Recent advances in bioelectronic noses based on olfactory receptors

Bioelectronic noses that mimic mammalian olfactory systems are considered intelligent chemical-array sensor devices. The selection of the materials used for the detection depends on their absorbability or catalysis to special odors. The finding of olfactory receptors coding gene and characterization leads to the development and elaboration of the e-smell system- the bioelectronic nose. The concept of mimicking insects and mammalian olfactory systems is of great curiosity for scientists to fabricate better, affordable, and small sensing systems. The primary recognition elements in e-nose such as human olfactory receptors and secondary signal transducers were used in nanoelectronics. The e-nose comprises three components such as sample handler, detection device, and data processor. The sensing biomaterials include olfactory neurons, odourant binding protein, olfactory receptors, and so on. The converter electronics include a device for measuring and analyzing the produced signals. The data analysis system is included to visualize the results. The limitations of current devices are sensor aging that requires replacement and recalibration. The investigation of nanomaterial for e-nose is widespread due to the ability of precise dimension and morphology control, tunable surface, etc., for various device applications. Nanomaterials provide ultrahigh sensitivity, integration of devices, and fast response kinetics. The nanowire chemiresistors, 2D materials, etc., act as critical elements in miniaturing e-noses for the future. Particularly, multiplexed e-nose processes the complex odor information. These sensing elements facilitate extended lifetime and stability and reduce the recalibration cycle. Fast response time (