Detection of explosive compounds using Photosystem II-based biosensor

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• 作者：Vijayender Bhalla¹  ; [Author Vitae] ; Xin Zhao  ; [Author Vitae] ; Valter Zazubovich ; ^{vzazubov@alcor.concordia.ca}  ; [Author Vitae]
• 关键词：Photosystem II ; Herbicides ; Picric acid ; TNT ; Screen-printed electrode
• 刊名：Journal of Electroanalytical Chemistry
• 出版年：2011
• 出版时间：1 July 2011
• 年：2011
• 卷：657
• 期：1-2
• 页码：84-90
• 全文大小：749 K

文摘

The efficacy of a Photosystem II (PS II)-based biosensor for the detection of explosive compounds has been explored. The idea is based on the close similarities in the chemical structures of the widespread explosives and herbicides, with the latter known to inhibit functioning of the PS II by attaching to the binding site of the Q_B mobile plastoquinone electron acceptor. The gold screen-printed electrodes (Au-SPE) functionalized with PS II-enriched particles were used for the detection of explosives in a droplet biosensor configuration. A crude preparation of PS II produced from spinach leaves, known as BBY particles, was employed to modify the Au-SPE working electrode employing BSA¨Cglutaraldehyde-based immobilization procedure. Inhibition of the PS II functioning was detected by photo-electrochemical measurements in the presence of a mediator (either non-native quinone or ferricyanide). The biosensor was highly responsive to herbicides (as expected) as well as to picric acid, with limits of detection in the nanomolar range, but trace detection of trinitrotoluene (TNT) was not effective. The detection limit for picric acid was 25 nM as compared to ?00 nM for TNT with duroquinone mediator. Low affinity of PS II to TNT has been corroborated by means of DCPIP assay; possible reasons for low affinity are discussed.