Preparation of surface acoustic wave odor sensors by laser-induced forward transfer

In this study it is presented the development of surface acoustic wave (SAW) biosensors for odor detection in the food industry. The SAW biosensors are coated by laser-induced forward transfer (LIFT) with wild-type bovine odorant binding protein (wtbOBP) solutions containing 20% and 50% glycerol. Optical microscopy investigations revealed that individual droplets could be printed from 50% glycerol solutions with a high resolution. Further investigations proved that despite the lower resolution of the 20% glycerol printed droplets it is possible to achieve higher uniformity in the coverage of the entire active area of the SAW biosensors. In addition, it is shown that the surface density of the wtbOBP LIFT-ed layer is four times higher than in the case of pipette deposition. Finally, the functionality of the SAW biosensors was investigated by testing the biosensors upon exposure to various concentrations of octenol vapors. A high sensitivity, i.e. of 5 Hz/ppm and detection limit in the low ppm range was obtained, lower that what has previously been reported with conventional methods.