J.D. Aguilera, P. de la Presa, P. Marín, M.C. Horrillo, D. Matatagui
The 3rd International Conference on Nanomaterials Applied to Life Sciences 2022 (NALS 2022)
Del 27 al 29 de abril de 2022, Santander, España
We built an innovative sensor based on the interaction between nanostructures and gases using spin waves to detect the induced magnetic changes. The device is sensitive to low gas concentration of acetone, ammonia, carbon monoxide and benzene. The presence of these substances in human breath is related to different metabolic mechanisms, so they could be used to diagnose complex diseases like cancer [1]. When traces of these gases diluted in air pass through zinc ferrite nanoparticles, which are contained in a 2 mm diameter teflon tube, the magnetic properties of the nanostructures change. This change is detected by means of spin waves: due to the known dependence of their propagation on the external field [2], their frequency will shift as the nanoparticles’ properties change. These excitations propagate along the surface of a 2 μm thick epitaxial film made of YIG (Yttrium Iron Garnet), a ferrimagnetic insulator with a quite narrow magnetic resonance line. The frequency of the spin waves is detected by means of an oscillator circuit connected to a frequency counter. Before manufacturing the device, the computer simulations and calculations described in [3] were replicated in order to optimize the design of the device.
The results show the possibility of developing new inexpensive, reusable, contactless magnetic sensors employing spin waves as mechanism of transduction. The device was exposed to the target gas for one minute, then purged with pure air for nine minutes. The sensitivity of the equipment is under 50 ppm of the reducing gases acetone, ammonia, carbon monoxide and benzene. Besides, the magnetic nanoparticles are reusable few minutes after each measurement, although the response decreases gradually (maybe longer purge times would prevent this phenomenon) until it gets stable when carbon monoxide or benzene are introduced. Considering the low concentrations of the target gases, the outcome of this novel experiment is rather promising.
Acknowledgments
The authors acknowledge the projects RTI2018-095856-B-C21 and RTI2018-095856-B-C22.
References
[1] W. Miekisch, J. Schubert, and G. F. E. Noeldge-Schomburg, Clin.Chim. Acta, 2004, 347, 25–39.
[2] J. R. Fragoso and D. Matatagui, Bicapas de guías magnónicas para el procesamiento de señales, Universidad Nacional Autonoma de Mexico, 2016.
[3] M. Pozo-Gómez, J. Aguilera-Martín, P. de la Presa, C. Cruz, P. Marín, D. Matatagui, and M. Horrillo, Modeling and simulation of a magnonic gas sensor to detect diseases in human breath, in 2021 13th Spanish Conference on Electron Devices (CDE), pp. 125-128, 2021.
