Odorant binding proteins based sniffing device for detection of tobacco

Affinity constants for a selection of Odorant Binding Proteins (OBPs) from mammalian and insect sources were determined toward volatile signature compounds from tobacco in the liquid phase using a fluorescent probe and competitive ligand binding. The most sensitive proteins were selected and these were immobilised on to diamond coated Surface Acoustic Wave (SAW) sensors to construct an array of eight sensors to detect tobacco volatiles. The system was then tested for its ability to detect vapours of tobacco itself as well as other markers. The results were positive, a pattern of responses across the array was observed as each sensor gave a specific response towards different analytes. To determine the stability of these OBP biosensors over time, the sensors were repeatedly exposed to pulses of saturated D(+)-carvone vapour over three months. Little degradation was observed and these sensors were able to sensitively detect the target analytes after this period.