scholarly journals Low Power Contactless Bioimpedance Sensor for Monitoring Breathing Activity

Sensors ◽  
2021 ◽  
Vol 21 (6) ◽  
pp. 2081
Author(s):  
Marko Pavlin ◽  
Franc Novak ◽  
Gregor Papa

An electronic circuit for contactless detection of impedance changes in a tissue is presented. It operates on the principle of resonant frequency change of the resonator having the observed tissue as a dielectric. The operating frequency reflects the tissue dielectric properties (i.e., the tissue composition and on the tissue physiological changes). The sensor operation was tested within a medical application by measuring the breathing of a patient, which was an easy detectable physiological process. The advantage over conventional contact bioimpedance measurement methods is that no direct contact between the resonator and the body is required. Furthermore, the sensor’s wide operating range, ability to adapt to a broad range of measured materials, fast response, low power consumption, and small outline dimensions enables applications not only in the medical sector, but also in other domains. This can be extended, for example, to food industry or production maintenance, where the observed phenomena are reflected in dynamic dielectric properties of the observed object or material.

Healthcare ◽  
2021 ◽  
Vol 9 (8) ◽  
pp. 1055
Author(s):  
Muni Raj Maurya ◽  
Haseena Onthath ◽  
Hagar Morsy ◽  
Najam-US-Sahar Riyaz ◽  
Muna Ibrahim ◽  
...  

Monitoring exhaled breath is a safe, noninvasive method for determining the health status of the human body. Most of the components in our exhaled breath can act as health biomarkers, and they help in providing information about various diseases. Nitric oxide (NO) is one such important biomarker in exhaled breath that indicates oxidative stress in our body. This work presents a simple and noninvasive quantitative analysis approach for detecting NO from exhaled breath. The sensing is based on the colorimetric assisted detection of NO by m-Cresol Purple, Bromophenol Blue, and Alizaringelb dye. The sensing performance of the dye was analyzed by ultraviolet–visible (UV–Vis) spectroscopy. The study covers various sampling conditions like the pH effect, temperature effect, concentration effect, and selective nature of the dye. The m-Cresol Purple dye exhibited a high sensitivity towards NO with a detection limit of ~0.082 ppm in the linear range of 0.002–0.5 ppm. Moreover, the dye apprehended a high degree of selectivity towards other biocompounds present in the breath, and no possible interfering cross-reaction from these species was observed. The dye offered a high sensitivity, selectivity, fast response, and stability, which benchmark its potential for NO sensing. Further, m-Cresol Purple dye is suitable for NO sensing from the exhaled breath and can assist in quantifying oxidative stress levels in the body for the possible detection of COVID-19.


2020 ◽  
Vol 236 ◽  
pp. 116064 ◽  
Author(s):  
Fajr I.M. Ali ◽  
Saleh T. Mahmoud ◽  
Falah Awwad ◽  
Yaser E. Greish ◽  
Ayah F.S. Abu-Hani

Biosensors ◽  
2020 ◽  
Vol 10 (8) ◽  
pp. 91 ◽  
Author(s):  
Mayank Garg ◽  
Martin Christensen ◽  
Alexander Iles ◽  
Amit Sharma ◽  
Suman Singh ◽  
...  

Ferritin is a clinically important biomarker which reflects the state of iron in the body and is directly involved with anemia. Current methods available for ferritin estimation are generally not portable or they do not provide a fast response. To combat these issues, an attempt was made for lab-on-a-chip-based electrochemical detection of ferritin, developed with an integrated electrochemically active screen-printed electrode (SPE), combining nanotechnology, microfluidics, and electrochemistry. The SPE surface was modified with amine-functionalized graphene oxide to facilitate the binding of ferritin antibodies on the electrode surface. The functionalized SPE was embedded in the microfluidic flow cell with a simple magnetic clamping mechanism to allow continuous electrochemical detection of ferritin. Ferritin detection was accomplished via cyclic voltammetry with a dynamic linear range from 7.81 to 500 ng·mL−1 and an LOD of 0.413 ng·mL−1. The sensor performance was verified with spiked human serum samples. Furthermore, the sensor was validated by comparing its response with the response of the conventional ELISA method. The current method of microfluidic flow cell-based electrochemical ferritin detection demonstrated promising sensitivity and selectivity. This confirmed the plausibility of using the reported technique in point-of-care testing applications at a much faster rate than conventional techniques.


2016 ◽  
Vol 47 (1) ◽  
pp. 1313-1316
Author(s):  
Hak-Su Kim ◽  
Woo-Seok Lee ◽  
Jun-Sik Yoon ◽  
Se-Don Kim ◽  
Sung-Ho Kim ◽  
...  
Keyword(s):  

Polymers ◽  
2019 ◽  
Vol 11 (11) ◽  
pp. 1898 ◽  
Author(s):  
Yue Cao ◽  
Daming Zhang ◽  
Yue Yang ◽  
Baizhu Lin ◽  
Jiawen Lv ◽  
...  

This article demonstrates a dispersed-monolayer graphene-doped polymer/silica hybrid Mach–Zehnder interferometer (MZI) thermal optical switch with low-power consumption and fast response. The polymer/silica hybrid MZI structure reduces the power consumption of the device as a result of the large thermal optical coefficient of the polymer material. To further decrease the response time of the thermal optical switch device, a polymethyl methacrylate, doped with monolayer graphene as a cladding material, has been synthesized. Our study theoretically analyzed the thermal conductivity of composites using the Lewis–Nielsen model. The predicted thermal conductivity of the composites increased by 133.16% at a graphene volume fraction of 0.263 vol %, due to the large thermal conductivity of graphene. Measurements taken of the fabricated thermal optical switch exhibited a power consumption of 7.68 mW, a rise time of 40 μs, and a fall time of 80 μs at a wavelength of 1550 nm.


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