Bio/Chem agent detection and decontamination
Kin P. Cheung
Electrical & Computer Engineering
The most dangerous bioagent attack is in the form of aerosol
An adult human inhales 10 – 100 liter per minute of air
Up to 2000 liter in 20 minutes
Infective doses of selected aerosol BW agents
Anthrax
8000–10,000 spores ~5 spores/Liter
Brucellosis
10–100 organisms
~0.01 /Liter
Plague
3000 organisms
~1 /Liter
Q fever
1–10 organisms
~0.001 /Liter
Tularemia
10–50 organisms
~0.01 /Liter
Smallpox
10–100 organisms
~0.01 /Liter
Viral encephalitides
10–100 organisms
~0.01 /Liter
Viral hemorrhagic fevers 1–10 organisms
~0.001 /Liter
Botulinum toxin
0.07 µg/kg
~3ng /Liter
Staph. enterotoxin B
0.02 ug/kg (lethal)
~1ng /Liter
D. R. Walt, D. R. Franz, Analytical Chem. 72(23), 738A(2000).
Assume a particle 104 heavier than air molecule
Average thermal velocity ~ 400cm/s
The impingement rate to a 1cm2 area detecting surface is:
10 6  400
 10 4 s 1  0.006 min
4
Passive detector is out of the question.
Sample concentration method that collect ~1000 liters of air in one
minute is needed.
Ultra compact detector is not a practical goal.
Large number of detectors are assumed to be in a distributed network
that requires minimum human intervention for extended period.
For civilian protection, sufficient time must be budgeted for after alarm
procedure:
~ 1 minute trigger time
One batch of consumable per minute.
Detector that requires consumable is not practical.
Immunoassay based technology is not attractive.
Optical detection has fundamental issues:
The basic composition of all life form are the same.
Very little difference between microbes
How to tell the difference between naturally occurring
and harmless aerosols from harmful one?
High false alarm rate is worse than no alarm.
The only region of spectrum that has the potential to distinguish one
microbe from another is the millimeter wave.
High-resolution THz spectroscopy is very promising.
A unique, ultra high sensitivity, ultra broad band, ultra high resolution
THz spectroscopy method is being developed for bio-aerosol
detection here at Rutgers.
The three ultras are of key important!
Bio/Chem agent decontamination using nonthermal, atmospheric pressure plasma
Atmospheric pressure, non-thermal plasma is well known to have high
potential for waste gas treatment and medical instrument sterilization.
The main problem has been cost.
The promising potential of plasmas for decon was clearly identified during the U.S. Military’s
Decon Front End Analysis (FEA) conducted in December 1998. This FEA forms the backbone of
the Joint Services Decon Master Plan. Technologies were graded against 21 different criteria that
were weighted by the military’s user community. Atmospheric-pressure plasma (APP) ranked high
in most functional areas.
The problems are energy efficiency, logistics, size and cost.
All atmospheric pressure plasma requires high voltage supply.
Some requires high power RF.
Some only operate in special carrier gas.
Most requires cooling
Most are not very reliable
Most are bulky
The ideal combination of high efficiency, operate in one air, running in
low DC voltage, compact, long life and low cost does not exist.
Practical implementation for home land defense is not yet possible.
We are building a unique plasma source using the combination
of MEMS and IC technology that will satisfy this ideal plasma
source requirement.
Emergency protection application:
A compact forced air plasma source coupled with air filter can be used to
create a positive pressure personal protection zone:
plasma
filter
fan
A low cost, bio/chem emergency protection garment can be made.