REVIEW pubs.acs.org/acschemicalneuroscience Mimicking Biological Design and Computing Principles in

The olfactory system allows an organism to detect and inter-pret chemical cues present in its environment. A range of day-to-day functions, including appetite stimulation, food fora-ging and evaluation, mate recognition, navigation, detection of threats, and even early diagnosis of diseases depend on efficient processing of olfactory cues.1 To perform these essential but complex olfactory tasks, most mammalian and insect species have evolved strikingly similar chemosensory systems. This suggests that the iterative process of evolution converged to a common set of design and computing rules for the purpose of odor recognition.2 Artificial systems for noninvasive chemical sensing, popularly referred to as “electronic nose technology ” or “e-nose ” for short have emerged recently.3 Like their biological inspiration, electro-nic noses typically combine an array of sensitive detectors capable of distinguishing different chemicals with a pattern recognition module to detect and identify odors.47 Here, we first identify and discuss biological design and computing principles that we believe are particularly relevant for the purpose of artificial olfaction. Second, we review recent progress in engineering approaches inspired by biological principles. 1. THE BIOLOGICAL OLFACTORY SYSTEM The olfactory system in vertebrates and invertebrates com-prises three main components: an odor delivery system that transports the odor molecules to the sensory neurons; a large sensor array that transduces the chemical information into electrical signals; and neural circuits that process the sensory inputs to meet various analytical challenges. A schematic diagram of the early stages of the biological olfactory system and its variou