Electrochemical Detection of Dual Exposure Biomarkers of Organophosphorus Agents Based on Reactivation of Inhibited Cholinesterase

Abstract

Considering inter- or intra-individual variation in the normal levels of acetylcholinesterase (AChE), real-time measurement of AChE via the reactivation from a postexposure sample was used, and thus a baseline-free and reliable approach was proposed for detecting/screening low-dose organophosphorus pesticides (OPs) poisons. The principle of this technology is on the basis of parallel measurements of AChE activity before and after reactivation from a postexposure to simultaneously provide the content of dual biomarkers of both enzyme inhibition and enzyme adducts. It is more accurate and reliable compared with only one biomarker (inhibition or adduct). Reactivation from a postexposure sample is a better individual enzyme baseline compared to pre-exposure from the population average level in currently available approaches. AChE activity was measured with an electrochemical method. Greatly enhanced sensitivity was achieved by using Fe3O4/Au nanocomposites to enrich thiocholine, the hydrolysis product of active AChE, followed by electrochemical oxidative desorption of the adsorbed thiocholine. The validation of this method for measurement of OP exposures was further explored with in vitro paraoxon inhibited human red blood cells (RBCs) samples and demonstrated its practicability.

Innovative approach for the electrochemical detection of non-electroactive organophosphorus pesticides using oxime as electroactive probe

“…In the past few decades, electrochemical methods were emerged as the most promising alternative technique for on-site detection of OPs due to their inherent virtues such as low cost, miniaturization and automation, simple preparation and high sensitivity [6]. Enzyme/antibody-based electrochemical biosensors have been found extensive used in OPs detection.…”

“…Oximes, such as pralidoxime (PAM), have been utilized as effective antidotes for OP compounds. As a kind of super nucleophile, oxime can reversibly bind to OP-inactivated AChE then attach to the free OPs, efficiently reversing and preventing other irreversible binding of OPs to AChE [6]. Taking advantage of the good reactivity between oximes and OPs, several oxime-based sensors have been developed by means of colorimetric [10], fluorescent [11], and chemiluminescent [12] methods.…”

In situ induced metal-enhanced fluorescence: A new strategy for biosensing the total acetylcholinesterase activity in sub-microliter human whole blood

“…While muscular and neuronal AChE is inaccessible for direct measurement, AChE in the blood is a reliable surrogate (Worek et al, 1999). Moreover, AChE and BChE activities (i.e., total AChE) in whole blood are biomarkers of organophosphate nerve agents or pesticide exposure because these compounds inhibit both ChEs (Lotti, 1995;Elsinghorst et al, 2013;Ge et al, 2013). Therefore, sensitive accurate determination of total AChE activities in whole blood is an important procedure in clinics, especially in point-of-care testing.…”

Enantiomeric separation by microchip electrophoresis using bovine serum albumin conjugated magnetic core‐shell Fe3O4@Au nanocomposites as stationary phase

“…Yang et al synthesized poly(acrylic acid)-coated gold magnetic NPs to construct a particle probe for detection of antitreponema pallidum antibodies with lateral flow immunoassay strip test system [38]. Ge et al used Fe 3 O 4 /Au nanocomposites to enrich thiocholine, the hydrolysis product of active acetylcholinesterase, for detecting low-dose organophosphorus pesticides on the basis of parallel measurements of acetylcholinesterase activity before and after reactivation [39]. However, to the best of our knowledge, there are no reports of BSA-conjugated Fe 3 O 4 @Au NPs as stationary phase for enantioselective separation of enantiomers in MCE.…”