Pesticide biosensors

Andreou V., Clonis Y., A portable fiber-optic pesticide biosensor based on immobilized cholinesterase and sol-gel entrapped bromocresol purple for in-field use, Biosens. Bioelectr. 2002 17 61-69. 

Enzymes used in pesticide biosensors and their features... 

Immobilization methods used in pesticide biosensors design... 

Whole cell and tissue-based pesticide biosensors... 

Acetylcholinesterase (AChE) isolated from various organisms has been used in the majority of pesticide biosensors. In the early 1950s potentiometric detection was adopted for pesticide detection. In the middle of the 1980s it was used for the construction of the first integrated biosensors for detection of pesticides based on inhibition of AChE. Later rapid changes in science and technology introduced novel genetically... 

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... 

Mainly, two principles are used in electrochemical pesticide biosensor design, either enzyme inhibition or hydrolysis of pesticide. Among these two approaches inhibition-based biosensors have been widely employed in analysis due to the simplicity and wide availability of the enzymes. The direct enzymatic hydrolysis of pesticide is also extremely attractive for biosensing, because the catalytic reaction is superior and faster than the inhibition [27],... 

MWNTs favored the detection of insecticide from 1.5 to 80 nM with a detection limit of InM at an inhibition of 10% (Fig. 2.7). Bucur et al. [58] employed two kinds of AChE, wild type Drosophila melanogaster and a mutant E69W, for the pesticide detection using flow injection analysis. Mutant AChE showed lower detection limit (1 X 10-7 M) than the wild type (1 X 10 6 M) for omethoate. An amperometric FIA biosensor was reported by immobilizing OPH on aminopropyl control pore glass beads [27], The amperometric response of the biosensor was linear up to 120 and 140 pM for paraoxon and methyl-parathion, respectively, with a detection limit of 20 nM (for both the pesticides). Neufeld et al. [59] reported a sensitive, rapid, small, and inexpensive amperometric microflow injection electrochemical biosensor for the identification and quantification of dimethyl 2,2 -dichlorovinyl phosphate (DDVP) on the spot. The electrochemical cell was made up of a screen-printed electrode covered with an enzymatic membrane and combined with a flow cell and computer-controlled potentiostat. Potassium hexacyanoferrate (III) was used as mediator to generate very sharp, rapid, and reproducible electric signals. Other reports on pesticide biosensors could be found in review [17],... 

WHOLE CELL AND TISSUE-BASED PESTICIDE BIOSENSORS... 

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). 

S. Ozaki, H. Nakagawa, K. Fukuda, S. Asakura, H. Kiuchi, T. Shigemori, and S. Takahashi, Re-activation of an amperometric organophosphate pesticide biosensor by 2-pyridinealdoxime methochloride. Sens. 

JL Martin, N Mionetto, T Noguer, F Ortega, C Roux. Enzyme sensors for the detection of pesticides. Biosensors Bioelectronics 8 273-280, 1993. 

N. Mionetto, J.-L. Marty and I. Karube, Acetylcholinesterase in organic solvents for the detection of pesticides biosensor application, Biosens. Bioelectron, 9 (1994) 463-470. 

Fig. 23.6. Sequence of reactions occurring at a pesticide biosensor based on an SPCE modified with AChE with a reversible mediator.

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

With amperometric transducers, two types of pesticides biosensors can be constructed. One possibility is a two-enzyme system using AChE and choline oxidase (ChOD) and thus employing either an oxygen sensor (Campanella et al., 1991) or a hydrogen peroxide detector (Marty et al., 1992 Palleschi et al., 1992) as the internal transducer. 

Most biosensors based on AChE have the enzymes immobilized on the surface of the sensor. The inhibition reaction being irreversible, the membrane with immobilized enzyme has to be replaced after several measurements or the biosensor can be use for only one determination. Due to this fact, the researchers tried to realize pesticide biosensors with a renewable surface or disposable biosensors based on screen-printed electrodes (SPE). The screen-printing technology provides a simple, fast and inexpensive method for mass production of disposable biosensors for different biomolecules starting with glucose, lactate and finishing with environmental contaminants as pesticides (Kulys et al., 1991) and herbicides (Skladal, 1992). 

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