Biomonitoring of Organophosphorus Agent Exposure by Reactivation of Cholinesterase Enzyme Based on Carbon Nanotube-Enhanced Flow-Injection Amperometric Detection

Details

• Personal Author:
  Du D ; Lin Y ; Smith JN ; Timchalk C ; Wang J
• Description:
  A portable, rapid, and sensitive assessment of subclinical organophosphorus (OP) agent exposure based on reactivation of cholinesterase (ChE) from OP-inhibited ChE using rat saliva (in vitro) was developed using an electrochemical sensor coupled with a microflow-injection system. The sensor was based on a carbon nanotube (CNT)-modified screen printed carbon electrode (SPE), which was integrated into a flow cell. Because of the extent of interindividual ChE activity variability, ChE biomonitoring often requires an initial baseline determination (noninhibited) of enzyme activity which is then directly compared with activity after OP exposure. This manuscript describes an alternative strategy where reactivation of the phosphorylated enzyme was exploited to enable measurement of both inhibited and baseline ChE activity (after reactivation by an oxime, i.e., pralidoxime iodide) in the same sample. The use of CNT makes the electrochemical detection of the products from enzymatic reactions more feasible with extremely high sensitivity (5% ChE inhibition) and selectivity. Paraoxon was selected as a model OP compound for in vitro inhibition studies. Some experimental parameters, e.g., inhibition and reactivation time, have been optimized such that 92-95% of ChE reactivation can be achieved over a broad range of ChE inhibition (5-94%) with paraoxon. The extent of enzyme inhibition using this electrochemical sensor correlates well with conventional enzyme activity measurements. On the basis of the double determinations of enzyme activity, this flow-injection device has been successfully used to detect paraoxon inhibition efficiency in saliva samples (95% of ChE activity is due to butyrylcholinesterase), which demonstrated its promise as a sensitive monitor of OP exposure in biological fluids. Since it excludes inter- or intraindividual variation in the normal levels of ChE, this new CNT-based electrochemical sensor thus provides a sensitive and quantitative tool for point-of-care assessment and noninvasive biomonitoring of the exposure to OP pesticides and chemical nerve agents. [Description provided by NIOSH]
• Subjects:
  Agriculture Biochemistry Biological Factors Chemistry Chemistry, Analytic Energy Metabolism Environmental Monitoring Hazardous Substances Immune System Insecticides Laboratories Occupational Health Organophosphates Risk Assessment Risk Factors Safety

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• Keywords:
  Agricultural-chemicals Air-sampling Analytical-chemistry Biochemical-analysis Biochemical-tests Biodynamics Biological-effects Biological-factors Biological-monitoring Biological-transport Biostatistics Exposure-assessment Exposure-levels Exposure-methods Immunochemistry Immunotoxins Insecticide-poisoning Laboratory-animals Laboratory-testing Metabolic-study Organo-phosphorus-compounds Pesticides Pesticides-and-agricultural-chemicals Pharmacodynamics Quantitative-analysis Risk-analysis Risk-factors Toxic-effects Toxins

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• ISSN:
  0003-2700
• Document Type:
  Text
• Funding:
  Grant
• Genre:
  Journal Article
• Place as Subject:
  OSHA Region 10 ; Washington
• CIO:
  National Institute for Occupational Safety and Health (NIOSH)
• Topic:
  Workplace Safety & Health
• Location:
  North America
• Volume:
  81
• Issue:
  22
• NIOSHTIC Number:
  nn:20036506
• Citation:
  Anal Chem 2009 Nov; 81(22):9314-9320
• Contact Point Address:
  Yuehe Lin, Key Laboratory of Pesticide and Chemical Biology of Ministry of Education, College of Chemistry, Central China Normal University, Wuhan 430079, PR China
• Email:
  yuehe.lin@pnl.gov
• Federal Fiscal Year:
  2010
• NORA Priority Area:
  Agriculture, Forestry and Fishing
• Performing Organization:
  Battelle Pacific Northwest Laboratories
• Peer Reviewed:
  True
• Start Date:
  20060901
• Source Full Name:
  Analytical Chemistry
• End Date:
  20170831
• Collection(s):
  National Institute for Occupational Safety and Health
• Main Document Checksum:
  urn:sha-512:a7466b2a6a37386c3a2f4bf6affea676398c649888c3337eb2a76a422f1ac416edf4f03009b363c174dc42be20baa7a9b3bb896fd23ed1c3f9be1e16a0ea8387
• Download URL:
  https://stacks.cdc.gov/view/cdc/187901/cdc_187901_DS1.pdf
• File Type:
  [PDF - 2.18 MB ]