Nerve Agents Assay Using Cholinesterase Based Biosensor

Abstract

Electrochemical biosensor based on electric eel acetylcholinesterase (AChE) (EC 3.1.1.7) was performed for assay of nerve agents -tabun, sarin, soman, cyclosarin, and VX. The biosensor used AChE as biorecognition element. The presence of nerve agents was accompanied by a strong inhibition of AChE activity. Enzyme activity is easily measurable by electrochemical oxidation of thiocholine created from acetylthiocholine (ATChCl) by AChE-catalyzed hydrolysis. The tested nerve agents were successfully assayed. The best limits of detection were achieved for sarin (5.88 Â 10 À10 M) and VX (8.51 Â 10 À10 M) after one-minute assay. The biosensor was found long term stable at low as well as laboratory temperature.

Biosensors based on cholinesterase inhibition for insecticides, nerve agents and aflatoxin B1 detection (review)

“…The monoenzymatic biosensor was developed using a platinum working electrode on which the AChE was immobilised and measuring the thiocholine at +450 mV vs Ag/AgCl [71]. In order to reduce the applied potential and the electrochemical interferences, two approaches can be followed: I) the use of redox mediators such as cobalt phthalocyanine (CoPc) [72] …”

Cholinesterase-based biosensors

“…There are several analytes which can be assayed by amperometric cholinesterase biosensor, i.e. pesticides (paraoxon, dichlorvos, sulfotep), nerve agents (sarin, soman), aflatoxin, novel anticholinergic drugs [71][72][73][74][75][76] . An amperometric biosensor with immobilized BChE was used for detection of nerve agents in the air 77 .…”

“…Gogol et al designed biosensor with immobilized BChE from horse serum onto the nafion layer by cross-linking with glutaraldehyde vapours for determination of cholinesterase inhibitors trichlorfon and coumaphos 143 . Pohanka et al designed an electrochemical biosensor with AChE immobilized via glutaraldehyde in the presence of BSA on three-electrode screen-printed sensor for detection of nerve agents -tabun, soman, sarin, cyclosarin and VX 72 . Besides simple immobilization of AChE via glutaraldehyde, there were described several techniques of enzyme immobilization via glutaraldehyde on a performed self-assembled monolayer 47,[144][145][146][147][148] .…”

“…Biosensors are used for early detection of chemical warfare agents, especially nerve gases, such as sarin, soman, tabun and VX 72,77,151,181,182 . Nerve gases have similar structure as organophosphorus insecticides, but present a much higher mammalian toxicity.…”

Electrochemical Biosensors for Determination of Organophosphorus Compounds: Review

“…AchE enzyme was used in combination with different types of supports for the fabrication of bio-sensing devices [17][18][19][20][21][22][23][24][25][26][27][28][29][30][31][32][33][34]. Table 1 summarizes the characteristics of different AchE-based biosensors.…”