A nano-sensor that works on the olfactory principle

THE human nose has inspired a team of researchers to create a similar device that smells the presence of toxic chemicals in the atmosphere.

The human sensor coordinates signals sent by thousands of sensory neurons to detect smells. The sensor, in this case, is a silicon chip which consists of nickel oxide nanoparticles acting as the neurons. When a chemical touches the surface of the oxide, it responds electrically; the response varies because each chemical has its own signature. The sensor detects the response and, in turn, helps identify the chemical.

Patricia Morris, professor of Chemistry at Ohio State University, with doctoral student Elvin Beach, had to first find a simple and easy way of making nanoparticles of nickel oxide. The nanoparticles would give the sensor a large surface area to quickly capture and identify a wide variety of chemical molecules. The team subjected nickel oxide to a pressure of 225