OP compounds strongly inhibit acetylcholinesterase (AChE) activity in animals and pests. AChE degrades the neurotransmitter acetylcholine into choline and acetate, and its inactivation results in acute or chronic dysfunction of the central nervous system [4]. With http://www.selleckchem.com/products/Roscovitine.html their extensive application over the past two decades, OP compounds are increasingly causing environmental problems such as contamination of water, vegetables, food and soil, Inhibitors,Modulators,Libraries thus becoming a great threat to human health and ecosystem balance. This indicates Inhibitors,Modulators,Libraries the importance of developing innovative methods for the effective detection of OP compounds.Many analytical methods for OP compound detection include gas chromatography, high-performance liquid chromatography and capillary electrophoresis [5].
These methods are used widely as criteria for inspection and quarantine because of their high sensitivity and specificity. However, these methods heavily depend on expensive instruments, time-consuming pretreatments, high-cost reagents Inhibitors,Modulators,Libraries and highly qualified technicians, and are not applicable in field monitoring. Biosensors based on specific biomolecular Inhibitors,Modulators,Libraries recognition, such as enzyme-substrate, antigen-antibody and DNA/DNA complexes, are suitable candidates for field testing because of their high specificity and sensitivity. Among the different biosensors, enzymatic analysis has been extensively investigated for OP compound monitoring. Two types of enzyme-based analytical methods have been widely studied: indirect quantitative detection of OP compounds using AChE and direct monitoring of OP compounds using organophosphorus hydrolase (OPH).
Indirect quantitation involves the measurement of the inhibition rate of AChE activity after Cilengitide exposure to OP compounds [6�C12]. Special substrates (e.g., acetylcholine or acetylthiocholine) are used to investigate the inhibition rate, which corresponds to the concentration of OP compounds. Enzyme inhibition in these systems is irreversible in most cases and could not be used for rapid and repetitive measurements in field analysis. By contrast, direct monitoring is concerned with the hydrolysis of OP compounds catalyzed by OPH without the addition of other substrates [13�C21]. These enzyme activities are not affected by substrates and could thus be used repeatedly. This method is more applicable and convenient in field analysis and several studies have reviewed the progress of biosensor development for OP compound analysis [22�C24].
The present study focused on optical biosensors based on methyl parathion hydrolase (MPH).The immobilization of biorecognition elements plays a key role in biosensor construction [25]. Several methods, selleck chemicals KPT-330 such as adsorption, entrapment, cross-linking and covalent binding, enable the immobilization of biomolecules on the solid surface of a transducer and are widely used in biosensor development.