Diamond micro-cantilevers as transducers for olfactory receptors - based biosensors: Application to the receptors M71, OR7D4 and OR1740
Résumé
Three olfactory receptors (ORs): Mouse M71, Human OR1740 and chimpanzee OR7D4 were immobilized for the first time onto synthetic diamond transducers surfaces. Both OR1740 and OR7D4 were grafted through covalent bonding of hexanoic acid radical on diamond followed by EDC/NHS peptidic coupling to the receptor. OR M71 was grafted using covalent attachment of nitriloacetic acid (NTA) as chelating agent, which could bind the 6His tagged receptor through nickel ions. Both grafting procedures were monitored by electrochemical impedance spectroscopy (EIS) on boron doped diamond (BDD) electrodes. Once validated the protocols were applied to the surface of bulk diamond micro-cantilevers. The resulting sensors were assessed for odorant detection in the liquid phase using a Laser Doppler read-out system. For instance OR M71 was found to exhibit a good sensitivity to acetophenone, down to 1 μM with a good selectivity against negative control 2-octanone.