Nanobiosensors based on individual olfactory receptors

AKIMOV, V.; ALFINITO, E.; BAUSELLS, E.; BENILOVA, I.; CASUSO PARAMO, I.; ERRACHID, A.; FERRARI, G.; FUMAGALLI, L.; GOMILA, G; GROSCLAUDE, J.; HOU, Y.; JAFFREZIC-RENAULT, N.; MARTELET, C.,; PAJOT-AUGY, E.; PENNETTA, C.; PERSUY, M.; PLA-ROCA, M.; REGGIANI, L.; RODRÍGUEZ SEGUÍ, S.A.; RUIZ, O.; SALESSE, R.; SAMITIER, J.; SAMPIETRO, M.; SOLDATKIN, A.; VIDIC, J.; VILLANUEVA, G.

ANALOG INTEGRATED CIRCUITS AND SIGNAL PROCESSING

SPRINGER

Año: 2008 vol. 57 p. 197 - 203

0925-1030

The animal olfactory system represents the gold standard of biosensors, due to its ability to identify and discriminate thousands of odorant compounds with very low thresholds. Using olfactory receptors (ORs) as sensing elements instead of chemical sensors, biosensors would benefit the naturally optimized molecular recognition of odorants to develop a new generation of bioelectronic noses. The purpose of SPOT-NOSED European project was the development of nanobiosensors based on single ORs anchored between nanoelectrodes, to mimic the performances of natural olfactory system. Nanobiosensors arrays could then increase odorant sensitivity or widen the odorant detection spectrum. ORs were expressed in yeasts plasmic membrane, and their functionality tested in whole yeasts. Then, nanosomes bearing the ORs were prepared from S. cerevisiae, and Surface Plasmon Resonance was performed on nanosomes for quantitative evaluation of OR response to odorant stimulation. ORs retain full activity and discrimination power in immobilized nanosomes, thus allowing their use in the fabrication of the nanobiosensors. Nanoelectrodes were fabricated using conventional photolithography and focused ion beam milling, with sizes in adequation with the nanosomes. ORs borne by nanosomes were specifically immobilized onto conducting substrates via mixed Self Assembled Monolayers, neutravidin and specific antibody to the ORs. The process was optimized by microcontact printing, and the  anchored nanovesicles visualized by Atomic Force Microscopy. A transimpedance preamplifier suited for low-noise wide-bandwidth measurements was designed to be directly connected to the nanoelectrodes. Electrochemical Impedancemetric Spectroscopy detected significant changes upon electrodes functionalization, grafting of ORs carried by nanosomes, and ORs conformationalchange induced by odorant binding.