Wearable Graphene-based smart face mask for Real-Time human respiration monitoring.

After the pandemic of SARS-CoV-2, the use of face-masks is considered the most effective way to prevent the spread of virus-containing respiratory fluid. As the virus targets the lungs directly, causing shortness of breath, continuous respiratory monitoring is crucial for evaluating health status. Therefore, the need for a smart face mask (SFM) capable of wirelessly monitoring human respiration in real-time has gained enormous attention. However, some challenges in developing these devices should be solved to make practical use of them possible. One key issue is to design a wearable SFM that is biocompatible and has fast responsivity for non-invasive and real-time tracking of respiration signals. Herein, we present a cost-effective and straightforward solution to produce innovative SFMs by depositing graphene-based coatings over commercial surgical masks. In particular, graphene nanoplatelets (GNPs) are integrated into a polycaprolactone (PCL) polymeric matrix. The resulting SFMs are characterized morphologically, and their electrical, electromechanical, and sensing properties are fully assessed. The proposed SFM exhibits remarkable durability (greater than1000 cycles) and excellent fast response time (∼42 ms), providing simultaneously normal and abnormal breath signals with clear differentiation. Finally, a developed mobile application monitors the mask wearer's breathing pattern wirelessly and provides alerts without compromising user-friendliness and comfort.

Wireless and Multi‐Person Respiration Monitoring using Facemask‐Integrated Flexible Meta‐Antennas

Respiration monitoring of a large population is important in containing the spread of viral respiratory infections such as the coronavirus disease 2019 (COVID‐19). Current technologies, however, lack the ability in respiration monitoring of multiple human subjects in a long‐term, robust, and low‐cost manner. Herein, wireless respiration monitoring of multiple human subjects using facemask‐integrated flexible meta‐antennas is demonstrated. The flexible meta‐antenna has an architecture of multi‐layered anisotropic hole‐array, which is optimized by theory and simulations to achieve high performances including good antenna gain, robustness against body interferences, and high air permeability favorable for facemask integration. A person's respiration patterns and respiration rates are wirelessly obtained by the meta‐antenna integrated with a temperature‐sensor‐embedded chip. Respiration monitoring of multiple subjects in long range and long term during daily activities is simultaneously demonstrated. In addition, a real‐time data processing system is introduced in which a local server, a cloud server, and an application layer are implemented for the real‐time display of respiration patterns and automatic recognition of abnormal status. The design of flexible meta‐antennas may lead to a distinct class of physiological sensors over a large population for applications in pandemic control and personalized healthcare. [ABSTRACT FROM AUTHOR] Copyright of Advanced Materials Technologies is the property of John Wiley & Sons, Inc. and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Stretchable, self‐healable, and breathable biomimetic iontronics with superior humidity‐sensing performance for wireless respiration monitoring

Stretchable, self‐healing, and breathable skin‐biomimetic‐sensing iontronics play an important role in human physiological signal monitoring and human–computer interaction. However, previous studies have focused on the mimicking of skin tactile sensing (pressure, strain, and temperature), and the development of more functionalities is necessary. To this end, a superior humidity‐sensitive ionic skin is developed based on a self‐healing, stretchable, breathable, and biocompatible polyvinyl alcohol–cellulose nanofibers organohydrogel film, showing a pronounced thickness‐dependent humidity‐sensing performance. The as‐prepared 62.47‐μm‐thick organohydrogel film exhibits a high response (25,000%) to 98% RH, excellent repeatability, and long‐term stability (120 days). Moreover, this ionic skin has excellent resistance to large mechanical deformation and damage, and the worn‐out material can still retain its humidity‐sensing capabilities after self‐repair. Humidity‐sensing mechanism studies show that the induced response is mainly related to the increase of proton mobility and interfacial charge transport efficiency after water adsorption. The superior humidity responsiveness is attributed to the reduced thickness and the increased specific surface area of the organohydrogel film, allowing real‐time recording of physiological signals. Notably, by combining with a self‐designed printed circuit board, a continuous and wireless respiration monitoring system is developed, presenting its great potential in wearable and biomedical electronics.

Unobtrusive In-Home Respiration Monitoring Using a Toilet Seat

Non-invasive monitoring of pulmonary health could revolutionize the care of health conditions ranging from COVID-19 to asthma to heart failure, but current technologies face challenges that limit their feasibility and adoption. Here, we introduce a novel approach to monitor respiration by measuring changes in impedance from the back of the thigh. The integration of electrodes into a toilet seat ensures patient compliance with unobtrusive daily respiration monitoring benefitting from repeatable electrode placement on the skin. In this work, the feasibility of the thigh and the sensitivity of impedance to respiration have been investigated empirically by comparing thorax and thigh-thigh bioimpedance measurements to spirometer measurements, and computationally, using finite element modeling. Empirical results show a measurable peak-peak impedance (0.022 ohm to 0.290 ohm for normal breathing across 8 subjects) with respiration across thigh-thigh and a high correlation (0.85) between lung tidal volume and impedance change due to respiration. Thigh-thigh bioimpedance measurements were found to be able to distinguish between shallow, normal, and deep breathing. Further, day-to-day variability in the relationship between impedance and tidal volume was investigated. The results suggest that the novel approach can be used to detect respiration rate and tidal volume and could provide valuable insight into disease state for conditions ranging from COVID-19 to heart failure. © 2022 IEEE.

Portable Respiration Monitoring System with an Embroidered Capacitive Facemask Sensor.

Respiration monitoring is a very important indicator of health status. It can be used as a marker in the recognition of a variety of diseases, such as sleep apnea, asthma or cardiac arrest. The purpose of the present study is to overcome limitations of the current state of the art in the field of respiration monitoring systems. Our goal was the development of a lightweight handheld device with portable operation and low power consumption. The proposed approach includes a textile capacitive sensor with interdigitated electrodes embroidered into the facemask, integrated with readout electronics. Readout electronics is based on the direct interface of the capacitive sensor and a microcontroller through just one analog and one digital pin. The microcontroller board and sensor are powered by a smartphone or PC through a USB cable. The developed mobile application for the Android™ operating system offers reliable data acquisition and acts as a bridge for data transfer to the remote server. The embroidered sensor was initially tested in a humidity-controlled chamber connected to a commercial impedance analyzer. Finally, in situ testing with 10 volunteering subjects confirmed stable operation with reliable respiration monitoring.

Highly Sensitive Cone-structured Porous Pressure Sensors for Respiration Monitoring Applications

A novel highly sensitive cone structured porous polydimethylsiloxane (PDMS) based pressure sensor capable of detecting very low-pressure ranges was developed for wearable respiration monitoring applications. The pressure sensor was fabricated using a master mold, a dielectric layer and fabric-based electrodes. The master mold with inverted cone structures was created using a rapid and precise three-dimensional (3D) printing technique. The dielectric layer with a porous and cone structures was prepared by annealing the mixture of PDMS, nitric acid (HNO3) and sodium bicarbonate (NaHCO3) in a master mold with inverted cone structures. The electrodes were developed by screen printing silver on fabric. A sensitivity of approximate to 530 %kPa(-1) was measured for the fabricated pressure sensor at ultra-low-pressure ranges from 0 Pa to 10 Pa. The porous-cone structures provided an excellent deformation and thus resulted in high sensitivity for detecting very low pressure ranges below 100 Pa (135 %kPa(-1)). As application demonstration, the pressure sensor was sewed inside a surgical mask and it's capability to detect different respiration rates (normal, fast, and deep breathes) was investigated. An airflow controller system and custom-built software was also developed for performing the continuous sensor data acquisition and capacitance conversions while changing the airflow rate.