Attempts to mimic human sensations have been steadily conducted along with technological advances. In the case of olfactory and taste senses in particular, mimicry can be applied to sensor technology for industrial, medical, and scientific purposes. Biological elements related to these two senses have acted as primary transducers, while nanoeletronic materials have been used as secondary transducers. Sensitive and selective bioelectronic nose and tongue have been developed using diverse biological elements, such as nanovesicle, nanodisc, and whole cell containing olfactory and taste receptors. These biosensors have great potential to be applied in various fields, such as disease diagnosis, assessment of food quality, environmental monitoring, public safety, and the standardization of smell. In this review, we introduce recently reported bioelectronic nose and tongue studies, and discuss future perspectives and possible applications.

Odor image sensor composed of 2-dimensional odor gas sensor can visualize odor space; odor flow or odor trace on the ground. Visualized image of odor can be recognized easily with our sense of sight. The 2D opto-chemical sensor is a key concept for practical use of a chemical sensor to solve calibration problems of chemical sensors. Odor quality visualization and prediction with machine learning based on molecular properties of odor substances and a relation network graph visualization.

A recent trend of a gadget to present smells called an olfactory display is described. Our group has developed the olfactory display to let a user sniff the smell from the mist generated by a Surface Acoustic Wave device to atomize a tiny liquid droplet spouted from a micro dispenser based upon a solenoid valve. It can quickly deliver the smell to the user’s nose because of its instantaneous atomization. We have developed both desktop and wearable olfactory displays based upon this principle. Then, the application contents of the olfactory display such as black coffee with sweetness originating from the smell and the scene to walk by a person with his/her smell were developed. Furthermore, the content with both olfactory and haptic senses was introduced.

Here we report on Tutorials and Sniffest from the ISOEN 2019 conference program. Sniffest is the student competition for machine olfaction. In ISOEN 2019, student teams brought a custom-made robot equipped with gas sensors, and competed in time trials in which the robots tried to track an odor trail laid on the floor. A short review is also reported for the special session on olfactory displays. In this session, we gave a presentation on a museum exhibition of our olfactory display system called a “smelling screen.” We also presented our attempts to apply the smelling screen to a large digital signage display panel.

A little gap between the direction of the latest research conducted on electronic nose and the needs of users who want to actively use electronic nose, has been felt for me recently, so if both can be helpful I gave a talk about the gap I felt at ISOEN 2019. The content of the talk is introduced in this paper.

The topics are from the viewpoints, sensitivity, influence of background odor, change over time in sensitivity, and adaptability to complex odor.