to measurable concentrations. The instrument response time is 15 minutes, fast enough to help prevent widespread contamination.

JPL's bacterial spore detection system is simple and robust, a prerequisite for continuous monitoring. The system is designed for constant and unattended monitoring of spaces such as public facilities and commercial buildings. Two features of the device prevent false alarms. JPL's detection technology discriminates against detecting aerosol components, such as dust, and the device only sounds an alarm when it detects a significant increase in spore count.

The system being used by Universal Detection Technology cannot distinguish between inorganic particles or biological substances such as bacterial spores. For the next 12 months, JPL will work to incorporate its bacterial spore detection technology to make the device sensitive enough for use by Universal as a bioterrorism warning monitor.

JPL initially became involved in monitoring bacterial spores to quantify the concentration of spores in spacecraft assembly facilities. These are the facilities where spacecraft are built and housed before missions launch. NASA has a planetary protection policy regulating biological contamination control for all spacecraft. Under this policy, JPL researchers must take precautions against accidentally transferring microbes to other planets. This experience gives JPL researchers unique capabilities to perform work in detecting microorganisms. The California Institute of Technology manages JPL for NASA.