Biosensors for organophosphorus pesticide

T. Neufeld, I. Eshkenazi, E. Cohen, and J. Rishpon, A micro flow injection electrochemical biosensor for organophosphorus pesticides. Biosens. Bioelectron. 15, 323-329 (2000). 

K.C. Gulla, M.D. Gouda, M.S. Thakur, and N.G. Karanth, Reactivation of immobilized acetyl cholinesterase in an amperometric biosensor for organophosphorus pesticide. Biochim. Biophys. Acta... 

Jaffrezic-Renault, N., New trends in biosensors for organophosphorus pesticides. Sensors, 1, 60-74,... 

On a different setup, Du et al. [31] cast sol-gel silica/gold nanoparticle nanocomposite films on a glassy carbon electrode, which was then impregnated with an acetylcholinesterase (AChE) enzyme (Figure 46.10). The construct was used as a biosensor for organophosphorus pesticide detection. In this system, gold nanoparticles not only offered a biocompatible microenvironment to retain the activity of adsorbed enzyme molecules but also acted as a wire to enhance the direct electron transfer rate between the enzyme active centers and the electrode surface, which otherwise would be blocked by the thick protein shell of the enzyme chemical structure. 

Other enzymes have also been immobilized on CNTs for the construction of electrochemical biosensors. Deo et al. [115] have described an amperometric biosensor for organophosphorus (OP) pesticides based on a CNT-modified transducer and OP hydrolase, which is used to measure as low as 0.15 pM paraoxon and 0.8 pM parathion with... 

Disposable Electrochemical Biosensors for Organophosphorus and Carbamate Pesticide... 

Acetylcholinesterase is by far the most widely used enzyme in the preparation of biosensors for determining pesticides, both because organophosphorus insecticides and carbamates represent over half of the entire insecticide market and because the acetylcholinesterase commercially available has a high degree of purity and specificity of action and may be paired with many transducers (potentiometric, amperometric) in both flow and nonflow systems [62]. The specific tendency of organophosphorus pesticides and carbamates to inhibit acetylcholinesterase has been exploited for the purpose of determining these compounds, which are first separated by means of HPLC, then detected through a post-column reaction with immobilized acetylcholinesterase [63]. 

The anticholinesterase inhibitors (organophosphorous and carbamate), have come into widespread use in the last decades, because they are less persistent in the environment than other pesticides, such as organochlorine. However their presence in water and food is a potential hazard to human health and there is a growing interest in their rapid and accurate determination. Standard methods, based on gas chromatography (GC), are very reliable but there is the need for fast and innovative methods. The use of enzymatic biosensors, and especially electrochemical biosensors, for organophosphorus and carbamate pesticides detection has been reported by many authors [22-26]. 

Kumaran, S. andMorita, M. (1995) Application of a cholinesterase biosensor to screen for organophosphorus pesticides extracted from soil. Talanta, 42 (4), 649-655. 

In view of the conductive and electrocatalytic features of carbon nanotubes (CNTs), AChE and choline oxidases (COx) have been covalently coimmobilized on multiwall carbon nanotubes (MWNTs) for the preparation of an organophosphorus pesticide (OP) biosensor [40, 41], Another OP biosensor has also been constructed by adsorption of AChE on MWNTs modified thick film [8], More recently AChE has been covalently linked with MWNTs doped glutaraldehyde cross-linked chitosan composite film [11], in which biopolymer chitosan provides biocompatible nature to the enzyme and MWNTs improve the conductive nature of chitosan. Even though these enzyme immobilization techniques have been reported in the last three decades, no method can be commonly used for all the enzymes by retaining their complete activity. 

Y. Lin, F. Lu, and J. Wang, Disposable carbon nanotube modified screen-printed biosensor for ampero-metric detection of organophosphorus pesticides and nerve agents. Electroanalysis 16, 145-149 (2004). 

J.J. Rippeth, T.D. Gibson, J.P. Hart, I.C. Hartley and G. Nelson, Flow-injection detector incorporating a screen-printed disposable amperomet-ric biosensor for monitoring organophosphorus pesticides, Analyst, 122 (1997) 1425-1429. 

Zourob M, Simonian A, Wild J et al (2007) Optical leaky waveguide biosensors for the detection of organophosphorus pesticides. The Analyst 132 114—120... 

The effect of irreversible inhibition of acetylcholinesterase has been used in dendrimer-based electrochemical biosensors for environmental applications. Acetylcholinesterase is a very efficient protein catalyst for the hydrolysis of its physiological substrate acetylcholine. Organophosphorus and carbamic pesticides, heavy metals and detergents exert strong specific... 

Yang G, White IM, Fan X (2008) An opto-fluidic ring resonator biosensor for the detection of organophosphorus pesticides. Sensors Actuators B Phys 133 105-112... 

D., (1995) Validation of an enzymatic biosensor with various liquid chromatographic techniques for determining organophosphorus pesticides and carbaryl in freeze-dried waters. Anal. Chim. Acta, 311, 265-271... 

Mulchandani P, Chen W, Mulchandani A et al. Amperometric microbial biosensor for direct determination of organophosphate pesticides using recombinant microorganism with surface expressed organophosphorus hydrolase. Biosens Bioelectron 2001 16(7-8) 433-437. 

Enzyme inhibition sensors are the most commonly reported enzyme-based biosensors for the detection of toxic compounds and heavy metal ions. The sensors are based on the selective inhibition of specific enzymes by classes of compounds or by the more general inhibition of enzyme activity. Most of the research carried out has been directed toward the detection of organophosphorus and carbamate insecticides and the triazine herbicides and metal ions analysis [72,73]. Several enzymes have been used in inhibition sensors for pesticides and heavy metal analysis using water, soil, and food samples including choline esterase, horseradish peroxidase, polyphenol oxidase, urease, and aldehyde dehydrogenase. 

---