The number of countries pursuing an offensive biological warfare program continues to increase. The priority of the Army's Biological Defense Program is to limit the effects of large area biological warfare attacks. The BIDS is being designed by the BIDS Team under the Soldier and Biological Chemical Command of the U.S. Army at Aberdeen Proving Ground in Edgewood, Maryland. The entire program is under the Program Director for Biological Defense Systems. The BIDS consists of 5 major subcomponents: (1) Vehicle, (2) Shelter, (3) Auxiliary Equipment, (4) Power, and (5) Biological Detection Suite. Here, in Edgewood, we have designed a system, made up of various Biological Detection equipment, that meets the Army's demand. We are currently nearing the end of Phase 1 of a two-phase program. In the next phase, we will be refining and automating what we have already designed to ensure optimal performance.
- Phase 1 -- Non Developmental Item (NDI) phase
- Phase 2 -- Pre-planned Program Improvement (P3I) 6.4 development phase
The Joint Program Manager for Biological Defense issued an Acquisition Decision Memorandum on 27 Feb 96 approving Type Classification - Standard for the Non-Developmentmental Item (NDI) BIDS, M31.
Test Equipment
High Volume Aerodynamic Particle Sizer (HVAPS) continuously samples the ambient air directing it through an opening to accelerate the velocity of aerosol particles. To measure particle velocity, a laser beam is split into two beams and the beams are focused onto two spots downstream of the opening. The light scattered by a particle passing through these beams is collected and focused on a photomultiplier tube. The time required for a particle to cross the distance between the two beams is used to calculate its aerodynamic diameter. The APS provides a measure of background aerosol concentration and particle size distribution. Changes in this background can indicate the presence of a man-made aerosol associated with a biological warfare attack.
Note: The HVAPS is a registered trademark of TSI Inc.
Liquid Sampler (LS) is similar to the Single Liquid Sample Collector except the wet collector has been replaced with a continuous flow liquid scrubber. It also includes a sample delivery system that transfers the concentrated liquid to sample tubes arranged in a carousel. On demand, the delivery system dispenses 0.5 ml sample into each of 6 sample tubes. These samples are then analyzed by the BIDS crew using various detection components.
Biological Sampler or Single Liquid Sample Collector is a high volume aerosol sampling and collection device. On demand, it samples the ambient air through a two-stage virtual impactor that concentrates aerosol particles in the 2 to 10 micrometer diameter size range. The concentrated particle stream is directed through a wet collector containing a buffer solution (40 ml). Particles are transferred from the air stream into the collection buffer. At the end of the sampling period (45 minutes), the wet collector is removed from the liquid collector and transported to a laboratory for analysis to confirm or deny the presence of biological agents.
Flow Cytometer (FCM) is a particle counting and sizing device which uses a liquid sample in which aerosol particles have separated into their subcomponents. The sample to be analyzed is injected into the center of a fast moving fluid stream which is then forced through an opening. Upon exiting the opening, the stream passes through a measurement station where particulates, such as bacterial cells, are illuminated by a light source. Scattered light is measured at different angles and wavelengths using a series of optical filters and photomultiplier tubes to provide information concerning the cell's size, shape, and fluorescence. A specially formulated dye is added to liquid samples and then placed in the FCM. The instrument automatically processes the samples and displays the results to the operator. Pattern recognition techniques, based on particle size and fluorescence, are used to reliably differentiate bacteria from natural airborne biological materials such as pollens and mold spores.
Note: The FCM is a registered trademark of Coulter Corporation.
Threshold Workstation (THS) monitors the results of specific antigen-antibody reactions. If either the Microluminometer or FCM indicates a positive reading, the third sample from the Carousel Liquid Sample Collector is mixed with antibodies against specific biological agents and then filtered through a specially coated ticket. If the specific agents are present, they remain bound to the surface of the ticket. Additional reagents are subsequently filtered through the ticket to label any bound agent with an enzyme. The ticked is then placed into a reader station where a substrate is added. A solid-state microsensor measures small changes in pH produced by the enzyme-substrate reaction which are directly proportional to the amount of agent present. The Threshold Workstation provides simultaneous detection of four different agents within 10 to 12 minutes.
Note: The THS Workstation is a registered trademark of Molecular Devices Corp.
Future Additions
Biological Detector - The Biological Detector (BD) will be integrated into the BIDS in phase 2(P3I) of our overall plan.
Mass Spectrometry - Chemical Biological Mass Spectrometer (CBMS) is an ion trap mass spectrometer that is capable of biological agent detection when connected to an aerosol collector/concentrator and of chemical detection when connected to a chemical probe. Agents are detected through an algorithm which contains the profiles of threat agents. The system's ability to operate in both the MS and MS/MS modes allow it to screen out battlefield interferents. The system is controlled by a touch screen computer.