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Accession Number ADA584127
Title Development of Peptide Nanotube-Modified Biosensors for Gas-Phase Organophosphate Detection.
Publication Date Mar 2013
Media Count 49p
Personal Author P. A. Baker
Abstract Vapor-phase detection of the model organophosphate malathion was achieved using enzymes encapsulated in peptide nanotubes and attached to gold screen-printed electrodes. Malathion was chosen as the model for this experiment because its binding mechanism with acetylcholinesterase (AChE) is identical to its more potent counterparts (such as sarin or VX), but it has an extremely low human toxicity, which makes it both practical and easy to use. The peptide nanotubes had horseradish peroxidase encapsulated inside and were coated with both acetylthiocholine (ASCh) and AChE on the outside. ASCh hydrolysis, which produces thiocholine, was catalyzed by the AChE. The thiocholine was then oxidized by the electrodes to produce a signal that could be measured by a cyclic voltammeter. This signal was inhibited in the presence of malathion vapor, with the extent of inhibition proportional to the malathion concentration. A calibration curve was first established in order to determine the concentration of malathion vapor in a given environment using standards of known concentrations of liquid malathion in a gas chromatograph. Once the vapor concentration was established, peptide-nanotube-modified, gold screen-printed electrodes were used to detect organophosphate vapor. The nanotube-modified electrodes were exposed to both AChE and ASCh and inserted into an airtight vial with a known concentration of malathion. Cyclic voltammograms were taken at each step to monitor the changes in activity. This research demonstrates the ability to use nano-modified biosensors for the detection of organophosphate vapor, an important development in countering weaponized organophosphate nerve agents and detecting commercially-used pesticides.
Keywords Acetylcholine
Acetylcholinesterase
Biological detection
Calibration
Carbon nanotubes
Catalysis
Chemical agent detection
Chemical agent detectors
Cholinesterase biosensors
Concentration(Composition)
Electrodes
Enzymes
Gas chromatography
Hydrolysis
Malathion
Nanostructures
Nerve agents
Organophosphate detection
Organophosphates
Oxidation
Peptide nanotubes
Peroxidases
Theses
Thiocholine
Vapor phases
Voltammeters
Voltammetry


 
Source Agency Non Paid ADAS
NTIS Subject Category 57B - Biochemistry
74D - Chemical, Biological, & Radiological Warfare
63F - Optical Detection
Corporate Author Air Force Inst. of Tech., Wright-Patterson AFB, OH. Graduate School of Engineering and Management.
Document Type Thesis
Title Note Master's thesis.
NTIS Issue Number 1402
Contract Number N/A

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