Marina Galliani1
EMSE1
With Covid-19 pandemic outbreak, the entire world faced multilevel healthcare system management challenges where the emergence to enable proper protection measures against infectious agents became critical. Face masks have been the most recommended personal protective equipment to limit the spreading of the infection. With the impelling interest in consumer-grade wearables [1], face masks are promising protective equipment suitable to be endowed with sensors that actively and noninvasively monitor bio parameters. The guidelines of the World Health Organization on the use of masks in the context of Covid-19 stated that they should be replaced “as soon as they become damp” [2]. The respiration rate is considered a vital parameter to identify breathlessness or difficulty breathing, both symptoms that might be correlated with an initial SARS-CoV-2 infection or respiratory diseases [3]. Therefore, we developed a sensor on a facial mask that simultaneously alerts the user about the barrier integrity of the mask and tracks the respiration rate. Such an e-mask is made by the direct inkjet printing a conductive polymer ink (PEDOT:PSS) in the shape of two interdigitated electrodes on the filter layer of the mask. By measuring the change in conductance between the two electrodes, we are able to follow the wetting level of the mask and the inhalation/exhalation cycles. Humidity chamber tests and a dedicated aerosol flow set-up allow assessing the sensor's sensitivity in the targeted humidity range related to the integrity failure (above 90%). A wearable proof of concept is demonstrated using commercially available Bluetooth portable electronics. Therefore, we demonstrated the feasibility of a built-in unobtrusive sensor to directly monitor facial masks barrier integrity and the respiration rate in real-time. Thanks to the adopted fabrication method and use of biocompatible [4] PEDOT:PSS, the sensor is safe and does not hinder the mask's filtering capabilities for the user. It can also be produced in a fast and scalable manner [5].<br/>[1] H. Jeong, J. A. Rogers, and S. Xu, “Continuous on-body sensing for the COVID-19 pandemic: Gaps and opportunities,” <i>Sci. Adv.</i>, vol. 6, no. 36, pp. 1–5, 2020, doi: 10.1126/sciadv.abd4794.<br/>[2] WHO, “Advice on the use of masks in the context of COVID-19,” <i>Who</i>, no. April, pp. 1–5, 2020, [Online]. Available: https://www.who.int/publications-.<br/>[3] S. Richardson <i>et al.</i>, “Presenting Characteristics, Comorbidities, and Outcomes Among 5700 Patients Hospitalized With COVID-19 in the New York City Area,” <i>JAMA</i>, vol. 323, no. 20, pp. 2052–2059, May 2020, doi: 10.1001/jama.2020.6775.<br/>[4] Z. Rahimzadeh, S. M. Naghib, Y. Zare, and K. Y. Rhee, “An overview on the synthesis and recent applications of conducting poly(3,4-ethylenedioxythiophene) (PEDOT) in industry and biomedicine,” <i>J. Mater. Sci.</i>, vol. 55, no. 18, pp. 7575–7611, 2020, doi: 10.1007/s10853-020-04561-2.<br/>[5] M. Magliulo <i>et al.</i>, “Printable and flexible electronics: From TFTs to bioelectronic devices,” <i>J. Mater. Chem. C</i>, vol. 3, no. 48, pp. 12347–12363, 2015, doi: 10.1039/c5tc02737c.