An amperometric microbial biosensor for the direct measurement of organophosphate nerve agents is described. The sensor is based on a carbon paste electrode containing genetically engineered cells expressing organophosphorus hydrolase (OPH) on the cell surface. OPH catalyzes the hydrolysis of organophosphorus pesticides with p-nitrophenyl substituent such as paraoxon, parathion and methyl parat...

Nerve agent-degrading enzymes Organophosphorus Acid Anhydrolase (OPAA) and Organophosphorus Hydrolase (OPH) covalently-coupled to solid supports were examined as drinking water system nerve agent decontaminants. Enzymes were bound to azlactone polyacrylamide, glyoxal agarose and glyoxal-aminopropyl controlled-pore glass and tested for stability in unbuffered tap water. Kinetic analyses showed t...

This investigation examined the utility of three recombinant protein-expression systems (COS cells, insect cells and insect larvae) to cost-effectively produce biologically active human butyrylcholinesterase (BuChE). It was determined that baculovirus-infected insect cells (Sf9 and High 5) expressed 3.5- and 8.2-fold, respectively, more active enzyme than COS-7 cells. Baculovirus-infected cabba...

Current events across the globe necessitate rapid technological advances to combat the epidemic of nerve agent chemical weapons. Biocatalysis has emerged as a viable tool in the detoxification of organophosphorus neurotoxins, such as the chemical weapons VX and sarin. Efficient detoxification of contaminated equipment, machinery, and soils are of principal concern. This study describes the inco...

We report, the surface presentation of organophosphorus hydrolase (OPH) and green fluorescent protein (GFP) fusions by employing the adhesin-involved-in-diffuse-adherence (AIDA-I) translocator domain as a transporter and anchoring motif. The surface location of the OPH-GFP fusion protein was confirmed by immunofluorescence microscopy, and protease accessibility, followed by Western blotting ana...

A microbial biosensor consisting of a dissolved oxygen electrode modified with the genetically engineered PNP-degrader Moraxella sp. displaying organophosphorus hydrolase (OPH) on the cell surface for sensitive, selective, rapid and direct determination of p-nitrophenyl (PNP)-substituted organophosphates (OPs) is reported. Surface-expressed OPH works in tandem with the PNP oxidation machinery o...

The realisation of a miniaturised potentiometric enzyme biosensor is presented. The biosensor chip utilises the enzyme organophosphorus hydrolase (OPH) for the direct determination of pesticides. The transducer structure of the sensor chip consists of a pHsensitive capacitive electrolyte-insulator-semiconductor (EIS) structure that reacts towards pH changes caused by the OPH-catalysed hydrolysi...