scholarly journals Multichannel Electrical Impedance Spectroscopy Analyzer with Microfluidic Sensors

Sensors ◽  
2019 ◽  
Vol 19 (8) ◽  
pp. 1891 ◽  
Author(s):  
Jaan Ojarand ◽  
Mart Min ◽  
Ants Koel
Keyword(s):  
Impedance Spectroscopy ◽  
Mechanical Design ◽  
Point Of Care ◽  
High Sensitivity ◽  
Electrical Impedance Spectroscopy ◽  
Signal Acquisition ◽  
Biological Matter ◽  
Microfluidic Sensors ◽  
Passive Electrical Properties ◽  
Novel Design

Impedance spectroscopy is a common approach in assessing passive electrical properties of biological matter. However, several problems appear in microfluidic devices in connection with the requirement for high sensitivity of signal acquisition from small volume sensors. The developed compact and inexpensive analyzer provides impedance spectroscopy measurement from three sensors, both connected in direct and differential modes. Measurement deficiencies are reduced with a novel design of sensors, measurement method, optimized electronics, signal processing, and mechanical design of the analyzer. Proposed solutions are targeted to the creation of reliable point-of-care (POC) diagnostic and monitoring appliances, including lab-on-a-chip type devices in the next steps of development. The test results show the good working ability of the developed analyzer; however, also limitations and problems that require attention and further improvement are appointed.

Current Source Design for Electrical Bioimpedance Spectroscopy

2008 ◽  
pp. 359-367 ◽  
Author(s):  
Fernando Seoane ◽  
Ramón Bragos ◽  
Kaj Lindecrantz ◽  
Pere Riu
Keyword(s):  
Electrical Properties ◽  
Impedance Spectroscopy ◽  
Biological Tissue ◽  
Electrical Impedance ◽  
Current Source ◽  
Electrical Impedance Spectroscopy ◽  
Bioimpedance Spectroscopy ◽  
Electrical Bioimpedance ◽  
Electronic Instrumentation ◽  
Passive Electrical Properties

The passive electrical properties of biological tissue have been studied since the 1920s, and with time, the use of Electrical Bioimpedance (EBI) in medicine has successfully spread (Schwan, 1999). Since the electrical properties of tissue are frequency-dependent (Schwan, 1957), observations of the bioimpedance spectrum have created the discipline of Electrical Impedance Spectroscopy (EIS), a discipline that has experienced a development closely related to the progress of electronic instrumentation and the dissemination of EBI technology through medicine.

scholarly journals Performance Evaluation of Multiple Electrodes Based Electrical Impedance Spectroscopic Probe for Screening of Cervical Intraepithelial Neoplasia

Electronics ◽  
2021 ◽  
Vol 10 (16) ◽  
pp. 1933
Author(s):  
Tingting Zhang ◽  
Youjeong Jeong ◽  
Dongchoon Park ◽  
Tongin Oh
Keyword(s):  
Electrical Properties ◽  
Impedance Spectroscopy ◽  
Cervical Intraepithelial Neoplasia ◽  
Electrical Impedance ◽  
Low Cost ◽  
High Sensitivity ◽  
Intraepithelial Neoplasia ◽  
Electrical Impedance Spectroscopy ◽  
Voltage Measurement ◽  
Wide Range

As regular cervical cancer screening becomes more common, the detection of cervical intraepithelial neoplasia (CIN) is increasing. We proposed a noninvasive and low-cost multi-channel electrical impedance spectroscopy (EIS) and probe with multiple active electrodes for screening CIN. Compared with four-electrode probes for impedance spectroscopy, the multiple active electrodes facilitated more flexible combination of current injection and voltage measurement, which allowed well-designed measurement protocols for focused sensitivity underneath the large size of the probe. Furthermore, the multiple active electrodes reduced the negative effects of the cabling between the system and probe inserted into the cervix. After presenting the basic performance, the EIS probe was tested by three different experimental phantoms using four different materials of electrical properties. The corresponding experimental results were presented to prove the functionality of the EIS probe and characterize the electrical properties at a wide range of frequencies from 0.625 to 100 kHz. It had high sensitivity underneath the surface of the probe and a rapidly decreased outer. Furthermore, we verified the frequency-dependent impedance changes using the giant vesicle phantoms with different amounts of extra- and intra-fluids separated by the insulating membranes. This study facilitates the feasibility into clinical practice for identifying CIN in the future.

scholarly journals Assessing ischemic injury in human intestine ex vivo with electrical impedance spectroscopy

2021 ◽  
Vol 12 (1) ◽  
pp. 82-88
Author(s):  
Jie Hou ◽  
Runar Strand-Amundsen ◽  
Stina Hødnebø ◽  
Tor Inge Tønnessen ◽  
Jan Olav Høgetveit
Keyword(s):  
Electrical Properties ◽  
Impedance Spectroscopy ◽  
Electrical Impedance ◽  
Electrical Impedance Spectroscopy ◽  
Time Interval ◽  
Human Intestine ◽  
Impedance Measurements ◽  
Intestinal Segments ◽  
Small Intestinal ◽  
Passive Electrical Properties

Abstract Electrical impedance spectroscopy is a well-established tool for monitoring changes in the electrical properties of tissue. Most tissue and organ types have been investigated in various studies. As for the small intestine, there are several published studies conducted on pig and rat models. This study investigates the changes in passive electrical properties of the complete wall of the human intestine non-invasively during ischemia. We aim to use the passive electrical properties to assess intestinal viability. The bioimpedance measurements were performed using a two-electrode set-up with a Solartron 1260 Impedance/gain-phase analyser. The small intestinal samples were resected from patients who underwent pancreaticoduodenectomy. Impedance measurements were conducted following resection by placing the electrodes on the surface of the intestine. A voltage was applied across the intestinal sample and the measured electrical impedance was obtained in the ZPlot software. Impedance data were further fitted into a Cole model to obtain the Cole parameters. The Py value was calculated from the extracted Cole parameters and used to assess the cell membrane integrity, thus evaluate the intestinal viability. Eight small intestinal segments from different patients were used in this study and impedance measurements were performed once an hour for a ten-hour period. One hour after resection, the impedance decreased, then increased the next two hours, before decreasing until the end of the experiment. For all the intestinal segments, the Py values first increased and reached a plateau which lasted for 1 - 2 hours, before it decreased irreversibly. The time interval where Py value reached the maximum is consistent with reported viable/non-viable limits from histological analysis.

Electrical Impedance Spectroscopy Estimation of Water Content in Leaves and Stems of White Birch (Betula platyphylla) Under Flooding Stress

2014 ◽  
Vol 49 (1) ◽  
pp. 105 ◽  
Author(s):  
Meng Yu ◽  
Gong Ruijuan ◽  
Di Bao ◽  
Xiang Diying ◽  
Zhang Gang ◽  
...  
Keyword(s):  
Impedance Spectroscopy ◽  
Water Content ◽  
Electrical Impedance ◽  
Electrical Impedance Spectroscopy ◽  
Betula Platyphylla ◽  
White Birch ◽  
Flooding Stress

Novel High Sensitivity Tuberculosis Point-of-Care Test for People Living with HIV

2018 ◽  
Author(s):  
Tobias Broger ◽  
Bianca Sossen ◽  
Elloise du Toit ◽  
Andrew D. Kerkhoff ◽  
Charlotte Schutz ◽  
...  
Keyword(s):  
Point Of Care ◽  
High Sensitivity ◽  
People Living With Hiv ◽  
Point Of Care Test ◽  
Living With Hiv

Trends in Diagnosis for Active Tuberculosis Using Nanomaterials

2019 ◽  
Vol 26 (11) ◽  
pp. 1946-1959 ◽  
Author(s):  
Le Minh Tu Phan ◽  
Lemma Teshome Tufa ◽  
Hwa-Jung Kim ◽  
Jaebeom Lee ◽  
Tae Jung Park
Keyword(s):  
Sensitivity And Specificity ◽  
High Efficiency ◽  
Point Of Care ◽  
High Sensitivity ◽  
Signs And Symptoms ◽  
Diagnostic Methods ◽  
Advantages And Disadvantages ◽  
Treatment And Prevention ◽  
Clinical Tools ◽  
Diagnostic Applications

Background:Tuberculosis (TB), one of the leading causes of death worldwide, is difficult to diagnose based only on signs and symptoms. Methods for TB detection are continuously being researched to design novel effective clinical tools for the diagnosis of TB.Objective:This article reviews the methods to diagnose TB at the latent and active stages and to recognize prospective TB diagnostic methods based on nanomaterials.Methods:The current methods for TB diagnosis were reviewed by evaluating their advantages and disadvantages. Furthermore, the trends in TB detection using nanomaterials were discussed regarding their performance capacity for clinical diagnostic applications.Results:Current methods such as microscopy, culture, and tuberculin skin test are still being employed to diagnose TB, however, a highly sensitive point of care tool without false results is still needed. The utilization of nanomaterials to detect the specific TB biomarkers with high sensitivity and specificity can provide a possible strategy to rapidly diagnose TB. Although it is challenging for nanodiagnostic platforms to be assessed in clinical trials, active TB diagnosis using nanomaterials is highly expected to achieve clinical significance for regular application. In addition, aspects and future directions in developing the high-efficiency tools to diagnose active TB using advanced nanomaterials are expounded.Conclusion:This review suggests that nanomaterials have high potential as rapid, costeffective tools to enhance the diagnostic sensitivity and specificity for the accurate diagnosis, treatment, and prevention of TB. Hence, portable nanobiosensors can be alternative effective tests to be exploited globally after clinical trial execution.

scholarly journals A Rapid, High-Sensitivity SARS-CoV-2 Nucleocapsid Immunoassay to Aid Diagnosis of Acute COVID-19 at the Point of Care: A Clinical Performance Study

2021 ◽  
Author(s):  
Paul K. Drain ◽  
Madhavi Ampajwala ◽  
Christopher Chappel ◽  
Andre B. Gvozden ◽  
Melanie Hoppers ◽  
...  
Keyword(s):  
Clinical Performance ◽  
Point Of Care ◽  
High Sensitivity ◽  
Performance Study

scholarly journals Evaluation of Production Lots of a Rapid Point-of-Care Lateral Flow Serological Test Intended for Identification of IgM and IgG against the N-Terminal Part of the Spike Protein (S1) of SARS-CoV-2

Viruses ◽  
2021 ◽  
Vol 13 (6) ◽  
pp. 1043
Author(s):  
Tove Hoffman ◽  
Linda Kolstad ◽  
Bengt Rönnberg ◽  
Åke Lundkvist
Keyword(s):  
Predictive Value ◽  
Serological Test ◽  
Point Of Care ◽  
External Validation ◽  
High Sensitivity ◽  
Lateral Flow ◽  
Spike Protein ◽  
Individual Level ◽  
Lateral Flow Test ◽  
Production Errors

The potential of rapid point-of-care (POC) tests has been subject of doubt due to an eventual risk of production errors. The aim was therefore to evaluate the two separate production lots of a commercial POC lateral flow test, intended for the detection of IgM and IgG against the SARS-CoV-2 spike protein (S1). Control samples consisted of serum from individuals with confirmed SARS-CoV-2 infection and pre-COVID-19 negative sera gathered from a biobank. The presence of anti-S1 IgM/IgG in the sera was verified by an in-house Luminex-based serological assay (COVID-19 SIA). One hundred samples were verified as positive for anti-S1 IgG and 74 for anti-S1 IgM. Two hundred samples were verified as negative for anti-S1 IgM/IgG. For the two lots of the POC-test, the sensitivities were 93.2% and 87.8% for IgM and 93.0% and 100% for IgG. The specificities were 100% for IgM and 99.5% for IgG. The positive predictive value was 100% for IgM and 98.9% and 99.0% for IgG. The negative predictive value was 97.6% and 95.7% for IgM, and 96.6% and 100% for IgG. The evaluated POC-test is suitable to assess anti-SARS-CoV-2 S1 IgM and IgG, as a measure of previous virus exposure on an individual level. The external validation of separate lots of rapid POC-tests is encouraged to ensure high sensitivity before market introduction.

A Rapid Approach to Measure Extracted Chlorophyll-a from Lettuce Leaves using Electrical Impedance Spectroscopy

2021 ◽  
Vol 232 (2) ◽  
Author(s):  
Rakibul Islam Chowdhury ◽  
Rinku Basak ◽  
Khan Arif Wahid ◽  
Katy Nugent ◽  
Helen Baulch
Keyword(s):  
Impedance Spectroscopy ◽  
Chlorophyll A ◽  
Electrical Impedance ◽  
Electrical Impedance Spectroscopy

scholarly journals Study of Reduced Graphene Oxide Dispersions via Electrical Impedance Spectroscopy

2020 ◽  
Vol 28 ◽  
pp. 1679-1685
Author(s):  
Angeliki-Eirini Dimou ◽  
Ioanna Sakellariou ◽  
George M. Maistros ◽  
Nikolaos D. Alexopoulos
Keyword(s):  
Graphene Oxide ◽  
Impedance Spectroscopy ◽  
Reduced Graphene Oxide ◽  
Electrical Impedance ◽  
Electrical Impedance Spectroscopy ◽  
Reduced Graphene
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