Figure 9.

(a) The olfactory neurons are the biological transducers of the olfactory signal. On the left is a schematic representation of the 3, 5-cyclic monophosphate (cAMP) signaling pathway [148]. This process inspired different designs to achieve highly sensitive detection of VOCs. (b) Jin et al. [23] integrated nanovesicles containing ORs and ion channels on field–effect transistors to enhance the potential difference caused by VOC binding. (c) Oh et al. [149] designed ion channel-coupled ORs for fundamental research purpose that could be integrated in biosensors. (d) The design proposed by Vidic et al. [22] used the desorption of the G protein upon VOC binding to enhance an SPR signal.