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Company-Se G, Nescolarde L, Pajares V, Torrego A, Riu PJ, Rosell J, Bragós R. Differentiation using minimally-invasive bioimpedance measurements of healthy and pathological lung tissue through bronchoscopy. Front Med (Lausanne) 2023; 10:1108237. [PMID: 37113605 PMCID: PMC10126248 DOI: 10.3389/fmed.2023.1108237] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2022] [Accepted: 03/17/2023] [Indexed: 04/29/2023] Open
Abstract
Purpose To use minimally-invasive transcatheter electrical impedance spectroscopy measurements for tissue differentiation among healthy lung tissue and pathologic lung tissue from patients with different respiratory diseases (neoplasm, fibrosis, pneumonia and emphysema) to complement the diagnosis at real time during bronchoscopic procedures. Methods Multi-frequency bioimpedance measurements were performed in 102 patients. The two most discriminative frequencies for impedance modulus (|Z|), phase angle (PA), resistance (R) and reactance (Xc) were selected based on the maximum mean pair-wise Euclidean distances between paired groups. One-way ANOVA for parametric variables and Kruskal-Wallis for non-parametric data tests have been performed with post-hoc tests. Discriminant analysis has also been performed to find a linear combination of features to separate among tissue groups. Results We found statistically significant differences for all the parameters between: neoplasm and pneumonia (p < 0.05); neoplasm and healthy lung tissue (p < 0.001); neoplasm and emphysema (p < 0.001); fibrosis and healthy lung tissue (p ≤ 0.001) and pneumonia and healthy lung tissue (p < 0.01). For fibrosis and emphysema (p < 0.05) only in |Z|, R and Xc; and between pneumonia and emphysema (p < 0.05) only in |Z| and R. No statistically significant differences (p > 0.05) are found between neoplasm and fibrosis; fibrosis and pneumonia; and between healthy lung tissue and emphysema. Conclusion The application of minimally-invasive electrical impedance spectroscopy measurements in lung tissue have proven to be useful for tissue differentiation between those pathologies that leads increased tissue and inflammatory cells and those ones that contain more air and destruction of alveolar septa, which could help clinicians to improve diagnosis.
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Affiliation(s)
- Georgina Company-Se
- Department of Electronic Engineering, Universitat Politècnica de Catalunya, Barcelona, Catalonia, Spain
| | - Lexa Nescolarde
- Department of Electronic Engineering, Universitat Politècnica de Catalunya, Barcelona, Catalonia, Spain
- *Correspondence: Lexa Nescolarde,
| | - Virginia Pajares
- Department of Respiratory Medicine, Hospital de la Santa Creu i Sant Pau, Barcelona, Catalonia, Spain
| | - Alfons Torrego
- Department of Respiratory Medicine, Hospital de la Santa Creu i Sant Pau, Barcelona, Catalonia, Spain
| | - Pere J. Riu
- Department of Electronic Engineering, Universitat Politècnica de Catalunya, Barcelona, Catalonia, Spain
| | - Javier Rosell
- Department of Electronic Engineering, Universitat Politècnica de Catalunya, Barcelona, Catalonia, Spain
| | - Ramon Bragós
- Department of Electronic Engineering, Universitat Politècnica de Catalunya, Barcelona, Catalonia, Spain
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Llucià-Valldeperas A, Bragós R, Bayés-Genís A. Simultaneous Electrical and Mechanical Stimulation to Enhance Cells' Cardiomyogenic Potential. J Vis Exp 2019. [PMID: 30735196 DOI: 10.3791/58934] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022] Open
Abstract
Cardiovascular diseases are the leading cause of death in developed countries. Consequently, the demand for effective cardiac cell therapies has motivated researchers in the stem cell and bioengineering fields to develop in vitro high-fidelity human myocardium for both basic research and clinical applications. However, the immature phenotype of cardiac cells is a limitation on obtaining tissues that functionally mimic the adult myocardium, which is mainly characterized by mechanical and electrical signals. Thus, the purpose of this protocol is to prepare and mature the target cell population through electromechanical stimulation, recapitulating physiological parameters. Cardiac tissue engineering is evolving toward more biological approaches, and strategies based on biophysical stimuli, thus, are gaining momentum. The device developed for this purpose is unique and allows individual or simultaneous electrical and mechanical stimulation, carefully characterized and validated. In addition, although the methodology has been optimized for this stimulator and a specific cell population, it can easily be adapted to other devices and cell lines. The results here offer evidence of the increased cardiac commitment of the cell population after electromechanical stimulation. Electromechanically stimulated cells show an increased expression of main cardiac markers, including early, structural, and calcium-regulating genes. This cell conditioning could be useful for further regenerative cell therapy, disease modeling, and high-throughput drug screening.
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Affiliation(s)
- Aida Llucià-Valldeperas
- Insuficiencia Cardiaca y Regeneración Cardiaca (ICREC) Research Program, Health Science Research Institute Germans Trias i Pujol; Amsterdam Universitair Medisch Centrum (UMC), Vrije Universiteit Amsterdam, Pulmonology and Physiology, Amsterdam Cardiovascular Sciences;
| | - Ramon Bragós
- Electronic and Biomedical Instrumentation Group, Departament d'Enginyeria Electrònica, Universitat Politècnica de Catalunya
| | - Antoni Bayés-Genís
- Insuficiencia Cardiaca y Regeneración Cardiaca (ICREC) Research Program, Health Science Research Institute Germans Trias i Pujol; Cardiology Service, Germans Trias i Pujol University Hospital; Department of Medicine, Universitat Autònoma de Barcelona; Centro de Investigación Biomédica en Red (CIBER) Cardiovascular, Instituto de Salud Carlos III
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Amorós-Figueras G, Jorge E, Alonso-Martin C, Traver D, Ballesta M, Bragós R, Rosell-Ferrer J, Cinca J. Endocardial infarct scar recognition by myocardial electrical impedance is not influenced by changes in cardiac activation sequence. Heart Rhythm 2017; 15:589-596. [PMID: 29197656 DOI: 10.1016/j.hrthm.2017.11.031] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/24/2017] [Indexed: 10/18/2022]
Abstract
BACKGROUND Measurement of myocardial electrical impedance can allow recognition of infarct scar and is theoretically not influenced by changes in cardiac activation sequence, but this is not known. OBJECTIVES The objectives of this study were to evaluate the ability of endocardial electrical impedance measurements to recognize areas of infarct scar and to assess the stability of the impedance data under changes in cardiac activation sequence. METHODS One-month-old myocardial infarction confirmed by cardiac magnetic resonance imaging was induced in 5 pigs submitted to coronary artery catheter balloon occlusion. Electroanatomic data and local electrical impedance (magnitude, phase angle, and amplitude of the systolic-diastolic impedance curve) were recorded at multiple endocardial sites in sinus rhythm and during right ventricular pacing. By merging the cardiac magnetic resonance and electroanatomic data, we classified each impedance measurement site either as healthy (bipolar amplitude ≥1.5 mV and maximum pixel intensity <40%) or scar (bipolar amplitude <1.5 mV and maximum pixel intensity ≥40%). RESULTS A total of 137 endocardial sites were studied. Compared to healthy tissue, areas of infarct scar showed 37.4% reduction in impedance magnitude (P < .001) and 21.5% decrease in phase angle (P < .001). The best predictive ability to detect infarct scar was achieved by the combination of the 4 impedance parameters (area under the receiver operating characteristic curve 0.96; 95% confidence interval 0.92-1.00). In contrast to voltage mapping, right ventricular pacing did not significantly modify the impedance data. CONCLUSION Endocardial catheter measurement of electrical impedance can identify infarct scar regions, and in contrast to voltage mapping, the impedance data are not affected by changes in cardiac activation sequence.
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Affiliation(s)
- Gerard Amorós-Figueras
- Department of Cardiology, Hospital de la Santa Creu i Sant Pau, IIB-Sant Pau, Universitat Autònoma de Barcelona, Barcelona, Spain
| | - Esther Jorge
- Department of Cardiology, Hospital de la Santa Creu i Sant Pau, IIB-Sant Pau, Universitat Autònoma de Barcelona, Barcelona, Spain; CIBERCV, Barcelona, Spain.
| | - Concepción Alonso-Martin
- Department of Cardiology, Hospital de la Santa Creu i Sant Pau, IIB-Sant Pau, Universitat Autònoma de Barcelona, Barcelona, Spain
| | | | - Maria Ballesta
- Electronic and Biomedical Instrumentation Group, Department of Electronic Engineering, Universitat Politècnica de Catalunya, Barcelona, Spain
| | - Ramon Bragós
- Electronic and Biomedical Instrumentation Group, Department of Electronic Engineering, Universitat Politècnica de Catalunya, Barcelona, Spain
| | - Javier Rosell-Ferrer
- CIBERCV, Barcelona, Spain; Electronic and Biomedical Instrumentation Group, Department of Electronic Engineering, Universitat Politècnica de Catalunya, Barcelona, Spain
| | - Juan Cinca
- Department of Cardiology, Hospital de la Santa Creu i Sant Pau, IIB-Sant Pau, Universitat Autònoma de Barcelona, Barcelona, Spain; CIBERCV, Barcelona, Spain
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Lecina M, Sanchez B, Solà C, Prat J, Roldán M, Hernández M, Bragós R, Paredes CJ, Cairó JJ. Structural changes of Arthrospira sp. after low energy sonication treatment for microalgae harvesting: Elucidating key parameters to detect the rupture of gas vesicles. Bioresour Technol 2017; 223:98-104. [PMID: 27788433 DOI: 10.1016/j.biortech.2016.10.030] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/25/2016] [Revised: 10/07/2016] [Accepted: 10/08/2016] [Indexed: 06/06/2023]
Abstract
The buoyancy suppression by low energy sonication (LES) treatment (0.8W·mL-1, 20kHz, 10s) has recently been proposed as an initial harvesting step for Arthrospira sp. This paper aims to describe the structural changes in Arthrospira sp. after LES treatment and to present how these structural changes affect the results obtained by different analytical techniques. Transmission electron microscopy (TEM) micrographs of trichomes evidenced the gas vesicles rupture but also revealed a rearrangement of thylakoids and more visible phycobilisomes were observed. Differences between treated and untreated samples were detected by confocal microscopy, flow cytometry and optical microscopy but not by electrical impedance spectroscopy (EIS). After LES treatment, 2-fold increase in autofluorescence at 610/660nm was measured (phycocyanin/allophycocyanin emission wavelengths) and a ten-fold decrease in side scatter light intensity (due to a reduction of trichome's inner complexity). This was further confirmed by optical microscopy showing changes on trichomes appearance (from wrinkled to smooth).
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Affiliation(s)
- Martí Lecina
- Department of Chemial, Biological and Environmental Engineering, Escola d'Enginyeria, Universitat Autònoma de Barcelona, 08193 Bellaterra, Spain.
| | - Benjamin Sanchez
- Electronic and Biomedical Instrumentation Group, Department of Electronic Engineering, Universitat Politècnica de Catalunya (UPC), Campus Nord, C-4, C/ Jordi Girona 1-3, 08034 Barcelona, Spain
| | - Carles Solà
- Department of Chemial, Biological and Environmental Engineering, Escola d'Enginyeria, Universitat Autònoma de Barcelona, 08193 Bellaterra, Spain
| | - Jordi Prat
- Department of Chemial, Biological and Environmental Engineering, Escola d'Enginyeria, Universitat Autònoma de Barcelona, 08193 Bellaterra, Spain
| | - Mònica Roldán
- Servei de Microscòpia, Universitat Autònoma de Barcelona, Edifici C, Facultat de Ciències, 08193 Bellaterra, Spain
| | - Mariona Hernández
- Dep. Productes Naturals, Biologia Vegetal i Edafologia, Facultat de Farmàcia, Universitat de Barcelona, Av. Joan XXIII s/n, 08028 Barcelona, Spain
| | - Ramon Bragós
- Electronic and Biomedical Instrumentation Group, Department of Electronic Engineering, Universitat Politècnica de Catalunya (UPC), Campus Nord, C-4, C/ Jordi Girona 1-3, 08034 Barcelona, Spain
| | - Carlos J Paredes
- Department of Chemial, Biological and Environmental Engineering, Escola d'Enginyeria, Universitat Autònoma de Barcelona, 08193 Bellaterra, Spain
| | - Jordi J Cairó
- Department of Chemial, Biological and Environmental Engineering, Escola d'Enginyeria, Universitat Autònoma de Barcelona, 08193 Bellaterra, Spain
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Gálvez‐Montón C, Bragós R, Soler‐Botija C, Díaz‐Güemes I, Prat‐Vidal C, Crisóstomo V, Sánchez‐Margallo FM, Llucià‐Valldeperas A, Bogónez‐Franco P, Perea‐Gil I, Roura S, Bayes‐Genis A. Noninvasive Assessment of an Engineered Bioactive Graft in Myocardial Infarction: Impact on Cardiac Function and Scar Healing. Stem Cells Transl Med 2016; 6:647-655. [PMID: 28191775 PMCID: PMC5442807 DOI: 10.5966/sctm.2016-0063] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2016] [Accepted: 07/28/2016] [Indexed: 01/09/2023] Open
Abstract
Cardiac tissue engineering, which combines cells and biomaterials, is promising for limiting the sequelae of myocardial infarction (MI). We assessed myocardial function and scar evolution after implanting an engineered bioactive impedance graft (EBIG) in a swine MI model. The EBIG comprises a scaffold of decellularized human pericardium, green fluorescent protein‐labeled porcine adipose tissue‐derived progenitor cells (pATPCs), and a customized‐design electrical impedance spectroscopy (EIS) monitoring system. Cardiac function was evaluated noninvasively by using magnetic resonance imaging (MRI). Scar healing was evaluated by using the EIS system within the implanted graft. Additionally, infarct size, fibrosis, and inflammation were explored by histopathology. Upon sacrifice 1 month after the intervention, MRI detected a significant improvement in left ventricular ejection fraction (7.5% ± 4.9% vs. 1.4% ± 3.7%; p = .038) and stroke volume (11.5 ± 5.9 ml vs. 3 ± 4.5 ml; p = .019) in EBIG‐treated animals. Noninvasive EIS data analysis showed differences in both impedance magnitude ratio (−0.02 ± 0.04 per day vs. −0.48 ± 0.07 per day; p = .002) and phase angle slope (−0.18° ± 0.24° per day vs. −3.52° ± 0.84° per day; p = .004) in EBIG compared with control animals. Moreover, in EBIG‐treated animals, the infarct size was 48% smaller (3.4% ± 0.6% vs. 6.5% ± 1%; p = .015), less inflammation was found by means of CD25+ lymphocytes (0.65 ± 0.12 vs. 1.26 ± 0.2; p = .006), and a lower collagen I/III ratio was detected (0.49 ± 0.06 vs. 1.66 ± 0.5; p = .019). An EBIG composed of acellular pericardium refilled with pATPCs significantly reduced infarct size and improved cardiac function in a preclinical model of MI. Noninvasive EIS monitoring was useful for tracking differential scar healing in EBIG‐treated animals, which was confirmed by less inflammation and altered collagen deposit. Stem Cells Translational Medicine2017;6:647–655
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Affiliation(s)
- Carolina Gálvez‐Montón
- ICREC (Heart Failure and Cardiac Regeneration) Research Programme, Fundació Institut d'Investigació en Ciències de la Salut Germans Trias i Pujol, Badalona, Barcelona, Spain;
| | - Ramon Bragós
- Electronic and Biomedical Instrumentation Group, Electronic Engineering Department, Universitat Politècnica de Catalunya, Barcelona, Spain
| | - Carolina Soler‐Botija
- ICREC (Heart Failure and Cardiac Regeneration) Research Programme, Fundació Institut d'Investigació en Ciències de la Salut Germans Trias i Pujol, Badalona, Barcelona, Spain;
| | | | - Cristina Prat‐Vidal
- ICREC (Heart Failure and Cardiac Regeneration) Research Programme, Fundació Institut d'Investigació en Ciències de la Salut Germans Trias i Pujol, Badalona, Barcelona, Spain;
| | | | | | - Aida Llucià‐Valldeperas
- ICREC (Heart Failure and Cardiac Regeneration) Research Programme, Fundació Institut d'Investigació en Ciències de la Salut Germans Trias i Pujol, Badalona, Barcelona, Spain;
| | - Paco Bogónez‐Franco
- Electronic and Biomedical Instrumentation Group, Electronic Engineering Department, Universitat Politècnica de Catalunya, Barcelona, Spain
| | - Isaac Perea‐Gil
- ICREC (Heart Failure and Cardiac Regeneration) Research Programme, Fundació Institut d'Investigació en Ciències de la Salut Germans Trias i Pujol, Badalona, Barcelona, Spain;
| | - Santiago Roura
- ICREC (Heart Failure and Cardiac Regeneration) Research Programme, Fundació Institut d'Investigació en Ciències de la Salut Germans Trias i Pujol, Badalona, Barcelona, Spain;
- Center of Regenerative Medicine in Barcelona, Barcelona, Spain
| | - Antoni Bayes‐Genis
- ICREC (Heart Failure and Cardiac Regeneration) Research Programme, Fundació Institut d'Investigació en Ciències de la Salut Germans Trias i Pujol, Badalona, Barcelona, Spain;
- Cardiology Service, Hospital Universitari Germans Trias i Pujol, Badalona, Barcelona, Spain;
- Department of Medicine, Autonomous University of Barcelona, Barcelona, Spain
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Fontova A, López-Repullo J, Lecina M, Bragós R, Cairó JJ. A Simplified implementation of the O.U.R. stationary liquid mass balance estimation method for On-line monitoring in Animal cell production processes. BMC Proc 2015. [PMCID: PMC4685378 DOI: 10.1186/1753-6561-9-s9-p56] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
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7
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García-Sánchez T, Azan A, Leray I, Rosell-Ferrer J, Bragós R, Mir LLM. Interpulse multifrequency electrical impedance measurements during electroporation of adherent differentiated myotubes. Bioelectrochemistry 2015; 105:123-35. [DOI: 10.1016/j.bioelechem.2015.05.018] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2014] [Revised: 05/25/2015] [Accepted: 05/31/2015] [Indexed: 01/26/2023]
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García-Sánchez T, Guitart M, Rosell-Ferrer J, Gómez-Foix AM, Bragós R. A new spiral microelectrode assembly for electroporation and impedance measurements of adherent cell monolayers. Biomed Microdevices 2014; 16:575-90. [DOI: 10.1007/s10544-014-9860-6] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
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Bogónez-Franco P, Nescolarde L, Gálvez-Montón C, Bragós R, Rosell-Ferrer J. An implantable bioimpedance monitor using 2.45 GHz band for telemetry. Physiol Meas 2012; 34:1-16. [DOI: 10.1088/0967-3334/34/1/1] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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10
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Soley A, Fontova A, Gálvez J, Sarró E, Lecina M, Bragós R, Cairó J, Gòdia F. Development of a simple disposable six minibioreactor system for suspension mammalian cell culture. Process Biochem 2012. [DOI: 10.1016/j.procbio.2011.12.022] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Sarró E, Lecina M, Fontova A, Solà C, Gòdia F, Cairó J, Bragós R. Electrical impedance spectroscopy measurements using a four-electrode configuration improve on-line monitoring of cell concentration in adherent animal cell cultures. Biosens Bioelectron 2012; 31:257-63. [DOI: 10.1016/j.bios.2011.10.028] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2011] [Revised: 10/13/2011] [Accepted: 10/17/2011] [Indexed: 11/25/2022]
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12
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Bogónez-Franco P, Nescolarde L, Bragós R, Rosell-Ferrer J, Yandiola I. Measurement errors in multifrequency bioelectrical impedance analyzers with and without impedance electrode mismatch. Physiol Meas 2009; 30:573-87. [PMID: 19491458 DOI: 10.1088/0967-3334/30/7/004] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
The purpose of this study is to compare measurement errors in two commercially available multi-frequency bioimpedance analyzers, a Xitron 4000B and an ImpediMed SFB7, including electrode impedance mismatch. The comparison was made using resistive electrical models and in ten human volunteers. We used three different electrical models simulating three different body segments: the right-side, leg and thorax. In the electrical models, we tested the effect of the capacitive coupling of the patient to ground and the skin-electrode impedance mismatch. Results showed that both sets of equipment are optimized for right-side measurements and for moderate skin-electrode impedance mismatch. In right-side measurements with mismatch electrode, 4000B is more accurate than SFB7. When an electrode impedance mismatch was simulated, errors increased in both bioimpedance analyzers and the effect of the mismatch in the voltage detection leads was greater than that in current injection leads. For segments with lower impedance as the leg and thorax, SFB7 is more accurate than 4000B and also shows less dependence on electrode mismatch. In both devices, impedance measurements were not significantly affected (p > 0.05) by the capacitive coupling to ground.
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Affiliation(s)
- P Bogónez-Franco
- Electronic Engineering Department, Technical University of Catalonia (UPC), Jordi Girona 1-3 Edifici C4, 08034 Barcelona, Spain.
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Bogónez-Franco P, Bragós R, Bayés-Genis A, Rosell-Ferrer J. Implantable bioimpedance monitor using ZigBee. Annu Int Conf IEEE Eng Med Biol Soc 2009; 2009:4868-4871. [PMID: 19963630 DOI: 10.1109/iembs.2009.5332452] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
In this paper, a novel implantable bioimpedance monitor using a free ZigBee protocol for the transmission of the measured data is described. The application field is the tissue and organ monitoring through electrical impedance spectroscopy in the 100 Hz - 200 kHz range. The specific application is the study of the viability and evolution of engineered tissue in cardiac regeneration. Additionally to the telemetric feature, the measured data are stored in a memory for backup purposes and can be downloaded at any time after an RF link break. In the debugging prototype, the system autonomy exceeds 1 month when a 14 frequencies impedance spectrum is acquired every 5 minutes. In the current implementation, the effective range of the RF link is reduced and needs for a range extender placed near the animal. Current work deals with improving this range.
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Affiliation(s)
- P Bogónez-Franco
- Instrumentation and Bioengineering Group (IEB) of the Universitat Politècnica de Catalunya (UPC), c/Jordi Girona 1-3, Barcelona, Spain.
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Seoane F, Ferreira J, Sanchéz JJ, Bragós R. An analog front-end enables electrical impedance spectroscopy system on-chip for biomedical applications. Physiol Meas 2008; 29:S267-78. [PMID: 18544823 DOI: 10.1088/0967-3334/29/6/s23] [Citation(s) in RCA: 69] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
The increasing number of applications of electrical bioimpedance measurements in biomedical practice, together with continuous advances in textile technology, has encouraged several researchers to make the first attempts to develop portable, even wearable, electrical bioimpedance measurement systems. The main target of these systems is personal and home monitoring. Analog Devices has made available AD5933, a new system-on-chip fully integrated electrical impedance spectrometer, which might allow the implementation of minimum-size instrumentation for electrical bioimpedance measurements. However, AD5933 as such is not suitable for most applications of electrical bioimpedance. In this work, we present a relatively simple analog front-end that adapts AD5933 to a four-electrode strategy, allowing its use in biomedical applications for the first time. The resulting impedance measurements exhibit a very good performance in aspects like load dynamic range and accuracy. This type of minimum-size, system-on-chip-based bioimpedance measurement system would lead researchers to develop and implement light and wearable electrical bioimpedance systems for home and personal health monitoring applications, a new and huge niche for medical technology development.
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Affiliation(s)
- Fernando Seoane
- School of Engineering, Medical Electronics Group, University College of Borås, Borås, Sweden.
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15
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Fontova A, Soley A, Gálvez J, Sarró E, Lecina M, Rosell J, Riu P, Cairó J, Gòdia F, Bragós R. Multiple automated minibioreactor system for multifunctional screening in biotechnology. Conf Proc IEEE Eng Med Biol Soc 2008; 2006:632-5. [PMID: 17946845 DOI: 10.1109/iembs.2006.260628] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
The current techniques applied in biotechnology allow to obtain many types of molecules that must be tested on cell cultures (high throughput screening HTS). Although such tests are usually carried out automatically on mini or microwell plates, the procedures in the preindustrial stage are performed almost manually on higher volume recipients known as bioreactors. The growth conditions in both stages are completely different. The screening system presented in this work is based on the multiwell test plates philosophy, a disposable multiple minibioreactor that allows reproduction of industrial bioreactor culture conditions: aeration, stirring, temperature, O2, pH and visible range optical absorbance measurements. It is possible to reproduce the growth conditions for both suspended and adherent animal cell types using 1 to 10 ml vol. bioreactors. In the case of bacteria or yeast, it is not possible to achieve a high biomass concentration, due to the reduced head volume air supply.
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Affiliation(s)
- A Fontova
- Electronic Engineering Dept., Technical University of Catalonia, Barcelona, Spain
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Farré J, Roura S, Prat-Vidal C, Soler-Botija C, Llach A, Molina CE, Hove-Madsen L, Cairó JJ, Gòdia F, Bragós R, Cinca J, Bayes-Genis A. FGF-4 increases in vitro expansion rate of human adult bone marrow-derived mesenchymal stem cells. Growth Factors 2007; 25:71-6. [PMID: 17852409 DOI: 10.1080/08977190701345200] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Human bone marrow-derived mesenchymal stem cells (MSCs) exhibit limited in vitro growth. Fibroblast growth factors (FGFs) elicit a variety of biological responses, such as cell proliferation, differentiation and migration. FGF-4 represents one of the FGFs with the highest cell mitogenic activity. We studied the effect of FGF-4 on MSCs growth and pluripotency. MSCs duplication time (Td) was significantly reduced with FGF-4 compared to controls (2.2 +/- 0.2 vs. 4.1 +/- 0.2 days, respectively; p = 0.03) while BMP-2 and SCF-1 did not exert a significant growth effect. MSC expression of surface markers, differentiation into adipogenic and osteogenic lineages, and baseline expression of cardiomyogenic genes were unaffected by FGF-4. In summary, exogenous FGF-4 increases the rate at which MSC proliferate and has no significant effect on MSC pluripotency.
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Affiliation(s)
- Jordi Farré
- Laboratory of Cell Physiology, Department of Cardiology, Institut Català de Ciencies Cardiovasculars, Hospital de la Santa Creu i Sant Pau, Universitat Autònoma de Barcelona, Sant Antoni Ma Claret 167, 08025 Barcelona, Spain
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17
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Seoane F, Bragós R, Lindecrantz K. Current source for multifrequency broadband electrical bioimpedance spectroscopy systems. A novel approach. Conf Proc IEEE Eng Med Biol Soc 2006; 2006:5121-5125. [PMID: 17945876 DOI: 10.1109/iembs.2006.259566] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
New research and clinical applications of broadband electrical bioimpedance spectroscopy arise; increasing the upper limit frequency used in the measurement systems. The current source, an essential block of an electrical bioimpedance impedance analyzer, must have a large-enough output impedance at any frequency of operation to keep the output current constant regardless of the value of working load. In this paper a novel approach to increase the output impedance of a common voltage controlled current source is proposed. The circuit is analyzed, implemented and tested. The results, remarking the significant effect of the circuit parasitic capacitances, show a clear increment of the output impedance, but smaller than the originally expected.
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Affiliation(s)
- Fernando Seoane
- School of Engineering, University College of Borås, Borås, Sweden.
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18
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Bragós R, Sarro E, Fontova A, Soley A, Cairó J, Bayés-Genís A, Rosell J. Four versus two-electrode measurement strategies for cell growing and differentiation monitoring using electrical impedance spectroscopy. Conf Proc IEEE Eng Med Biol Soc 2006; 2006:2106-2109. [PMID: 17946497 DOI: 10.1109/iembs.2006.260287] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
The aim of this work is to provide optimization tools for cell and tissue engineering processes through continuous monitoring of cell cultures. Structural cell properties can be obtained from non-destructive electrical measurements by using electrical impedance spectroscopy (EIS). EIS measurements on monolayer animal cell cultures are usually performed using a two-electrode strategy. Because of this, the measurement is very sensitive to the electrode covering ratio and to the degree of adherence of cells. Of course, these parameters give useful information but can mask the behaviour of the cell layer above the electrodes. In a previous work, preliminary measurements with commercial microelectrode structures were performed with simulated grow processes using the settlement of cell suspensions with two and four microelectrode strategies to validate the technique. In this work, real cell growths of Vero cells are described and the resulting EIS biomass density estimators are compared to cell counts. The four-electrode impedance spectra are fitted to the Cole-Cole impedance model and the time course of their parameters are extracted and studied.
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Affiliation(s)
- R Bragós
- Electron. Eng. Dept., Tech. Univ. of Catalonia UPC, Campus Nord, C-4 c/ Jordi Girona 1-3, 08034 Barcelona, Spain.
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19
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Soley A, Lecina M, Gámez X, Cairó JJ, Riu P, Rosell X, Bragós R, Gòdia F. On-line monitoring of yeast cell growth by impedance spectroscopy. J Biotechnol 2005; 118:398-405. [PMID: 16026878 DOI: 10.1016/j.jbiotec.2005.05.022] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2004] [Revised: 05/23/2005] [Accepted: 05/30/2005] [Indexed: 10/25/2022]
Abstract
The application of impedance spectroscopy to estimate on-line cell concentration was studied. The estimation was based on the relative variation between electrical impedance measured at low (10 kHz) and high frequencies (10 MHz). Studies were carried out to characterise the influence of changes in physical and chemical parameters on the impedance measurement. Two different possibilities to perform on-line measurements were tested: a simple set-up, based on an in situ probe, gave good results but was not suitable for high agitation and aeration rates. An ex situ flow-through on-line measuring cell was used to overcome these problems, showing a better performance. The use of this set-up for the growth monitorisation of a Saccharomyces cerevisiae culture showed an efficient performance, having the correlation between estimated and measured S. cerevisiae a Pearson coefficient of 0.999.
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Affiliation(s)
- A Soley
- Departament d'Enginyeria Química, Escola Tècnica Superior d'Enginyeria, Universitat Autònoma de Barcelona, 08193 Cerdanyola del Vallès, Barcelona, Spain.
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20
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Warren M, Bragós R, Casas O, Rodríguez-Sinovas A, Rosell J, Anivarro I, Cinca J. Percutaneous electrocatheter technique for on-line detection of healed transmural myocardial infarction. Pacing Clin Electrophysiol 2000; 23:1283-7. [PMID: 10962753 DOI: 10.1111/j.1540-8159.2000.tb00945.x] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Healed myocardial infarction has been recognized by its particular tissue electrical impedance spectrum measured with intramural needle electrodes in animal models. The aim of this study was to develop a percutaneous approach for in vivo recognition of areas of healed myocardial infarction by measuring myocardial electrical impedance with an intracavitary contact electrocatheter. Electrical impedance (resistance and phase angle) of normal myocardium and of a 2-month-old anterior transmural infarction were measured in nine chloralose anesthetized pigs by applying alternating currents from 1 kHz to 1 MHZ between a bipolar intracavitary catheter and a reference electrode placed on the epicardium (group I, n = 4) or on the precordium (group II, n = 5). Resistance of the infarcted myocardium was lower than that of healthy tissue at all current frequencies (ANOVA, P < 0.001) (i.e., at 1 kHz: 15 +/- 4 omega vs 50 +/- 19 omega in group I, and 64 +/- 13 omega vs 76 +/- 13 omega in group II). Phase angle at 316 kHz best differentiated transmural infarction from normal tissue (group I: -2.5 +/- 1.9 degrees vs -14.8 +/- 4.6 degrees, P < 0.001; group II: +0.7 +/- 1.0 degrees vs -2.7 +/- 1.4 degrees, P < 0.001). This study shows that analysis of myocardial impedance spectrum using a percutaneous intracavitary contact catheter approach permits on-line recognition of areas of healed transmural myocardial infarction. This technique may be useful to optimize clinical application of energy sources (i.e., radiofrequency ablation, laser myocardial revascularization).
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Affiliation(s)
- M Warren
- Experimental Cardiology Laboratory, Hospital Vall d'Hebron, Autonomous University of Barcelona, Spain
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21
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Abstract
In this work we show the algorithms developed to extract the Cole parameters from multi-frequency EIT. With these parameters it is possible to obtain information about various different tissues and their pathologies. The algorithms developed obtain the Cole-model parameters from the real and imaginary parts of impedance, or using only the real part, without problems of convergence. A study of the influence of noise is performed with simulations. We find a correct solution in all cases with signal to noise ratio in the data higher than 40 dB. Finally, we show parametric images of the human abdomen obtained with these algorithms.
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Affiliation(s)
- O Casas
- Departament d'Enginyeria Electronica, Universitat Politecnica de Catalunya, Barcelona, Spain
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22
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Casas O, Bragós R, Riu PJ, Rosell J, Tresànchez M, Warren M, Rodriguez-Sinovas A, Carreño A, Cinca J. In vivo and in situ ischemic tissue characterization using electrical impedance spectroscopy. Ann N Y Acad Sci 1999; 873:51-8. [PMID: 10372149 DOI: 10.1111/j.1749-6632.1999.tb09448.x] [Citation(s) in RCA: 70] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
The investigation of processes of ischemia in different organ tissues is very important for the development of methods of protection and preservation during surgical procedures. Electrical impedance spectroscopy was used to distinguish between different tissues and their degree of ischemia. We describe mathematical methods used to adjust experimental data to Cole-Cole models for one-circle and two-circle impedance loci and a study of the main parameters for representing the behavior of ischemia in time. In vivo and in situ postmortem measurements of different tissues from pigs are shown in the 100 Hz to 1 MHz range. The Cole parameters that best characterize the ischemia are R0 and fc.
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Affiliation(s)
- O Casas
- Departament d'Enginyeria Electrònica, Universitat Politècnica de Catalunya, Barcelona, Spain
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Abstract
The biomass density in biotechnological processes is often determined by indirect and manual methods. Electrical impedance spectroscopy can provide online viable biomass density estimators. In this work, we present two linear estimators obtained with this technique. Four different microorganisms were measured. The detection threshold was approximately 1 g/L (dry weight) for bacteria and 0.5 g/L for yeast. Liposome suspensions were also used to validate the methods. The monitoring of the continuous growth of a yeast culture is also presented.
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Affiliation(s)
- R Bragós
- Departament d'Enginyeria Electrònica, Universitat Politècnica de Catalunya, Barcelona, Spain
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Cinca J, Warren M, Rodríguez-Sinovas A, Tresànchez M, Carreño A, Bragós R, Casas O, Domingo A, Soler-Soler J. Passive transmission of ischemic ST segment changes in low electrical resistance myocardial infarct scar in the pig. Cardiovasc Res 1998; 40:103-12. [PMID: 9876322 DOI: 10.1016/s0008-6363(98)00145-x] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/17/2022] Open
Abstract
OBJECTIVES To analyze the passive electrical properties of a healed infarction and assess their role on transmission of contiguous ischemic ST segment potential changes. METHODS We measured tissue resistivity (omega cm) at 1 kHz and the epicardial ST segment during 1 h of proximal reocclusion of the left anterior descending (LAD) coronary artery in 12 anesthetized pigs with one-month-old transmural infarction elicited by LAD ligature below the first branch. The impedance spectrum (1 to 1000 kHz) of normal and infarcted myocardium was measured in seven other pigs with similar infarctions. Electrical transmission of current pulses (30 microA) in infarcted tissue and in test solutions was also investigated. RESULTS The infarct scar has a lower than normal resistivity (110 +/- 30 omega cm vs. 235 +/- 60 omega cm, p < 0.0001) and, unlike the normal myocardium, resistivity and phase angle of the scar did not change at increasing current frequencies, reflecting no capacitative response. LAD reocclusion induced a resistivity rise (510 +/- 135 omega cm, p < 0.01) and a ST segment elevation (0.6 +/- 0.7 to 9.5 +/- 5.1 mV, p = 0.002) in the ischemic peri-infarction zone, whereas the infarcted area showed ST segment elevation (0.5 +/- 0.5 to 3.8 +/- 2.6 mV, p = 0.03) with no resistivity changes. Potential decay of both ST segment and current pulses in the scar and in 0.9% NaCl solution was less than 1 mV/mm. Transmural deposition of connective tissue was seen in the center of the infarction. CONCLUSIONS A one-month-old transmural infarction is a low resistance, noncapacitative medium that allows a good transmission of current pulses and of ST segment potential changes generated by contiguous peri-infarction ischemia.
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Affiliation(s)
- J Cinca
- Laboratorio de Cardiología Experimental, Hospital General Universitari Vall d'Hebron, Universitat Autònoma de Barcelona, Spain.
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Abstract
This paper deals with the design, implementation and performance of TIE-4sys, an electrical impedance tomograph. This instrument is a parallel broad-band real-time system. It measures impedance using an array of 16 electrodes and reconstructs the images using a weighted back-projection technique. The objective of this development is to enable multifrequency EIT clinical studies to be undertaken. The system is capable of acquiring 25 frames/s and makes multifrequency cardiac-gated images. The frequency range is from 10 kHz to 250 kHz and the signal to noise ratio for the real component is better than 60 dB.
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Affiliation(s)
- O Casas
- Department d'Enginyeria Electrònica, Universitat Politècnica de Catalunya, Barcelona, Spain
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26
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Abstract
Dynamic and multifrequency imaging methods have been demonstrated both theoretically and experimentally. Multifrequency methods are able to produce images of static structures inside the measured object. Data collection systems, however, are affected by errors due to their non-ideal frequency behaviour. If the frequencies used in the measurement were close enough, the system would behave in almost the same way. In this case, however, the impedance change displayed by biological tissues is small, so the situation is similar to dynamic imaging. We call this method the quasi-differential imaging method. We have designed and built an instrument able to apply signals from 1 kHz to 1 MHz, with frequency increments of 10 Hz. Patient interface circuits and demodulators were designed to display a flat response in the full frequency range of operation. Signals are digitized with 16 bit resolution and sent to the host computer using a high-speed serial interface. This allows a maximum measurement speed of about 8 images/s. All the system parts were full characterized out of the system and the results of these measurements are given as an indication of the limits of its use as a quasi-static imaging or quasi-differential imaging data collection system.
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Affiliation(s)
- P J Riu
- Department d'Enginyeria Electrònica, Universitat Politècnica de Catalunya, Barcelona, Spain
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27
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Abstract
A current source suitable for application in electrical impedance tomography (EIT) is described. The first stage of the commercially available current-feedback amplifier AD844 constitutes a current-conveyor implementation and allows the construction of wide-bandwidth current sources, thus avoiding the mismatching and temperature-induced problems that arise in discrete realizations. The lack in gain accuracy of this circuit is overcome by the inclusion of its input buffer in an operational amplifier (op amp) feedback loop. Saturation problems that appear when placing a DC-blocking capacitor between the source and the electrode are solved by a DC feedback that maintains DC voltage at the output near to 0 V without reducing the output impedance of the source. Two AC-coupled current sources, in both inverting and non-inverting configurations, are described and their possible applications to EIT are listed.
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Affiliation(s)
- R Bragós
- Department d'Enginyeria Electrònica, Universitat Politècnica de Catalunya, Barcelona, Spain
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