Premium
Nanoparticle‐Based Electrochemical Immunosensor for the Detection of Phosphorylated Acetylcholinesterase: An Exposure Biomarker of Organophosphate Pesticides and Nerve Agents
Author(s) -
Liu Guodong,
Wang Jun,
Barry Richard,
Petersen Catherine,
Timchalk Charles,
Gassman Paul L,
Lin Yuehe
Publication year - 2008
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.200800412
Subject(s) - detection limit , chemistry , acetylcholinesterase , chromatography , nuclear chemistry , nerve agent , fourier transform infrared spectroscopy , dielectric spectroscopy , electrochemistry , combinatorial chemistry , biochemistry , enzyme , chemical engineering , electrode , engineering
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 p M to 4 n M phosphorylated AChE, and the limit of detection is estimated to be 8.0 p M . 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.