Ashok Mulchandani

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We report herein a whole cell-based amperometric biosensor for highly selective, highly sensitive, direct, single-step, rapid, and cost-effective determination of organophosphate pesticides with a p-nitrophenyl substituent. The biosensor was comprised of a p-nitrophenol degrader, Pseudomonas putida JS444, genetically engineered to express organophosphorus(More)
Environmental monitoring relies on compact, portable sensor systems capable of detecting pollutants in real-time. An integrated chemical sensor array system is developed for detection and identification of environmental pollutants in diesel and gasoline exhaust fumes. The system consists of a low noise floor analog front-end (AFE) followed by a signal(More)
Molecular beacons are oligonucleotide probes that become fluorescent upon hybridization. We developed a real-time PCR assay to detect the presence of Salmonella species using these fluorogenic reporter molecules. A 122-base-pair section of the himA was used as the amplification target. Molecular beacons were designed to recognize a 16-base-pair region on(More)
We report a sensitive, selective, and fast responding room temperature chemiresistive sensor for hydrogen sulfide detection and quantification using polyaniline nanowires-gold nanoparticles hybrid network. The sensor was fabricated by facile electrochemical technique. Initially, polyaniline nanowires with a diameter of 250–320 nm bridging the gap between a(More)
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 pH-sensitive capacitive electrolyte-insulator-semiconductor (EIS) structure that reacts towards pH(More)
Bifunctional fusion proteins consisting of organophosphate hydrolase (OPH) moieties linked to a Clostridium-derived cellulose-binding domain (CBD) were shown to be highly effective in degrading organophosphate nerve agents, enabling purification and immobilization onto different cellulose materials in essentially a single step. Enzyme kinetics studies were(More)
Graphene exhibits unique 2-D structural, chemical, and electronic properties that lead to its many potential applications. In order to expand the scope of its usage, graphene hybrids which combine the synergetic properties of graphene along with metals/metal oxides and other nanostructured materials have been synthesized and are a widely emerging field of(More)
Low-cost, low power consumption gas sensors that can detect or quantify various gas analytes are of increasing interest for various applications ranging from mobile health, to environmental exposure assessment and homeland security. In particular miniature gas sensors based on nanomaterials that can be manufactured in the form of sensor arrays present great(More)
A genetically engineered microorganism (GEM) capable of simultaneously degrading organophosphate and organochlorine pesticides was constructed for the first time by display of organophosphorus hydrolase (OPH) on the cell surface of a hexachlorocyclohexane (HCH)-degrading Sphingobium japonicum UT26. The GEM could potentially be used for removing the two(More)
Electrical and gas sensing properties of single-walled carbon nanotube networks functionalized with polyaniline (PANI-SWNTs) were systematically investigated to understand the gas sensing mechanisms and optimize sensing performance. The temperature-dependent electrical resistance and field-effect transistor (FET) transfer characteristics indicated that the(More)