Ultra-sensitive conductometric detection of pesticides based on inhibition of esterase activity in Arthrospira platensis.

Abstract : Enzymatic conductometric biosensor, using immobilized Arthrospira platensis cells on gold interdigitated electrodes, for the detection of pesticides in water, was elaborated. Cholinesterase activity (AChE) was inhibited by pesticides and a variation of the local conductivity was measured after addition of the substrate acetylthiocholine chloride (AChCl). The Michaelis-Menten constant (Km) was evaluated to be 1.8 mM through a calibration curve of AChCl. Inhibition of AChE was observed with paraoxon-methyl, parathion-methyl, triazine and diuron with a detection limit of 10(-18) M, 10(-20) M, 10(-20) M and 10(-12) M, respectively and the half maximal inhibitory concentration (IC50) was determined at 10(-16) M, 10(-20) M, 10(-18) M and 10(-06) M, respectively. An important decrease of response time τ90% was recorded for AChE response towards AChCl after 30 min cell exposure to pesticides. Scanning electron microscopy images revealed a degradation of the cell surface in presence of pesticides at 10(-06) M.
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Submitted on : Monday, August 12, 2013 - 2:39:26 PM
Last modification on : Thursday, March 7, 2019 - 11:46:54 AM

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Nadèje Tekaya, Olga Saiapina, Hatem Ben Ouada, Florence Lagarde, Hafedh Ben Ouada, et al.. Ultra-sensitive conductometric detection of pesticides based on inhibition of esterase activity in Arthrospira platensis.. Environmental Pollution, Elsevier, 2013, 178, pp.182-188. ⟨10.1016/j.envpol.2013.03.013⟩. ⟨hal-00851121⟩

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