- UDT's device being developed in collaboration with JPL essentially functions as an Anthrax ‘Smoke Detector.' The device continuously monitors the air for Anthrax spores, it then uses a microwave to “pop” the spores thus releasing 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 notifying both a buildings internal security as well as local emergency services through the devices landline or wireless networking capability. The devices response time is 15 minutes, fast enough to help prevent widespread contamination.
- UDT'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 device samples - or ‘breathes' – at a rate slightly faster than humans do. The alarm goes off in half the time it takes for an average human to acquire enough spores to reach a lethal level. It is monitoring the air at all times, so it's an early warning system.
- (a) An electron microscope image of a spore (~1 µm diameter) highlighting
DPA-rich endopore core.
- (b) Unbound Tb3+ ion (shaded ball) by itself has a low absorption cross section
(<1 M-1cm-1)
- and consequently has low luminescence intensity.
|
Photograph Source: Venkateswaran et al., 2003, Intern. J. Syst. Evol. Microbiol. , 53:165. |
- Binding of the light-harvesting DPA (absorption cross section >104M-1cm-1), originating from
endospores, gives rise to intense Tb luminescence due to an absorption, energy
transfer, emission mechanism.
- (c) Two cuvets on a UV lamp filled with 1 mM TbCl3 (Tb cuvet), and
1 mM TbCl3 + 1 µM DPA (Tb-DPA cuvet), respectively. The amount
of DPA in the Tb-DPA cuvet corresponds to 106 spores/ml.
|
|
|
|
|
