Journal article
Magnetic electrochemical sensing platform for biomonitoring of exposure to organophosphorus pesticides and nerve agents based on simultaneous measurement of total enzyme amount and enzyme activity
Analytical chemistry (Washington), Vol.83(10), pp.3770-3777
05/15/2011
Handle:
https://hdl.handle.net/2376/108985
PMID: 21462919
Abstract
We report a new approach for electrochemical quantification of enzymatic inhibition and phosphorylation for biomonitoring of exposure to organophosphorus (OP) pesticides and nerve agents based on a magnetic bead (MB) immunosensing platform. The principle of this approach is based on the combination of MB immunocapture-based enzyme activity assay and competitive immunoassay of the total amount of enzyme for simultaneous detection of enzyme inhibition and phosphorylation in biological fluids. Butyrylcholinesterase (BChE) was chosen as a model enzyme. In competitive immunoassay, the target BChE in a sample competes with the BChE immobilized on the MBs to bind to the limited sites of anti-BChE antibody labeled with quantum dots (QD-anti-BChE), followed by stripping voltammetric analysis of the bound QD conjugate on the MBs. This assay shows a linear response over the total BChE concentration range of 0.1-20 nM. Simultaneous real time BChE activity was measured on an electrochemical carbon nanotube-based sensor coupled with a microflow injection system after immunocapture by the MB-anti-BChE conjugate. Therefore, the formed phosphorylated BChE adduct (OP-BChE) can be estimated by the difference values of the total amount of BChE (including active and OP-inhibited) and active BChE from established calibration curves. This approach not only eliminates the difficulty in screening of low-dose OP exposure (less than 20% inhibition of BChE) because of individual variation of BChE values but also avoids the drawback of the scarce availability of OP-BChE antibody. It is sensitive enough to detect 0.5 nM OP-BChE, which is less than 2% BChE inhibition. This method offers a new method for rapid, accurate, selective, and inexpensive quantification of OP-BChE and enzyme inhibition for biomonitoring of OP and nerve agent exposures.
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Details
- Title
- Magnetic electrochemical sensing platform for biomonitoring of exposure to organophosphorus pesticides and nerve agents based on simultaneous measurement of total enzyme amount and enzyme activity
- Creators
- Dan Du - Pacific Northwest National Laboratory, Richland, Washington 99352, USAJun WangLimin WangDonglai LuJordan N SmithCharles TimchalkYuehe Lin
- Publication Details
- Analytical chemistry (Washington), Vol.83(10), pp.3770-3777
- Academic Unit
- School of Mechanical and Materials Engineering
- Publisher
- United States
- Grant note
- R01 OH008173-01 / NIOSH CDC HHS U01 NS058161-01 / NINDS NIH HHS
- Identifiers
- 99900547258801842
- Language
- English
- Resource Type
- Journal article