Researchers Develop Electronic Nose for Portable Electronics and Healthcare
The on-chip printed e-nose is a proof of concept for this kind of low-cost and sensitive devices
Electronic noses, or devices that can identify gases and particles, have been around for a while now and are utilized to identify everything from explosives to alcohol. With the onset of the IoT and wearable devices, electronic noses have found wide-spread use in the medical field. Now researchers from Skoltech have developed a low-cost and sensitive, on-chip printed electronic nose that is application-specific for portable electronics and healthcare alike.
The gas-analytical system can perform noninvasive diagnostics of human breath, including COPD (Chronic Obstructive Pulmonary Disease), using a compact sensor system to detect complex signals of gaseous compounds efficiently. The team designed the multi-sensor device using additive manufacturing- printing nanocrystalline films of eight different metal oxides (manganese, cerium, zirconium, zinc, chromium, cobalt, tin, and titanium) onto a multielectrode chip.
"For this work, we used microplotter printing and true solution inks. There are a few things that make it valuable," states senior research scientist Fedor Fedorov. "First, the resolution of the printing is close to the distance between electrodes on the chip, which is optimized for more convenient measurements. We show these technologies are compatible. Second, we managed to use several different oxides, which enables more orthogonal signal from the chip resulting in improved selectivity."
In a series of experiments, the engineers found that the device could sniff out the differences of several alcohol vapors, including methanol, ethanol, isopropanol, and n-butanol, which are difficult to tell apart in small concentrations. The team used an LDA (Linear Discriminant Analysis) algorithm to analyze the gases' chemical signatures but state other machine learning algorithms could be utilized if needed. However, there is one drawback to using the device as it operates at high temperatures (200 to 4000C), but metamaterials such as graphene and Mxenes (2D transition metal carbides) could bring those numbers down to room temperature.
