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Feaster TK, Ewoldt JK, Avila A, Casciola M, Narkar A, Chen CS, Blinova K. Nonclinical evaluation of chronic cardiac contractility modulation on 3D human engineered cardiac tissues. J Cardiovasc Electrophysiol 2024; 35:895-905. [PMID: 38433304 DOI: 10.1111/jce.16222] [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] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/27/2023] [Revised: 01/29/2024] [Accepted: 02/09/2024] [Indexed: 03/05/2024]
Abstract
INTRODUCTION Cardiac contractility modulation (CCM) is a medical device-based therapy delivering non-excitatory electrical stimulations to the heart to enhance cardiac function in heart failure (HF) patients. The lack of human in vitro tools to assess CCM hinders our understanding of CCM mechanisms of action. Here, we introduce a novel chronic (i.e., 2-day) in vitro CCM assay to evaluate the effects of CCM in a human 3D microphysiological system consisting of engineered cardiac tissues (ECTs). METHODS Cryopreserved human induced pluripotent stem cell-derived cardiomyocytes were used to generate 3D ECTs. The ECTs were cultured, incorporating human primary ventricular cardiac fibroblasts and a fibrin-based gel. Electrical stimulation was applied using two separate pulse generators for the CCM group and control group. Contractile properties and intracellular calcium were measured, and a cardiac gene quantitative PCR screen was conducted. RESULTS Chronic CCM increased contraction amplitude and duration, enhanced intracellular calcium transient amplitude, and altered gene expression related to HF (i.e., natriuretic peptide B, NPPB) and excitation-contraction coupling (i.e., sodium-calcium exchanger, SLC8). CONCLUSION These data represent the first study of chronic CCM in a 3D ECT model, providing a nonclinical tool to assess the effects of cardiac electrophysiology medical device signals complementing in vivo animal studies. The methodology established a standardized 3D ECT-based in vitro testbed for chronic CCM, allowing evaluation of physiological and molecular effects on human cardiac tissues.
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Affiliation(s)
- Tromondae K Feaster
- Office of Science and Engineering Laboratories, Center for Devices and Radiological Health, US Food and Drug Administration, Silver Spring, Maryland, USA
| | - Jourdan K Ewoldt
- Department of Biomedical Engineering, Boston University, Boston, Massachusetts, USA
| | - Anna Avila
- Office of Science and Engineering Laboratories, Center for Devices and Radiological Health, US Food and Drug Administration, Silver Spring, Maryland, USA
| | - Maura Casciola
- Office of Science and Engineering Laboratories, Center for Devices and Radiological Health, US Food and Drug Administration, Silver Spring, Maryland, USA
| | - Akshay Narkar
- Office of Science and Engineering Laboratories, Center for Devices and Radiological Health, US Food and Drug Administration, Silver Spring, Maryland, USA
| | - Christopher S Chen
- Department of Biomedical Engineering, Boston University, Boston, Massachusetts, USA
- Wyss Institute for Biologically Inspired Engineering, Harvard University, Boston, Massachusetts, USA
| | - Ksenia Blinova
- Office of Science and Engineering Laboratories, Center for Devices and Radiological Health, US Food and Drug Administration, Silver Spring, Maryland, USA
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Casciola M, Feaster TK, Caiola MJ, Keck D, Blinova K. Human in vitro assay for irreversible electroporation cardiac ablation. Front Physiol 2023; 13:1064168. [PMID: 36699682 PMCID: PMC9869257 DOI: 10.3389/fphys.2022.1064168] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2022] [Accepted: 11/29/2022] [Indexed: 01/12/2023] Open
Abstract
Introduction: Pulsed electric field (PEF) cardiac ablation has been recently proposed as a technique to treat drug resistant atrial fibrillation by inducing cell death through irreversible electroporation (IRE). Improper PEF dosing can result in thermal damage or reversible electroporation. The lack of comprehensive and systematic studies to select PEF parameters for safe and effective IRE cardiac treatments hinders device development and regulatory decision-making. Human induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs) have been proposed as an alternative to animal models in the evaluation of cardiac electrophysiology safety. Methods: We developed a novel high-throughput in vitro assay to quantify the electric field threshold (EFT) for electroporation (acute effect) and cell death (long-term effect) in hiPSC-CMs. Monolayers of hiPSC-CMs were cultured in high-throughput format and exposed to clinically relevant biphasic PEF treatments. Electroporation and cell death areas were identified using fluorescent probes and confocal microscopy; electroporation and cell death EFTs were quantified by comparison of fluorescent images with electric field numerical simulations. Results: Study results confirmed that PEF induces electroporation and cell death in hiPSC-CMs, dependent on the number of pulses and the amplitude, duration, and repetition frequency. In addition, PEF-induced temperature increase, absorbed dose, and total treatment time for each PEF parameter combination are reported. Discussion: Upon verification of the translatability of the in vitro results presented here to in vivo models, this novel hiPSC-CM-based assay could be used as an alternative to animal or human studies and can assist in early nonclinical device development, as well as inform regulatory decision-making for cardiac ablation medical devices.
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Feaster TK, Casciola M, Narkar A, Blinova K. Evaluation of Cardiac Contractility Modulation Therapy in 2D Human Stem Cell-Derived Cardiomyocytes. J Vis Exp 2022. [PMID: 36591970 DOI: 10.3791/64848] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Human induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs) are currently being explored for multiple in vitro applications and have been used in regulatory submissions. Here, we extend their use to cardiac medical device safety or performance assessments. We developed a novel method to evaluate cardiac medical device contractile properties in robustly contracting 2D hiPSC-CMs monolayers plated on a flexible extracellular matrix (ECM)-based hydrogel substrate. This tool enables the quantification of the effects of cardiac electrophysiology device signals on human cardiac function (e.g., contractile properties) with standard laboratory equipment. The 2D hiPSC-CM monolayers were cultured for 2-4 days on a flexible hydrogel substrate in a 48-well format. The hiPSC-CMs were exposed to standard cardiac contractility modulation (CCM) medical device electrical signals and compared to control (i.e., pacing only) hiPSC-CMs. The baseline contractile properties of the 2D hiPSC-CMs were quantified by video-based detection analysis based on pixel displacement. The CCM-stimulated 2D hiPSC-CMs plated on the flexible hydrogel substrate displayed significantly enhanced contractile properties relative to baseline (i.e., before CCM stimulation), including an increased peak contraction amplitude and accelerated contraction and relaxation kinetics. Furthermore, the utilization of the flexible hydrogel substrate enables the multiplexing of the video-based cardiac-excitation contraction coupling readouts (i.e., electrophysiology, calcium handling, and contraction) in healthy and diseased hiPSC-CMs. The accurate detection and quantification of the effects of cardiac electrophysiological signals on human cardiac contraction is vital for cardiac medical device development, optimization, and de-risking. This method enables the robust visualization and quantification of the contractile properties of the cardiac syncytium, which should be valuable for nonclinical cardiac medical device safety or effectiveness testing. This paper describes, in detail, the methodology to generate 2D hiPSC-CM hydrogel substrate monolayers.
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Affiliation(s)
- Tromondae K Feaster
- Office of Science and Engineering Laboratories, Center for Devices and Radiological Health, U.S. Food and Drug Administration
| | - Maura Casciola
- Office of Science and Engineering Laboratories, Center for Devices and Radiological Health, U.S. Food and Drug Administration
| | - Akshay Narkar
- Office of Science and Engineering Laboratories, Center for Devices and Radiological Health, U.S. Food and Drug Administration
| | - Ksenia Blinova
- Office of Science and Engineering Laboratories, Center for Devices and Radiological Health, U.S. Food and Drug Administration;
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Feaster TK, Feric N, Pallotta I, Narkar A, Casciola M, Graziano MP, Aschar-Sobbi R, Blinova K. Acute effects of cardiac contractility modulation stimulation in conventional 2D and 3D human induced pluripotent stem cell-derived cardiomyocyte models. Front Physiol 2022; 13:1023563. [PMID: 36439258 PMCID: PMC9686332 DOI: 10.3389/fphys.2022.1023563] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2022] [Accepted: 10/28/2022] [Indexed: 11/11/2022] Open
Abstract
Cardiac contractility modulation (CCM) is a medical device therapy whereby non-excitatory electrical stimulations are delivered to the myocardium during the absolute refractory period to enhance cardiac function. We previously evaluated the effects of the standard CCM pulse parameters in isolated rabbit ventricular cardiomyocytes and 2D human induced pluripotent stem cell-derived cardiomyocyte (hiPSC-CM) monolayers, on flexible substrate. In the present study, we sought to extend these results to human 3D microphysiological systems to develop a robust model to evaluate various clinical CCM pulse parameters in vitro. HiPSC-CMs were studied in conventional 2D monolayer format, on stiff substrate (i.e., glass), and as 3D human engineered cardiac tissues (ECTs). Cardiac contractile properties were evaluated by video (i.e., pixel) and force-based analysis. CCM pulses were assessed at varying electrical ‘doses’ using a commercial pulse generator. A robust CCM contractile response was observed for 3D ECTs. Under comparable conditions, conventional 2D monolayer hiPSC-CMs, on stiff substrate, displayed no contractile response. 3D ECTs displayed enhanced contractile properties including increased contraction amplitude (i.e., force), and accelerated contraction and relaxation slopes under standard acute CCM stimulation. Moreover, 3D ECTs displayed enhanced contractility in a CCM pulse parameter-dependent manner by adjustment of CCM pulse delay, duration, amplitude, and number relative to baseline. The observed acute effects subsided when the CCM stimulation was stopped and gradually returned to baseline. These data represent the first study of CCM in 3D hiPSC-CM models and provide a nonclinical tool to assess various CCM device signals in 3D human cardiac tissues prior to in vivo animal studies. Moreover, this work provides a foundation to evaluate the effects of additional cardiac medical devices in 3D ECTs.
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Affiliation(s)
- Tromondae K. Feaster
- Office of Science and Engineering Laboratories, Center for Devices and Radiological Health, U.S. Food and Drug Administration, Silver Spring, MD, United States
| | - Nicole Feric
- Valo Health Inc, Alexandria Center for Life Sciences, New York, NY, United States
| | - Isabella Pallotta
- Valo Health Inc, Alexandria Center for Life Sciences, New York, NY, United States
| | - Akshay Narkar
- Office of Science and Engineering Laboratories, Center for Devices and Radiological Health, U.S. Food and Drug Administration, Silver Spring, MD, United States
| | - Maura Casciola
- Office of Science and Engineering Laboratories, Center for Devices and Radiological Health, U.S. Food and Drug Administration, Silver Spring, MD, United States
| | - Michael P. Graziano
- Valo Health Inc, Alexandria Center for Life Sciences, New York, NY, United States
| | - Roozbeh Aschar-Sobbi
- Valo Health Inc, Alexandria Center for Life Sciences, New York, NY, United States
| | - Ksenia Blinova
- Office of Science and Engineering Laboratories, Center for Devices and Radiological Health, U.S. Food and Drug Administration, Silver Spring, MD, United States
- *Correspondence: Ksenia Blinova,
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Narkar A, Feaster TK, Casciola M, Blinova K. Human in vitro neurocardiac coculture (ivNCC) assay development for evaluating cardiac contractility modulation. Physiol Rep 2022; 10:e15498. [PMID: 36325586 PMCID: PMC9630755 DOI: 10.14814/phy2.15498] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2022] [Revised: 10/06/2022] [Accepted: 10/08/2022] [Indexed: 11/06/2022] Open
Abstract
Two of the most prominent organ systems, the nervous and the cardiovascular systems, are intricately connected to maintain homeostasis in mammals. Recent years have shown tremendous efforts toward therapeutic modulation of cardiac contractility and electrophysiology by electrical stimulation. Neuronal innervation and cardiac ganglia regulation are often overlooked when developing in vitro models for cardiac devices, but it is likely that peripheral nervous system plays a role in the clinical effects. We developed an in vitro neurocardiac coculture (ivNCC) model system to study cardiac and neuronal interplay using human induced pluripotent stem cell (hiPSC) technology. We demonstrated significant expression and colocalization of cardiac markers including troponin, α-actinin, and neuronal marker peripherin in neurocardiac coculture. To assess functional coupling between the cardiomyocytes and neurons, we evaluated nicotine-induced β-adrenergic norepinephrine effect and found beat rate was significantly increased in ivNCC as compared to monoculture alone. The developed platform was used as a nonclinical model for the assessment of cardiac medical devices that deliver nonexcitatory electrical pulses to the heart during the absolute refractory period of the cardiac cycle, that is, cardiac contractility modulation (CCM) therapy. Robust coculture response was observed at 14 V/cm (5 V, 64 mA), monophasic, 2 ms pulse duration for pacing and 20 V/cm (7 V, 90 mA) phase amplitude, biphasic, 5.14 ms pulse duration for CCM. We observed that the CCM effect and kinetics were more pronounced in coculture as compared to cardiac monoculture, supporting a hypothesis that some part of CCM mechanism of action can be attributed to peripheral nervous system stimulation. This study provides novel characterization of CCM effects on hiPSC-derived neurocardiac cocultures. This innervated human heart model can be further extended to investigate arrhythmic mechanisms, neurocardiac safety, and toxicity post-chronic exposure to materials, drugs, and medical devices. We present data on acute CCM electrical stimulation effects on a functional and optimized coculture using commercially available hiPSC-derived cardiomyocytes and neurons. Moreover, this study provides an in vitro human heart model to evaluate neuronal innervation and cardiac ganglia regulation of contractility by applying CCM pulse parameters that closely resemble clinical setting. This ivNCC platform provides a potential tool for investigating aspects of cardiac and neurological device safety and performance.
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Affiliation(s)
- Akshay Narkar
- Center for Devices and Radiological HealthUS Food and Drug AdministrationSilver SpringMarylandUSA
| | - Tromondae K. Feaster
- Center for Devices and Radiological HealthUS Food and Drug AdministrationSilver SpringMarylandUSA
| | - Maura Casciola
- Center for Devices and Radiological HealthUS Food and Drug AdministrationSilver SpringMarylandUSA
| | - Ksenia Blinova
- Center for Devices and Radiological HealthUS Food and Drug AdministrationSilver SpringMarylandUSA
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Casciola M, Keck D, Feaster TK, Blinova K. Human cardiomyocytes are more susceptible to irreversible electroporation by pulsed electric field than human esophageal cells. Physiol Rep 2022; 10:e15493. [PMID: 36301726 PMCID: PMC9612150 DOI: 10.14814/phy2.15493] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2022] [Revised: 09/21/2022] [Accepted: 09/28/2022] [Indexed: 12/14/2022] Open
Abstract
Pulse electric field-based (PEF) ablation is a technique whereby short high-intensity electric fields inducing irreversible electroporation (IRE) are applied to various tissues. Here, we implemented a standardized in vitro model to compare the effects of biphasic symmetrical pulses (100 pulses, 1-10 μs phase duration (d), 10-1000 Hz pulse repetition rate (f)) using two different human cellular models: human-induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs) and human esophageal smooth muscle cells (hESMCs) cultured in monolayer format. We report the PEF-induced irreversibly electroporated cell monolayer areas and the corresponding electric field thresholds (EFTs) for both cardiac and esophageal cultures. Our results suggest marked cell type specificity with EFT estimated to be 2-2.5 times lower in hiPSC-CMs than in hESMCs when subjected to identical PEF treatments (e.g., 0.90 vs 1.85 kV/cm for the treatment of 100 pulses with d = 5 μs, f = 10 Hz, and 0.65 vs 1.67 kV/cm for the treatment of 100 pulses with d = 10 μs, f = 10 Hz). PEF treatment can result in increased temperature around the stimulating electrodes and lead to unanticipated thermal tissue damage that is proportional to the peak temperature rise and to the duration of the PEF-induced elevated temperatures. In our study, temperature increases ranged from less than 1°C to as high as 30°C, however, all temperature changes were transient and quickly returned to baseline and the highest observed ∆T returned to 50% of its maximum recorded temperature in tens of seconds.
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Affiliation(s)
- Maura Casciola
- Division of Biomedical Physics, Office of Science and Engineering Laboratories, Center for Devices and Radiological HealthUS Food and Drug AdministrationSilver SpringMarylandUSA
| | - Devin Keck
- Division of Biomedical Physics, Office of Science and Engineering Laboratories, Center for Devices and Radiological HealthUS Food and Drug AdministrationSilver SpringMarylandUSA
| | - Tromondae K. Feaster
- Division of Biomedical Physics, Office of Science and Engineering Laboratories, Center for Devices and Radiological HealthUS Food and Drug AdministrationSilver SpringMarylandUSA
| | - Ksenia Blinova
- Division of Biomedical Physics, Office of Science and Engineering Laboratories, Center for Devices and Radiological HealthUS Food and Drug AdministrationSilver SpringMarylandUSA
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Feaster TK, Ewoldt J, Casciola M, Narkar A, Chen CS, Blinova K. Abstract P1123: Establishment Of An In Vitro Method To Evaluate Chronic Cardiac Contractility Modulation Signals In 3d Human Engineered Cardiac Tissues. Circ Res 2022. [DOI: 10.1161/res.131.suppl_1.p1123] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Background:
Cardiac contractility modulation (CCM) is a medical device-based therapy delivering non-excitatory electrical simulations to the heart during the absolute refractory period to enhance cardiac function. We previously evaluated the acute effects of CCM in isolated rabbit-CM and 2D hiPSC-CM monolayers, on flexible substrate, and found enhanced calcium and contractility. In the present study, we sought to extend these results to chronic studies in 3D human engineered cardiac tissues (ECTs) to develop a robust model to evaluate the long-term effects of CCM stimulation
in vitro
on intact human cardiac tissues.
Methods:
HiPSC-CMs and cardiac fibroblasts in a fibrin-based gel were combined to form ECTs (Figure 1). Morphology and contractility were evaluated. We found ECTs displayed baseline peak contraction amplitude of 194.8±80.8 a.u., (n=5) and peak force and stress of 26.5±6.8 uN, (n=5) and 87.9±22.0.8 Pa, (n=5) respectively. ECT displayed robust baseline electrophysiological (AP) properties and calcium handling properties. Chronic CCM pulses (i.e., 30 minutes) were applied using a commercial pulse generator. Under these conditions ECTs displayed enhanced contractile kinetics 29.0±0.04 %, (P<0.01, n=4), relaxation kinetics 23.0±0.05 %, (P<0.05, n=4), and shorter duration 32.0±0.03 %, (P<0.01, n=4) relative to time matched control.
Conclusion:
This study provides a comprehensive characterization of chronic CCM effects on 3D ECTs. Future studies will investigate prolonged time points. These data provide an
in vitro
model to assess physiologically relevant mechanisms and evaluate safety and efficacy of future cardiac electrophysiology medical devices.
Disclaimer:
The mention of commercial products, their sources, or their use in connection with material reported herein is not to be construed as either an actual or implied endorsement of such products by the Department of Health and Human Services.
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Affiliation(s)
- TK Feaster
- U.S. Food and Drug Administration, Silver Spring, MD
| | | | | | - Akshay Narkar
- U.S. Food and Drug Administration, Silver Spring, MD
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Feaster TK, Casciola M, Narkar A, Blinova K. Acute effects of cardiac contractility modulation on human induced pluripotent stem cell-derived cardiomyocytes. Physiol Rep 2021; 9:e15085. [PMID: 34729935 PMCID: PMC8564440 DOI: 10.14814/phy2.15085] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [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: 08/25/2021] [Revised: 10/04/2021] [Accepted: 10/08/2021] [Indexed: 12/20/2022] Open
Abstract
Cardiac contractility modulation (CCM) is an intracardiac therapy whereby nonexcitatory electrical simulations are delivered during the absolute refractory period of the cardiac cycle. We previously evaluated the effects of CCM in isolated adult rabbit ventricular cardiomyocytes and found a transient increase in calcium and contractility. In the present study, we sought to extend these results to human cardiomyocytes using human induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs) to develop a robust model to evaluate CCM in vitro. HiPSC-CMs (iCell Cardiomyocytes2 , Fujifilm Cellular Dynamic, Inc.) were studied in monolayer format plated on flexible substrate. Contractility, calcium handling, and electrophysiology were evaluated by fluorescence- and video-based analysis (CellOPTIQ, Clyde Biosciences). CCM pulses were applied using an A-M Systems 4100 pulse generator. Robust hiPSC-CMs response was observed at 14 V/cm (64 mA) for pacing and 28 V/cm (128 mA, phase amplitude) for CCM. Under these conditions, hiPSC-CMs displayed enhanced contractile properties including increased contraction amplitude and faster contraction kinetics. Likewise, calcium transient amplitude increased, and calcium kinetics were faster. Furthermore, electrophysiological properties were altered resulting in shortened action potential duration (APD). The observed effects subsided when the CCM stimulation was stopped. CCM-induced increase in hiPSC-CMs contractility was significantly more pronounced when extracellular calcium concentration was lowered from 2 mM to 0.5 mM. This study provides a comprehensive characterization of CCM effects on hiPSC-CMs. These data represent the first study of CCM in hiPSC-CMs and provide an in vitro model to assess physiologically relevant mechanisms and evaluate safety and effectiveness of future cardiac electrophysiology medical devices.
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Affiliation(s)
- Tromondae K. Feaster
- Office of Science and Engineering LaboratoriesCenter for Devices and Radiological HealthUS Food and Drug AdministrationSilver SpringMarylandUSA
| | - Maura Casciola
- Office of Science and Engineering LaboratoriesCenter for Devices and Radiological HealthUS Food and Drug AdministrationSilver SpringMarylandUSA
| | - Akshay Narkar
- Office of Science and Engineering LaboratoriesCenter for Devices and Radiological HealthUS Food and Drug AdministrationSilver SpringMarylandUSA
| | - Ksenia Blinova
- Office of Science and Engineering LaboratoriesCenter for Devices and Radiological HealthUS Food and Drug AdministrationSilver SpringMarylandUSA
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Casciola M, Tiranchi AS, Feaster T, Blinova K. B-AB06-04 HUMAN IN VITRO MODEL FOR PRECLINICAL EVALUATION OF PULSED ELECTRIC FIELD-BASED DEVICES FOR NON-THERMAL CARDIAC ABLATION. Heart Rhythm 2021. [DOI: 10.1016/j.hrthm.2021.06.039] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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Feaster T, Casciola M, Narkar A, Blinova K. B-PO03-019 CARDIAC CONTRACTILITY MODULATION STIMULATION DURING SYSTOLE ENHANCES CONTRACTION AND CALCIUM HANDLING PROPERTIES IN HUMAN-INDUCED PLURIPOTENT STEM CELL-DERIVED CARDIOMYOCYTES. Heart Rhythm 2021. [DOI: 10.1016/j.hrthm.2021.06.495] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Sözer EB, Pakhomov AG, Semenov I, Casciola M, Kim V, Vernier PT, Zemlin CW. Analysis of electrostimulation and electroporation by high repetition rate bursts of nanosecond stimuli. Bioelectrochemistry 2021; 140:107811. [PMID: 33862549 DOI: 10.1016/j.bioelechem.2021.107811] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2020] [Revised: 03/26/2021] [Accepted: 03/28/2021] [Indexed: 12/16/2022]
Abstract
Exposures to short-duration, strong electric field pulses have been utilized for stimulation, ablation, and the delivery of molecules into cells. Ultrashort, nanosecond duration pulses have shown unique benefits, but they require higher field strengths. One way to overcome this requirement is to use trains of nanosecond pulses with high repetition rates, up to the MHz range. Here we present a theoretical model to describe the effects of pulse trains on the plasma membrane and intracellular membranes modeled as resistively charged capacitors. We derive the induced membrane potential and the stimulation threshold as functions of pulse number, pulse duration, and repetition rate. This derivation provides a straightforward method to calculate the membrane charging time constant from experimental data. The derived excitation threshold agrees with nerve stimulation experiments, indicating that nanosecond pulses are not more effective than longer pulses in charging nerve fibers. The derived excitation threshold does not, however, correctly predict the nanosecond stimulation of cardiomyocytes. We show that a better agreement is possible if multiple charging time constants are considered. Finally, we expand the model to intracellular membranes and show that pulse trains do not lead to charge buildup, but can create significant oscillations of the intracellular membrane potential.
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Affiliation(s)
- Esin B Sözer
- Frank Reidy Research Center for Bioelectrics, Old Dominion University, Norfolk, VA 23508, USA.
| | - Andrei G Pakhomov
- Frank Reidy Research Center for Bioelectrics, Old Dominion University, Norfolk, VA 23508, USA
| | - Iurii Semenov
- Frank Reidy Research Center for Bioelectrics, Old Dominion University, Norfolk, VA 23508, USA
| | - Maura Casciola
- Frank Reidy Research Center for Bioelectrics, Old Dominion University, Norfolk, VA 23508, USA
| | - Vitalii Kim
- Frank Reidy Research Center for Bioelectrics, Old Dominion University, Norfolk, VA 23508, USA
| | - P Thomas Vernier
- Frank Reidy Research Center for Bioelectrics, Old Dominion University, Norfolk, VA 23508, USA
| | - Christian W Zemlin
- Frank Reidy Research Center for Bioelectrics, Old Dominion University, Norfolk, VA 23508, USA.
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Poudel A, Oludiran A, Sözer EB, Casciola M, Purcell EB, Muratori C. Growth in a biofilm sensitizes Cutibacterium acnes to nanosecond pulsed electric fields. Bioelectrochemistry 2021; 140:107797. [PMID: 33773215 DOI: 10.1016/j.bioelechem.2021.107797] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2020] [Revised: 02/24/2021] [Accepted: 02/26/2021] [Indexed: 10/21/2022]
Abstract
The Gram-positive anaerobic bacterium Cutibacterium acnes (C. acnes) is a commensal of the human skin, but also an opportunistic pathogen that contributes to the pathophysiology of the skin disease acne vulgaris. C. acnes can form biofilms; cells in biofilms are more resilient to antimicrobial stresses. Acne therapeutic options such as topical or systemic antimicrobial treatments often show incomplete responses. In this study we measured the efficacy of nanosecond pulsed electric fields (nsPEF), a new promising cell and tissue ablation technology, to inactivate C. acnes. Our results show that all tested nsPEF doses (250 to 2000 pulses, 280 ns pulses, 28 kV/cm, 5 Hz; 0.5 to 4 kJ/ml) failed to inactivate planktonic C. acnes and that pretreatment with lysozyme, a naturally occurring cell-wall-weakening enzyme, increased C. acnes vulnerability to nsPEF. Surprisingly, growth in a biofilm appears to sensitize C. acnes to nsPEF-induced stress, as C. acnes biofilm-derived cells showed increased cell death after nsPEF treatments that did not affect planktonic cells. Biofilm inactivation by nsPEF was confirmed by treating intact biofilms grown on glass coverslips with an indium oxide conductive layer. Altogether our results show that, contrary to other antimicrobial agents, nsPEF kill more efficiently bacteria in biofilms than planktonic cells.
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Affiliation(s)
- Asia Poudel
- Old Dominion University, Department of Chemistry and Biochemistry, USA
| | - Adenrele Oludiran
- Old Dominion University, Department of Chemistry and Biochemistry, USA
| | - Esin B Sözer
- Old Dominion University, Frank Reidy Research Center for Bioelectrics, USA
| | - Maura Casciola
- Old Dominion University, Frank Reidy Research Center for Bioelectrics, USA; Center for Devices and Radiological Health, US Food and Drug Administration, Silver Spring, MD 20993, USA
| | - Erin B Purcell
- Old Dominion University, Department of Chemistry and Biochemistry, USA.
| | - Claudia Muratori
- Old Dominion University, Frank Reidy Research Center for Bioelectrics, USA.
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Casciola M, Feaster TK, Pakhomov AG, Blinova K. Abstract 256: Human
In Vitro
Model for Preclinical Evaluation of Irreversible Electroporation Devices Used for Cardiac Ablation. Circ Res 2020. [DOI: 10.1161/res.127.suppl_1.256] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Irreversible Electroporation (IRE) has gained significant interest as an alternative treatment for atrial fibrillation (AF). Typically, to terminate AF, thermal energy is delivered to the arrhythmic tissue causing rare but serious damage to surrounding areas. IRE is a non-thermal approach that has the potential to be faster yet more targeted. We are developing a novel, species relevant, standard laboratory test to evaluate IRE cardiac ablation using human induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs) as a model. hiPSC-CMs were cultured in monolayers. Pulses were delivered by a AVOZ D7B generator through contact electrodes. Electric field (E) distribution maps were obtained with numerical simulations, Sim4Life v3.2. Electroporation (EP) was quantified by florescence with YO-PRO-1 10 minutes after exposure. hiPSC-CMs were exposed to a range of electrical parameters including 120 unipolar pulses of 5 μs duration, at 1 kHz frequency (Fig. 1). We found that the EP threshold was ~1.5 kV/cm in line with previous reports on single adult ventricular mouse cardiomyocytes (Semenov et al. 2018). The treated area increased with the voltage (V) applied. These data suggest that this assay can delineate the extent of EP. In this work we will vary different pulse parameters (durations, amplitude, shape, repetition rate and number) to evaluate their effects on different human cell lines anatomically adjacent to the heart.
Fig.1: (A) Representation of the EP threshold determined by overlaying the E map (B) with a fluorescence image of pulse-treated hiPSC-CMs (C). To define the E threshold the distributions values obtained by modeling 1 V applied was scaled by the experimental V.
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Affiliation(s)
| | | | - Andrei G Pakhomov
- Frank Reidy Rsch Cntr for Bioelectrics, Old Dominion Univ, Norfolk, VA
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Michel O, Pakhomov AG, Casciola M, Saczko J, Kulbacka J, Pakhomova ON. Electropermeabilization does not correlate with plasma membrane lipid oxidation. Bioelectrochemistry 2020; 132:107433. [DOI: 10.1016/j.bioelechem.2019.107433] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2019] [Revised: 11/20/2019] [Accepted: 11/22/2019] [Indexed: 12/24/2022]
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Casciola M, Xiao S, Apollonio F, Paffi A, Liberti M, Muratori C, Pakhomov AG. Cancellation of nerve excitation by the reversal of nanosecond stimulus polarity and its relevance to the gating time of sodium channels. Cell Mol Life Sci 2019; 76:4539-4550. [PMID: 31055644 DOI: 10.1007/s00018-019-03126-0] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2019] [Revised: 04/19/2019] [Accepted: 04/30/2019] [Indexed: 12/30/2022]
Abstract
The initiation of action potentials (APs) by membrane depolarization occurs after a brief vulnerability period, during which excitation can be abolished by the reversal of the stimulus polarity. This vulnerability period is determined by the time needed for gating of voltage-gated sodium channels (VGSC). We compared nerve excitation by ultra-short uni- and bipolar stimuli to define the time frame of bipolar cancellation and of AP initiation. Propagating APs in isolated frog sciatic nerve were elicited by cathodic pulses (200 ns-300 µs), followed by an anodic (canceling) pulse of the same duration after a 0-200-µs delay. We found that the earliest and the latest boundaries for opening the critical number of VGSC needed to initiate AP are, respectively, between 11 and 20 µs and between 100 and 200 µs after the onset of depolarization. Stronger depolarization accelerated AP initiation, apparently due to faster VGSC opening, but not beyond the 11-µs limit. Bipolar cancellation was augmented by reducing pulse duration, shortening the delay between pulses, decreasing the amplitude of the cathodic pulse, and increasing the amplitude of the anodic one. Some of these characteristics contrasted the bipolar cancellation of cell membrane electroporation (Pakhomov et al. in Bioelectrochemistry 122:123-133, 2018; Gianulis et al. in Bioelectrochemistry 119:10-19, 2017), suggesting different mechanisms. The ratio of nerve excitation thresholds for a unipolar cathodic pulse and a symmetrical bipolar pulse increased as a power function as the pulse duration decreased, in remarkable agreement with the predictions of SENN model of nerve excitation (Reilly and Diamant in Health Phys 83(3):356-365, 2002).
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Affiliation(s)
- Maura Casciola
- Frank Reidy Research Center for Bioelectrics, Old Dominion University, 4211 Monarch Way, Suite 300, Norfolk, VA, 23508, USA
| | - Shu Xiao
- Frank Reidy Research Center for Bioelectrics, Old Dominion University, 4211 Monarch Way, Suite 300, Norfolk, VA, 23508, USA
- Department of Electrical and Computer Engineering, Old Dominion University, Norfolk, VA, USA
| | - Francesca Apollonio
- Department of Information Engineering, Electronics and Telecommunications (D.I.E.T.), Sapienza University of Rome, Rome, Italy
| | - Alessandra Paffi
- Department of Information Engineering, Electronics and Telecommunications (D.I.E.T.), Sapienza University of Rome, Rome, Italy
| | - Micaela Liberti
- Department of Information Engineering, Electronics and Telecommunications (D.I.E.T.), Sapienza University of Rome, Rome, Italy
| | - Claudia Muratori
- Frank Reidy Research Center for Bioelectrics, Old Dominion University, 4211 Monarch Way, Suite 300, Norfolk, VA, 23508, USA
| | - Andrei G Pakhomov
- Frank Reidy Research Center for Bioelectrics, Old Dominion University, 4211 Monarch Way, Suite 300, Norfolk, VA, 23508, USA.
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Azarov JE, Semenov I, Casciola M, Pakhomov AG. Excitation of murine cardiac myocytes by nanosecond pulsed electric field. J Cardiovasc Electrophysiol 2019; 30:392-401. [PMID: 30582656 DOI: 10.1111/jce.13834] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [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: 11/14/2018] [Revised: 12/18/2018] [Accepted: 12/21/2018] [Indexed: 01/26/2023]
Abstract
INTRODUCTION Opening of voltage-gated sodium channels takes tens to hundreds of microseconds, and mechanisms of their opening by nanosecond pulsed electric field (nsPEF) stimuli remain elusive. This study was aimed at uncovering the mechanisms of how nsPEF elicits action potentials (APs) in cardiomyocytes. METHODS AND RESULTS Fluorescent imaging of optical APs (FluoVolt) and Ca2+ -transients (Fluo-4) was performed in enzymatically isolated murine ventricular cardiomyocytes stimulated by 200-nanosecond trapezoidal pulses. nsPEF stimulation evoked tetrodotoxin-sensitive APs accompanied or preceded by slow sustained depolarization (SSD) and, in most cells, by transient afterdepolarization waves. SSD threshold was lower than the AP threshold (1.26 ± 0.03 vs 1.34 ± 0.03 kV/cm, respectively, P < 0.001). Inhibition of l-type calcium and sodium-calcium exchanger currents reduced the SSD amplitude and increased the AP threshold ( P < 0.05). The threshold for Ca 2+ -transients (1.40 ± 0.04 kV/cm) was not significantly affected by a tetrodotoxin-verapamil cocktail, suggesting the activation of a Ca 2+ entry pathway independent from the opening of Na + or Ca 2+ voltage-gated channels. Removal of external Ca 2+ decreased the SSD amplitude ( P = 0.004) and blocked Ca 2+ -transients but not APs. The incidence of transient afterdepolarization waves was decreased by verapamil and by removal of external Ca 2+ ( P = 0.002). CONCLUSIONS The study established that nsPEF stimulation caused calcium entry into cardiac myocytes (including routes other than voltage-gated calcium channels) and SSD. Tetrodotoxin-sensitive APs were mediated by SSD, whose amplitude depended on the calcium entry. Plasma membrane electroporation was the most likely primary mechanism of SSD with additional contribution from l-type calcium and sodium-calcium exchanger currents.
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Affiliation(s)
- Jan E Azarov
- Frank Reidy Research Center for Bioelectrics, Old Dominion University, Norfolk, Virginia.,Laboratory of Cardiac Physiology, Institute of Physiology, Komi Science Center, Ural Branch, Russian Academy of Sciences, Syktyvkar, Russia.,Department of Physiology, Medical Institute of Pitirim Sorokin Syktyvkar State University, Syktyvkar, Russia
| | - Iurii Semenov
- Frank Reidy Research Center for Bioelectrics, Old Dominion University, Norfolk, Virginia
| | - Maura Casciola
- Frank Reidy Research Center for Bioelectrics, Old Dominion University, Norfolk, Virginia
| | - Andrei G Pakhomov
- Frank Reidy Research Center for Bioelectrics, Old Dominion University, Norfolk, Virginia
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Semenov I, Grigoryev S, Neuber JU, Zemlin CW, Pakhomova ON, Casciola M, Pakhomov AG. Excitation and injury of adult ventricular cardiomyocytes by nano- to millisecond electric shocks. Sci Rep 2018; 8:8233. [PMID: 29844431 PMCID: PMC5974370 DOI: 10.1038/s41598-018-26521-2] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2018] [Accepted: 05/08/2018] [Indexed: 12/13/2022] Open
Abstract
Intense electric shocks of nanosecond (ns) duration can become a new modality for more efficient but safer defibrillation. We extended strength-duration curves for excitation of cardiomyocytes down to 200 ns, and compared electroporative damage by proportionally more intense shocks of different duration. Enzymatically isolated murine, rabbit, and swine adult ventricular cardiomyocytes (VCM) were loaded with a Ca2+ indicator Fluo-4 or Fluo-5N and subjected to shocks of increasing amplitude until a Ca2+ transient was optically detected. Then, the voltage was increased 5-fold, and the electric cell injury was quantified by the uptake of a membrane permeability marker dye, propidium iodide. We established that: (1) Stimuli down to 200-ns duration can elicit Ca2+ transients, although repeated ns shocks often evoke abnormal responses, (2) Stimulation thresholds expectedly increase as the shock duration decreases, similarly for VCMs from different species, (3) Stimulation threshold energy is minimal for the shortest shocks, (4) VCM orientation with respect to the electric field does not affect the threshold for ns shocks, and (5) The shortest shocks cause the least electroporation injury. These findings support further exploration of ns defibrillation, although abnormal response patterns to repetitive ns stimuli are of a concern and require mechanistic analysis.
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Affiliation(s)
- Iurii Semenov
- Frank Reidy Research Center for Bioelectrics, Old Dominion University, Norfolk, VA, 23508, USA
| | - Sergey Grigoryev
- Frank Reidy Research Center for Bioelectrics, Old Dominion University, Norfolk, VA, 23508, USA
| | - Johanna U Neuber
- Frank Reidy Research Center for Bioelectrics, Old Dominion University, Norfolk, VA, 23508, USA.,Department of Electrical and Computer Engineering, Old Dominion University, Norfolk, VA, 23508, USA
| | - Christian W Zemlin
- Frank Reidy Research Center for Bioelectrics, Old Dominion University, Norfolk, VA, 23508, USA.,Department of Electrical and Computer Engineering, Old Dominion University, Norfolk, VA, 23508, USA
| | - Olga N Pakhomova
- Frank Reidy Research Center for Bioelectrics, Old Dominion University, Norfolk, VA, 23508, USA
| | - Maura Casciola
- Frank Reidy Research Center for Bioelectrics, Old Dominion University, Norfolk, VA, 23508, USA
| | - Andrei G Pakhomov
- Frank Reidy Research Center for Bioelectrics, Old Dominion University, Norfolk, VA, 23508, USA.
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Semenov I, Casciola M, Ibey BL, Xiao S, Pakhomov AG. Electropermeabilization of cells by closely spaced paired nanosecond-range pulses. Bioelectrochemistry 2018; 121:135-141. [PMID: 29413863 DOI: 10.1016/j.bioelechem.2018.01.013] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2017] [Revised: 01/26/2018] [Accepted: 01/26/2018] [Indexed: 01/10/2023]
Abstract
Decreasing the time gap between two identical electric pulses is expected to render bioeffects similar to those of a single pulse of equivalent total duration. In this study, we show that it is not necessarily true, and that the effects vary for different permeabilization markers. We exposed individual CHO or NG108 cells to one 300-ns pulse (3.7-11.6 kV/cm), or a pair of such pulses (0.4-1000 μs interval), or to a single 600-ns pulse of the same amplitude. Electropermeabilization was evaluated (a) by the uptake of YO-PRO-1 (YP) dye; (b) by the amplitude of elicited Ca2+ transients, and (c) by the entry of Tl+ ions. For YP uptake, applying a 600-ns pulse or a pair of 300-ns pulses doubled the effect of a single 300-ns pulse; this additive effect did not depend on the time interval between pulses or the electric field, indicating that already permeabilized cells are as susceptible to electropermeabilization as naïve cells. In contrast, Ca2+ transients and Tl+ uptake increased in a supra-additive fashion when two pulses were delivered instead of one. Paired pulses at 3.7 kV/cm with minimal separation (0.4 and 1 μs) elicited 50-100% larger Ca2+ transients than either a single 600-ns pulse or paired pulses with longer separation (10-1000 μs). This paradoxically high efficiency of the closest spaced pulses was emphasized when Ca2+ transients were elicited in a Ca2+-free solution (when the endoplasmic reticulum (ER) was the sole significant source of Ca2+), but was eliminated by Ca2+ depletion from the ER and was not observed for Tl+ entry through the electropermeabilized membrane. We conclude that closely spaced paired pulses specifically target ER, by either permeabilizing it to a greater extent than a single double-duration pulse thus causing more Ca2+ leak, or by amplifying Ca2+-induced Ca2+ release by an unknown mechanism.
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Affiliation(s)
- Iurii Semenov
- Frank Reidy Research Center for Bioelectrics, Old Dominion University, Norfolk, VA 23508, USA
| | - Maura Casciola
- Frank Reidy Research Center for Bioelectrics, Old Dominion University, Norfolk, VA 23508, USA
| | - Bennet L Ibey
- Radio Frequency Bioeffects Branch, Air Force Research Laboratories, Ft. Sam Houston, San Antonio, TX, USA
| | - Shu Xiao
- Frank Reidy Research Center for Bioelectrics, Old Dominion University, Norfolk, VA 23508, USA; Department of Electrical and Computer Engineering, Old Dominion University, Norfolk, VA 23508, USA
| | - Andrei G Pakhomov
- Frank Reidy Research Center for Bioelectrics, Old Dominion University, Norfolk, VA 23508, USA.
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Boccalon E, Nocchetti M, Pica M, Romani A, Casciola M. Layered double hydroxide and zirconium phosphate as ion exchangers for the removal of ‘black crusts’ from the surface of ancient monuments. Dalton Trans 2018; 47:2976-2985. [DOI: 10.1039/c7dt03957c] [Citation(s) in RCA: 11] [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: 11/21/2022]
Abstract
Two ion exchanger solids (LDH and ZrP) as an innovative tool to remove gypsum from ancient monuments.
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Affiliation(s)
- E. Boccalon
- Dipartimento di Chimica Biologia e Biotecnologie
- University of Perugia
- 06123 Perugia
- Italy
| | - M. Nocchetti
- Dipartimento di Scienze Farmaceutiche
- University of Perugia
- Perugia
- Italy
| | - M. Pica
- Dipartimento di Scienze Farmaceutiche
- University of Perugia
- Perugia
- Italy
| | - A. Romani
- Dipartimento di Chimica Biologia e Biotecnologie
- University of Perugia
- 06123 Perugia
- Italy
| | - M. Casciola
- Dipartimento di Chimica Biologia e Biotecnologie
- University of Perugia
- 06123 Perugia
- Italy
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Muratori C, Pakhomov AG, Gianulis E, Meads J, Casciola M, Mollica PA, Pakhomova ON. Activation of the phospholipid scramblase TMEM16F by nanosecond pulsed electric fields (nsPEF) facilitates its diverse cytophysiological effects. J Biol Chem 2017; 292:19381-19391. [PMID: 28982976 PMCID: PMC5702676 DOI: 10.1074/jbc.m117.803049] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2017] [Revised: 09/20/2017] [Indexed: 12/17/2022] Open
Abstract
Nanosecond pulsed electric fields (nsPEF) are emerging as a novel modality for cell stimulation and tissue ablation. However, the downstream protein effectors responsible for nsPEF bioeffects remain to be established. Here we demonstrate that nsPEF activate TMEM16F (or Anoctamin 6), a protein functioning as a Ca2+-dependent phospholipid scramblase and Ca2+-activated chloride channel. Using confocal microscopy and patch clamp recordings, we investigated the relevance of TMEM16F activation for several bioeffects triggered by nsPEF, including phosphatidylserine (PS) externalization, nanopore-conducted currents, membrane blebbing, and cell death. In HEK 293 cells treated with a single 300-ns pulse of 25.5 kV/cm, Tmem16f expression knockdown and TMEM16F-specific inhibition decreased nsPEF-induced PS exposure by 49 and 42%, respectively. Moreover, the Tmem16f silencing significantly decreased Ca2+-dependent chloride channel currents activated in response to the nanoporation. Tmem16f expression also affected nsPEF-induced cell blebbing, with only 20% of the silenced cells developing blebs compared with 53% of the control cells. This inhibition of cellular blebbing correlated with a 25% decrease in cytosolic free Ca2+ transient at 30 s after nanoporation. Finally, in TMEM16F-overexpressing cells, a train of 120 pulses (300 ns, 20 Hz, 6 kV/cm) decreased cell survival to 34% compared with 51% in control cells (*, p < 0.01). Taken together, these results indicate that TMEM16F activation by nanoporation mediates and enhances the diverse cellular effects of nsPEF.
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Affiliation(s)
| | | | - Elena Gianulis
- From the Frank Reidy Research Center for Bioelectrics, and
| | - Jade Meads
- From the Frank Reidy Research Center for Bioelectrics, and
| | - Maura Casciola
- From the Frank Reidy Research Center for Bioelectrics, and
| | - Peter A Mollica
- the Department of Medical Diagnostics and Translational Sciences, Old Dominion University, Norfolk, Virginia 23508
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Gianulis EC, Casciola M, Xiao S, Pakhomova ON, Pakhomov AG. Electropermeabilization by uni- or bipolar nanosecond electric pulses: The impact of extracellular conductivity. Bioelectrochemistry 2017; 119:10-19. [PMID: 28865240 DOI: 10.1016/j.bioelechem.2017.08.005] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2017] [Revised: 07/05/2017] [Accepted: 08/15/2017] [Indexed: 02/03/2023]
Abstract
Cellular effects caused by nanosecond electric pulses (nsEP) can be reduced by an electric field reversal, a phenomenon known as bipolar cancellation. The reason for this cancellation effect remains unknown. We hypothesized that assisted membrane discharge is the mechanism for bipolar cancellation. CHO-K1 cells bathed in high (16.1mS/cm; HCS) or low (1.8mS/cm; LCS) conductivity solutions were exposed to either one unipolar (300-ns) or two opposite polarity (300+300-ns; bipolar) nsEP (4-40kV/cm) with increasing interpulse intervals (0.1-50μs). Time-lapse YO-PRO-1 (YP) uptake revealed enhanced membrane permeabilization in LCS compared to HCS at all tested voltages. The time-dependence of bipolar cancellation was similar in both solutions, using either identical (22kV/cm) or isoeffective nsEP treatments (12 and 32kV/cm for LCS and HCS, respectively). However, cancellation was significantly stronger in LCS when the bipolar nsEP had no, or very short (<1μs), interpulse intervals. Finally, bipolar cancellation was still present with interpulse intervals as long as 50μs, beyond the time expected for membrane discharge. Our findings do not support assisted membrane discharge as the mechanism for bipolar cancellation. Instead they exemplify the sustained action of nsEP that can be reversed long after the initial stimulus.
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Affiliation(s)
- Elena C Gianulis
- Frank Reidy Research Center for Bioelectrics, Old Dominion University, Norfolk, VA 23508, USA.
| | - Maura Casciola
- Frank Reidy Research Center for Bioelectrics, Old Dominion University, Norfolk, VA 23508, USA
| | - Shu Xiao
- Frank Reidy Research Center for Bioelectrics, Old Dominion University, Norfolk, VA 23508, USA; Department of Electrical and Computer Engineering, Old Dominion University, Norfolk, VA 23508, USA
| | - Olga N Pakhomova
- Frank Reidy Research Center for Bioelectrics, Old Dominion University, Norfolk, VA 23508, USA
| | - Andrei G Pakhomov
- Frank Reidy Research Center for Bioelectrics, Old Dominion University, Norfolk, VA 23508, USA
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Muratori C, Pakhomov AG, Heller L, Casciola M, Gianulis E, Grigoryev S, Xiao S, Pakhomova ON. Electrosensitization Increases Antitumor Effectiveness of Nanosecond Pulsed Electric Fields In Vivo. Technol Cancer Res Treat 2017; 16:987-996. [PMID: 28585492 PMCID: PMC5762058 DOI: 10.1177/1533034617712397] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
Nanosecond pulsed electric fields are emerging as a new modality for tissue and tumor ablation. We previously reported that cells exposed to pulsed electric fields develop hypersensitivity to subsequent pulsed electric field applications. This phenomenon, named electrosensitization, is evoked by splitting the pulsed electric field treatment in fractions (split-dose treatments) and causes in vitro a 2- to 3-fold increase in cytotoxicity. The aim of this study was to show the benefit of split-dose treatments for in vivo tumor ablation by nanosecond pulsed electric field. KLN 205 squamous carcinoma cells were embedded in an agarose gel or grown subcutaneously as tumors in mice. Nanosecond pulsed electric field ablations were produced using a 2-needle probe with a 6.5-mm interelectrode distance. In agarose gel, splitting a pulsed electric field dose of 300, 300-ns pulses (20 Hz, 4.4-6.4 kV) in 2 equal fractions increased cell death up to 3-fold compared to single-train treatments. We then compared the antitumor effectiveness of these treatments in vivo. At 24 hours after treatment, sensitizing tumors by a split-dose pulsed electric field exposure (150 + 150, 300-ns pulses, 20 Hz, 6.4 kV) caused a 4- and 2-fold tumor volume reduction as compared to sham and single-train treatments, respectively. Tumor volume reduction that exceeds 75% was 43% for split-dose–treated animals compared to only 12% for single-dose treatments. The difference between the 2 experimental groups remained statistically significant for at least 1 week after the treatment. The results show that electrosensitization occurs in vivo and can be exploited to assist in vivo cancer ablation.
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Affiliation(s)
- Claudia Muratori
- Frank Reidy Research Center for Bioelectrics, Old Dominion University, Norfolk, VA, USA
| | - Andrei G Pakhomov
- Frank Reidy Research Center for Bioelectrics, Old Dominion University, Norfolk, VA, USA
| | - Loree Heller
- Frank Reidy Research Center for Bioelectrics, Old Dominion University, Norfolk, VA, USA
| | - Maura Casciola
- Frank Reidy Research Center for Bioelectrics, Old Dominion University, Norfolk, VA, USA
| | - Elena Gianulis
- Frank Reidy Research Center for Bioelectrics, Old Dominion University, Norfolk, VA, USA
| | - Sergey Grigoryev
- Frank Reidy Research Center for Bioelectrics, Old Dominion University, Norfolk, VA, USA
| | - Shu Xiao
- Frank Reidy Research Center for Bioelectrics, Old Dominion University, Norfolk, VA, USA
| | - O N Pakhomova
- Frank Reidy Research Center for Bioelectrics, Old Dominion University, Norfolk, VA, USA
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Denzi A, Merla C, Casciola M, Hwang JCM, Cheng X, Apollonio F, Liberti M. Microchambers for cell exposure: from the design to applications. Annu Int Conf IEEE Eng Med Biol Soc 2017; 2016:4232-4235. [PMID: 28269216 DOI: 10.1109/embc.2016.7591661] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
In the last decades, the advances in the micro and nano fabrication techniques have led to the development of microdevices that improved the possibility of analysis at cell level. These devices can be used in different applications (e.g., cell detection and identification, manipulation, cell treatments). The requisites, that are necessary to achieve, are different for various applications and represent the starting point of the project. The numerical multiphysics models can be very advantageous to analyze the performances of such devices and to predict their operation. Aim of this work is to give a look of the design rules of microchamber devices in particular for their application in electric field exposure. Two different applications for cell discrimination and characterization are reported considering time and frequency domain measurements.
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Rems L, Tarek M, Casciola M, Miklavčič D. Properties of lipid electropores II: Comparison of continuum-level modeling of pore conductance to molecular dynamics simulations. Bioelectrochemistry 2016; 112:112-24. [DOI: 10.1016/j.bioelechem.2016.03.005] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2015] [Revised: 03/24/2016] [Accepted: 03/27/2016] [Indexed: 12/18/2022]
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Casciola M, Tarek M. A molecular insight into the electro-transfer of small molecules through electropores driven by electric fields. Biochim Biophys Acta 2016; 1858:2278-2289. [PMID: 27018309 DOI: 10.1016/j.bbamem.2016.03.022] [Citation(s) in RCA: 56] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/01/2016] [Revised: 03/21/2016] [Accepted: 03/21/2016] [Indexed: 11/26/2022]
Abstract
The transport of chemical compounds across the plasma membrane into the cell is relevant for several biological and medical applications. One of the most efficient techniques to enhance this uptake is reversible electroporation. Nevertheless, the detailed molecular mechanism of transport of chemical species (dyes, drugs, genetic materials, …) following the application of electric pulses is not yet fully elucidated. In the past decade, molecular dynamics (MD) simulations have been conducted to model the effect of pulsed electric fields on membranes, describing several aspects of this phenomenon. Here, we first present a comprehensive review of the results obtained so far modeling the electroporation of lipid membranes, then we extend these findings to study the electrotransfer across lipid bilayers subject to microsecond pulsed electric fields of Tat11, a small hydrophilic charged peptide, and of siRNA. We use in particular a MD simulation protocol that allows to characterize the transport of charged species through stable pores. Unexpectedly, our results show that for an electroporated bilayer subject to transmembrane voltages in the order of 500mV, i.e. consistent with experimental conditions, both Tat11 and siRNA can translocate through nanoelectropores within tens of ns. We discuss these results in comparison to experiments in order to rationalize the mechanism of drug uptake by cells. This article is part of a Special Issue entitled: Biosimulations edited by Ilpo Vattulainen and Tomasz Róg.
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Affiliation(s)
- Maura Casciola
- Université de Lorraine, UMR 7565, F-54506 Vandoeuvre les Nancy, France; Department of Information Engineering, Electronics and Telecommunications (D.I.E.T), Sapienza University of Rome, 00184 Rome, Italy; Center for Life Nano Science@Sapienza, Istituto Italiano di Tecnologia, 00161 Rome, Italy
| | - Mounir Tarek
- Université de Lorraine, UMR 7565, F-54506 Vandoeuvre les Nancy, France; CNRS, UMR 7565, F-54506 Vandoeuvre les Nancy, France.
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Casciola M, Kasimova MA, Rems L, Zullino S, Apollonio F, Tarek M. Properties of lipid electropores I: Molecular dynamics simulations of stabilized pores by constant charge imbalance. Bioelectrochemistry 2016; 109:108-16. [PMID: 26883056 DOI: 10.1016/j.bioelechem.2016.01.006] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2015] [Revised: 01/20/2016] [Accepted: 01/26/2016] [Indexed: 11/16/2022]
Abstract
Molecular dynamics (MD) simulations have become a powerful tool to study electroporation (EP) in atomic detail. In the last decade, numerous MD studies have been conducted to model the effect of pulsed electric fields on membranes, providing molecular models of the EP process of lipid bilayers. Here we extend these investigations by modeling for the first time conditions comparable to experiments using long (μs-ms) low intensity (~kV/cm) pulses, by studying the characteristics of pores formed in lipid bilayers maintained at a constant surface tension and subject to constant charge imbalance. This enables the evaluation of structural (size) and electrical (conductance) properties of the pores formed, providing information hardly accessible directly by experiments. Extensive simulations of EP of simple phosphatidylcholine bilayers in 1M NaCl show that hydrophilic pores with stable radii (1-2.5 nm) form under transmembrane voltages between 420 and 630 mV, allowing for ionic conductance in the range of 6.4-29.5 nS. We discuss in particular these findings and characterize both convergence and size effects in the MD simulations. We further extend these studies in a follow-up paper (Rems et al., Bioelectrochemistry, Submitted), by proposing an improved continuum model of pore conductance consistent with the results from the MD simulations.
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Affiliation(s)
- Maura Casciola
- Université de Lorraine, UMR 7565, F-54506 Vandoeuvre les Nancy, France; Department of Information Engineering, Electronics and Telecommunications (D.I.E.T), Sapienza University of Rome, 00184 Rome, Italy; Center for Life Nano Science@Sapienza, Istituto Italiano di Tecnologia, 00161 Rome, Italy
| | - Marina A Kasimova
- Université de Lorraine, UMR 7565, F-54506 Vandoeuvre les Nancy, France
| | - Lea Rems
- University of Ljubljana, Faculty of Electrical Engineering, Tržaška 25, SI-1000 Ljubljana, Slovenia
| | - Sara Zullino
- Université de Lorraine, UMR 7565, F-54506 Vandoeuvre les Nancy, France; Department of Information Engineering, Electronics and Telecommunications (D.I.E.T), Sapienza University of Rome, 00184 Rome, Italy
| | - Francesca Apollonio
- Department of Information Engineering, Electronics and Telecommunications (D.I.E.T), Sapienza University of Rome, 00184 Rome, Italy
| | - Mounir Tarek
- Université de Lorraine, UMR 7565, F-54506 Vandoeuvre les Nancy, France; CNRS, UMR 7565, F-54506 Vandoeuvre les Nancy, France.
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Casciola M, Bonhenry D, Liberti M, Apollonio F, Tarek M. A molecular dynamic study of cholesterol rich lipid membranes: comparison of electroporation protocols. Bioelectrochemistry 2014; 100:11-7. [DOI: 10.1016/j.bioelechem.2014.03.009] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2013] [Revised: 03/20/2014] [Accepted: 03/20/2014] [Indexed: 01/25/2023]
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Kasimova M, Delemotte L, Polak A, Miklavcic D, Casciola M, Apollonio F, Breton M, Mir L, Shaytan A, Shaitan K, Tarek M. Molecular Insights into Electroporation and Electrotransfer through Model Cell Membranes. Biophys J 2014. [DOI: 10.1016/j.bpj.2013.11.1701] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022] Open
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Ho MC, Casciola M, Levine ZA, Vernier PT. Molecular dynamics simulations of ion conductance in field-stabilized nanoscale lipid electropores. J Phys Chem B 2013; 117:11633-40. [PMID: 24001115 DOI: 10.1021/jp401722g] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Molecular dynamics (MD) simulations of electrophoretic transport of monovalent ions through field-stabilized electropores in POPC lipid bilayers permit systematic characterization of the conductive properties of lipid nanopores. The radius of the electropore can be controlled by the magnitude of the applied sustaining external electric field, which also drives the transport of ions through the pore. We examined pore conductances for two monovalent salts, NaCl and KCl, at physiological concentrations. Na(+) conductance is significantly less than K(+) and Cl(-) conductance and is a nonlinear function of pore radius over the range of pore radii investigated. The single pore electrical conductance of KCl obtained from MD simulation is comparable to experimental values measured by chronopotentiometry.
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Affiliation(s)
- Ming-Chak Ho
- Department of Physics and Astronomy, Dornsife College of Letters, Arts, and Sciences, University of Southern California , Los Angeles, California, United States
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Wu YH, Arnaud-Cormos D, Casciola M, Sanders JM, Leveque P, Vernier PT. Moveable Wire Electrode Microchamber for Nanosecond Pulsed Electric-Field Delivery. IEEE Trans Biomed Eng 2013. [DOI: 10.1109/tbme.2012.2228650] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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Merla C, Denzi A, Paffi A, Casciola M, d'Inzeo G, Apollonio F, Liberti M. Novel passive element circuits for microdosimetry of nanosecond pulsed electric fields. IEEE Trans Biomed Eng 2012; 59:2302-11. [PMID: 22692873 DOI: 10.1109/tbme.2012.2203133] [Citation(s) in RCA: 60] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Microdosimetric models for biological cells have assumed increasing significance in the development of nanosecond pulsed electric field technology for medical applications. In this paper, novel passive element circuits, able to take into account the dielectric dispersion of the cell, are provided. The circuital analyses are performed on a set of input pulses classified in accordance with the current literature. Accurate data in terms of transmembrane potential are obtained in both time and frequency domains for different cell models. In addition, a sensitivity study of the transfer function for the cell geometrical and dielectric parameters has been carried out. This analysis offers a new, simple, and efficient tool to characterize the nsPEFs' action at the cellular level.
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Affiliation(s)
- C Merla
- Italian Inter-University Centre of Electromagnetic Fieldsand Bio-Systems, Italian National Agency for New Technologies, Energy,and Sustainable Economic Development, Rome, Italy.
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Wu YH, Arnaud-Cormos D, Casciola M, Sanders JM, Leveque P, Vernier PT. Versatile broadband electrode assembly for cell electroporation. Annu Int Conf IEEE Eng Med Biol Soc 2012; 2012:2563-2566. [PMID: 23366448 DOI: 10.1109/embc.2012.6346487] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
In this paper, a versatile electrode assembly for cell electroporation is proposed. For validation of the delivery system, biological cell electroporation experiments using 2.5 ns and 5 ns, 10 MV/m pulsed electric fields have been conducted. Electromagnetic, time domain, and frequency analyses demonstrate the broadband behavior of the delivery system.
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Affiliation(s)
- Yu-Hsuan Wu
- Mork Family Department of Chemical Engineering and Materials Science, VsOE, USC, Los Angeles, CA, USA
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Di Vona M, Sgreccia E, Donnadio A, Casciola M, Chailan J, Auer G, Knauth P. Composite polymer electrolytes of sulfonated poly-ether-ether-ketone (SPEEK) with organically functionalized TiO2. J Memb Sci 2011. [DOI: 10.1016/j.memsci.2010.12.044] [Citation(s) in RCA: 70] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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Bongiovanni R, Casciola M, Di Gianni A, Donnadio A, Malucelli G. Epoxy-nanocomposites containing exfoliated zirconium phosphate: Preparation via cationic photopolymerisation and physicochemical characterisation. Eur Polym J 2009. [DOI: 10.1016/j.eurpolymj.2009.06.022] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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Paciaroni A, Casciola M, Cornicchi E, Marconi M, Onori G, Pica M, Narducci R. Temperature-Dependent Dynamics of Water Confined in Nafion Membranes. J Phys Chem B 2006; 110:13769-76. [PMID: 16836322 DOI: 10.1021/jp0572176] [Citation(s) in RCA: 33] [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: 11/30/2022]
Abstract
We performed a neutron scattering study to investigate the dynamical behavior of water absorbed in Nafion at low hydration level as a function of temperature in the range 200-300 K. To single out the spectral contribution of the confined water, the measurements were done on samples hydrated with both H(2)O and D(2)O. Due to the strong incoherent scattering cross section of hydrogen atoms with respect to deuterium, in the difference spectra, the contribution from the Nafion membrane is subtracted out and the signal originates essentially from protons in the liquid phase. The main quantities we extracted as a function of the momentum transfer are the elastic incoherent structure factor (EISF) and the line width of the quasielastic component. Their trend suggests that the motion of hydrogen atoms can be schematized as a random jumping inside a confining region, which can be related to the boundaries of the space where water molecules move in the cluster they form around the sulfonic acid site. Through the calculated EISF, we obtained information on the size of such a region, which increases up to 260 K and then attains a constant value. Above this temperature, the number of water protons that are dynamically activated in the accessible time window increases with a faster rate. The jump diffusion dynamics is characterized by a typical jumping time which is stable at 5.3 ps up to approximately 260 K and then gradually decreases. The ensemble of the findings indicates that, within the limits of the energy resolution of the present experiment, water absorbed in the Nafion membrane undergoes a dynamical transition at around 260 K. We discuss the possible relationship of this dynamical onset with the behavior of the electrical conductivity of the membrane as a function of the temperature.
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Affiliation(s)
- A Paciaroni
- Dipartimento di Fisica dell'Università di Perugia and INFM-CRS SOFT Unità di Perugia, Via A. Pascoli, I-06123 Perugia, Italy.
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Alberti G, Casciola M, Vivani R, Biswas RK. Preparation and characterization of zirconium phosphate phosphonates, ZrPO4(H2PO4)1-x(RPO2OH)x.nH2O, with .gamma.-layer structure (R = CH3, C3H7, C6H11). Inorg Chem 2002. [DOI: 10.1021/ic00073a022] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Reh�kov� M, Sopkov� A, Casciola M, Failla S. A study of the silver form of a natural zeolitic material of the clinoptilolite type. J INCL PHENOM MACRO 1995. [DOI: 10.1007/bf00708769] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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Casciola M, Andersen EK, Andersen IGK, Dahl O, Nielsen M, Lehmann MS, Tokii T. Formation and Intercalation of Hexamethylenetetramine in the Layered Structure of alpha-Zirconium Phosphate. ACTA ACUST UNITED AC 1990. [DOI: 10.3891/acta.chem.scand.44-0459] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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Alberti G, Bernasconi M, Casciola M. Preparation of γ-zirconium phosphate microcrystals with high degree of crystallinity and proton conductivity of their hydrogen and ammonium forms. ACTA ACUST UNITED AC 1989. [DOI: 10.1016/0923-1137(89)90110-3] [Citation(s) in RCA: 50] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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Alberti G, Bernasconi M, Casciola M, Costantino U. Ion exchange of some divalent and trivalent cations on the surface of zirconium acid phosphate micro-crystals. J Chromatogr A 1978. [DOI: 10.1016/s0021-9673(00)91786-2] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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Alberti G, Casciola M, Costantino U, Levi G. Inorganic ion exchange membranes consisting of microcrystals of zirconium phosphate supported by Kynar®. J Memb Sci 1978. [DOI: 10.1016/s0376-7388(00)83021-5] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
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50
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Alberti G, Bertrami R, Casciola M, Costantino U, Gupta J. Crystalline insoluble acid salts of tetravalent metals—XXI ion exchange mechanism of alkaline earth metal. ACTA ACUST UNITED AC 1976. [DOI: 10.1016/0022-1902(76)80368-5] [Citation(s) in RCA: 42] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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