Pesticide biosensors developments

Most of the pesticide biosensors are designed based on the inhibitory property of enzymes. AChE and butyrylcholinesterase (BChE) are widely used in the development of pesticide biosensors [17, 18], Inhibition leads to a decrease in activity, which... 

M. Ayyagari, S. Kametkar, R. Pande, K.A. Marx, J. Kumar, S.K. Tripathy, J. Akkara, and D.L. Kaplan, Chemiluminescence-based inhibition kinetics of alkaline phosphatase in the development of a pesticide biosensor. Biotechnol. Prog. 11, 699-703 (1995). 

As mentioned in the previous section, the response, the stability and the enzyme activity found greatly enhanced at the MWCNT platform. Other than CNTs, AuNPs also possess some unique properties and recent years it has been widely employed in the biosensors to immobilize biomolecules. Thus in this section we discuss about the application of AuNP matrix for the immobilization of AChE for pesticide sensor development. With the use of AuNPs, the efficiency and the stability of the pesticide sensor gets greatly amplified. Moreover, the nanoparticles matrix offers much friendly environment for the immobilized enzyme and thus the catalytic activity of the enzyme got greatly amplified. Interestingly, Shulga et al. applied AChE immobilized colloidal AuNPs sensor for the nM determination of carbofuran, a CA pesticide [16], The enzyme-modified electrode sensor was also utilized for the sensitive electrochemical detection of thiocholine from the enzyme catalyzed hydrolysis of acetylthiocholine chloride (ATCl). The fabrication and the enzyme catalyzed reaction at the AuNPs coated electrode surface is shown in Fig. 6. 

The first SPR immunosensor for detection of pesticides was developed by Mimmni et al. [22] in the early 1990s. They used an SPR sensor developed by Biacore AB, Sweden, with the atrazine derivative bound to dextran matrix on the sensor chip. The detection of atrazine was performed using the inhibition assay and monoclonal antibodies. The sensor response was subsequently amplified by secondary antibody, which was bound to the antibody captured by the atrazine derivative (sandwich assay, see Chap. 7 in this volume [54]). This biosensor was demonstrated to measure atrazine in distilled and tap water within the range 0.05-1 ng mL in 15 min and exhibited relatively low crossreactivity with simazine and tetrabutyl atrazine (20%). The sensor surface was regenerated with 100 mM sodium hydroxide in 20% acetonitrile. 

DEVELOPMENT OF A PESTICIDES BIOSENSOR USING CARBON-BASED ELECTRODE SYSTEMS... 

Compared to research and development for biosensors for clinical applications [39, 40], not much research has been carried out in the field of environmental control. Biosensors for pesticide control in water are still in a developmental stag and no biosensors are commercially available to date for this field of application. Field tests are presently carried out with the mediated amperometric biosensor developed by Rawson et al. [31], but the sensitivity and specificy of this biosensor is not sufflcient for the high demands of drinking water quality control. 

A piezoelectric biosensor, for the detection of several organophosphorus pesticides was developed (Halamek et al., 2005). The sensor was based on the immobilization of a reversible inhibitor of cholinesterase on the surface of the sensor. The binding of AChE to this inhibitor was monitored with a mass-sensitive piezoelectric quartz crystal. In the presence of an inhibiting substance in the sample, the binding of the enzyme to the immobilized compound was reduced, and the decrease of mass change was proportional to the concentration of the analyte in the sample. This sensor was applied to the determination of pesticides in river water samples. 

The first work in the literature named as inhibition BioET was a collaborative work between our laboratory and a French laboratory commanding pesticide analysis. In this work, the BioET was developed, employing an array of inhibition biosensors and ANNs [15]. The array of biosensors was formed by three ampero-metric pesticide biosensors that used different AChE enzymes the wild type from electric eel (EE) and two different genetically modified enzymes (B1 and B394). The system was employed for the simultaneous determination and/or resolution of mixtures of two pesticides, dichlorvos and carbofuran, with mean values of... 

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