Magnetic electrochemical immunoassays with quantum dot labels for detection of phosphorylated acetylcholinesterase in plasma

Hua Wang; Jun Wang; Charles Timchalk; Yuehe Lin

doi:10.1021/ac801211s

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Magnetic electrochemical immunoassays with quantum dot labels for detection of phosphorylated acetylcholinesterase in plasma

Journal article

Open access

Peer reviewed

Magnetic electrochemical immunoassays with quantum dot labels for detection of phosphorylated acetylcholinesterase in plasma

Hua Wang, Jun Wang, Charles Timchalk and Yuehe Lin

Analytical chemistry (Washington), Vol.80(22), pp.8477-8484

11/15/2008

DOI: https://doi.org/10.1021/ac801211s

Handle:

https://hdl.handle.net/2376/112868

PMCID: PMC2817973

PMID: 18855408

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https://doi.org/10.1021/ac801211sView

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Abstract

Phosphorylation

Humans

Polyethylene Glycols - chemistry

Magnetics

Organophosphorus Compounds - metabolism

Phosphoproteins - blood

Time Factors

Cattle

Acetylcholinesterase - immunology

Sensitivity and Specificity

Surface Properties

Immunoassay - methods

Serum Albumin, Bovine - chemistry

Biomarkers - metabolism

Environmental Monitoring

Acetylcholinesterase - blood

Antibody Affinity

Biomarkers - blood

Environmental Exposure

Phosphoserine - metabolism

Animals

Adsorption

Quantum Dots

Staining and Labeling

Electrochemistry

Acetylcholinesterase - metabolism

A new magnetic electrochemical immunoassay has been developed as a tool for biomonitoring exposures to organophosphate (OP) compounds, e.g., insecticides and chemical nerve agents, by directly detecting organophosphorylated acetylcholinesterase (OP-AChE). This immunoassay uniquely incorporates highly efficient magnetic separation with ultrasensitive square wave voltammetry (SWV) analysis with quantum dots (QDs) as labels. A pair of antibodies was used to achieve the specific recognition of OP-AChE that was prepared with paraoxon as an OP model agent. Antiphosphoserine polyclonal antibodies were anchored on amorphous magnetic particles preferably chosen to capture OP-AChE from the sample matrixes by binding their phosphoserine moieties that were exposed through unfolding the protein adducts. This was validated by electrochemical examinations and enzyme-linked immunosorbent assays. Furthermore, antihuman AChE monoclonal antibodies were labeled with cadmium-source QDs to selectively recognize the captured OP-AChE, as characterized by transmission electron microscopy. The subsequent electrochemical SWV analysis of the cadmium component released by acid from the coupled QDs was conducted on disposable screen-printed electrodes. Experimental results indicated that the SWV-based immunoassays could yield a linear response over a broad concentration range of 0.3-300 ng/mL OP-AChE in human plasma with a detection limit of 0.15 ng/mL. Such a novel electrochemical immunoassay holds great promise as a simple, selective, sensitive, and field-deployable tool for the effective biomonitoring and diagnosis of potential exposures to nerve agents and pesticides.

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Title: Magnetic electrochemical immunoassays with quantum dot labels for detection of phosphorylated acetylcholinesterase in plasma
Creators: Hua Wang - Pacific Norwest National Laboratory, Richland, Washington 99352, USA
Jun Wang
Charles Timchalk
Yuehe Lin
Publication Details: Analytical chemistry (Washington), Vol.80(22), pp.8477-8484
Academic Unit: Mechanical and Materials Engineering, School of
Publisher: United States
Grant note: R01 OH008173 / NIOSH CDC HHS U01 NS058161 / NINDS NIH HHS U01 NS058161-02 / NINDS NIH HHS U01 NS058161-03 / NINDS NIH HHS U01 NS058161-01 / NINDS NIH HHS
Identifiers: 99900547687201842
Language: English
Resource Type: Journal article