title: Organophosphate vapor detection on gold electrodes using peptide nanotubes.
abstract: Peptide nanotubes (PNTs) encapsulating horseradish peroxidase and surface coated with acetylcholinesterase (AChE) were attached to gold screen printed electrodes to construct a novel gas phase organophosphate (OP) biosensor. When the sensor with the AChE enzyme is put in contact with acetylthiocholine (ATCh), the ATCh is hydrolyzed to produce thiocholine, which is then oxidized by horseradish peroxidase (HRP). Direct electron transfer between HRP and electrode is achieved through PNTs. The signal produced by the electron transfer is measured with cyclic voltammetry (CV). The presence of an OP compound inhibits this signal by binding with the AChE enzyme. In this study, gas phase malathion was used as a model OP due to the fact that it displays the identical binding mechanism with acetylcholinesterase (AChE) as its more potent counterparts such as sarin and VX, but has low toxicity, making it more practical and safer to handle. The CV signal was proportionally inhibited by malathion vapor concentrations as low as 12 ppbv. Depending on the method used in their preparation, the electrodes maintained their activity for up to 45 days. This research demonstrates the potential of applying nano-modified biosensors for the detection of low levels of OP vapor, an important development in countering weaponized organophosphate nerve agents and detecting commercially-used OP pesticides.
authors.affiliation: Department of Systems Engineering and Management, Air Force Institute of Technology, WPAFB, OH 45433, USA.
authors.forename: Peter A
authors.initials: PA
authors.lastname: Baker
authors.affiliation: Department of Systems Engineering and Management, Air Force Institute of Technology, WPAFB, OH 45433, USA. Electronic address: mark.goltz@afit.edu.
authors.forename: Mark N
authors.initials: MN
authors.lastname: Goltz
authors.affiliation: Energetic Materials Branch, Munitions Directorate, Air Force Research Laboratory, Eglin AFB, FL 32542, USA.
authors.forename: Amanda M
authors.initials: AM
authors.lastname: Schrand
authors.affiliation: Department of Chemical Engineering, Kwangwoon University, South Korea.
authors.forename: Do Young
authors.initials: DY
authors.lastname: Yoon
authors.affiliation: Department of Chemical and Environmental Engineering, University of Toledo, Toledo, OH 43606, USA.
authors.forename: Dong-Shik
authors.initials: DS
authors.lastname: Kim
mesh_terms: D000110:Acetylcholinesterase / Q000737:chemistry; D000818:Animals; D015374:Biosensing Techniques / Q000295:instrumentation*; D004566:Electrodes; D004593:Electrophorus; D004800:Enzymes, Immobilized / Q000737:chemistry; D004867:Equipment Design; D005740:Gases / Q000032:analysis*; D006046:Gold / Q000737:chemistry*; D006735:Horseradish Peroxidase / Q000737:chemistry; D007306:Insecticides / Q000032:analysis; D057230:Limit of Detection; D008294:Malathion / Q000032:analysis; D045333:Nanotubes, Peptide / Q000737:chemistry*; D010755:Organophosphates / Q000032:analysis*; D014835:Volatilization
chemical_list: D004800:Enzymes, Immobilized; D005740:Gases; D007306:Insecticides; D045333:Nanotubes, Peptide; D010755:Organophosphates; D006046:Gold; D006735:Horseradish Peroxidase; D000110:Acetylcholinesterase; D008294:Malathion
keywords: Acetylcholinesterase; Cyclic voltammetry; Horseradish peroxidase; Malathion; Organophosphate vapor; Peptide nanotubes