Nanoparticle‐Based Electrochemical Immunosensor for the Detection of Phosphorylated Acetylcholinesterase: An Exposure Biomarker of Organophosphate Pesticides and Nerve Agents

Abstract

A nanoparticle-based electrochemical immunosensor has been developed for the detection of phosphorylated acetylcholinesterase (AChE), which is a potential biomarker of exposure to organophosphate (OP) pesticides and chemical warfare nerve agents. Zirconia nanoparticles (ZrO(2) NPs) were used as selective sorbents to capture the phosphorylated AChE adduct, and quantum dots (ZnS@CdS, QDs) were used as tags to label monoclonal anti-AChE antibody to quantify the immunorecognition events. The sandwich-like immunoreactions were performed among the ZrO(2) NPs, which were pre-coated on a screen printed electrode (SPE) by electrodeposition, phosphorylated AChE and QD-anti-AChE. The captured QD tags were determined on the SPE by electrochemical stripping analysis of its metallic component (cadmium) after an acid-dissolution step. Paraoxon was used as the model OP insecticide to prepare the phosphorylated AChE adducts to demonstrate proof of principle for the sensor. The phosphorylated AChE adduct was characterized by Fourier transform infrared spectroscopy (FTIR) and mass spectroscopy. The binding affinity of anti-AChE to the phosphorylated AChE was validated with an enzyme-linked immunosorbent assay. The parameters (e.g., amount of ZrO(2) NP, QD-anti-AChE concentration,) that govern the electrochemical response of immunosensors were optimized. The voltammetric response of the immunosensor is highly linear over the range of 10 pM to 4 nM phosphorylated AChE, and the limit of detection is estimated to be 8.0 pM. The immunosensor also successfully detected phosphorylated AChE in human plasma. This new nanoparticle-based electrochemical immunosensor provides an opportunity to develop field-deployable, sensitive, and quantitative biosensors for monitoring exposure to a variety of OP pesticides and nerve agents.

Flower-like tungsten oxide particles: Synthesis, characterization and dimethyl methylphosphonate sensing properties

“…Some methods such as luminescence [5][6][7], electrochemistry [8] for detection of these nerve agents have been described in recent reports. However, these methods are usually limited by low sensitivity, operational complexity and non-portability.…”

Modified Cholinesterase Technology in the Construction of Biosensors for Organophosphorus Nerve Agents and Pesticides Detection

“…Also other nanoparticles were used, Au-CdS, placed on a gold electrode with AChE (Zayats et al, 2003; as cited in Shulga & Kirchoff, 2007). The use of nanoparticles also includes carbon, zircon and CdS particles (Ion et al, 2010;Liu et al, 2008).…”

Determination of Methyl Parathion in Water and Its Removal on Zirconia Using Optical Enzyme Assay

“…The significance of ZrO 2 in remediation lies in its thermal stability, nontoxic nature, and strong affinity for phosphoric group. Applications of ZrO 2 have been reported in OP analysis which includes as sensing element for OP in electrochemical studies [24][25][26][27], as reusable cartridge in water purification [28,29], and for adsorption of proteins [30][31][32]. We report determination of MP using highly sensitive enzyme inhibition assay in 384 well plates where ZrO 2 is utilized as novel material for AChE adsorption.…”