Introduction to nano-e-nose

In the present era of artificial intelligence (AI), the real-time measurements using electronic skin, electronic tongue, and in particular, electronic noses are considered to be a pillar or backbone of data generation and corresponding analysis crucial for various industrial applications. The use of nano-e-noses has gained critical significance in health and environmental safety applications. They are the artificial olfaction systems that employ the multiple sensor arrays integrated with the various AI and machine learning algorithms. The current revolution in the e-noses has a major contribution to point of care devices, wireless sensors in robotics, wearable electronics, and self-powered devices. It is known that, for commercial-grade devices, the fulfillment of the 4-S (Sensitivity, Selectivity, Stability, and Suitability) criteria is the prerequisite. This can be achieved by engineering nanomaterials and patterned devices. Hence, reviewing the progress and current state of the art is very crucial for designing the industrial roadmap. This chapter provides a brief discussion on various nanomaterials and techniques used for developing nano e-noses. Nanomaterials have a high surface area to volume ratios and the ability to tune the physicochemical properties up to the atomic and molecular levels. In addition, the alignment of these nanomaterials in nanopatterns has defined and enabled a new class of electronic configuration called lab-on-a-chip or nanodevices. The overview of the concepts of nano-e-noses, nanomaterials wealth, corresponding fabrication tools, and state of the art is provided in detail. A brief discussion on the various statistical tools used in data analysis for successful discrimination of the output signals is also provided. The major emphasis has been provided to discuss the recent advances in the field citing some of the recent works of literature.