Biosensor Based on Self-Assembling Acetylcholinesterase on Carbon Nanotubes for Flow injection/Amperometric Detection of Organophosphate Pesticides and Nerve Agents

Journal Article · Wed Feb 01 04:00:00 EST 2006 · Analytical Chemistry

DOI:https://doi.org/10.1021/ac051559q· OSTI ID:877552

Liu, Guodong; Lin, Yuehe

A highly sensitive flow-injection amperometric biosensor for organophosphate pesticides and nerve agents based on self-assembly of acetylcholinesterase (AChE) on carbon nanotube (CNT)-modified glassy carbon (GC) electrode is described. AChE is immobilized on the negatively-charged CNT surface by alternatively assembling a cationic polydiallyldimethylammonium chloride (PDDA) layer and an AChE layer. Transmission electron microscopy images confirm the formation of layer-by-layer nanostructures on carboxyl functionalized CNTs. The unique sandwich-like structure (PDDA/AChE/PDDA) on the CNT surface formed by self-assembly provides a favorable microenvironment to keep the bioactivity of AChE and to prevent enzyme molecule leakage. The electrocatalytic activity of CNT leads to a greatly improved electrochemical detection of the enzymatically generated thiocholine product, including a low oxidation overvoltage (+150 mV), higher sensitivity, and stability. The developed PDDA/AChE/PDDA/CNT/GC biosensor integrated into a flow injection system was used to monitor organophosphate pesticides and nerve agents, such as paraoxon. The sensor performance, including inhibition time and regeneration conditions, was optimized with respect to operating conditions. Under the optimal conditions, the biosensor was used to measure as low as 0.4 pM paraoxon with a 6-min inhibition time. The biosensor had excellent operational lifetime stability with no decrease in the activity of enzymes for more than 20 repeated measurements over a 1-week period. The developed biosensor system is an ideal tool for online monitoring of organophosphate pesticides and nerve agents.

• Research Organization: Pacific Northwest National Laboratory (PNNL), Richland, WA (US), Environmental Molecular Sciences Laboratory (EMSL)
• Sponsoring Organization: USDOE
• DOE Contract Number: AC05-76RL01830
• OSTI ID: 877552
• Report Number(s): PNNL-SA-46970; 12490; 6899
• Journal Information: Analytical Chemistry, Journal Name: Analytical Chemistry Journal Issue: 3 Vol. 78
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
45 MILITARY TECHNOLOGY, WEAPONRY, AND NATIONAL DEFENSE
54 ENVIRONMENTAL SCIENCES
AMPEROMETRY
BIOLOGICAL WARFARE AGENTS
CARBON
CARBOXYLESTERASES
Carbon nanotubes
DETECTION
Environmental Molecular Sciences Laboratory
IMMOBILIZED ENZYMES
NANOSTRUCTURES
PESTICIDES
PROBES
biosensor
nerve agents
pesticides