Journal articles: 'Instrumentation for EIS'

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Grossi, Marco, and Bruno Riccò. "Electrical impedance spectroscopy (EIS) for biological analysis and food characterization: a review." Journal of Sensors and Sensor Systems 6, no. 2 (August 28, 2017): 303–25. http://dx.doi.org/10.5194/jsss-6-303-2017.

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Abstract. Electrical impedance spectroscopy (EIS), in which a sinusoidal test voltage or current is applied to the sample under test to measure its impedance over a suitable frequency range, is a powerful technique to investigate the electrical properties of a large variety of materials. In practice, the measured impedance spectra, usually fitted with an equivalent electrical model, represent an electrical fingerprint of the sample providing an insight into its properties and behavior. EIS is used in a broad range of applications as a quick and easily automated technique to characterize solid, liquid, semiliquid, organic as well as inorganic materials. This paper presents an updated review of EIS main implementations and applications.

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LENTKA, Grzegorz. "Programmable dynamically changing RC model for evaluation of Dynamic EIS methods and instrumentation." PRZEGLĄD ELEKTROTECHNICZNY 1, no. 11 (November 5, 2018): 61–64. http://dx.doi.org/10.15199/48.2018.11.14.

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Burgos-Flórez, Francisco, Alexander Rodríguez, Eliana Cervera, Valtencir Zucolotto, Marco Sanjuán, and Pedro J. Villalba. "TBISTAT: An open-source, wireless portable, electrochemical impedance spectroscopy capable potentiostat for the point-of-care detection of S100B in plasma samples." PLOS ONE 17, no. 2 (February 7, 2022): e0263738. http://dx.doi.org/10.1371/journal.pone.0263738.

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Point-of-Care (POC) testing for biomarker detection demands techniques that are easy to use, readily available, low-cost, and with rapid response times. This paper describes the development of a fully open-source, modular, wireless, battery-powered, smartphone-controlled, low-cost potentiostat capable of conducting electrochemical impedance spectroscopy for the electrochemical detection of the S100B protein captured in an ANTI-S100B functionalized thin-film gold interdigitated electrode platform to support traumatic brain injury diagnosis and treatment. EIS results from the developed potentiostat were validated with a commercial benchtop potentiostat by comparing impedance magnitude and phase values along the EIS frequency range. In addition, an experimental design was performed for detecting S100B in spiked human plasma samples with S100B concentrations of clinical utility, and a calibration curve was found for quantifying S100B detection. No statistically significant differences were found between EIS results from the developed potentiostat and the commercial potentiostat. Statistically significant differences in the changes in charge transfer resistance signal between each tested S100B concentration (p < 0.05) were found, with a limit of detection of 35.73 pg/mL. The modularity of the proposed potentiostat allows easier component changes according to the application demands in power, frequency excitation ranges, wireless communication protocol, signal amplification and transduction, precision, and sampling frequency of ADC, among others, when compared to state-of-the-art open-source EIS potentiostats. In addition, the use of minimal, easy acquirable open-source hardware and software, high-level filtering, accurate ADC, Fast Fourier Transform with low spectral leakage, wireless communication, and the simple user interface provides a framework for facilitating EIS analysis and developing new affordable instrumentation for POC biosensors integrated systems.

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Bencivenga, Filippo, Marco Zangrando, Cristian Svetina, Alessandro Abrami, Andrea Battistoni, Roberto Borghes, Flavio Capotondi, et al. "Experimental setups for FEL-based four-wave mixing experiments at FERMI." Journal of Synchrotron Radiation 23, no. 1 (January 1, 2016): 132–40. http://dx.doi.org/10.1107/s1600577515021104.

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The recent advent of free-electron laser (FEL) sources is driving the scientific community to extend table-top laser research to shorter wavelengths adding elemental selectivity and chemical state specificity. Both a compact setup (mini-TIMER) and a separate instrument (EIS-TIMER) dedicated to four-wave-mixing (FWM) experiments has been designed and constructed, to be operated as a branch of the Elastic and Inelastic Scattering beamline: EIS. The FWM experiments that are planned at EIS-TIMER are based on the transient grating approach, where two crossed FEL pulses create a controlled modulation of the sample excitations while a third time-delayed pulse is used to monitor the dynamics of the excited state. This manuscript describes such experimental facilities, showing the preliminary results of the commissioning of the EIS-TIMER beamline, and discusses original experimental strategies being developed to study the dynamics of matter at the fs–nm time–length scales. In the near future such experimental tools will allow more sophisticated FEL-based FWM applications, that also include the use of multiple and multi-color FEL pulses.

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Bifano, Luca, and Gerhard Fischerauer. "Unsicherheit der elektrischen Impedanzspektroskopie bei Schüttgütern." tm - Technisches Messen 89, s1 (September 1, 2022): 2–7. http://dx.doi.org/10.1515/teme-2022-0053.

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Zusammenfassung Während die prinzipielle Eignung der elektrischen Impedanzspektroskopie (EIS) zur Charakterisierung und Zustandsüberwachung von Materialsystemen gesichert ist, bestehen bei der Reproduzierbarkeit und der Unsicherheit von EIS-Messungen in Feldanwendungen vielfach noch Erkenntnislücken. Dies gilt besonders bei Schüttgütern - wir interessieren uns speziell für Gießereisande -, weil man Schwankungen bei der Schüttungsdichte oder der Befüllungshöhe von Messzellen erwarten darf. Wir haben diese offene Frage der Messunsicherheit mit einer Messzelle untersucht, bei der zwischen zwei planparallelen Elektroden wiederholt Schüttungen eingefüllt und die resultierende Impedanz der Anordnung in einem Frequenzbereich von 20 Hz bis 1MHz gemessen wurde. Die Unsicherheit der EIS-Gerätschaften an sich wurde über Wiederholungsmessungen bei gleichbleibender Messzellenfüllung bestimmt. Der Einfluss des Befüllungsvorgangs und damit der Schüttungszusammensetzung auf die Gesamtunsicherheit wurde über mehrmalige Befüllungs- Entleerungs-Zyklen mit ein und demselben Schüttgut untersucht. Es konnte gezeigt werden, dass die Gesamtmessunsicherheit klein genug ist, dass eine Klassifizierung verschiedener Sandzustände, sei es mit klassischen Methoden oder mit Hilfe von KI-Methoden, machbar erscheint.

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Schüler, M., T. Sauerwald, and A. Schütze. "Metal oxide semiconductor gas sensor self-test using Fourier-based impedance spectroscopy." Journal of Sensors and Sensor Systems 3, no. 2 (September 25, 2014): 213–21. http://dx.doi.org/10.5194/jsss-3-213-2014.

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Abstract. For the self-test of semiconductor gas sensors, we combine two multi-signal processes: temperature-cycled operation (TCO) and electrical impedance spectroscopy (EIS). This combination allows one to discriminate between irreversible changes of the sensor, i.e., changes caused by poisoning, as well as changes in the gas atmosphere. To integrate EIS and TCO, impedance spectra should be acquired in a very short time period, in which the sensor can be considered time invariant, i.e., milliseconds or less. For this purpose we developed a Fourier-based high-speed, low-cost impedance spectroscope. It provides a binary excitation signal through an FPGA (field programable gate array), which also acquires the data. To determine impedance spectra, it uses the ETFE (empirical transfer function estimate) method, which calculates the impedance by evaluating the Fourier transformations of current and voltage. With this approach an impedance spectrum over the range from 61 kHz to 100 MHz is acquired in ca. 16 μs. We carried out TCO–EIS measurements with this spectroscope and a commercial impedance analyzer (Agilent 4294A), with a temperature cycle consisting of six equidistant temperature steps between 200 and 450 °C, with lengths of 30 s (200 °C) and 18 s (all others). Discrimination of carbon monoxide (CO) and methane (CH4) is possible by LDA (linear discriminant analysis) using either TCO or EIS data, thus enabling a validation of results by comparison of both methods.

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Park, Su-Moon, Jung-Suk Yoo, Byoung-Yong Chang, and Eun-Shil Ahn. "Novel instrumentation in electrochemical impedance spectroscopy and a full description of an electrochemical system." Pure and Applied Chemistry 78, no. 5 (January 1, 2006): 1069–80. http://dx.doi.org/10.1351/pac200678051069.

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The evolution of impedance measurement methods into the current state of the art is reviewed briefly, and recent efforts to develop new instruments to make electrochemical impedance spectroscopy (EIS) measurements faster and more accurate are described. The most recent approach for impedance measurement uses a multichannel detection technique, which is analogous to a spectroscopic measurement such as in Fourier transform infrared spectroscopy. This method, which is capable of making impedance measurements in real time during an electrochemical experiment, allows us to come up with a new integrated equation that makes a full description of an electrochemical system possible.

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Magar, Hend S., Rabeay Y. A. Hassan, and Ashok Mulchandani. "Electrochemical Impedance Spectroscopy (EIS): Principles, Construction, and Biosensing Applications." Sensors 21, no. 19 (October 1, 2021): 6578. http://dx.doi.org/10.3390/s21196578.

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Electrochemical impedance spectroscopy (EIS) is a powerful technique used for the analysis of interfacial properties related to bio-recognition events occurring at the electrode surface, such as antibody–antigen recognition, substrate–enzyme interaction, or whole cell capturing. Thus, EIS could be exploited in several important biomedical diagnosis and environmental applications. However, the EIS is one of the most complex electrochemical methods, therefore, this review introduced the basic concepts and the theoretical background of the impedimetric technique along with the state of the art of the impedimetric biosensors and the impact of nanomaterials on the EIS performance. The use of nanomaterials such as nanoparticles, nanotubes, nanowires, and nanocomposites provided catalytic activity, enhanced sensing elements immobilization, promoted faster electron transfer, and increased reliability and accuracy of the reported EIS sensors. Thus, the EIS was used for the effective quantitative and qualitative detections of pathogens, DNA, cancer-associated biomarkers, etc. Through this review article, intensive literature review is provided to highlight the impact of nanomaterials on enhancing the analytical features of impedimetric biosensors.

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Huh, Sooin, Hye-Jin Kim, Seungah Lee, Jinwoo Cho, Aera Jang, and Joonsung Bae. "Utilization of Electrical Impedance Spectroscopy and Image Classification for Non-Invasive Early Assessment of Meat Freshness." Sensors 21, no. 3 (February 2, 2021): 1001. http://dx.doi.org/10.3390/s21031001.

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This study presents a system for assessing the freshness of meat with electrical impedance spectroscopy (EIS) in the frequency range of 125 Hz to 128 kHz combined with an image classifier for non-destructive and low-cost applications. The freshness standard is established by measuring the aerobic plate count (APC), 2-thiobarbituric acid reactive substances (TBARS), and composition analysis (crude fat, crude protein, and moisture) values of the microbiological detection to represent the correlation between EIS and meat freshness. The EIS and images of meat are combined to predict the freshness with the Adaboost classification and gradient boosting regression algorithms. As a result, when the elapsed time of beef storage for 48 h is classified into three classes, the time prediction accuracy is up to 85% compared to prediction accuracy of 56.7% when only images are used without EIS information. Significantly, the relative standard deviation (RSD) of APC and TBARS value predictions with EIS and images datum achieves 0.890 and 0.678, respectively.

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Tanumihardja, Esther, Douwe S. de Bruijn, Rolf H. Slaats, Wouter Olthuis, and Albert van den Berg. "Monitoring Contractile Cardiomyocytes via Impedance Using Multipurpose Thin Film Ruthenium Oxide Electrodes." Sensors 21, no. 4 (February 18, 2021): 1433. http://dx.doi.org/10.3390/s21041433.

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A ruthenium oxide (RuOx) electrode was used to monitor contractile events of human pluripotent stem cells-derived cardiomyocytes (hPSC-CMs) through electrical impedance spectroscopy (EIS). Using RuOx electrodes presents an advantage over standard thin film Pt electrodes because the RuOx electrodes can also be used as electrochemical sensor for pH, O2, and nitric oxide, providing multisensory functionality with the same electrode. First, the EIS signal was validated in an optically transparent well-plate setup using Pt wire electrodes. This way, visual data could be recorded simultaneously. Frequency analyses of both EIS and the visual data revealed almost identical frequency components. This suggests both the EIS and visual data captured the similar events of the beating of (an area of) hPSC-CMs. Similar EIS measurement was then performed using the RuOx electrode, which yielded comparable signal and periodicity. This mode of operation adds to the versatility of the RuOx electrode’s use in in vitro studies.

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Zhu, Yong, Zhihui Hu, and Zhenyu He. "Edge Intelligence Service Orchestration with Process Mining." Applied Sciences 12, no. 20 (October 16, 2022): 10436. http://dx.doi.org/10.3390/app122010436.

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In the post-cloud computing era, edge computing as a distributed computing paradigm, integrating the core capabilities of computing, storage, network, and application, provides EIS (edge intelligence service), such as real-time business, data optimization, intelligent application, security, and privacy protection. The EIS has become the core value driver to promote the IoE (Internet of Everything), to dig deeply into data value and create a new ecology of application scenarios. With the emergence of new business processes, EIS orchestration has also become a hot topic in academic research. A design methodology based on a complete “describe-synthesize-verify-evaluate” process was established to explore executable design specifications for EIS by means of model validation and running instances. As proof of concept, a CPN (colored Petri net) prototype was simulated and its operational processes were discovered by process mining from event data available in EIS for behavior verification. The instances running on WISE-PaaS demonstrate the feasibility of the research methodology, which aims to optimize EIS through service orchestration.

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Chacón, Manuel, Natalia Vázquez, Sergio Alonso-Alonso, Mairobi Persinal-Medina, Sara Llames, Marta Pevida, Ignacio Alcalde, Jesús Merayo-Lloves, and Álvaro Meana. "Improved Tool for Predicting Skin Irritation on Reconstructed Human Epidermis Models Based on Electrochemical Impedance Spectroscopy." Biosensors 13, no. 2 (January 20, 2023): 162. http://dx.doi.org/10.3390/bios13020162.

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The rabbit skin irritation test has been the standard for evaluating the irritation potential of chemicals; however, alternative methods that do not use animal testing are actively encouraged. Reconstructed human epidermis (RhE) models mimic the biochemical and physiological properties of the human epidermis and can be used as an alternative method. On RhE methods, the metabolic activity of RhE models is used to predict skin irritation, with a reduction in metabolic activity indicating a reduced number of viable cells and linking cell death to skin irritation processes. However, new challenges have emerged as the use of RhE models increases, including the need for non-invasive and marker-free methodologies to assess cellular states. Electrochemical impedance spectroscopy (EIS) is one such methodology that can meet these requirements. In this study, our results showed that EIS can differentiate between irritant and non-irritant chemicals, with a significant increase in the capacitance values observed in the irritant samples. A ROC curve analysis showed that the prediction method based on EIS met OECD TG 439 requirements at all time points and had 95% within-laboratory reproducibility. Comparison with the MTT viability assay showed that prediction using EIS achieved higher sensitivity, specificity, and accuracy. These results suggest that EIS could potentially replace animal testing in the evaluation of irritation potential and could be a valuable addition to in vitro testing strategies.

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Savcheva, Antonia. "Overview of XRT performance and first results." Proceedings of the International Astronomical Union 3, S247 (September 2007): 326–36. http://dx.doi.org/10.1017/s1743921308015044.

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AbstractIn this review we present a short introduction to the X-ray Telescope on Hinode. We discuss its capabilities and new features and compare it with Yohkoh SXT. We also discuss some of the first results that include observations of X-ray jets in coronal holes, shear change in flares, sigmoid eruptions and evolution, application of filter ratios and differential emission measure analysis, structure of active regions, fine structure of X-ray bright points, and modeling non-potential fields around filaments. Finally, we describe how XRT works with other ground and space-based instrumentation, in particular with TRACE, EIS, SOT, and SOLIS.

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Stanica, Luciana, Mihnea Rosu-Hamzescu, Mihaela Gheorghiu, Miruna Stan, Loredana Antonescu, Cristina Polonschii, and Eugen Gheorghiu. "Electric Cell-Substrate Impedance Sensing of Cellular Effects under Hypoxic Conditions and Carbonic Anhydrase Inhibition." Journal of Sensors 2017 (2017): 1–10. http://dx.doi.org/10.1155/2017/9290478.

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Tumor hypoxia provides a dynamic environment for the cancer cells to thrive and metastasize. Evaluation of cell growth, cell-cell, and cell surface interactions in hypoxic conditions is therefore highly needed in the establishment of treatment options. Electric cell-substrate impedance sensing (ECIS) has been traditionally used in the evaluation of cellular platforms as a real-time, label-free impedance-based method to study the activities of cells grown in tissue cultures, but its application for hypoxic environments is seldom reported. We present real-time evaluation of hypoxia-induced bioeffects with a focus on hypoxic pH regulation of tumor environment. To this end, multiparametric real-time bioanalytical platform using electrical impedance spectroscopy (EIS) and human colon cancer HT-29 cells is advanced. A time series of EIS data enables monitoring with high temporal resolution the alterations occurring within the cell layer, especially at the cell-substrate level. We reveal the dynamic changes of cellular processes during hypoxic conditions and in response to application of acetazolamide (AZA), a carbonic anhydrase inhibitor. Optical evaluation and pH assessment complemented the electrical analysis towards establishing a pattern of cellular changes. The proposed bioanalytical platform indicates wide applicability towards evaluation of bioeffects of hypoxia at cellular level.

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Hafaid, Imen, Asma Gallouz, Walid Mohamed Hassen, Adnane Abdelghani, Zina Sassi, Francois Bessueille, and Nicole Jaffrezic-Renault. "Sensitivity Improvement of an Impedimetric Immunosensor Using Functionalized Iron Oxide Nanoparticles." Journal of Sensors 2009 (2009): 1–12. http://dx.doi.org/10.1155/2009/746548.

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This work has explored the development of impedimetric immunosensors based on magnetic iron nanoparticles (IrNP) functionalized with streptavidin to which a biotinylated FAB part of the antibody has been bound using a biotin-streptavidin interaction. SPR analysis shows a deviation on the measured (angle) during antigen-antibody recognition whereas label free detection using by EIS allows us to monitor variation of polarization resistance. Before detection, layers were analyzed by FTIR and AFM. Compared to immobilization of antibody on bare gold surface using aminodecanethiol SAM, antibody immobilization on nanoparticles permitted to reach lower detection limit: 500 pg/ml instead of 1 ng/ml to in the case of EIS and 300 ng/ml instead of 4.5 μg/ml in the case of SPR. Thus, it permitted to improve the sensitivity: from 257.3 Ω⋅cm2⋅μg−1⋅mlto 1871 Ω⋅cm2⋅μg−1⋅mlin the case of EIS and from0.003°μg−1⋅mlto0.094°μg−1⋅mlin the case of SPR.

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Du, Xin, Yahui Song, Xinxin Xuan, Shuzhen Chen, Xia Wu, Heng Bo Jiang, Eui-Seok Lee, and Xiaohui Wang. "Characterization of a Bioresorbable Magnesium-Reinforced PLA-Integrated GTR/GBR Membrane as Dental Applications." Scanning 2020 (September 19, 2020): 1–10. http://dx.doi.org/10.1155/2020/6743195.

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Inferior mechanical properties have always been a limitation of the bioresorbable membranes in GBR/GTR. This study is aimed at fabricating a bioresorbable magnesium-reinforced polylactic acid- (PLA-) integrated membrane and investigating its mechanical properties, degradation rate, and biocompatibility. The uncoated and fluoride-coated magnesium alloys, AZ91, were made into strips. Then, magnesium-reinforced PLA-integrated membrane was made through integration. PLA strips were used in the control group instead of magnesium strips. Specimens were cut into rectangular shape and immersed in Hank’s Balanced Salt Solution (HBSS) at 37°C for 4, 8, and 12 d. The weight loss of the AZ91 strips was measured. Three-point bending tests were conducted before and after the immersion to determine the maximum load on specimens. Potentiodynamic polarization (PDP), electrochemical impedance spectroscopy (EIS), scanning electron microscopy (SEM), and energy-dispersive spectroscopy (EDS) were conducted on coated and uncoated AZ91 plates to examine corrosion resistance. Murine fibroblast and osteoblast cells were cultured on circular specimens and titanium disks for 1, 3, and 5 d. Thereafter, WST test was performed to examine cell proliferation. As a result, the coated and uncoated groups showed higher maximum loads than the control group at all time points. The weight loss of AZ91 strips used in the coated group was lower than that in the uncoated group. PDP, EIS, SEM, and EDS showed that the coated AZ91 had a better corrosion resistance than the uncoated AZ91. The cell proliferation test showed that the addition of AZ91 did not have an adverse effect on osteoblast cells. Conclusively, the magnesium-reinforced PLA-integrated membrane has excellent load capacity, corrosion resistance, cell affinity, and proper degradation rate. Moreover, it has great potential as a bioresorbable membrane in the GBR/GTR application.

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Zhou, Zhen, Xiaoyu Zhang, Tiean Zhou, Fushen Huang, and Jinjun Chen. "Quartz Crystal Microbalance Technology Coupled with Impedance for the Dynamic Monitoring of the Cardiomyocyte Beating Function and Drug Screening." Biosensors 13, no. 2 (January 28, 2023): 198. http://dx.doi.org/10.3390/bios13020198.

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The main sensing techniques used to study myocardial pulsation are electrical impedance sensing (EIS) and by quartz crystal microbalance (QCM). While electrical impedance technology is the gold standard for the study of myocardial pulsation, the clinical application of drugs is being followed up in real time additionally, thus, QCM technology needs to be further developed as a very important class of quality sensor technology. Moreover, the application of EIS, in combination with the QCM, for monitoring myocardial pulsation, has been rarely reported. In this paper, a series of cell growth and adhesion conditions were optimized using rat primary cardiomyocytes, and QCM was used in combination with EIS to monitor the adhesion and the myocardial pulsation ability of the cells in real time. Furthermore, cardiomyocytes that adhered to the QCM and EIS were treated with isoprenaline (ISO), a positive inotropic drug, and verapamil (VRP), a negative inotropic drug. Next, the cell index (CI)-time (T) plots, beating amplitude (BA) and beating rate (BR) of the cardiomyocytes were calculated and changes in these parameters, before and after, dosing were evaluated. The results showed that the QCM technique results were not only consistent with the results obtained with EIS, but also that the QCM technique had a certain degree of sensitivity for the calculation of cardiomyocyte beating. Thus, our findings validate the reliability and validity of the QCM technique for measuring cardiomyocyte beating and drug testing. We hope that further studies would evaluate the application of the QCM technology for clinical use.

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Abdul Halim, Suhaila Idayu, Chin Han Chan, and Jan Apotheker. "Basics of teaching electrochemical impedance spectroscopy of electrolytes for ion-rechargeable batteries – part 1: a good practice on estimation of bulk resistance of solid polymer electrolytes." Chemistry Teacher International 3, no. 2 (March 8, 2021): 105–15. http://dx.doi.org/10.1515/cti-2020-0011.

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Abstract In this publication, we present the basic to characterize the electrical properties of electrolytes that are widely used in ion-rechargeable batteries using electrochemical impedance spectroscopy (EIS). This simplified yet insightful background provided may be used for educational purposes, especially for beginners or young researchers for both undergraduate and postgraduate students. We start with introduction of electrolytes and electrochemical impedance spectroscopy (EIS) instrumentation, following with the step-by-step guidelines using three different procedures to estimate the bulk resistance (R b) of the electrolytes, which is inversely proportional to the conductivity (σ DC) of the materials R b ∝ 1 / σ DC $\left({R}_{\mathrm{b}}\propto 1/{\sigma }_{\mathrm{DC}}\right)$ . Several examples and exercises on estimation of quantity R b are supplemented for educational purposes. Comparison was made on estimation of R b using manual graphical procedures, mathematical regression procedures using commercial graphical software and equivalent circuit fitting procedures using exclusive EIS software. The results suggest that the manual graphical technique may serves as a useful approach for beginners before venturing to exclusive software. Besides, the instructors may use the procedures to coach the users to extract reliable and reproducible data before data interpretation. Lastly, the phenomenological approach on dielectric relaxation for solid polymer electrolytes [poly(ethylene oxide) (PEO) + lithium salt] and non-solid polymer electrolytes [poly(methyl acrylate) (PMA) + lithium salt], in the classic sense will be addressed in terms of impedance (Z*), permittivity (ε*), tangent loss (tan δ), modulus (M*) and conductivity (σ*) spectra in Part 2.

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Chmayssem, Ayman, Constantin Edi Tanase, Nicolas Verplanck, Maxime Gougis, Véronique Mourier, Abdelkader Zebda, Amir M. Ghaemmaghami, and Pascal Mailley. "New Microfluidic System for Electrochemical Impedance Spectroscopy Assessment of Cell Culture Performance: Design and Development of New Electrode Material." Biosensors 12, no. 7 (June 24, 2022): 452. http://dx.doi.org/10.3390/bios12070452.

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Electrochemical impedance spectroscopy (EIS) is widely accepted as an effective and non-destructive method to assess cell health during cell-culture. However, there is a lack of compact devices compatible with microfluidic integration and microscopy that could provide the real-time and non-invasive monitoring of cell-cultures using EIS. In this paper, we reported the design and characterization of a modular EIS testing system based on a patented technology. This device was fabricated using easily processable methodologies including screen-printing of the impedance electrodes and molding or micromachining of the cell culture chamber with an easy assembly procedure. Accordingly, to obtain processable, biocompatible and sterilizable electrode materials that lower the impact of interfacial impedance on TEER (Transepithelial electrical resistance) measurements, and to enable concomitant microscopy observations, we optimized the formulation of the electrode inks and the design of the EIS electrodes, respectively. First, electrode materials were based on carbon biocompatible inks enriched with IrOx particles to obtain low interfacial impedance electrodes approaching the performances of classical non-biocompatible Ag/AgCl second-species electrodes. Secondly, we proposed three original electrode designs, which were compared to classical disk electrodes that were optically compatible with microscopy. We assessed the impact of the electrode design on the response of the impedance sensor using COMSOL Multiphysics. Finally, the performance of the impedance spectroscopy devices was assessed in vitro using human airway epithelial cell cultures.

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Ozdalgic, Berin, Munire Gul, Zihni Onur Uygun, Nazente Atçeken, and Savas Tasoglu. "Emerging Applications of Electrochemical Impedance Spectroscopy in Tear Film Analysis." Biosensors 12, no. 10 (October 5, 2022): 827. http://dx.doi.org/10.3390/bios12100827.

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Human tear film, with a flow rate of 1–3 µL/min, is a rich bodily fluid that transmits a variety of metabolites and hormones containing proteins, lipids and electrolytes that provide clues about ocular and systemic diseases. Analysis of disease biomarkers such as proteins, mRNA, enzymes and cytokines in the tear film, collected by noninvasive methods, can provide significant results for sustaining a predictive, preventive and personalized medicine regarding various diseases such as glaucoma, diabetic retinopathy, keratoconus, dry eye, cancer, Alzheimer’s disease, Parkinson’s disease and COVID-19. Electrochemical impedance spectroscopy (EIS) offers a powerful technique for analyzing these biomarkers. EIS detects electrical equivalent circuit parameters related to biorecognition of receptor–analyte interactions on the electrode surface. This method is advantageous as it performs a label-free detection and allows the detection of non-electroactive compounds that cannot be detected by direct electron transfer, such as hormones and some proteins. Here, we review the opportunities regarding the integration of EIS into tear fluid sampling approaches.

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Liu, Yun, Zhi Dang, Yin Xu, and Tianyuan Xu. "Pyrite Passivation by Triethylenetetramine: An Electrochemical Study." Journal of Analytical Methods in Chemistry 2013 (2013): 1–8. http://dx.doi.org/10.1155/2013/387124.

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The potential of triethylenetetramine (TETA) to inhibit the oxidation of pyrite in H2SO4solution had been investigated by using the open-circuit potential (OCP), cyclic voltammetry (CV), potentiodynamic polarization, and electrochemical impedance (EIS), respectively. Experimental results indicate that TETA is an efficient coating agent in preventing the oxidation of pyrite and that the inhibition efficiency is more pronounced with the increase of TETA. The data from potentiodynamic polarization show that the inhibition efficiency (η%) increases from 42.08% to 80.98% with the concentration of TETA increasing from 1% to 5%. These results are consistent with the measurement of EIS (43.09% to 82.55%). The information obtained from potentiodynamic polarization also displays that the TETA is a kind of mixed type inhibitor.

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Zhao, Wenjiao, Magnus Rohde, Ijaz Ul Mohsin, Carlos Ziebert, and Hans J. Seifert. "Heat Generation in NMC622 Coin Cells during Electrochemical Cycling: Separation of Reversible and Irreversible Heat Effects." Batteries 6, no. 4 (November 10, 2020): 55. http://dx.doi.org/10.3390/batteries6040055.

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The thermal behavior of a commercial lithium-ion cell with the cathode material LiNi0.6Mn0.2Co0.2O2 (NMC622) was investigated during the cycling process using a Tian-Calvet calorimeter (C80, SETARAM Instrumentation, France). Various current flows of 42.5, 85, and 170 mA corresponding to charging rates of 0.5, 1, and 2 C, respectively, were applied in the measurements. The corresponding heat flow rates were measured by the C80 calorimeter at 30 °C. The reversible heat effect due to the reversible electrochemical reaction was quantified by the entropy change measurement. The irreversible heat effect due to internal resistances was determined by the electrochemical impedance spectroscopy (EIS) and the galvanostatic intermittent titration technique (GITT). The results were compared with the direct measurement of the heat effect by calorimetry during electrochemical cycling.

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Kim, Jaehwan, Ki-Tae Park, and Tae Ho Kwon. "Influencing Factors of Steel States in Concrete Based on Electrochemical Impedance Spectroscopic Measurements." Applied Sciences 12, no. 24 (December 8, 2022): 12611. http://dx.doi.org/10.3390/app122412611.

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To cope with the premature deterioration of reinforced concrete structures caused by chloride-induced corrosion, the corrosion rate is required to be estimated and the transport parameters calculated. The electrochemical impedance spectroscopy (EIS) technique can evaluate steel corrosion behaviors at different frequencies. However, its capacity to interpret the impedance response of the system (steel embedded in concrete) is still challenged. Although concrete is a good barrier used to secure structural performance, one of the main obstacles associated with electrical measurements relates to the cases in which concrete contains unexpected or invisible variables, such as changes in pore structure induced by the continuous hydration process. In addition, the fact that steel embedded in concrete is controlled during experiments is technically challenging. Due to these limitations, various circuits have been proposed to explain the corrosion behavior of steel in concrete. EIS measurements are very sensitive to small perturbations. During the analysis process of EIS data, it is possible to introduce unexpected errors attributed to variables; thus, the estimated corrosion values based on the analysis rate may be misleading. To overcome the limitations, it is necessary to confirm the impedance responses first in controlled variable cases. In this study, EIS measurements were conducted for active/passive states of steel in concrete in various conditions to minimize variable errors which are likely induced by operators.

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Rajabzadeh, Mahdi, Jonathan Ungethum, Andreas Herkle, Carolin Schilpp, Joachim Becker, Michael Fauler, Oliver Wittekindt, Manfred Frick, and Maurits Ortmanns. "A PCB-Based 24-Ch. MEA-EIS Allowing Fast Measurement of TEER." IEEE Sensors Journal 21, no. 12 (June 15, 2021): 13048–59. http://dx.doi.org/10.1109/jsen.2021.3067823.

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De Angelis, Alessio, Emanuele Buchicchio, Francesco Santoni, Antonio Moschitta, and Paolo Carbone. "Uncertainty Characterization of a Practical System for Broadband Measurement of Battery EIS." IEEE Transactions on Instrumentation and Measurement 71 (2022): 1–9. http://dx.doi.org/10.1109/tim.2022.3156994.

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Roehrich, Brian, and Lior Sepunaru. "Characterization of Single Particles By Electrochemical Impedance." ECS Meeting Abstracts MA2022-01, no. 50 (July 7, 2022): 2125. http://dx.doi.org/10.1149/ma2022-01502125mtgabs.

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The ubiquity of nanomaterials in electrochemical energy conversion technologies has driven intense interest in unravelling the material’s structure- function relationships. In response, single- entity electrochemistry has been developed as a technique to study the properties of individual nanoparticles, one at a time. This approach engenders a bottom-up understanding, linking the activities of the single particles to the emergent properties of the ensemble. The “nano-impact” technique, a subset of single-entity electrochemistry, uses low-noise instrumentation to measure current transients arising from individual particles which stochastically collide with an ultramicroelectrode. These transients have been successfully used to measure the size of both insulating and redox-active nanoparticles, as well as the activity of single electrocatalysts. However, it remains challenging to study certain classes of materials on a single-entity basis. One such class is pseudocapacitors – materials which mix electronic and ionic conductivity, critical components of ion batteries and other next-generation energy storage technologies. While careful experimental design and data analysis have allowed the detection and qualitative characterization of single ion-intercalating particles, their nature as mixed conductors makes quantitative information difficult to obtain amperometrically. This hurdle is due to the measured current response being dictated by one or more possible factors: electron transfer, ion diffusion within the particle or across the particle/electrolyte interface, or ion transfer in the bulk. To overcome this, electrochemical impedance spectroscopy (EIS) is commonly used to characterize bulk pseudocapacitors. In EIS, a small-magnitude sinusoidal (AC) voltage is applied to the working electrode and the current response is recorded. Different timescales can be probed by varying the AC frequency – the high frequency response is dominated by fast processes, such as capacitance, while the low frequency response contains information on electron transfers and mass transport. In this way, EIS gives a full picture of the electroactive material and can unravel the coexisting electronic and ionic conductivity of mixed conductors. In this presentation, I will discuss our development of an EIS-based technique to detect and characterize single particles. We implemented fast-Fourier transform based EIS to rapidly acquire impedance spectra spanning several decades of frequencies. The spectra are fit to an equivalent circuit model and monitored as a function of time. Discrete changes in various equivalent circuit parameters are observed, corresponding to single particle-electrode impact events. Using a model system of polystyrene microbeads, we demonstrate that discrete increases in the charge-transfer resistance can be used to accurately measure the contact area between the individual bead and the ultramicroelectrode. I will also discuss our recent progress towards detecting single ion-intercalating nanoparticles and characterizing their charge storage ability on a single particle basis. These advances expand both the scope of single-entity electrochemistry and the depth of information gleaned from a single measurement of a single particle.

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Hassan, Qusai, Soha Ahmadi, and Kagan Kerman. "Recent Advances in Monitoring Cell Behavior Using Cell-Based Impedance Spectroscopy." Micromachines 11, no. 6 (June 13, 2020): 590. http://dx.doi.org/10.3390/mi11060590.

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Cell-based impedance spectroscopy (CBI) is a powerful tool that uses the principles of electrochemical impedance spectroscopy (EIS) by measuring changes in electrical impedance relative to a voltage applied to a cell layer. CBI provides a promising platform for the detection of several properties of cells including the adhesion, motility, proliferation, viability and metabolism of a cell culture. This review gives a brief overview of the theory, instrumentation, and detection principles of CBI. The recent applications of the technique are given in detail for research into cancer, neurodegenerative diseases, toxicology as well as its application to 2D and 3D in vitro cell cultures. CBI has been established as a biophysical marker to provide quantitative cellular information, which can readily be adapted for single-cell analysis to complement the existing biomarkers for clinical research on disease progression.

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Farooq, A., A. Hannan, R. Ahmad, and K. M. Deen. "The effect of chemical treatment on the adhesion strength and structural integrity of the epoxy coatings." Surface Topography: Metrology and Properties 9, no. 4 (December 1, 2021): 045055. http://dx.doi.org/10.1088/2051-672x/ac443c.

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Abstract This research aims to investigate the effect of chemical treatment on the integrity of the epoxy coating applied on mild steel substrates. Grit blasted steel samples were chemically treated in 10 vol.% NaOCl solution, 10 vol.% CrCl3 and 30 vol.% H3PO4–5 vol.% HNO3 solutions prior to coating application. Post-cleaning surface morphology and chemical composition revealed the formation of oxidation products on steel surface. Under optimized conditions, a dry film thickness of 135 ± 3 μm of epoxy coating was achieved. The CT2 sample (pre-treated with CrCl3) presented higher coating adhesion strength (∼4.12 MPa) and the lowest rust area of ∼0.03% compared to other chemically treated samples during 720 h of immersion in 5 wt.% NaCl solution. The coating degradation mechanism was evaluated by electrochemical impedance spectroscopy (EIS) after 24, 48, 72 and 120 h of immersion in 3.5 wt. % NaCl solution. EIS analysis of the coated samples pretreated with NaOCl and CrCl3 solutions exhibited low water uptake and limited corrosion due to hindrance in the diffusion of ionic species through the coating. However, coated steel samples pretreated in acidic solutions displayed appreciable corrosion damage as confirmed from salt spray and immersion tests. For instance, the delamination of the CT3 and CT4 (acid pre-treated) coatings was confirmed from the EIS analysis., which represented the formation of a double layer and occurrence of faradaic (corrosion) reactions as the coating-substrate interface, resulting in ∼15%–30% delamination in 120 h of exposure.

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Pammi Guru, Krishna Thej, Nusrat Praween, and Palash Kumar Basu. "Investigating the Electric Field Lysis of Exosomes Immobilized on the Screen-Printed Electrode and Electrochemical Sensing of the Lysed-Exosome-Derived Protein." Biosensors 13, no. 3 (February 27, 2023): 323. http://dx.doi.org/10.3390/bios13030323.

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It is important to isolate exosomes (<150 nm) from biofluid for diagnosis or prognosis purposes, followed by sensing of exosomal proteins. In the present work, exosomes are isolated from human serum by immobilizing on a Screen-Printed Electrode (SPE) followed by electric field lysis and electrochemical impedance spectroscopy (EIS)-based sensing of relevant exosomal proteins (HSP70 and HER2). Upon immobilization of exosomes on the surface, the role of different electrical signals (sinusoidal and square wave) in the lysis of exosomes was studied by varying the frequency and voltage. HSP70 was used for EIS to determine the optimal voltage and frequency for lysing the exosomes. It was observed that the low frequencies and, specifically, sinusoidal signals are ideal for lysing exosomes as compared to square signals. The relative quantity of HSP70 obtained by lysing with different voltages (sinusoidal waveform) was compared using Western blotting. After electric field lysis of the exosome with an optimized signal, HER2, a breast cancer biomarker, was detected successfully from serum by EIS. In the proposed technique, 3.5 × 108 exosomes/mL were isolated from serum. With the limit of detection of 10 pg, the designed cell showed a linear detection of HER2 from 0.1 ng to 1 µg. It was observed from the results that the electric field lysis of exosomes not only plays a significant role in releasing the cargo protein but also improves the sensing of surface proteins associated with exosomes.

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Cui, Dawei, Jinlong Wang, Ailing Sun, Hongmei Song, and Wenqing Wei. "Anomalously Faster Deterioration of LiNi0.8Co0.15Al0.05O2/Graphite High-Energy 18650 Cells at 1.5 C than 2.0 C." Scanning 2018 (July 31, 2018): 1–7. http://dx.doi.org/10.1155/2018/2593780.

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Discharge rate is a key parameter affecting the cycle life of lithium-ion batteries (LIB). Normally, lithium-ion batteries deteriorate more severely at a higher discharge rate. In this paper, we report that the cycle performance of LiNi0.8Co0.15Al0.05O2/graphite high-energy 2.8 Ah 18650 cells is abnormally worse at a 1.5 C discharge rate than at a 2.0 C discharge rate. Combining macromethods with micromethods, the capacity/rate performance, electrochemical impedance spectroscopy (EIS), and scanning electron microscope (SEM) morphology of the electrodes are systematically investigated. We have found that the impedance of the negative electrodes after 2.0 C aged is smaller than that after 1.5 C aged, through EIS analysis, and the discharge rate performance of the negative electrodes after 2.0 C aged is better than that after 1.5 C aged through coin cell analysis. In addition, some special microcracks in the negative electrodes of aged cells are observed through SEM analysis, which can accelerate the side reaction between active and electrolyte and form the thicker SEI which will hinder the Li+ insertion and cause resistance increase. In short, the LiNi0.8Co0.15Al0.05O2/graphite-based lithium-ion batteries show better cycle life at a 2.0 C discharge rate than at a 1.5 C discharge rate which indicates that the negative electrodes contribute more than the positive electrodes.

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Tan, Sue Woon, Won-Yong Jeon, Bo Kyeong Yoon, and Joshua A. Jackman. "Mechanistic Evaluation of Antimicrobial Lipid Interactions with Tethered Lipid Bilayers by Electrochemical Impedance Spectroscopy." Sensors 22, no. 10 (May 13, 2022): 3712. http://dx.doi.org/10.3390/s22103712.

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There is extensive interest in developing real-time biosensing strategies to characterize the membrane-disruptive properties of antimicrobial lipids and surfactants. Currently used biosensing strategies mainly focus on tracking membrane morphological changes such as budding and tubule formation, while there is an outstanding need to develop a label-free biosensing strategy to directly evaluate the molecular-level mechanistic details by which antimicrobial lipids and surfactants disrupt lipid membranes. Herein, using electrochemical impedance spectroscopy (EIS), we conducted label-free biosensing measurements to track the real-time interactions between three representative compounds—glycerol monolaurate (GML), lauric acid (LA), and sodium dodecyl sulfate (SDS)—and a tethered bilayer lipid membrane (tBLM) platform. The EIS measurements verified that all three compounds are mainly active above their respective critical micelle concentration (CMC) values, while also revealing that GML induces irreversible membrane damage whereas the membrane-disruptive effects of LA are largely reversible. In addition, SDS micelles caused membrane solubilization, while SDS monomers still caused membrane defect formation, shedding light on how antimicrobial lipids and surfactants can be active in, not only micellar form, but also as monomers in some cases. These findings expand our mechanistic knowledge of how antimicrobial lipids and surfactants disrupt lipid membranes and demonstrate the analytical merits of utilizing the EIS sensing approach to comparatively evaluate membrane-disruptive antimicrobial compounds.

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Elgiddawy, Nada, Shiwei Ren, Wadih Ghattas, Waleed M. A. El Rouby, Ahmed O. El-Gendy, Ahmed A. Farghali, Abderrahim Yassar, and Hafsa Korri-Youssoufi. "Antimicrobial Activity of Cationic Poly(3-hexylthiophene) Nanoparticles Coupled with Dual Fluorescent and Electrochemical Sensing: Theragnostic Prospect." Sensors 21, no. 5 (March 2, 2021): 1715. http://dx.doi.org/10.3390/s21051715.

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Designing therapeutic and sensor materials to diagnose and eliminate bacterial infections remains a significant challenge for active theragnostic nanoprobes. In the present work, fluorescent/electroactive poly(3-hexylthiophene) P3HT nanoparticles (NPs) stabilized with quaternary ammonium salts using cetyltrimethylammonium bromide (CTAB), (CTAB-P3HT NPs) were prepared using a simple mini-emulsion method. The morphology, spectroscopic properties and electronic properties of CTAB-P3HT NPs were characterized by DLS, zeta potential, SEM, TEM, UV-vis spectrophotometry, fluorescence spectroscopy and electrochemical impedance spectroscopy (EIS). In an aqueous solution, CTAB-P3HT NPs were revealed to be uniformly sized, highly fluorescent and present a highly positively charged NP surface with good electroactivity. Dual detection was demonstrated as the binding of the bacteria to NPs could be observed by fluorescence quenching as well as by the changes in EIS. Binding of E. coli to CTAB-P3HT NPs was demonstrated and LODs of 5 CFU/mL and 250 CFU/mL were obtained by relying on the fluorescence spectroscopy and EIS, respectively. The antimicrobial activity of CTAB-P3HT NPs on bacteria and fungi was also studied under dark and nutritive conditions. An MIC and an MBC of 2.5 µg/mL were obtained with E. coli and with S. aureus, and of 0.312 µg/mL with C. albicans. Additionally a good biocompatibility toward normal human cells (WI38) was observed, which opens the way to their possible use as a therapeutic agent.

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Scandurra, Graziella, Antonella Arena, Emanuele Cardillo, Gino Giusi, and Carmine Ciofi. "Portable and Highly Versatile Impedance Meter for Very Low Frequency Measurements." Applied Sciences 11, no. 17 (September 5, 2021): 8234. http://dx.doi.org/10.3390/app11178234.

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Electrical Impedance Spectroscopy (EIS) is a characterization technique that is gaining more and more importance in various fields of research and applications. The frequency range of investigation varies according to the type of application. In some fields (biology, medicine, energy) it is useful to be able to perform measurements at very low frequency values (down to a few mHz or even below). While impedance meters operating at frequencies in the range from a few tens of Hz up to a few MHz can be regarded as quite standard pieces of instrumentation commonly available in many laboratories, instrumentation for measurements at very low frequencies, although commercially available, is less common. The subject of this work is the design, realization and testing of a low frequency impedance measurement platform that has the advantage of being portable, rather inexpensive, and yet highly versatile. In our approach, we exploit a personal computer and a soundboard as a powerful system for digital signal generation and analysis that, with the help of low complexity and low-cost external hardware and a public domain software for the implementation of the core system, allow to tailor the platform for targeting specific applications with minimal effort. As an example, we will demonstrate the application of the system to the investigation of polypyrrole-based supercapacitor structures.

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Shahub, Sarah, Kai-Chun Lin, Sriram Muthukumar, and Shalini Prasad. "A Proof-of-Concept Electrochemical Skin Sensor for Simultaneous Measurement of Glial Fibrillary Acidic Protein (GFAP) and Interleukin-6 (IL-6) for Management of Traumatic Brain Injuries." Biosensors 12, no. 12 (November 30, 2022): 1095. http://dx.doi.org/10.3390/bios12121095.

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This work demonstrates the use of a noninvasive, sweat-based dual biomarker electrochemical sensor for continuous, prognostic monitoring of a Traumatic Brain Injury (TBI) with the aim of enhancing patient outcomes and reducing the time to treatment after injury. A multiplexed SWEATSENSER was used for noninvasive continuous monitoring of glial fibrillary acidic protein (GFAP) and Interleukin-6 (IL-6) in a human sweat analog and in human sweat. Electrochemical impedance spectroscopy (EIS) and chronoamperometry (CA) were used to measure the sensor response. The assay chemistry was characterized using Fourier Transform Infrared Spectroscopy (FTIR). The SWEATSENSER was able to detect GFAP and IL-6 in sweat over a dynamic range of 3 log orders for GFAP and 2 log orders for IL-6. The limit of detection (LOD) for GFAP detection in the sweat analog was estimated to be 14 pg/mL using EIS and the LOD for IL-6 was estimated to be 10 pg/mL using EIS. An interference study was performed where the specific signal was significantly higher than the non-specific signal. Finally, the SWEATSENSER was able to distinguish between GFAP and IL-6 in simulated conditions of a TBI in human sweat. This work demonstrates the first proof-of-feasibility of a multiplexed TBI marker combined with cytokine and inflammatory marker detection in passively expressed sweat in a wearable form-factor that can be utilized toward better management of TBIs. This is the first step toward demonstrating a noninvasive enabling technology that can enable baseline tracking of an inflammatory response.

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Amouzadeh Tabrizi, Mahmoud, and Pablo Acedo. "An Electrochemical Immunosensor for the Determination of Procalcitonin Using the Gold-Graphene Interdigitated Electrode." Biosensors 12, no. 10 (September 20, 2022): 771. http://dx.doi.org/10.3390/bios12100771.

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Procalcitonin (PCT) is considered a sepsis and infection biomarker. Herein, an interdigitated electrochemical immunosensor for the determination of PCT has been developed. The interdigitated electrode was made of the laser-engraved graphene electrode decorated with gold (LEGE/Aunano). The scanning electron microscopy indicated the LEGE/Aunano has been fabricated successfully. After that, the anti-PTC antibodies were immobilized on the surface of the electrode by using 3-mercaptopropionic acid. The electrochemical performance of the fabricated immunosensor was studied using electrochemical impedance spectroscopy (EIS). The EIS method was used for the determination of PCT in the concentration range of 2.5–800 pg/mL with a limit of detection of 0.36 pg/mL. The effect of several interfering agents such as the C reactive protein (CRP), immunoglobulin G (IgG), and human serum albumin (HSA) was also studied. The fabricated immunosensor had a good selectivity to the PCT. The stability of the immunosensor was also studied for 1 month. The relative standard deviation (RSD) was obtained to be 5.2%.

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Leo, Angelo, Anna Grazia Monteduro, Silvia Rizzato, Angelo Milone, and Giuseppe Maruccio. "Miniaturized Sensors for Detection of Ethanol in Water Based on Electrical Impedance Spectroscopy and Resonant Perturbation Method—A Comparative Study." Sensors 22, no. 7 (April 2, 2022): 2742. http://dx.doi.org/10.3390/s22072742.

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The development of highly sensitive, portable and low-cost sensors for the evaluation of ethanol content in liquid is particularly important in several monitoring processes, from the food industry to the pharmaceutical industry. In this respect, we report the optimization of two sensing approaches based on electrical impedance spectroscopy (EIS) and complementary double split ring resonators (CDSRRs) for the detection of ethanol in water. Miniaturized EIS sensors were realized with interdigitated electrodes, and the ethanol sensing was carried out in liquid solutions without any functionalization of the electrodes. Impedance fitting analysis, with an equivalent circuit over a frequency range from 100 Hz to 1 MHz, was performed to estimate the electric parameters, which allowed us to evaluate the amount of ethanol in water solutions. On the other hand, complementary double split ring resonators (CDSRRs) were optimized by adjusting the device geometry to achieve higher quality factors while operating at a low fundamental frequency despite the small size (useful for compact electronic packaging). Both sensors were found to be efficient for the detection of low amounts of ethanol in water, even in the presence of salts. In particular, EIS sensors proved to be effective in performing a broadband evaluation of ethanol concentration and are convenient when low cost is the priority. On the other end, the employment of split ring resonators allowed us to achieve a very low limit of detection of 0.2 v/v%, and provides specific advantages in the case of known environments where they can enable fast real-time single-frequency measurements.

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Cimpoeșu, Ramona, Petrică Vizureanu, Ioan Știrbu, Alina Sodor, Georgeta Zegan, Marius Prelipceanu, Nicanor Cimpoeșu, and Nicoleta Ioanid. "Corrosion-Resistance Analysis of HA Layer Deposited through Electrophoresis on Ti4Al4Zr Metallic Substrate." Applied Sciences 11, no. 9 (May 5, 2021): 4198. http://dx.doi.org/10.3390/app11094198.

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An alloy surface with possible applications in the medical field, Ti4A14Zr, was improved through the deposition of a thin hydroxyapatite (HA) layer. In this paper, we analyzed the growth of a HA layer through electrophoresis and the corrosion resistance of the metallic sample covered with the ceramic layer. The substrate surface was processed via chemical procedures before the HA deposition. The state of the metallic surface and that of the layer of HA were investigated using scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS) analysis of the chemical composition. The results indicate a high increase in the corrosion resistance associated with the ceramic layer compared to the metallic basic layer. Moreover, the analysis revealed the formation of a homogeneous TiO2 layer on the surface of the metallic substrate. The titanium oxide layer identified by SEM–EDS and confirmed by EIS was very homogeneous and resistant, with a compact microstructural appearance and submicron dimension. The layer composed of TiO2 and HA provided good corrosion protection.

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Nouaze, Joseph Christian, Jae Hyung Kim, Gye Rok Jeon, and Jae Ho Kim. "Monitoring of Indoor Farming of Lettuce Leaves for 16 Hours Using Electrical Impedance Spectroscopy (EIS) and Double-Shell Model (DSM)." Sensors 22, no. 24 (December 10, 2022): 9671. http://dx.doi.org/10.3390/s22249671.

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An electrical impedance spectroscopy (EIS) experiment was performed using a double-shell electrical model to investigate the feasibility of detecting physiological changes in lettuce leaves over 16 h. Four lettuce plants were used, and the impedance spectra of the leaves were measured five times per plant every hour at frequencies of 500 Hz and 300 kHz. Estimated R-C parameters were computed, and the results show that the lettuce leaves closely fit the double-shell model (DSM). The average resistance ratios of R1 = 10.66R4 and R1 = 3.34R2 show high resistance in the extracellular fluid (ECF). A rapid increase in resistance (R1, R2, and R4) and a decrease in capacitance (C3 and C5) during water uptake were observed. In contrast, a gradual decrease in resistance and an increase in capacitance were observed while the LED light was on. Comparative studies of leaf physiology and electrical value changes support the idea that EIS is a great technique for the early monitoring of plant growth for crop production.

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Srivastava, A. K. "Evidence of wave harmonics in a brightened magnetic network observed from Hinode/EIS." New Astronomy 15, no. 7 (October 2010): 621–27. http://dx.doi.org/10.1016/j.newast.2010.02.006.

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Schulze, Holger, Harry Wilson, Ines Cara, Steven Carter, Edward N. Dyson, Ravikrishnan Elangovan, Stephen Rimmer, and Till T. Bachmann. "Label-Free Electrochemical Sensor for Rapid Bacterial Pathogen Detection Using Vancomycin-Modified Highly Branched Polymers." Sensors 21, no. 5 (March 8, 2021): 1872. http://dx.doi.org/10.3390/s21051872.

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Rapid point of care tests for bacterial infection diagnosis are of great importance to reduce the misuse of antibiotics and burden of antimicrobial resistance. Here, we have successfully combined a new class of non-biological binder molecules with electrochemical impedance spectroscopy (EIS)-based sensor detection for direct, label-free detection of Gram-positive bacteria making use of the specific coil-to-globule conformation change of the vancomycin-modified highly branched polymers immobilized on the surface of gold screen-printed electrodes upon binding to Gram-positive bacteria. Staphylococcus carnosus was detected after just 20 min incubation of the sample solution with the polymer-functionalized electrodes. The polymer conformation change was quantified with two simple 1 min EIS tests before and after incubation with the sample. Tests revealed a concentration dependent signal change within an OD600 range of Staphylococcus carnosus from 0.002 to 0.1 and a clear discrimination between Gram-positive Staphylococcus carnosus and Gram-negative Escherichia coli bacteria. This exhibits a clear advancement in terms of simplified test complexity compared to existing bacteria detection tests. In addition, the polymer-functionalized electrodes showed good storage and operational stability.

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Mazurków, Julia Maria, Anna Kusior, and Marta Radecka. "Electrochemical Characterization of Modified Glassy Carbon Electrodes for Non-Enzymatic Glucose Sensors." Sensors 21, no. 23 (November 27, 2021): 7928. http://dx.doi.org/10.3390/s21237928.

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The diversity of materials proposed for non-enzymatic glucose detection and the lack of standardized protocols for assessing sensor performance have caused considerable confusion in the field. Therefore, methods for pre-evaluation of working electrodes, which will enable their conscious design, are currently intensively sought. Our approach involved comprehensive morphologic and structural characterization of copper sulfides as well as drop-casted suspensions based on three different polymers—cationic chitosan, anionic Nafion, and nonionic polyvinylpyrrolidone (PVP). For this purpose, scanning electron microscopy (SEM), X-ray diffraction (XRD), and Raman spectroscopy were applied. Subsequently, comparative studies of electrochemical properties of bare glassy carbon electrode (GCE), polymer- and copper sulfides/polymer-modified GCEs were performed using electrochemical impedance spectroscopy (EIS) and voltammetry. The results from EIS provided an explanation for the enhanced analytical performance of Cu-PVP/GCE over chitosan- and Nafion-based electrodes. Moreover, it was found that the pH of the electrolyte significantly affects the electrocatalytic behavior of copper sulfides, indicating the importance of OHads in the detection mechanism. Additionally, diffusion was denoted as a limiting step in the irreversible electrooxidation process that occurs in the proposed system.

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Verpoorten, Eve, Giulia Massaglia, Candido Fabrizio Pirri, and Marzia Quaglio. "Electrospun PEO/PEDOT:PSS Nanofibers for Wearable Physiological Flex Sensors." Sensors 21, no. 12 (June 15, 2021): 4110. http://dx.doi.org/10.3390/s21124110.

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Flexible sensors are fundamental devices for human body monitoring. The mechanical strain and physiological parameters coupled sensing have attracted increasing interest in this field. However, integration of different sensors in one platform usually involves complex fabrication process-flows. Simplification, even if essential, remains a challenge. Here, we investigate a piezoresistive and electrochemical active electrospun nanofibers (NFs) mat as the sensitive element of the wearable physiological flex sensing platform. The use of one material sensitive to the two kinds of stimuli reduces the process-flow to two steps. We demonstrate that the final NFs pH-Flex Sensor can be used to monitor the deformation of a human body joint as well as the pH of the skin. A unique approach has been selected for pH sensing, based on Electrochemical Impedance Spectroscopy (EIS). A linear dependence of the both the double layer capacitance and charge transfer re-sistance with the pH value was obtained by EIS, as well as a linear trend of the electrical resistance with the bending deformation. Gauge factors values calculated after the bending test were 45.84 in traction and 208.55 in compression mode, reflecting the extraordinary piezoresistive behavior of our nanostructured NFs.

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Andrews, George, Olga Neveling, Dirk Johannes De Beer, Evans M. N. Chirwa, Hendrik G. Brink, and Trudi-Heleen Joubert. "Non-Destructive Impedance Monitoring of Bacterial Metabolic Activity towards Continuous Lead Biorecovery." Sensors 22, no. 18 (September 17, 2022): 7045. http://dx.doi.org/10.3390/s22187045.

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The adverse health effects of the presence of lead in wastewater streams are well documented, with conventional methods of lead recovery and removal suffering from disadvantages such as high energy costs, the production of toxic sludge, and low lead selectivity. Klebsiella pneumoniae and Paraclostridium bifermentans have been identified as potential lead-precipitating species for use in a lead recovery bioreactor. Electrical impedance spectroscopy (EIS) on a low-cost device is used to determine the potential for the probe-free and label-free monitoring of cell growth in a bioreactor containing these bacteria. A complex polynomial is fit for several reactive equivalent circuit components. A direct correlation is found between the extracted supercapacitance and the plated colony-forming unit count during the exponential growth phase, and a qualitative correlation is found between all elements of the measured reactance outside the exponential growth phase. Strong evidence is found that Pb(II) ions act as an anaerobic respiration co-substrate for both cells observed, with changes in plated count qualitatively mirrored in the Pb(II) concentration. Guidance is given on the implementation of EIS devices for continuous impedance monitoring.

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Srivastava, A. K., and B. N. Dwivedi. "Signature of slow acoustic oscillations in a non-flaring loop observed by EIS/Hinode." New Astronomy 15, no. 1 (January 2010): 8–15. http://dx.doi.org/10.1016/j.newast.2009.05.006.

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Rodrı́guez, V. D. "CDW-EIS theoretical calculations of projectile deflection for single ionization in highly charged ion–atom collisions." Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms 205 (May 2003): 498–503. http://dx.doi.org/10.1016/s0168-583x(03)00947-9.

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Li, Jing, Byung Kun Kim, Kang-Kyun Wang, Ji-Eun Im, Han Nim Choi, Dong-Hwan Kim, Seong In Cho, Won-Yong Lee, and Yong-Rok Kim. "Sensing Estrogen with Electrochemical Impedance Spectroscopy." Journal of Analytical Methods in Chemistry 2016 (2016): 1–6. http://dx.doi.org/10.1155/2016/9081375.

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This study demonstrates the application feasibility of electrochemical impedance spectroscopy (EIS) in measuring estrogen (17β-estradiol) in gas phase. The present biosensor gives a linear response (R2=0.999) for 17β-estradiol vapor concentration from 3.7 ng/L to 3.7 × 10−4 ng/L with a limit of detection (3.7 × 10−4 ng/L). The results show that the fabricated biosensor demonstrates better detection limit of 17β-estradiol in gas phase than the previous report with GC-MS method. This estrogen biosensor has many potential applications for on-site detection of a variety of endocrine disrupting compounds (EDCs) in the gas phase.

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Bao, Huilu, Jianping Li, Jianming Wen, Li Cheng, Yili Hu, Yu Zhang, Nen Wan, and Masahiro Takei. "Quantitative Evaluation of Burn Injuries Based on Electrical Impedance Spectroscopy of Blood with a Seven-Parameter Equivalent Circuit." Sensors 21, no. 4 (February 21, 2021): 1496. http://dx.doi.org/10.3390/s21041496.

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A quantitative and rapid burn injury detection method has been proposed based on the electrical impedance spectroscopy (EIS) of blood with a seven-parameter equivalent circuit. The degree of burn injury is estimated from the electrical impedance characteristics of blood with different volume proportions of red blood cells (RBCs) and heated red blood cells (HRBCs). A quantitative relationship between the volume portion HHCT of HRBCs and the electrical impedance characteristics of blood has been demonstrated. A seven -parameter equivalent circuit is employed to quantify the relationship from the perspective of electricity. Additionally, the traditional Hanai equation has been modified to verify the experimental results. Results show that the imaginary part of impedance ZImt under the characteristic frequency (fc) has a linear relationship with HHCT which could be described by ZImt = −2.56HHCT − 2.01 with a correlation coefficient of 0.96. Moreover, the relationship between the plasma resistance Rp and HHCT is obtained as Rp = −7.2HHCT + 3.91 with a correlation coefficient of 0.96 from the seven -parameter equivalent circuit. This study shows the feasibility of EIS in the quantitative detection of burn injury by the quantitative parameters ZImt and Rp, which might be meaningful for the follow-up clinical treatment for burn injury.

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48

Ismaiel, Ebrahim, Anita Zátonyi, and Zoltán Fekete. "Dimensionality Reduction and Prediction of Impedance Data of Biointerface." Sensors 22, no. 11 (May 31, 2022): 4191. http://dx.doi.org/10.3390/s22114191.

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Electrochemical impedance spectroscopy (EIS) is the golden tool for many emerging biomedical applications that describes the behavior, stability, and long-term durability of physical interfaces in a specific range of frequency. Impedance measurements of any biointerface during in vivo and clinical applications could be used for assessing long-term biopotential measurements and diagnostic purposes. In this paper, a novel approach to predicting impedance behavior is presented and consists of a dimensional reduction procedure by converting EIS data over many days of an experiment into a one-dimensional sequence of values using a novel formula called day factor (DF) and then using a long short-term memory (LSTM) network to predict the future behavior of the DF. Three neural interfaces of different material compositions with long-term in vitro aging tests were used to validate the proposed approach. The results showed good accuracy in predicting the quantitative change in the impedance behavior (i.e., higher than 75%), in addition to good prediction of the similarity between the actual and the predicted DF signals, which expresses the impedance fluctuations among soaking days. The DF approach showed a lower computational time and algorithmic complexity compared with principal component analysis (PCA) and provided the ability to involve or emphasize several important frequencies or impedance range in a more flexible way.

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Adiraju, Anurag, Rohan Munjal, Christian Viehweger, Ammar Al-Hamry, Amina Brahem, Jawaid Hussain, Sanhith Kommisetty, Aditya Jalasutram, Christoph Tegenkamp, and Olfa Kanoun. "Towards Embedded Electrochemical Sensors for On-Site Nitrite Detection by Gold Nanoparticles Modified Screen Printed Carbon Electrodes." Sensors 23, no. 6 (March 9, 2023): 2961. http://dx.doi.org/10.3390/s23062961.

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The transition of electrochemical sensors from lab-based measurements to real-time analysis requires special attention to different aspects in addition to the classical development of new sensing materials. Several critical challenges need to be addressed including a reproducible fabrication procedure, stability, lifetime, and development of cost-effective sensor electronics. In this paper, we address these aspects exemplarily for a nitrite sensor. An electrochemical sensor has been developed using one-step electrodeposited (Ed) gold nanoparticles (EdAu) for the detection of nitrite in water, which shows a low limit of detection of 0.38 µM and excellent analytical capabilities in groundwater. Experimental investigations with 10 realized sensors show a very high reproducibility enabling mass production. A comprehensive investigation of the sensor drift by calendar and cyclic aging was carried out for 160 cycles to assess the stability of the electrodes. Electrochemical impedance spectroscopy (EIS) shows significant changes with increasing aging inferring the deterioration of the electrode surface. To enable on-site measurements outside the laboratory, a compact and cost-effective wireless potentiostat combining cyclic and square wave voltammetry, and EIS capabilities has been designed and validated. The implemented methodology in this study builds a basis for the development of further on-site distributed electrochemical sensor networks.

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Crescentini, Marco, Alessio De Angelis, Roberta Ramilli, Guido De Angelis, Marco Tartagni, Antonio Moschitta, Pier Andrea Traverso, and Paolo Carbone. "Online EIS and Diagnostics on Lithium-Ion Batteries by Means of Low-Power Integrated Sensing and Parametric Modeling." IEEE Transactions on Instrumentation and Measurement 70 (2021): 1–11. http://dx.doi.org/10.1109/tim.2020.3031185.

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Journal articles on the topic 'Instrumentation for EIS'

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