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Briz P, López-Alonso B, Sarnago H, Burdío JM, Lucía O. Tumor location on electroporation therapies by means of multi-electrode structures and machine learning. Bioelectrochemistry 2023; 154:108510. [PMID: 37536054 DOI: 10.1016/j.bioelechem.2023.108510] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2023] [Revised: 06/02/2023] [Accepted: 07/12/2023] [Indexed: 08/05/2023]
Abstract
Electroporation is a phenomenon produced in the cell membrane when it is exposed to high pulsed electric fields that increases its permeability. Among other application fields, this phenomenon can be exploited in a clinical environment for tumor ablation therapies. In this context to achieve optimum results, it is convenient to focus the treatment on the tumor tissue to minimize side effects. In this work, a pre-treatment tumor location method is developed, with the purpose of being able to precisely target the therapy. This is done by taking different impedance measurements with a multi-output electroporation generator in conjunction with a multi-electrode structure. Data are processed by means of a vector of independent artificial neural networks, trained and tested with simulation data, and validated with phantom gels. This algorithm proved to provide suitable accuracy in spite of the low electrode count compared to the number of electrodes of a standard electrical impedance tomography device.
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Affiliation(s)
- P Briz
- Department of Electronic Engineering and Communications, I3A. University of Zaragoza, Maria de Luna 1, Zaragoza 50018, Spain.
| | - B López-Alonso
- Department of Electronic Engineering and Communications, I3A. University of Zaragoza, Maria de Luna 1, Zaragoza 50018, Spain
| | - H Sarnago
- Department of Electronic Engineering and Communications, I3A. University of Zaragoza, Maria de Luna 1, Zaragoza 50018, Spain
| | - J M Burdío
- Department of Electronic Engineering and Communications, I3A. University of Zaragoza, Maria de Luna 1, Zaragoza 50018, Spain
| | - O Lucía
- Department of Electronic Engineering and Communications, I3A. University of Zaragoza, Maria de Luna 1, Zaragoza 50018, Spain
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2
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Adams WP, Raisch TB, Zhao Y, Davalos R, Barrett S, King DR, Bain CB, Colucci-Chang K, Blair GA, Hanlon A, Lozano A, Veeraraghavan R, Wan X, Deschenes I, Smyth JW, Hoeker GS, Gourdie RG, Poelzing S. Extracellular Perinexal Separation Is a Principal Determinant of Cardiac Conduction. Circ Res 2023; 133:658-673. [PMID: 37681314 PMCID: PMC10561697 DOI: 10.1161/circresaha.123.322567] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/20/2023] [Accepted: 08/29/2023] [Indexed: 09/09/2023]
Abstract
BACKGROUND Cardiac conduction is understood to occur through gap junctions. Recent evidence supports ephaptic coupling as another mechanism of electrical communication in the heart. Conduction via gap junctions predicts a direct relationship between conduction velocity (CV) and bulk extracellular resistance. By contrast, ephaptic theory is premised on the existence of a biphasic relationship between CV and the volume of specialized extracellular clefts within intercalated discs such as the perinexus. Our objective was to determine the relationship between ventricular CV and structural changes to micro- and nanoscale extracellular spaces. METHODS Conduction and Cx43 (connexin43) protein expression were quantified from optically mapped guinea pig whole-heart preparations perfused with the osmotic agents albumin, mannitol, dextran 70 kDa, or dextran 2 MDa. Peak sodium current was quantified in isolated guinea pig ventricular myocytes. Extracellular resistance was quantified by impedance spectroscopy. Intercellular communication was assessed in a heterologous expression system with fluorescence recovery after photobleaching. Perinexal width was quantified from transmission electron micrographs. RESULTS CV primarily in the transverse direction of propagation was significantly reduced by mannitol and increased by albumin and both dextrans. The combination of albumin and dextran 70 kDa decreased CV relative to albumin alone. Extracellular resistance was reduced by mannitol, unchanged by albumin, and increased by both dextrans. Cx43 expression and conductance and peak sodium currents were not significantly altered by the osmotic agents. In response to osmotic agents, perinexal width, in order of narrowest to widest, was albumin with dextran 70 kDa; albumin or dextran 2 MDa; dextran 70 kDa or no osmotic agent, and mannitol. When compared in the same order, CV was biphasically related to perinexal width. CONCLUSIONS Cardiac conduction does not correlate with extracellular resistance but is biphasically related to perinexal separation, providing evidence that the relationship between CV and extracellular volume is determined by ephaptic mechanisms under conditions of normal gap junctional coupling.
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Affiliation(s)
- William P. Adams
- Center for Vascular and Heart Research at Fralin Biomedical Research Institute at VTC
- Translational Biology, Medicine and Health Program at Virginia Tech
| | - Tristan B. Raisch
- Center for Vascular and Heart Research at Fralin Biomedical Research Institute at VTC
- Translational Biology, Medicine and Health Program at Virginia Tech
| | - Yajun Zhao
- School of Biomedical Engineering and Sciences, Virginia Tech
| | - Rafael Davalos
- School of Biomedical Engineering and Sciences, Virginia Tech
| | | | - D. Ryan King
- Center for Vascular and Heart Research at Fralin Biomedical Research Institute at VTC
- Translational Biology, Medicine and Health Program at Virginia Tech
| | - Chandra B. Bain
- Center for Vascular and Heart Research at Fralin Biomedical Research Institute at VTC
| | - Katrina Colucci-Chang
- Center for Vascular and Heart Research at Fralin Biomedical Research Institute at VTC
- School of Biomedical Engineering and Sciences, Virginia Tech
| | - Grace A. Blair
- Center for Vascular and Heart Research at Fralin Biomedical Research Institute at VTC
- Translational Biology, Medicine and Health Program at Virginia Tech
| | - Alexandra Hanlon
- Virginia Tech Center for Biostatistics and Health Data Science, Roanoke, Virginia
| | - Alicia Lozano
- Virginia Tech Center for Biostatistics and Health Data Science, Roanoke, Virginia
| | - Rengasayee Veeraraghavan
- Department of Biomedical Engineering, College of Engineering, The Ohio State University
- The Frick Center for Heart Failure and Arrhythmia, Dorothy M. Davis Heart and Lung Research Institute, College of Medicine, The Ohio State University Wexner Medical Center
| | - Xiaoping Wan
- The Frick Center for Heart Failure and Arrhythmia, Dorothy M. Davis Heart and Lung Research Institute, College of Medicine, The Ohio State University Wexner Medical Center
| | - Isabelle Deschenes
- The Frick Center for Heart Failure and Arrhythmia, Dorothy M. Davis Heart and Lung Research Institute, College of Medicine, The Ohio State University Wexner Medical Center
| | - James W. Smyth
- Center for Vascular and Heart Research at Fralin Biomedical Research Institute at VTC
- Department of Biological Sciences, College of Science, Virginia Tech
- Department of Basic Science Education, Virginia Tech Carilion School of Medicine, Roanoke, Virginia
| | - Gregory S. Hoeker
- Center for Vascular and Heart Research at Fralin Biomedical Research Institute at VTC
| | - Robert G. Gourdie
- Center for Vascular and Heart Research at Fralin Biomedical Research Institute at VTC
- School of Biomedical Engineering and Sciences, Virginia Tech
- Department of Basic Science Education, Virginia Tech Carilion School of Medicine, Roanoke, Virginia
| | - Steven Poelzing
- Center for Vascular and Heart Research at Fralin Biomedical Research Institute at VTC
- Translational Biology, Medicine and Health Program at Virginia Tech
- School of Biomedical Engineering and Sciences, Virginia Tech
- Department of Basic Science Education, Virginia Tech Carilion School of Medicine, Roanoke, Virginia
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3
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Ong S, Kullmann A, Mertens S, Rosa D, Diaz-Botia CA. Electrochemical Testing of a New Polyimide Thin Film Electrode for Stimulation, Recording, and Monitoring of Brain Activity. MICROMACHINES 2022; 13:1798. [PMID: 36296151 PMCID: PMC9611492 DOI: 10.3390/mi13101798] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/20/2022] [Revised: 10/13/2022] [Accepted: 10/15/2022] [Indexed: 06/16/2023]
Abstract
Subdural electrode arrays are used for monitoring cortical activity and functional brain mapping in patients with seizures. Until recently, the only commercially available arrays were silicone-based, whose thickness and lack of conformability could impact their performance. We designed, characterized, manufactured, and obtained FDA clearance for 29-day clinical use (510(k) K192764) of a new thin-film polyimide-based electrode array. This study describes the electrochemical characterization undertaken to evaluate the quality and reliability of electrical signal recordings and stimulation of these new arrays. Two testing paradigms were performed: a short-term active soak with electrical stimulation and a 29-day passive soak. Before and after each testing paradigm, the arrays were evaluated for their electrical performance using Electrochemical Impedance Spectroscopy (EIS), Cyclic Voltammetry (CV) and Voltage Transients (VT). In all tests, the impedance remained within an acceptable range across all frequencies. The different CV curves showed no significant changes in shape or area, which is indicative of stable electrode material. The electrode polarization remained within appropriate limits to avoid hydrolysis.
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Jara-Quijada E, Pérez-Won M, Tabilo-Munizaga G, González-Cavieres L, Lemus-Mondaca R. An Overview Focusing on Food Liposomes and Their Stability to Electric Fields. FOOD ENGINEERING REVIEWS 2022. [DOI: 10.1007/s12393-022-09306-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
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5
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Dijk G, Poulkouras R, OConnor RP. Electroporation Microchip with Integrated Conducting Polymer Electrode Array for Highly Sensitive Impedance Measurement. IEEE Trans Biomed Eng 2022; 69:2363-2369. [PMID: 35041593 DOI: 10.1109/tbme.2022.3143542] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
OBJECTIVE Monitoring of impedance changes during electroporation-based treatments can be used to study the biological response and provide feedback regarding treatment progression. However, seamless integration of the sensing electrodes with the setup can be challenging and high impedance sensing electrodes limit the recording sensitivity as well as the spatial resolution. Here, we present an all-in-one microchip containing stimulation electrodes, as well as an array of low impedance, micro-scale sensing electrodes for highly sensitive electrical impedance spectroscopy. METHODS An in vitro platform is fabricated with integrated stimulation and sensing electrodes. To reduce the impedance, the sensing electrodes are coated with the conducting polymer PEDOT:PSS. The performance is studied during the growth of a confluent cell layer and treatment with electrical pulses. RESULTS Coated electrodes, compared to uncoated electrodes, show more pronounced impedance changes in a broader frequency range throughout the formation of a confluent cell layer and electrical treatment. CONCLUSION PEDOT:PSS coatings enhance monitoring of impedance changes with micro-scale electrodes, enabling high spatial resolution and increased sensitivity. SIGNIFICANCE Enhanced monitoring techniques can be utilized to study electroporation dynamics and monitor treatment progression for better understanding of underlying mechanisms and improved outcomes.
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6
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Evaluation of electroporated area using 2,3,5-triphenyltetrazolium chloride in a potato model. Sci Rep 2021; 11:20431. [PMID: 34650212 PMCID: PMC8516888 DOI: 10.1038/s41598-021-99987-2] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2021] [Accepted: 10/05/2021] [Indexed: 12/17/2022] Open
Abstract
Irreversible electroporation (IRE) is a tissue ablation method, uses short high electric pulses and results in cell death in target tissue by irreversibly permeabilizing the cell membrane. Potato is commonly used as a tissue model for electroporation experiments. The blackened area that forms 12 h after electric pulsing is regarded as an IRE-ablated area caused by melanin accumulation. Here, the 2,3,5-triphenyltetrazolium chloride (TTC) was used as a dye to assess the IRE-ablated area 3 h after potato model ablation. Comparison between the blackened area and TTC-unstained white area in various voltage conditions showed that TTC staining well delineated the IRE-ablated area. Moreover, whether the ablated area was consistent over time and at different staining times was investigated. In addition, the presumed reversible electroporation (RE) area was formed surrounding the IRE-ablated area. Overall, TTC staining can provide a more rapid and accurate electroporated area evaluation.
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7
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Oshin EA, Guo S, Jiang C. Determining tissue conductivity in tissue ablation by nanosecond pulsed electric fields. Bioelectrochemistry 2021; 143:107949. [PMID: 34583212 PMCID: PMC8643318 DOI: 10.1016/j.bioelechem.2021.107949] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2020] [Revised: 09/10/2021] [Accepted: 09/15/2021] [Indexed: 02/03/2023]
Abstract
Nanosecond pulsed electric field (nsPEF) causes the permeabilization of the cell membrane and has been used to non-thermally treat cancerous tissues. As increased permeabilization in membranes were reported to be accompanied by impedance changes, the ablation effect of nsPEF on tissues can be monitored via the changes in tissue conductivity. In this study, effects of nsPEF on biological tissues were evaluated by determining the conductivities of potato and 4 T1-luc breast tumor tissues ex vivo from a murine model subjected to multiple 100-ns, 1-10 kV pulses. Using a four-needle electrode system with a calibrated electrode constant of 1.1 ± 0.1 cm, the conductivities of tissues was determined from both the network-analyzer measurement, before and after treatment, and voltage-current measurement in real-time. The conductivity of the potato tissue was measured for a frequency range of 0.1-3 MHz, and it increased with increasing pulse number and voltage amplitude. The conductivity of the tumor tissue was also observed to increase with pulse number and pulse voltage over a similar frequency range. In addition, the linear correlation between the ablation area in a treated potato tissue and the conductivity change in the tissue suggests that conductivity analysis of biological tissue under treatment could be a fast and sensitive approach to evaluate the effectiveness of a nsPEF treatment.
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Affiliation(s)
- Edwin A. Oshin
- Frank Reidy Research Center for Bioelectrics, Old Dominion University, Norfolk, VA, USA,Department of Electrical and Computer Engineering, Old Dominion University, Norfolk, VA, USA
| | - Siqi Guo
- Frank Reidy Research Center for Bioelectrics, Old Dominion University, Norfolk, VA, USA
| | - Chunqi Jiang
- Frank Reidy Research Center for Bioelectrics, Old Dominion University, Norfolk, VA, USA,Department of Electrical and Computer Engineering, Old Dominion University, Norfolk, VA, USA
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8
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Lorenzo MF, Bhonsle SP, Arena CB, Davalos RV. Rapid Impedance Spectroscopy for Monitoring Tissue Impedance, Temperature, and Treatment Outcome During Electroporation-Based Therapies. IEEE Trans Biomed Eng 2021; 68:1536-1546. [PMID: 33156779 PMCID: PMC8127872 DOI: 10.1109/tbme.2020.3036535] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
OBJECTIVE Electroporation-based therapies (EBTs) employ high voltage pulsed electric fields (PEFs) to permeabilize tumor tissue; this results in changes in electrical properties detectable using electrical impedance spectroscopy (EIS). Currently, commercial potentiostats for EIS are limited by impedance spectrum acquisition time ( ∼ 10 s); this timeframe is much larger than pulse periods used with EBTs ( ∼ 1 s). In this study, we utilize rapid EIS techniques to develop a methodology for characterizing electroporation (EP) and thermal effects associated with high-frequency irreversible EP (H-FIRE) in real-time by monitoring inter-burst impedance changes. METHODS A charge-balanced, bipolar rectangular chirp signal is proposed for rapid EIS. Validation of rapid EIS measurements against a commercial potentiostat was conducted in potato tissue using flat-plate electrodes and thereafter for the measurement of impedance changes throughout IRE treatment. Flat-plate electrodes were then utilized to uniformly heat potato tissue; throughout high-voltage H-FIRE treatment, low-voltage inter-burst impedance measurements were used to continually monitor impedance change and to identify a frequency at which thermal effects are delineated from EP effects. RESULTS Inter-burst impedance measurements (1.8 kHz - 4.93 MHz) were accomplished at 216 discrete frequencies. Impedance measurements at frequencies above ∼ 1 MHz served to delineate thermal and EP effects in measured impedance. CONCLUSION We demonstrate rapid-capture ( 1 s) EIS which enables monitoring of inter-burst impedance in real-time. For the first time, we show impedance analysis at high frequencies can delineate thermal effects from EP effects in measured impedance. SIGNIFICANCE The proposed waveform demonstrates the potential to perform inter-burst EIS using PEFs compatible with existing pulse generator topologies.
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9
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Merola G, Fusco R, Di Bernardo E, D’Alessio V, Izzo F, Granata V, Contartese D, Cadossi M, Audenino A, Perazzolo Gallo G. Design and Characterization of a Minimally Invasive Bipolar Electrode for Electroporation. BIOLOGY 2020; 9:biology9090303. [PMID: 32967343 PMCID: PMC7563710 DOI: 10.3390/biology9090303] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/11/2020] [Revised: 09/18/2020] [Accepted: 09/18/2020] [Indexed: 12/21/2022]
Abstract
OBJECTIVE To test a new bipolar electrode for electroporation consisting of a single minimally invasive needle. METHODS A theoretical study was performed by using Comsol Multiphysics® software. The prototypes of electrode have been tested on potatoes and pigs, adopting an irreversible electroporation protocol. Different applied voltages and different geometries of bipolar electrode prototype have been evaluated. RESULTS Simulations and pre-clinical tests have shown that the volume of ablated area is mainly influenced by applied voltage, while the diameter of the electrode had a lesser impact, making the goal of minimal-invasiveness possible. The conductive pole's length determined an increase of electroporated volume, while the insulated pole length inversely affects the electroporated volume size and shape; when the insulated pole length decreases, a more regular shape of the electric field is obtained. Moreover, the geometry of the electrode determined a different shape of the electroporated volume. A parenchymal damage in the liver of pigs due to irreversible electroporation protocol was observed. CONCLUSION The minimally invasive bipolar electrode is able to treat an electroporated volume of about 10 mm in diameter by using a single-needle electrode. Moreover, the geometry and the electric characteristics can be selected to produce ellipsoidal ablation volumes.
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Affiliation(s)
- Giulia Merola
- Oncology Medical and Research & Development Division, Igea SpA, 41012 Carpi, Italy; (G.M.); (E.D.B.); (V.D.); (M.C.); (G.P.G.)
| | - Roberta Fusco
- Oncology Medical and Research & Development Division, Igea SpA, 41012 Carpi, Italy; (G.M.); (E.D.B.); (V.D.); (M.C.); (G.P.G.)
- Correspondence:
| | - Elio Di Bernardo
- Oncology Medical and Research & Development Division, Igea SpA, 41012 Carpi, Italy; (G.M.); (E.D.B.); (V.D.); (M.C.); (G.P.G.)
| | - Valeria D’Alessio
- Oncology Medical and Research & Development Division, Igea SpA, 41012 Carpi, Italy; (G.M.); (E.D.B.); (V.D.); (M.C.); (G.P.G.)
| | - Francesco Izzo
- Hepatobiliary Surgical Oncology Unit, “Istituto Nazionale Tumori IRCCS Fondazione Pascale—IRCCS di Napoli”, 80131 Naples, Italy;
| | - Vincenza Granata
- Radiology Unit, “Istituto Nazionale Tumori IRCCS Fondazione Pascale—IRCCS di Napoli”, 80131 Naples, Italy;
| | - Deyanira Contartese
- Complex Structure of Surgical Sciences and Technologies, IRCCS Istituto Ortopedico Rizzoli, Via di Barbiano 1/10, 40136 Bologna, Italy;
| | - Matteo Cadossi
- Oncology Medical and Research & Development Division, Igea SpA, 41012 Carpi, Italy; (G.M.); (E.D.B.); (V.D.); (M.C.); (G.P.G.)
| | - Alberto Audenino
- Department of Mechanical and Aerospace Engineering, Politecnico di Torino, 10138 Turin, Italy;
| | - Giacomo Perazzolo Gallo
- Oncology Medical and Research & Development Division, Igea SpA, 41012 Carpi, Italy; (G.M.); (E.D.B.); (V.D.); (M.C.); (G.P.G.)
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Physiological changes may dominate the electrical properties of liver during reversible electroporation: Measurements and modelling. Bioelectrochemistry 2020; 136:107627. [PMID: 32784102 DOI: 10.1016/j.bioelechem.2020.107627] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2020] [Revised: 07/30/2020] [Accepted: 07/30/2020] [Indexed: 01/19/2023]
Abstract
This study presents electrical measurements (both conductivity during the pulses and impedance spectroscopy before and after) performed in liver tissue of mice during electroporation with classical electrochemotherapy conditions (8 pulses of 100 µs duration). A four-needle electrode arrangement inserted in the tissue was used for the measurements. The undesirable effects of the four-electrode geometry, notably concerning its sensitivity, were quantified and discussed showing how the electrode geometry chosen for the measurements can impact the results. Numerical modelling was applied to the information collected during the pulse, and to the impedance spectra acquired before and after the pulses sequence. Our results show that the numerical results were not consistent, suggesting that other collateral phenomena not considered in the model are at work during electroporation in vivo. We show how the modification in the volume of the intra and extra cellular media, likely caused by the vascular lock effect, could at least partially explain the recorded impedance evolution. In the present study we demonstrate the significant impact that physiological effects have on impedance changes following electroporation at the tissue scale and the potential need of introducing them into the numerical models. The code for the numerical model is publicly available at https://gitlab.inria.fr/poignard/4-electrode-system.
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11
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López-Alonso B, Sarnago H, Lucía Ó, Briz P, Burdío JM. Real-Time Impedance Monitoring During Electroporation Processes in Vegetal Tissue Using a High-Performance Generator. SENSORS 2020; 20:s20113158. [PMID: 32498417 PMCID: PMC7309040 DOI: 10.3390/s20113158] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/05/2020] [Revised: 05/26/2020] [Accepted: 06/01/2020] [Indexed: 12/13/2022]
Abstract
Classical application of electroporation is carried out by using fixed protocols that do not clearly assure the complete ablation of the desired tissue. Nowadays, new methods that pursue the control of the treatment by studying the change in impedance during the applied pulses as a function of the electric field are being developed. These types of control seek to carry out the treatment in the fastest way, decreasing undesired effects and treatment time while ensuring the proper tumour ablation. The objective of this research is to determine the state of the treatment by continuously monitoring the impedance by using a novel versatile high-voltage generator and sensor system. To study the impedance dynamics in real time, the use of pulses of reduced voltage, below the threshold of reversible electroporation, is tested to characterise the state-of-the-treatment without interfering with it. With this purpose, a generator that provides both low voltage for sense tissue changes and high voltage for irreversible electroporation (IRE) was developed. In conclusion, the characterisation of the effects of electroporation in vegetal tissue, combined with the real-time monitoring of the state-of-the-treatment, will enable the provision of safer and more effective treatments.
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12
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Zhao Y, Zheng S, Beitel-White N, Liu H, Yao C, Davalos RV. Development of a Multi-Pulse Conductivity Model for Liver Tissue Treated With Pulsed Electric Fields. Front Bioeng Biotechnol 2020; 8:396. [PMID: 32509742 PMCID: PMC7248411 DOI: 10.3389/fbioe.2020.00396] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2019] [Accepted: 04/08/2020] [Indexed: 12/18/2022] Open
Abstract
Pulsed electric field treatment modalities typically utilize multiple pulses to permeabilize biological tissue. This electroporation process induces conductivity changes in the tissue, which are indicative of the extent of electroporation. In this study, we characterized the electroporation-induced conductivity changes using all treatment pulses instead of solely the first pulse as in conventional conductivity models. Rabbit liver tissue was employed to study the tissue conductivity changes caused by multiple, 100 μs pulses delivered through flat plate electrodes. Voltage and current data were recorded during treatment and used to calculate the tissue conductivity during the entire pulsing process. Temperature data were also recorded to quantify the contribution of Joule heating to the conductivity according to the tissue temperature coefficient. By fitting all these data to a modified Heaviside function, where the two turning points (E0, E1) and the increase factor (A) are the main parameters, we calculated the conductivity as a function of the electric field (E), where the parameters of the Heaviside function (A and E0) were functions of pulse number (N). With the resulting multi-factor conductivity model, a numerical electroporation simulation can predict the electrical current for multiple pulses more accurately than existing conductivity models. Moreover, the saturating behavior caused by electroporation can be explained by the saturation trends of the increase factor A in this model. The conductivity change induced by electroporation has a significant increase at about the first 30 pulses, then tends to saturate at 0.465 S/m. The proposed conductivity model can simulate the electroporation process more accurately than the conventional conductivity model. The electric field distribution computed using this model is essential for treatment planning in biomedical applications utilizing multiple pulsed electric fields, and the method proposed here, relating the pulse number to the conductivity through the variables in the Heaviside function, may be adapted to investigate the effect of other parameters, like pulse frequency and pulse width, on electroporation.
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Affiliation(s)
- Yajun Zhao
- Department of Biomedical Engineering and Mechanics, Virginia Tech, Blacksburg, VA, United States.,Bioelectromechanical Systems Laboratory, Virginia Tech, Blacksburg, VA, United States
| | - Shuang Zheng
- State Key Laboratory of Power Transmission Equipment and System Security and New Technology, Chongqing University, Chongqing, China.,School of Electrical Engineering, Chongqing University, Chongqing, China
| | - Natalie Beitel-White
- Bioelectromechanical Systems Laboratory, Virginia Tech, Blacksburg, VA, United States.,Department of Electrical and Computer Engineering at Virginia Tech, Blacksburg, VA, United States
| | - Hongmei Liu
- State Key Laboratory of Power Transmission Equipment and System Security and New Technology, Chongqing University, Chongqing, China.,School of Electrical Engineering, Chongqing University, Chongqing, China
| | - Chenguo Yao
- State Key Laboratory of Power Transmission Equipment and System Security and New Technology, Chongqing University, Chongqing, China.,School of Electrical Engineering, Chongqing University, Chongqing, China
| | - Rafael V Davalos
- Department of Biomedical Engineering and Mechanics, Virginia Tech, Blacksburg, VA, United States.,Bioelectromechanical Systems Laboratory, Virginia Tech, Blacksburg, VA, United States
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Liu H, Shi F, Tang X, Zheng S, Kolb J, Yao C. Application of bioimpedance spectroscopy to characterize chemoresistant tumor cell selectivity of nanosecond pulse stimulation. Bioelectrochemistry 2020; 135:107570. [PMID: 32526679 DOI: 10.1016/j.bioelechem.2020.107570] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2019] [Revised: 05/12/2020] [Accepted: 05/13/2020] [Indexed: 02/08/2023]
Abstract
The discriminating effects of nanosecond pulsed electric fields (nsPEFs) between chemoresistant tumor cells (CRTCs) and their respective homologous chemosensitive tumor cells (CSTCs) were investigated based on bioimpedance spectroscopy (BIS). The electrical properties of individual untreated cells were determined by fitting the impedance spectra to an equivalent circuit model and then using aided simulations to calculate the nuclear envelope transmembrane potential (nTMP) and electroporation area on the nuclear envelope. Additionally, fluorescence staining assays of cell monolayers after nanopulse stimulation (80 pulses, 200 ns, 3 kV) were conducted to validate the simulation results. The staining results indicated that CRTCs showed a larger ablation area and lower lethal threshold compared to CSTCs after exposure to the same nsPEF energy, which was in accordance with the higher nTMP and larger electroporation area calculated for CRTCs. The increase in the lethal effects of nsPEFs on CRTCs compared to CSTCs mainly resulted from the superposition of the changes in the electrical properties and nuclear size. The work shows that BIS can distinguish CRTCs and CSTCs and the corresponding nsPEF effects, suggesting potential applications for the optimization of novel anti-chemoresistance methods, including nsPEF-treatments.
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Affiliation(s)
- Hongmei Liu
- School of Electrical Engineering, Chongqing University, Chongqing 400033, China; State Key Laboratory of Power Transmission Equipment & System Security and New Technology, Chongqing 400033, China
| | - Fukun Shi
- Suzhou Institute of Biomedical Engineering and Technology, Chinese Academy of Sciences, 215163 Suzhou, China; Leibniz Institute for Plasma Science and Technology (INP), Greifswald 17489, Germany; Institute of Physics, University of Rostock, Rostock 18059, Germany
| | - Xiao Tang
- School of Electrical Engineering, Chongqing University, Chongqing 400033, China; State Key Laboratory of Power Transmission Equipment & System Security and New Technology, Chongqing 400033, China
| | - Shuang Zheng
- School of Electrical Engineering, Chongqing University, Chongqing 400033, China; State Key Laboratory of Power Transmission Equipment & System Security and New Technology, Chongqing 400033, China
| | - Juergen Kolb
- Leibniz Institute for Plasma Science and Technology (INP), Greifswald 17489, Germany; Institute of Physics, University of Rostock, Rostock 18059, Germany
| | - Chenguo Yao
- School of Electrical Engineering, Chongqing University, Chongqing 400033, China; State Key Laboratory of Power Transmission Equipment & System Security and New Technology, Chongqing 400033, China.
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Electronic Emulator of Biological Tissue as an Electrical Load during Electroporation. APPLIED SCIENCES-BASEL 2020. [DOI: 10.3390/app10093103] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Electroporation is an emerging technology, with great potential in many different medical and biotechnological applications, food engineering and biomass processing. Large variations of biological load characteristics, however, represent a great challenge in electroporator design, which results in different solutions. Because a clinical electroporator is a medical device, it must comply with medical device regulative and standards. However, none of the existing standards directly address the operation or electroporator’s performance requirements. In order to evaluate clinical, laboratory and prototype electroporation devices during the development process, or to evaluate their final performance considering at least from the perspective of output pulse parameters, we present a case study on the design of an electronic emulator of biological tissue as an electrical load during electroporation. The proposed electronic load emulator is a proof of concept, which enables constant and sustainable testing and unbiased comparison of different electroporators’ operations. We developed an analog electrical circuit that has equivalent impedance to the beef liver tissue in combination with needle electrodes, during high voltage pulse delivery and/or electroporation. Current and voltage measurements during electroporation of beef liver tissue ex vivo, were analyzed and parametrized to define the analog circuit equation. An equivalent circuit was simulated, built and validated. The proposed concept of an electronic load emulator can be used for “classical” electroporator (i.e., not nanosecond) performance evaluation and comparison of their operation. Additionally, it facilitates standard implementation regarding the testing protocol and enables quality assurance.
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