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Kasparyan G, Hub JS. Molecular Simulations Reveal the Free Energy Landscape and Transition State of Membrane Electroporation. PHYSICAL REVIEW LETTERS 2024; 132:148401. [PMID: 38640376 DOI: 10.1103/physrevlett.132.148401] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/05/2023] [Accepted: 02/29/2024] [Indexed: 04/21/2024]
Abstract
The formation of pores over lipid membranes by the application of electric fields, termed membrane electroporation, is widely used in biotechnology and medicine to deliver drugs, vaccines, or genes into living cells. Continuum models for describing the free energy landscape of membrane electroporation were proposed decades ago, but they have never been tested against spatially detailed atomistic models. Using molecular dynamics (MD) simulations with a recently proposed reaction coordinate, we computed potentials of mean force of pore nucleation and pore expansion in lipid membranes at various transmembrane potentials. Whereas the free energies of pore expansion are compatible with previous continuum models, the experimentally important free energy barrier of pore nucleation is at variance with established models. The discrepancy originates from different geometries of the transition state; previous continuum models assumed the presence of a membrane-spanning defect throughout the process, whereas, according to the MD simulations, the transition state of pore nucleation is typically passed before a transmembrane defect has formed. A modified continuum model is presented that qualitatively agrees with the MD simulations. Using kinetics of pore opening together with transition state theory, our free energies of pore nucleation are in excellent agreement with previous experimental data.
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Affiliation(s)
- Gari Kasparyan
- Theoretical Physics and Center for Biophysics, Saarland University, 66123 Saarbrücken, Germany
| | - Jochen S Hub
- Theoretical Physics and Center for Biophysics, Saarland University, 66123 Saarbrücken, Germany
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2
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Zare F, Ghasemi N, Bansal N, Hosano H. Advances in pulsed electric stimuli as a physical method for treating liquid foods. Phys Life Rev 2023; 44:207-266. [PMID: 36791571 DOI: 10.1016/j.plrev.2023.01.007] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2023] [Accepted: 01/28/2023] [Indexed: 02/05/2023]
Abstract
There is a need for alternative technologies that can deliver safe and nutritious foods at lower costs as compared to conventional processes. Pulsed electric field (PEF) technology has been utilised for a plethora of different applications in the life and physical sciences, such as gene/drug delivery in medicine and extraction of bioactive compounds in food science and technology. PEF technology for treating liquid foods involves engineering principles to develop the equipment, and quantitative biochemistry and microbiology techniques to validate the process. There are numerous challenges to address for its application in liquid foods such as the 5-log pathogen reduction target in food safety, maintaining the food quality, and scale up of this physical approach for industrial integration. Here, we present the engineering principles associated with pulsed electric fields, related inactivation models of microorganisms, electroporation and electropermeabilization theory, to increase the quality and safety of liquid foods; including water, milk, beer, wine, fruit juices, cider, and liquid eggs. Ultimately, we discuss the outlook of the field and emphasise research gaps.
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Affiliation(s)
- Farzan Zare
- School of Information Technology and Electrical Engineering, The University of Queensland, Brisbane, St Lucia QLD 4072, Australia; School of Agriculture and Food Sciences, The University of Queensland, St Lucia QLD 4072, Australia
| | - Negareh Ghasemi
- School of Information Technology and Electrical Engineering, The University of Queensland, Brisbane, St Lucia QLD 4072, Australia
| | - Nidhi Bansal
- School of Agriculture and Food Sciences, The University of Queensland, St Lucia QLD 4072, Australia
| | - Hamid Hosano
- Biomaterials and Bioelectrics Department, Institute of Industrial Nanomaterials, Kumamoto University, Kumamoto 860-8555, Japan.
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3
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Rao X, Chen S, Alfadhl Y, Chen X, Sun L, Yu L, Zhou J. Pulse width and intensity effects of pulsed electric fields on cancerous and normal skin cells. Sci Rep 2022; 12:18039. [PMID: 36302879 PMCID: PMC9613658 DOI: 10.1038/s41598-022-22874-x] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2022] [Accepted: 10/20/2022] [Indexed: 01/24/2023] Open
Abstract
Microsecond pulsed electric fields (PEF) have previously been used for various tumour therapies, such as gene therapy, electrochemotherapy and irreversible electroporation (IRE), due to its demonstrated ability. However, recently nanosecond pulsed electric fields (nsPEF) have also been used as a potential tumor therapy via inducing cell apoptosis or immunogenic cell death to prevent recurrence and metastasis by interacting with intracellular organelles. A large proportion of the existing in-vitro studies of nsPEF on cells also suggests cell necrosis and swelling/blebbing can be induced, but the replicability and potential for other effects on cells suggesting a complicated process which requires further investigation. Therefore, this study investigated the effects of pulse width and intensity of nsPEF on the murine melanoma cells (B16) and normal murine fibroblast cells (L929) through electromagnetic simulation and in-vitro experiments. Through examining the evolution patterns of potential difference and electric fields on the intracellular compartments, the simulation has shown a differential effect of nsPEF on normal and cancerous skin cells, which explains well the results observed in the reported experiments. In addition, the modelling has provided a clear evidence that a few hundreds of ns PEF may have caused a mixed mode of effects, i.e. a 'cocktail effect', including cell electroporation and IRE due to an over their threshold voltage induced on the plasma membrane, as well as cell apoptosis and other biological effects caused by its interaction with the intracellular compartments. The in-vitro experiments in the pulse range of the hundreds of nanoseconds showed a possible differential cytotoxicity threshold of electric field intensity between B16 cells and L929 cells.
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Affiliation(s)
- Xin Rao
- grid.411963.80000 0000 9804 6672School of Electronics and Information, Hangzhou Dianzi University, Hangzhou, 310018 China
| | - Sophia Chen
- grid.7445.20000 0001 2113 8111School of Medicine, Imperial College London, London, SW7 2AZ UK
| | - Yasir Alfadhl
- grid.4868.20000 0001 2171 1133School of Electronic Engineering and Computer Science, Queen Mary University of London, London, E1 4NS UK
| | - Xiaodong Chen
- grid.411963.80000 0000 9804 6672School of Electronics and Information, Hangzhou Dianzi University, Hangzhou, 310018 China ,grid.4868.20000 0001 2171 1133School of Electronic Engineering and Computer Science, Queen Mary University of London, London, E1 4NS UK
| | - Lingling Sun
- grid.411963.80000 0000 9804 6672School of Electronics and Information, Hangzhou Dianzi University, Hangzhou, 310018 China
| | - Liyang Yu
- grid.411963.80000 0000 9804 6672School of Electronics and Information, Hangzhou Dianzi University, Hangzhou, 310018 China
| | - Jun Zhou
- grid.54549.390000 0004 0369 4060School of Electronic Science and Engineering, University of Electronic Science and Technology of China, Chengdu, 610054 China
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4
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Guo F, Wang J, Zhou J, Qian K, Qu H, Liu P, Zhai S. All-atom molecular dynamics simulations of the combined effects of different phospholipids and cholesterol content on electroporation. RSC Adv 2022; 12:24491-24500. [PMID: 36128384 PMCID: PMC9425445 DOI: 10.1039/d2ra03895a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2022] [Accepted: 07/27/2022] [Indexed: 11/21/2022] Open
Abstract
In this paper, we applied all-atom molecular dynamics (MD) simulations to study the effects of phospholipids and cholesterol content on bilayer membrane electroporation.
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Affiliation(s)
- Fei Guo
- Institute of Ecological Safety, Chongqing University of Posts and Telecommunications, Chongqing 400065, China
| | - Ji Wang
- Institute of Ecological Safety, Chongqing University of Posts and Telecommunications, Chongqing 400065, China
| | - Jiong Zhou
- Institute of Ecological Safety, Chongqing University of Posts and Telecommunications, Chongqing 400065, China
| | - Kun Qian
- Institute of Ecological Safety, Chongqing University of Posts and Telecommunications, Chongqing 400065, China
| | - Hongchun Qu
- Institute of Ecological Safety, Chongqing University of Posts and Telecommunications, Chongqing 400065, China
| | - Ping Liu
- Institute of Ecological Safety, Chongqing University of Posts and Telecommunications, Chongqing 400065, China
| | - Shidong Zhai
- Institute of Ecological Safety, Chongqing University of Posts and Telecommunications, Chongqing 400065, China
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5
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Weng J, Wang A, Zhang D, Liao C, Li G. A double bilayer to study the nonequilibrium environmental response of GIRK2 in complex states. Phys Chem Chem Phys 2021; 23:15784-15795. [PMID: 34286758 DOI: 10.1039/d1cp01785c] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
G protein-gated inwardly rectifying potassium (GIRK) channels play essential roles in electrical signaling in neurons and muscle cells. Nonequilibrium environments provide crucial driving forces behind many cellular events. Here, we apply the antiparallel alignment double bilayer model to study GIRK2 in response to the time-dependent membrane potential. Using molecular dynamics and umbrella sampling, we examined the time-dependent environmental impact on the ion conduction, energy basis, and primary motions of GIRK2 in different complex states with phosphatidylinositol-4,5-bisphosphate (PIP2) and G-protein βγ subunits (Gβγ). The antiparallel alignment double bilayer model enables us to study the transport performance in inward and outward K+ and mixed K+ and Na+. We obtained the recoverable discharge process of GIRK2 complexed with both PIP2 and Gβγ, compared with occasional conduction under PIP2-only regulation. Calculations of potential of mean force suggest different regulation by the helix bundle crossing (HBC) gate and G-loop gate regarding different complex states and under a membrane potential. In a nonequilibrium environment, distinct functional rocking motions of GIRK2 were identified under strengthened correlations between the transmembrane helices and downstream cytoplasmic domains with binding of PIP2, cations, and Gβγ. The findings suggest the potential domain motions and dynamics associated with a nonequilibrium environment and highlight the application of the antiparallel alignment double bilayer model to investigate factors in an asymmetric environment.
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Affiliation(s)
- Junben Weng
- State Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian, China. and University of Chinese Academy of Sciences, Beijing, China
| | - Anhui Wang
- State Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian, China.
| | - Dinglin Zhang
- State Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian, China. and University of Chinese Academy of Sciences, Beijing, China
| | - Chenyi Liao
- State Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian, China.
| | - Guohui Li
- State Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian, China.
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Pakhomov AG, Pakhomova ON. The interplay of excitation and electroporation in nanosecond pulse stimulation. Bioelectrochemistry 2020; 136:107598. [PMID: 32711366 DOI: 10.1016/j.bioelechem.2020.107598] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2020] [Revised: 07/09/2020] [Accepted: 07/10/2020] [Indexed: 12/11/2022]
Abstract
Conventional electric stimuli of micro- and millisecond duration excite or activate cells at voltages 10-100 times below the electroporation threshold. This ratio is remarkably different for nanosecond electric pulses (nsEP), which caused excitation and activation only at or above the electroporation threshold in diverse cell lines, primary cardiomyocytes, neurons, and chromaffin cells. Depolarization to the excitation threshold often results from (or is assisted by) the loss of the resting membrane potential due to ion leaks across the membrane permeabilized by nsEP. Slow membrane resealing and the build-up of electroporation damages prevent repetitive excitation by nsEP. However, peripheral nerves and muscles are exempt from this rule and withstand multiple cycles of excitation by nsEP without the loss of function or signs of electroporation. We show that the damage-free excitation by nsEP may be enabled by the membrane charging time constant sufficiently large to (1) cap the peak transmembrane voltage during nsEP below the electroporation threshold, and (2) extend the post-nsEP depolarization long enough to activate voltage-gated ion channels. The low excitatory efficacy of nsEP compared to longer pulses makes them advantageous for medical applications where the neuromuscular excitation is an unwanted side effect, such as electroporation-based cancer and tissue ablation.
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Affiliation(s)
- Andrei G Pakhomov
- Frank Reidy Research Center for Bioelectrics, Old Dominion University, Norfolk, VA 23508, USA.
| | - Olga N Pakhomova
- Frank Reidy Research Center for Bioelectrics, Old Dominion University, Norfolk, VA 23508, USA
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7
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Yadav DK, Kumar S, Choi EH, Kim MH. Electric-field-induced electroporation and permeation of reactive oxygen species across a skin membrane. J Biomol Struct Dyn 2020; 39:1343-1353. [PMID: 32072876 DOI: 10.1080/07391102.2020.1730972] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Electroporation processes affect the permeability of cell membranes, which can be utilized for the delivery of plasma species in cancer therapy. By means of computational dynamics, many aspects of membrane electroporation have been unveiled at the atomic level for lipid membranes. Herein, a molecular dynamics simulation study was performed on native and oxidized membrane systems with transversal electric fields. The simulation result shows that the applied electric field mainly affects the membrane properties so that electroporation takes place and these pores are lined by hydrophilic headgroups of the lipid components. The calculated hydrophobic thickness, lateral diffusion and pair correlation revealed the role of 5α-CH in creation of water-pore in an oxidized membrane. Additionally, the permeability of reactive oxygen species was examined through these electroporated systems. The permeability study suggested that water pores in the membrane facilitate the penetration of these species across the membrane to the interior of the cell. These findings may have significance in experimental applications in vivo as once the reactive oxygen species reaches the interior of the cell, they may cause oxidative stress and induce apoptosis.Communicated by Ramaswamy H. Sarma.
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Affiliation(s)
- Dharmendra Kumar Yadav
- College of Pharmacy, Gachon University of Medicine and Science, Incheon, South Korea.,Gachon Institute of Pharmaceutical Science & Department of Pharmacy, College of Pharmacy, Gachon University, Incheon, South Korea
| | - Surendra Kumar
- College of Pharmacy, Gachon University of Medicine and Science, Incheon, South Korea.,Gachon Institute of Pharmaceutical Science & Department of Pharmacy, College of Pharmacy, Gachon University, Incheon, South Korea
| | - Eun-Ha Choi
- Plasma Bioscience Research Center/PDP Research Center, Kwangwoon University, Seoul, South Korea
| | - Mi-Hyun Kim
- College of Pharmacy, Gachon University of Medicine and Science, Incheon, South Korea.,Gachon Institute of Pharmaceutical Science & Department of Pharmacy, College of Pharmacy, Gachon University, Incheon, South Korea
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8
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Nanosecond pulses targeting intracellular ablation increase destruction of tumor cells with irregular morphology. Bioelectrochemistry 2019; 132:107432. [PMID: 31918056 DOI: 10.1016/j.bioelechem.2019.107432] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2019] [Revised: 11/22/2019] [Accepted: 11/22/2019] [Indexed: 01/04/2023]
Abstract
The decrease in killing sensitivity of the cell membrane to microsecond pulse electric fields (μs-PEFs) is ascribed mainly to the aberrant morphology of cancer cells, with clear statistical correlations observed between cell size and shape defects and the worsening of the electrical response to the PEF. In this paper, nanosecond pulsed electric fields (ns-PEFs) inducing the nucleus effect and μs-PEFs targeting the cell membrane were combined to enhance destruction of irregular cells. The fluorescence dissipation levels of the nuclear membrane and cell membrane exposed to the μs, ns, and ns + μs pulse protocols were measured and compared, and a dynamic electroporation model of irregular cells was established by the finite element software COMSOL. The results suggest that the cell membrane disruption induced by μs-PEFs is worse for extremely irregular cells and depends strongly on cellular morphology. However, the nuclear membrane disruption induced by ns-PEFs does not scale with irregularity, suggesting the use of a combination of ns-PEFs with μs-PEFs to target the nuclear and cell membranes. We demonstrate that ns + μs pulses can significantly enhance the fluorescence dissipation of the cell and nuclear membranes. Overall, our findings indicate that ns + μs pulses may be useful in the effective killing of irregular cells.
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9
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Haberkorn I, Buchmann L, Hiestand M, Mathys A. Continuous nanosecond pulsed electric field treatments foster the upstream performance of Chlorella vulgaris-based biorefinery concepts. BIORESOURCE TECHNOLOGY 2019; 293:122029. [PMID: 31473378 DOI: 10.1016/j.biortech.2019.122029] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/07/2019] [Revised: 08/14/2019] [Accepted: 08/16/2019] [Indexed: 06/10/2023]
Abstract
Nanosecond pulsed electric field treatment (nsPEF) is an innovative, technology-driven, and resource-efficient approach to foster the upstream performance of microalgae-based biorefinery concepts to transform microalgae into economic more viable raw materials for the biobased industry. A processing window applying three treatments of 100 ns, 5 Hz, and 10 kV cm-1 to industrially relevant phototrophic Chlorella vulgaris in the early exponential growth phase significantly increased biomass yields by up to 17.53 ± 10.46% (p = 3.18 × 10-5). Treatments had limited effects on the carbon and pigment contents, but the protein content was decreased. The longest possible pulse width (100 ns) resulted in the highest biomass yield indicating underlying working mechanisms of enhanced cell proliferation based on intracellular and plasma membrane-related effects. The applicability to eukaryotes and prokaryotes, such as C. vulgaris and cyanobacteria highlights the possible impacts of nsPEF across multiple domains of the biobased industry relying on single-cell-based value-chains.
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Affiliation(s)
- Iris Haberkorn
- ETH Zurich, Department of Health Sciences and Technology, Institute of Food, Nutrition and Health, Sustainable Food Processing Laboratory, Schmelzbergstrasse 9, Zurich 8092, Switzerland
| | - Leandro Buchmann
- ETH Zurich, Department of Health Sciences and Technology, Institute of Food, Nutrition and Health, Sustainable Food Processing Laboratory, Schmelzbergstrasse 9, Zurich 8092, Switzerland
| | - Michèle Hiestand
- ETH Zurich, Department of Health Sciences and Technology, Institute of Food, Nutrition and Health, Sustainable Food Processing Laboratory, Schmelzbergstrasse 9, Zurich 8092, Switzerland
| | - Alexander Mathys
- ETH Zurich, Department of Health Sciences and Technology, Institute of Food, Nutrition and Health, Sustainable Food Processing Laboratory, Schmelzbergstrasse 9, Zurich 8092, Switzerland.
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10
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Chen G, Huang K, Miao M, Feng B, Campanella OH. Molecular Dynamics Simulation for Mechanism Elucidation of Food Processing and Safety: State of the Art. Compr Rev Food Sci Food Saf 2018; 18:243-263. [PMID: 33337012 DOI: 10.1111/1541-4337.12406] [Citation(s) in RCA: 40] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2018] [Revised: 10/07/2018] [Accepted: 10/10/2018] [Indexed: 12/14/2022]
Abstract
Molecular dynamics (MD) simulation is a useful technique to study the interaction between molecules and how they are affected by various processes and processing conditions. This review summarizes the application of MD simulations in food processing and safety, with an emphasis on the effects that emerging nonthermal technologies (for example, high hydrostatic pressure, pulsed electric field) have on the molecular and structural characteristics of foods and biomaterials. The advances and potential projection of MD simulations in the science and engineering aspects of food materials are discussed and focused on research work conducted to study the effects of emerging technologies on food components. It is expected by showing key case studies that it will stir novel developments as a valuable tool to study the effects of emerging food technologies on biomaterials. This review is useful to food researchers and the food industry, as well as researchers and practitioners working on flavor and nutraceutical encapsulations, dietary carbohydrate product developments, modified starches, protein engineering, and other novel food applications.
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Affiliation(s)
- Gang Chen
- School of Food Science and Technology, Henan Univ. of Technology, 100 Lianhua St., Zhengzhou 450001, Henan, P. R. China.,State Key Laboratory of Food Science and Technology, Jiangnan Univ., 1800 Lihu Ave., Wuxi, 214122, Jiangsu, P. R. China
| | - Kai Huang
- State Key Laboratory of Food Science and Technology, Jiangnan Univ., 1800 Lihu Ave., Wuxi, 214122, Jiangsu, P. R. China
| | - Ming Miao
- State Key Laboratory of Food Science and Technology, Jiangnan Univ., 1800 Lihu Ave., Wuxi, 214122, Jiangsu, P. R. China
| | - Biao Feng
- State Key Laboratory of Food Science and Technology, Jiangnan Univ., 1800 Lihu Ave., Wuxi, 214122, Jiangsu, P. R. China
| | - Osvaldo H Campanella
- State Key Laboratory of Food Science and Technology, Jiangnan Univ., 1800 Lihu Ave., Wuxi, 214122, Jiangsu, P. R. China.,Agricultural and Biological Engineering, and Dept. of Food Science, Whistler Center for Carbohydrate Research, Purdue Univ., 745 Agriculture Mall Dr., West Lafayette, IN, 47906, U.S.A
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11
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Li C, Ke Q, Yao C, Mi Y, Liu H, Lv Y, Yao C. Cell electrofusion based on nanosecond/microsecond pulsed electric fields. PLoS One 2018; 13:e0197167. [PMID: 29795594 PMCID: PMC5967737 DOI: 10.1371/journal.pone.0197167] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2017] [Accepted: 04/27/2018] [Indexed: 11/19/2022] Open
Abstract
Traditionally, microsecond pulsed electric field was widely used in cell electrofusion technology. However, it was difficult to fuse the cells with different sizes. Because the effect of electroporation based on microsecond pulses was greatly influenced by cell sizes. It had been reported that the differences between cell sizes can be ignored when cells were exposed to nanosecond pulses. However, pores induced by those short nanosecond pulses tended to be very small (0.9 nm) and the pores were more easy to recover. In this work, a finite element method was used to simulate the distribution, radius and density of the pores. The innovative idea of "cell electrofusion based on nanosecond/microsecond pulses" was proposed in order to combine the advantages of nanosecond pulses and microsecond pulses. The model consisted of two contact cells with different sizes. Three kinds of pulsed electric fields were made up of two 100-ns, 10-kV/cm pulses; two 10-μs, 1-kV/cm pulses; and a sequence of a 100-ns, 10-kV/cm pulse, followed by a 10-μs, 1-kV/cm pulse. Some obvious advantageous can be found when nanosecond/microsecond pulses were considered. The pore radius was large enough (70nm) and density was high (5×1013m-2) in the cell junction area. Moreover, pores in the non-contact area of the cell membrane were small (1-10 nm) and sparse (109-1012m-2). Areas where the transmembrane voltage was higher than 1V were only concentrated in the cell junction. The transmembrane voltage of other areas were at most 0.6V when we tested the rest of the cell membrane. Cell fusion efficiency can be improved remarkably because electroporation was concentrated in the cell contact area.
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Affiliation(s)
- Chengxiang Li
- The State Key Laboratory of Power Transmission Equipment & System Security and New Technology, School of Electrical Engineering, Chongqing University, Chongqing, China
| | - Qiang Ke
- The State Key Laboratory of Power Transmission Equipment & System Security and New Technology, School of Electrical Engineering, Chongqing University, Chongqing, China
| | - Chenguo Yao
- The State Key Laboratory of Power Transmission Equipment & System Security and New Technology, School of Electrical Engineering, Chongqing University, Chongqing, China
| | - Yan Mi
- The State Key Laboratory of Power Transmission Equipment & System Security and New Technology, School of Electrical Engineering, Chongqing University, Chongqing, China
| | - Hongmei Liu
- The State Key Laboratory of Power Transmission Equipment & System Security and New Technology, School of Electrical Engineering, Chongqing University, Chongqing, China
| | - Yanpeng Lv
- The State Key Laboratory of Power Transmission Equipment & System Security and New Technology, School of Electrical Engineering, Chongqing University, Chongqing, China
| | - Cheng Yao
- The State Key Laboratory of Power Transmission Equipment & System Security and New Technology, School of Electrical Engineering, Chongqing University, Chongqing, China
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12
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Atomistic Simulations of Electroporation of Model Cell Membranes. ADVANCES IN ANATOMY EMBRYOLOGY AND CELL BIOLOGY 2018; 227:1-15. [PMID: 28980037 DOI: 10.1007/978-3-319-56895-9_1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
Electroporation is a phenomenon that modifies the fundamental function of the cell since it perturbs transiently or permanently the integrity of its membrane. Today, this technique is applied in fields ranging from biology and biotechnology to medicine, e.g., for drug and gene delivery into cells, tumor therapy, etc., in which it made it to preclinical and clinical treatments. Experimentally, due to the complexity and heterogeneity of cell membranes, it is difficult to provide a description of the electroporation phenomenon in terms of atomically resolved structural and dynamical processes, a prerequisite to optimize its use. Atomistic modeling in general and molecular dynamics (MD) simulations in particular have proven to be an effective approach for providing such a level of detail. This chapter provides the reader with a comprehensive account of recent advances in using such a technique to complement conventional experimental approaches in characterizing several aspects of cell membranes electroporation.
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13
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Schoenbach KH. From the basic science of biological effects of ultrashort electrical pulses to medical therapies. Bioelectromagnetics 2018. [DOI: 10.1002/bem.22117] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Affiliation(s)
- Karl H. Schoenbach
- Frank Reidy Research Center for Bioelectrics; Old Dominion University; Norfolk Virginia
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14
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Delivery devices for exposure of biological cells to nanosecond pulsed electric fields. Med Biol Eng Comput 2017; 56:85-97. [PMID: 28674780 DOI: 10.1007/s11517-017-1676-0] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2016] [Accepted: 06/25/2017] [Indexed: 12/11/2022]
Abstract
In this paper, delivery devices for nanosecond pulsed electric field exposure of biological samples in direct contact with electrodes or isolated are presented and characterized. They are based on a modified electroporation cuvette and two transverse electromagnetic cells (TEM cells). The devices were used to apply pulses with high intensity (4.5 kV) and short durations (3 and 13 ns). The delivery devices were electromagnetically characterized in the frequency and time domains. Field intensities of around 5, 0.5, and 12 MV m-1 were obtained by numerical simulations of the biological sample positioned in the three delivery devices. Two delivery systems had a homogenous electric field spatial distribution, and one was adapted to permit a highly localized exposure in the vicinity of a needle. Experimental biological investigations were carried out at different field intensities for five cancer cell lines. The results using flow cytometry showed that cells kept polarized mitochondrial membrane but lost plasma membrane integrity following a dose-response trend after exposure to different electric field intensities. Certain cell types (U87, MCF7) showed higher sensitivities to nsPEFs than other lines tested.
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15
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Yusupov M, Van der Paal J, Neyts E, Bogaerts A. Synergistic effect of electric field and lipid oxidation on the permeability of cell membranes. Biochim Biophys Acta Gen Subj 2017; 1861:839-847. [DOI: 10.1016/j.bbagen.2017.01.030] [Citation(s) in RCA: 99] [Impact Index Per Article: 14.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2016] [Revised: 12/25/2016] [Accepted: 01/26/2017] [Indexed: 11/29/2022]
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16
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Draz MS, Wang YJ, Chen FF, Xu Y, Shafiee H. Electrically Oscillating Plasmonic Nanoparticles for Enhanced DNA Vaccination against Hepatitis C Virus. ADVANCED FUNCTIONAL MATERIALS 2017; 27:1604139. [PMID: 29180949 PMCID: PMC5701658 DOI: 10.1002/adfm.201604139] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/19/2023]
Abstract
The promise of DNA vaccines is far-reaching. However, the development of potent immunization methods remains a key challenge for its use in clinical applications. Here, an approach for in vivo DNA vaccination by electrically activated plasmonic Au nanoparticles is reported. The electrical excitation of plasmonic nanoparticles can drive vibrational and dipole-like oscillations that are able to disrupt nearby cell membranes. In combination with their intrinsic ability to focus and magnify the electric field on the surface of cells, Au nanoparticles allow enhanced cell poration and facilitate the uptake of DNA vaccine. Mice immunized with this approach showed up to 100-fold higher gene expression compared to control treatments (without nanoparticles) and exhibited significantly increased levels of both antibody and cellular immune responses against a model hepatitis C virus DNA vaccine. This approach can be tuned to establish controlled and targeted delivery of different types of therapeutic molecules into cells and live animals as well.
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Affiliation(s)
- Mohamed Shehata Draz
- Division of Engineering in Medicine, Department of Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, MA 02115, USA. Faculty of Science Tanta University Tanta 31527, Egypt. State Key Laboratory for Diagnosis and Treatment of Infectious Diseases, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, The First Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou, Zhejiang 310003, P. R. China
| | - Ying-Jie Wang
- State Key Laboratory for Diagnosis and Treatment of Infectious Diseases, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, The First Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou, Zhejiang 310003, P. R. China
| | - Frank Fanqing Chen
- Life Sciences Division, Lawrence Berkeley National Laboratory, Mailstop 977, 1 Cyclotron Road, Berkeley, CA 94720, USA
| | - Yuhong Xu
- School of Pharmacy, Shanghai Jiao Tong University, Shanghai 200240, P. R. China
| | - Hadi Shafiee
- Division of Engineering in Medicine, Department of Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, MA 02115, USA. Department of Medicine, Harvard Medical School, Boston, MA 02115, USA
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17
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Casciola M, Tarek M. A molecular insight into the electro-transfer of small molecules through electropores driven by electric fields. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 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] [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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18
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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] [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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19
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Trainito C, Français O, Le Pioufle B. Analysis of pulsed electric field effects on cellular tissue with Cole–Cole model: Monitoring permeabilization under inhomogeneous electrical field with bioimpedance parameter variations. INNOV FOOD SCI EMERG 2015. [DOI: 10.1016/j.ifset.2015.02.004] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
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20
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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] [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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21
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Sridhara V, Joshi R. Evaluations of a mechanistic hypothesis for the influence of extracellular ions on electroporation due to high-intensity, nanosecond pulsing. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2014; 1838:1793-800. [DOI: 10.1016/j.bbamem.2014.03.010] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/27/2013] [Revised: 03/17/2014] [Accepted: 03/18/2014] [Indexed: 10/25/2022]
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22
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Miklavčič D, Mali B, Kos B, Heller R, Serša G. Electrochemotherapy: from the drawing board into medical practice. Biomed Eng Online 2014; 13:29. [PMID: 24621079 PMCID: PMC3995705 DOI: 10.1186/1475-925x-13-29] [Citation(s) in RCA: 240] [Impact Index Per Article: 24.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2013] [Accepted: 03/04/2014] [Indexed: 12/14/2022] Open
Abstract
Electrochemotherapy is a local treatment of cancer employing electric pulses to improve transmembrane transfer of cytotoxic drugs. In this paper we discuss electrochemotherapy from the perspective of biomedical engineering and review the steps needed to move such a treatment from initial prototypes into clinical practice. In the paper also basic theory of electrochemotherapy and preclinical studies in vitro and in vivo are briefly reviewed. Following this we present a short review of recent clinical publications and discuss implementation of electrochemotherapy into standard of care for treatment of skin tumors, and use of electrochemotherapy for other targets such as head and neck cancer, deep-seated tumors in the liver and intestinal tract, and brain metastases. Electrodes used in these specific cases are presented with their typical voltage amplitudes used in electrochemotherapy. Finally, key points on what should be investigated in the future are presented and discussed.
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Affiliation(s)
- Damijan Miklavčič
- Faculty of electrical Engineering, Department of Biomedical Engineering, University of Ljubljana, Trzaska 25, Ljubljana SI-1000, Slovenia.
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23
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Tolstykh GP, Beier HT, Roth CC, Thompson GL, Payne JA, Kuipers MA, Ibey BL. Activation of intracellular phosphoinositide signaling after a single 600 nanosecond electric pulse. Bioelectrochemistry 2013; 94:23-9. [DOI: 10.1016/j.bioelechem.2013.05.002] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2013] [Revised: 03/10/2013] [Accepted: 05/13/2013] [Indexed: 02/03/2023]
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24
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Villanueva DY, Lim JB, Klauda JB. Influence of ester-modified lipids on bilayer structure. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2013; 29:14196-14203. [PMID: 24156542 DOI: 10.1021/la403919h] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
Lipid membranes function as barriers for cells to prevent unwanted chemicals from entering the cell and wanted chemicals from leaving. Because of their hydrophobic interior, membranes do not allow water to penetrate beyond the headgroup region. We performed molecular simulations to examine the effects of ester-modified lipids, which contain ester groups along their hydrocarbon chains, on bilayer structure. We chose two lipids from those presented in Menger et al. [J. Am. Chem. Soc. 2006, 128, 14034] with ester groups in (1) the upper half of the lipid chain (MEPC) and (2) the middle and end of the lipid chain (MGPC). MGPC (30%)/POPC bilayers formed stable water pores of diameter 5-7 Å, but MGPC (22%)/POPC and MEPC (30%)/POPC bilayers did not form these defects. These pores were similar to those formed during electroporation; i.e., the head groups lined the pore and allowed water and ions to transport across the bilayer. However, we found that lateral organization of the MGPC lipids into clusters, instead of an electric field or charge disparity as in electroporation, was essential for pore formation. On the basis of this, we propose an overall mechanism for pore formation. The similarities between the ester-modified lipids and byproducts of lipid peroxidation with multiple hydrophilic groups in the middle of the chain suggest that free radical reactions with unsaturated lipids and sterols result in fundamental changes that may be similar to what is seen in bilayers with ester-modified lipids.
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Affiliation(s)
- Diana Y Villanueva
- Department of Chemical and Biomolecular Engineering, University of Maryland , College Park, Maryland 20742, United States
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25
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Marracino P, Migliorati M, Paffi A, Liberti M, Denzi A, d'Inzeo G, Apollonio F. Signal transduction on enzymes: the effect of electromagnetic field stimuli on superoxide dismutase (SOD). ANNUAL INTERNATIONAL CONFERENCE OF THE IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. ANNUAL INTERNATIONAL CONFERENCE 2013; 2012:5674-7. [PMID: 23367217 DOI: 10.1109/embc.2012.6347282] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Protein functions and characteristics can highly differ from physiological conditions in presence of chemical, mechanical or electromagnetic stimuli. In this work we provide a rigorous picture of electric field effects on proteins behavior investigating, at atomistic details, the possible ways in which an external signal can be transduced into biochemical effects. Results from molecular dynamics (MD) simulations of a single superoxidismutase (SOD) enzyme in presence of high exogenous alternate electric fields will be discussed.
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Affiliation(s)
- P Marracino
- Department of Information Engineering, Electronics and Telecomunications.
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26
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Xiao D, Yao C, Liu H, Li C, Cheng J, Guo F, Tang L. Irreversible electroporation and apoptosis in human liver cancer cells induced by nanosecond electric pulses. Bioelectromagnetics 2013; 34:512-20. [PMID: 23740887 DOI: 10.1002/bem.21796] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2012] [Accepted: 04/18/2013] [Indexed: 02/06/2023]
Abstract
The goal of this study was to assess the effect of nanosecond electric pulses on HepG2 human liver cancer cells. Electric pulses with a high strength of 10 kV/cm, duration of 500 ns and frequency of 1 Hz were applied to the cells. After delivery of electric pulses, apoptosis, intracellular calcium ion concentrations, transmembrane mitochondrial potentials, electropermeabilization and recovery from electropermeabilization in cells were investigated. The results showed that electric pulse treatment for 20 s and more could trigger apoptosis in cells. Real-time observation indicated an immediate increase in intracellular calcium ion concentration and a dramatic decrease in mitochondrial membrane potential in cells responding to electric pulses. In subsequent experiments, propidium iodide uptake in cells emerged after exposure to electric pulses, indicating electropermeabilization of the cell membrane. Furthermore, recovery from electropermeabilization was not observed even 4 h after the stimulation, demonstrating that irreversible electropermeabilization was induced by electric pulses. In conclusion, electric pulses with a high strength and nanosecond duration can damage cancer cells, accompanied by a series of intracellular changes, providing strong evidence for the application of electric pulses in cancer treatment.
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Affiliation(s)
- Deyou Xiao
- Key Laboratory of Biorheological Science and Technology, Ministry of Education, College of Bioengineering, Chongqing University, Chongqing, China
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27
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Min Y, Yang Y, Poojari Y, Liu Y, Wu JC, Hansford DJ, Epstein AJ. Sulfonated Polyaniline-Based Organic Electrodes for Controlled Electrical Stimulation of Human Osteosarcoma Cells. Biomacromolecules 2013; 14:1727-31. [DOI: 10.1021/bm301221t] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Affiliation(s)
- Yong Min
- Institute of Advanced
Materials, Nanjing University of Posts and Telecommunications, Nanjing 210046, People’s
Republic of China
| | | | | | - Yidong Liu
- Institute of Advanced
Materials, Nanjing University of Posts and Telecommunications, Nanjing 210046, People’s
Republic of China
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28
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Tokman M, Lee JH, Levine ZA, Ho MC, Colvin ME, Vernier PT. Electric field-driven water dipoles: nanoscale architecture of electroporation. PLoS One 2013; 8:e61111. [PMID: 23593404 PMCID: PMC3623848 DOI: 10.1371/journal.pone.0061111] [Citation(s) in RCA: 71] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2012] [Accepted: 03/05/2013] [Indexed: 12/02/2022] Open
Abstract
Electroporation is the formation of permeabilizing structures in the cell membrane under the influence of an externally imposed electric field. The resulting increased permeability of the membrane enables a wide range of biological applications, including the delivery of normally excluded substances into cells. While electroporation is used extensively in biology, biotechnology, and medicine, its molecular mechanism is not well understood. This lack of knowledge limits the ability to control and fine-tune the process. In this article we propose a novel molecular mechanism for the electroporation of a lipid bilayer based on energetics analysis. Using molecular dynamics simulations we demonstrate that pore formation is driven by the reorganization of the interfacial water molecules. Our energetics analysis and comparisons of simulations with and without the lipid bilayer show that the process of poration is driven by field-induced reorganization of water dipoles at the water-lipid or water-vacuum interfaces into more energetically favorable configurations, with their molecular dipoles oriented in the external field. Although the contributing role of water in electroporation has been noted previously, here we propose that interfacial water molecules are the main players in the process, its initiators and drivers. The role of the lipid layer, to a first-order approximation, is then reduced to a relatively passive barrier. This new view of electroporation simplifies the study of the problem, and opens up new opportunities in both theoretical modeling of the process and experimental research to better control or to use it in new, innovative ways.
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Affiliation(s)
- Mayya Tokman
- School of Natural Sciences, University of California Merced, Merced, California, USA.
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29
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Linghu L, Tan Y, Lou Y, Hu L, Yang H, Yu T. Nanosecond electric pulses induce DNA breaks in cisplatin-sensitive and -resistant human ovarian cancer cells. Biochem Biophys Res Commun 2013; 430:695-9. [DOI: 10.1016/j.bbrc.2012.11.089] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2012] [Accepted: 11/20/2012] [Indexed: 01/25/2023]
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30
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Breton M, Delemotte L, Silve A, Mir LM, Tarek M. Transport of siRNA through Lipid Membranes Driven by Nanosecond Electric Pulses: An Experimental and Computational Study. J Am Chem Soc 2012; 134:13938-41. [DOI: 10.1021/ja3052365] [Citation(s) in RCA: 78] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Marie Breton
- Université Paris-Sud, Laboratoire de Vectorologie et Thérapeutiques
Anticancéreuses, UMR 8203, Orsay F-91405, France
- CNRS,
Laboratoire de Vectorologie et Thérapeutiques Anticancéreuses,
UMR 8203, Orsay F-91405, France
- Institut Gustave Roussy, Laboratoire de Vectorologie et Thérapeutiques
Anticancéreuses, UMR 8203, Villejuif F-94805, France
| | - Lucie Delemotte
- Université de Lorraine, UMR Structure et Réactivité
des Systèmes Moléculaires Complexes, CNRS, Nancy 54003,
France
| | - Aude Silve
- Université Paris-Sud, Laboratoire de Vectorologie et Thérapeutiques
Anticancéreuses, UMR 8203, Orsay F-91405, France
- CNRS,
Laboratoire de Vectorologie et Thérapeutiques Anticancéreuses,
UMR 8203, Orsay F-91405, France
- Institut Gustave Roussy, Laboratoire de Vectorologie et Thérapeutiques
Anticancéreuses, UMR 8203, Villejuif F-94805, France
| | - Lluis M. Mir
- Université Paris-Sud, Laboratoire de Vectorologie et Thérapeutiques
Anticancéreuses, UMR 8203, Orsay F-91405, France
- CNRS,
Laboratoire de Vectorologie et Thérapeutiques Anticancéreuses,
UMR 8203, Orsay F-91405, France
- Institut Gustave Roussy, Laboratoire de Vectorologie et Thérapeutiques
Anticancéreuses, UMR 8203, Villejuif F-94805, France
| | - Mounir Tarek
- Université de Lorraine, UMR Structure et Réactivité
des Systèmes Moléculaires Complexes, CNRS, Nancy 54003,
France
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31
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Molecular Dynamics Simulations of Lipid Membrane Electroporation. J Membr Biol 2012; 245:531-43. [DOI: 10.1007/s00232-012-9434-6] [Citation(s) in RCA: 101] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2011] [Accepted: 04/30/2012] [Indexed: 10/28/2022]
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32
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Joshi RP, Hu Q. Case for applying subnanosecond high-intensity, electrical pulses to biological cells. IEEE Trans Biomed Eng 2012; 58:2860-6. [PMID: 21937300 DOI: 10.1109/tbme.2011.2161478] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
In this paper, model analysis into the time-dependent transmembrane potential at the outer cell membrane is presented, for applied high-intensity electric pulses having durations in the nanosecond range or smaller. It is argued that the frequency-dependent dielectric response of cell membranes could be used to advantage for stronger bioeffects by employing shorter pulses. Our model calculations predict faster transmembrane voltages and larger electroporation densities for a given external energy with pulse durations in the subnanosecond regime. This temporal regime would be used, for example, in the electrotherapy of mixed cell ensembles having different dielectric response properties.
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Affiliation(s)
- Ravindra P Joshi
- Department of Electrical and Computer Engineering, Old Dominion University, Norfolk, VA 23529-0246, USA.
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33
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Camera F, Paffi A, Merla C, Denzi A, Apollonio F, Marracino P, d'Inzeo G, Liberti M. Effects of nanosecond pulsed electric fields on the activity of a Hodgkin and Huxley neuron model. ANNUAL INTERNATIONAL CONFERENCE OF THE IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. ANNUAL INTERNATIONAL CONFERENCE 2012; 2012:2567-2570. [PMID: 23366449 DOI: 10.1109/embc.2012.6346488] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
The cell membrane poration is one of the main assessed biological effects of nanosecond pulsed electric fields (nsPEF). This structural change of the cell membrane appears soon after the pulse delivery and lasts for a time period long enough to modify the electrical activity of excitable membranes in neurons. Inserting such a phenomenon in a Hodgkin and Huxley neuron model by means of an enhanced time varying conductance resulted in the temporary inhibition of the action potential generation. The inhibition time is a function of the level of poration, the pore resealing time and the background stimulation level of the neuron. Such results suggest that the neuronal activity may be efficiently modulated by the delivery of repeated pulses. This opens the way to the use of nsPEFs as a stimulation technique alternative to the conventional direct electric stimulation for medical applications such as chronic pain treatment.
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Affiliation(s)
- F Camera
- Italian Inter-University Centre for the Study of Electromagnetic Fields and Bio-systems (ICEmB) at Sapienza University of Rome, Rome 00184, Italy
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34
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Plasma membrane charging of Jurkat cells by nanosecond pulsed electric fields. EUROPEAN BIOPHYSICS JOURNAL: EBJ 2011; 40:947-57. [PMID: 21594746 DOI: 10.1007/s00249-011-0710-7] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/12/2011] [Revised: 04/13/2011] [Accepted: 04/28/2011] [Indexed: 02/03/2023]
Abstract
The initial effect of nanosecond pulsed electric fields (nsPEFs) on cells is a change of charge distributions along membranes. This first response is observed as a sudden shift in the plasma transmembrane potential that is faster than can be attributed to any physiological event. These immediate, yet transient, effects are only measurable if the diagnostic is faster than the exposure, i.e., on a nanosecond time scale. In this study, we monitored changes in the plasma transmembrane potential of Jurkat cells exposed to nsPEFs of 60 ns and amplitudes from 5 to 90 kV/cm with a temporal resolution of 5 ns by means of the fast voltage-sensitive dye Annine-6. The measurements suggest the contribution of both dipole effects and asymmetric conduction currents across opposite sides of the cell to the charging. With the application of higher field strengths the membrane charges until a threshold voltage value of 1.4-1.6 V is attained at the anodic pole. This indicates when the ion exchange rates exceed charging currents, thus providing strong evidence for pore formation. Prior to reaching this threshold, the time for the charging of the membrane by conductive currents is qualitatively in agreement with accepted models of membrane charging, which predict longer charging times for lower field strengths. The comparison of the data with previous studies suggests that the sub-physiological induced ionic imbalances may trigger other intracellular signaling events leading to dramatic outcomes, such as apoptosis.
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35
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Arena CB, Sano MB, Rylander MN, Davalos RV. Theoretical considerations of tissue electroporation with high-frequency bipolar pulses. IEEE Trans Biomed Eng 2011; 58:1474-82. [PMID: 21189230 DOI: 10.1109/tbme.2010.2102021] [Citation(s) in RCA: 89] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
This study introduces the use of high-frequency pulsed electric fields for tissue electroporation. Through the development of finite element models and the use of analytical techniques, electroporation with rectangular, bipolar pulses is investigated. The electric field and temperature distribution along with the associated transmembrane potential development are considered in a heterogeneous skin fold geometry. Results indicate that switching polarity on the nanosecond scale near the charging time of plasma membranes can greatly improve treatment outcomes in heterogeneous tissues. Specifically, high-frequency fields ranging from 500 kHz to 1 MHz are best suited to penetrate epithelial layers without inducing significant Joule heating, and cause electroporation in underlying cells.
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Affiliation(s)
- Christopher B Arena
- Virginia Tech-Wake Forest School of Biomedical Engineering and Sciences, Bioelectromechanical Systems Laboratory, Virginia Polytechnic Institute and State University, Blacksburg, VA 24061, USA.
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36
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Synergistic effects of local temperature enhancements on cellular responses in the context of high-intensity, ultrashort electric pulses. Med Biol Eng Comput 2011; 49:713-8. [PMID: 21340640 DOI: 10.1007/s11517-011-0745-z] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2010] [Accepted: 01/27/2011] [Indexed: 10/18/2022]
Abstract
Results of self-consistent analyses of cells show the possibility of temperature increases at membranes in response to a single nanosecond, high-voltage pulse, at least over small sections of the membrane. Molecular Dynamics simulations indicate that such a temperature increase could facilitate poration, which is one example of a bio-process at the plasma membrane. Our study thus suggests that the use of repetitive high-intensity voltage pulses could open up possibilities for a host of synergistic bio-responses involving both thermal and electrically driven phenomena.
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37
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Merla C, Paffi A, Apollonio F, Leveque P, d'Inzeo G, Liberti M. Microdosimetry for nanosecond pulsed electric field applications: a parametric study for a single cell. IEEE Trans Biomed Eng 2011; 58:1294-302. [PMID: 21216699 DOI: 10.1109/tbme.2010.2104150] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
A microdosimetric study of nanosecond pulsed electric fields, including dielectric dispersivity of cell compartments, is proposed in our paper. A quasi-static solution based on the Laplace equation was adapted to wideband signals and used to address the problem of electric field estimation at cellular level. The electric solution was coupled with an asymptotic electroporation model able to predict membrane pore density. An initial result of our paper is the relevance of the dielectric dispersivity, providing evidence that both the transmembrane potential and the pore density are strongly influenced by the choice of modeling used. We note the crucial role played by the dielectric properties of the membrane that can greatly impact on the poration of the cell. This can partly explain the selective action reported on cancerous cells in mixed populations, if one considers that tumor cells may present different dielectric responses. Moreover, these kinds of studies can be useful to determine the appropriate setting of nsPEF generators as well as for the design and optimization of new-generation devices.
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Affiliation(s)
- Caterina Merla
- Italian Inter-University Center for the Study of Electromagnetic Fields and BioSystems (ICEmB) at ENEA, Italian Agency for New Technologies, Energy and Sustainable Economic Development, Rome 00123, Italy.
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38
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Gurtovenko AA, Anwar J, Vattulainen I. Defect-Mediated Trafficking across Cell Membranes: Insights from in Silico Modeling. Chem Rev 2010; 110:6077-103. [DOI: 10.1021/cr1000783] [Citation(s) in RCA: 158] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Affiliation(s)
- Andrey A. Gurtovenko
- Institute of Macromolecular Compounds, Russian Academy of Sciences, Bolshoi Prospect 31, V.O., St. Petersburg, 199004 Russia, Computational Laboratory, Institute of Pharmaceutical Innovation, University of Bradford, Bradford, West Yorkshire BD7 1DP, U.K., Department of Physics, Tampere University of Technology, P.O. Box 692, FI-33101 Tampere, Finland, Aalto University, School of Science and Technology, Finland, and MEMPHYS—Center for Biomembrane Physics, University of Southern Denmark, Odense, Denmark
| | - Jamshed Anwar
- Institute of Macromolecular Compounds, Russian Academy of Sciences, Bolshoi Prospect 31, V.O., St. Petersburg, 199004 Russia, Computational Laboratory, Institute of Pharmaceutical Innovation, University of Bradford, Bradford, West Yorkshire BD7 1DP, U.K., Department of Physics, Tampere University of Technology, P.O. Box 692, FI-33101 Tampere, Finland, Aalto University, School of Science and Technology, Finland, and MEMPHYS—Center for Biomembrane Physics, University of Southern Denmark, Odense, Denmark
| | - Ilpo Vattulainen
- Institute of Macromolecular Compounds, Russian Academy of Sciences, Bolshoi Prospect 31, V.O., St. Petersburg, 199004 Russia, Computational Laboratory, Institute of Pharmaceutical Innovation, University of Bradford, Bradford, West Yorkshire BD7 1DP, U.K., Department of Physics, Tampere University of Technology, P.O. Box 692, FI-33101 Tampere, Finland, Aalto University, School of Science and Technology, Finland, and MEMPHYS—Center for Biomembrane Physics, University of Southern Denmark, Odense, Denmark
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39
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Bowman AM, Nesin OM, Pakhomova ON, Pakhomov AG. Analysis of plasma membrane integrity by fluorescent detection of Tl(+) uptake. J Membr Biol 2010; 236:15-26. [PMID: 20623351 DOI: 10.1007/s00232-010-9269-y] [Citation(s) in RCA: 133] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2009] [Accepted: 06/11/2010] [Indexed: 02/03/2023]
Abstract
The exclusion of polar dyes by healthy cells is widely employed as a simple and reliable test for cell membrane integrity. However, commonly used dyes (propidium, Yo-Pro-1, trypan blue) cannot detect membrane defects which are smaller than the dye molecule itself, such as nanopores that form by exposure to ultrashort electric pulses (USEPs). Instead, here we demonstrate that opening of nanopores can be efficiently detected and studied by fluorescent measurement of Tl(+) uptake. Various mammalian cells (CHO, GH3, NG108), loaded with a Tl(+)-sensitive fluorophore FluxOR and subjected to USEPs in a Tl(+)-containing bath buffer, displayed an immediate (within <100 ms), dose-dependent surge of fluorescence. In all tested cell lines, the threshold for membrane permeabilization to Tl(+) by 600-ns USEP was at 1-2 kV/cm, and the rate of Tl(+) uptake increased linearly with increasing the electric field. The lack of concurrent entry of larger dye molecules suggested that the size of nanopores is less than 1-1.5 nm. Tested ion channel inhibitors as well as removal of the extracellular Ca(2+) did not block the USEP effect. Addition of a Tl(+)-containing buffer within less than 10 min after USEP also caused a fluorescence surge, which confirms the minutes-long lifetime of nanopores. Overall, the technique of fluorescent detection of Tl(+) uptake proved highly effective, noninvasive and sensitive for visualization and analysis of membrane defects which are too small for conventional dye uptake detection methods.
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Affiliation(s)
- Angela M Bowman
- Frank Reidy Research Center for Bioelectrics, Old Dominion University, 4211 Monarch Way, Suite 320, Norfolk, VA 23508, USA
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40
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Beebe SJ, Schoenbach KH. Nanosecond pulsed electric fields: a new stimulus to activate intracellular signaling. J Biomed Biotechnol 2010; 2005:297-300. [PMID: 16489262 PMCID: PMC1361491 DOI: 10.1155/jbb.2005.297] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Affiliation(s)
- Stephen J. Beebe
- Frank Reidy Research Center for Bioelectrics, Eastern
Virginia Medical School and Old Dominion University,
Norfolk, VA 23510, USA
- *Philippe H. Beaune:
| | - Karl H. Schoenbach
- Frank Reidy Research Center for Bioelectrics, Eastern
Virginia Medical School and Old Dominion University,
Norfolk, VA 23510, USA
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41
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Hu Q, Fadiran O, Li W, Joshi RP. Dielectrophoresis and Electrorotation of Spheroidal Cells after nsPEF Induced Electroporation. ACTA ACUST UNITED AC 2010. [DOI: 10.1109/icbbe.2010.5514999] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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42
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Tang L, Yao C, Sun C. Apoptosis induction with electric pulses - a new approach to cancer therapy with drug free. Biochem Biophys Res Commun 2009; 390:1098-101. [PMID: 19853584 DOI: 10.1016/j.bbrc.2009.10.092] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2009] [Accepted: 10/16/2009] [Indexed: 02/03/2023]
Abstract
Electrical pulses have been widely used in biomedical fields, whose applications depend on the parameters such as durations and electric intensity. Conventional electroporation (0.1-1kV/cm, 100micros) has been used in cell fusion, transfection and electrochemotherapy. Recent studies with high-intensity (MV/cm) electric field applications with durations of several tens of nanoseconds can affect intracellular signal transduction and intracellular structures with plasma intact, resulting in an application of intracellular manipulation. The most recent development is the finding that parameters between those two ranges could be used to induce apoptosis of cancer cells. Proposal of apoptosis induction and tumor inhibition has advantages to pursue the treatment of cancer free of cytotoxic drugs.
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Affiliation(s)
- Liling Tang
- State Key Laboratory of Power Transmission Equipment & System and New Technology, Chongqing University, Chongqing 400044, China.
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43
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Hu Q, Joshi R. Analysis of Intense, Subnanosecond Electrical Pulse-Induced Transmembrane Voltage in Spheroidal Cells With Arbitrary Orientation. IEEE Trans Biomed Eng 2009; 56:1617-26. [DOI: 10.1109/tbme.2009.2015459] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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44
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Portet T, Camps i Febrer F, Escoffre JM, Favard C, Rols MP, Dean DS. Visualization of membrane loss during the shrinkage of giant vesicles under electropulsation. Biophys J 2009; 96:4109-21. [PMID: 19450482 PMCID: PMC2712208 DOI: 10.1016/j.bpj.2009.02.063] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2008] [Revised: 02/20/2009] [Accepted: 02/20/2009] [Indexed: 11/26/2022] Open
Abstract
We study the effect of permeabilizing electric fields applied to two different types of giant unilamellar vesicles, the first formed from EggPC lipids and the second formed from DOPC lipids. Experiments on vesicles of both lipid types show a decrease in vesicle radius, which is interpreted as being due to lipid loss during the permeabilization process. We show that the decrease in size can be qualitatively explained as a loss of lipid area, which is proportional to the area of the vesicle that is permeabilized. Three possible modes of membrane loss were directly observed: pore formation, vesicle formation, and tubule formation.
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Affiliation(s)
- Thomas Portet
- Institut de Pharmacologie et de Biologie Structurale, Centre National de la Recherche Scientifique, UMR 5089
- Laboratoire de Physique Théorique, Centre National de la Recherche Scientifique, UMR 5152, Université Paul Sabatier, Toulouse, France
| | - Franc Camps i Febrer
- Institut de Pharmacologie et de Biologie Structurale, Centre National de la Recherche Scientifique, UMR 5089
| | - Jean-Michel Escoffre
- Institut de Pharmacologie et de Biologie Structurale, Centre National de la Recherche Scientifique, UMR 5089
| | - Cyril Favard
- Institut Fresnel, Centre National de la Recherche Scientifique, UMR 6133, Marseille, France
| | - Marie-Pierre Rols
- Institut de Pharmacologie et de Biologie Structurale, Centre National de la Recherche Scientifique, UMR 5089
| | - David S. Dean
- Laboratoire de Physique Théorique, Centre National de la Recherche Scientifique, UMR 5152, Université Paul Sabatier, Toulouse, France
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Scarlett SS, White JA, Blackmore PF, Schoenbach KH, Kolb JF. Regulation of intracellular calcium concentration by nanosecond pulsed electric fields. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2009; 1788:1168-75. [DOI: 10.1016/j.bbamem.2009.02.006] [Citation(s) in RCA: 79] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/02/2008] [Revised: 01/14/2009] [Accepted: 02/02/2009] [Indexed: 11/16/2022]
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46
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Wang S, Chen J, Chen MT, Vernier PT, Gundersen MA, Valderrábano M. Cardiac myocyte excitation by ultrashort high-field pulses. Biophys J 2009; 96:1640-8. [PMID: 19217879 DOI: 10.1016/j.bpj.2008.11.011] [Citation(s) in RCA: 57] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2008] [Accepted: 11/05/2008] [Indexed: 02/03/2023] Open
Abstract
In unexcitable, noncardiac cells, ultrashort (nanosecond) high-voltage (megavolt-per-meter) pulsed electrical fields (nsPEF) can mobilize intracellular Ca2+ and create transient nanopores in the plasmalemma. We studied Ca2+ responses to nsPEF in cardiac cells. Fluorescent Ca2+ or voltage signals were recorded from isolated adult rat ventricular myocytes deposited in an electrode microchamber and stimulated with conventional pulses (CPs; 0.5-2.4 kV/cm, 1 ms) or nsPEF (10-80 kV/cm, 4 ns). nsPEF induced Ca2+ transients in 68/104 cells. Repeating nsPEF increased the likelihood of Ca2+ transient induction (61.8% for <10 nsPEF vs. 80.6% for > or =10 nsPEF). Repetitive Ca2+ waves arising at the anodal side and Ca2+ destabilization occurred after repeated nsPEF (12/29) or during steady-state single nsPEF delivery at 2 Hz. Removing extracellular Ca2+ abolished responses to nsPEF. Verapamil did not affect nsPEF-induced Ca2+ transients, but decreased responses to CP. Tetrodotoxin and KB-R7943 increased the repetition threshold in response to nsPEF: 1-20 nsPEF caused local anodal Ca2+ waves without Ca2+ transients, and > or =20 nsPEF caused normal transients. Ryanodine-thapsigargin and caffeine protected against nsPEF-induced Ca2+ waves and showed less recovery of diastolic Ca2+ levels than CP. Voltage recordings demonstrated action potentials triggered by nsPEF, even in the presence of tetrodotoxin. nsPEF can mobilize intracellular Ca2+ in cardiac myocytes by inducing action potentials. Anodal Ca2+ waves and resistance to Na+ and Ca2+ channel blockade suggest nonselective ion channel transport via sarcolemmal nanopores as a triggering mechanism.
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Affiliation(s)
- Sufen Wang
- Division of Cardiac Electrophysiology, Department of Cardiology, The Methodist Hospital, Houston, Texas, USA
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47
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Hu Q, Joshi RP. Transmembrane voltage analyses in spheroidal cells in response to an intense ultrashort electrical pulse. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2009; 79:011901. [PMID: 19257063 DOI: 10.1103/physreve.79.011901] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/12/2008] [Revised: 10/09/2008] [Indexed: 05/27/2023]
Abstract
Self-consistent evaluations of both the transmembrane potential (TMP) and possible electroporation density across membrane of spheroidal cells in response to ultrashort, high-intensity pulses are reported and discussed. Most treatments in the literature have been based on spherical cells, and this represents a step towards more realistic analyses. The present study couples the Laplace equation with Smoluchowski theory of pore formation, to yield dynamic membrane conductivities that influence the TMP. It is shown that the TMP induced by pulsed external voltages can be substantial higher in oblate spheroids as compared to spherical or prolate spheroidal cells. Flattening of the surface area in oblate spheroids leads to both higher electric fields seen by the membrane, and allows a great fraction of the surface area to be porated. This suggests that biomedical applications such as drug delivery and electrochemotherapy could work best for flatter-shaped cells, and secondary field-enabled orienting would be beneficial. Results for arbitrary field orientations and different cell sizes have also been presented.
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Affiliation(s)
- Q Hu
- Department of Engineering and Technology, Central Michigan University, Mt Pleasant, Michigan 48859, USA
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48
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Ziegler MJ, Vernier PT. Interface Water Dynamics and Porating Electric Fields for Phospholipid Bilayers. J Phys Chem B 2008; 112:13588-96. [DOI: 10.1021/jp8027726] [Citation(s) in RCA: 102] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Affiliation(s)
- Matthew J. Ziegler
- Mork Family Department of Chemical Engineering and Materials Science, Viterbi School of Engineering, University of Southern California, Los Angeles, California 90089-0271, MOSIS, Information Sciences Institute, Viterbi School of Engineering, University of Southern California, Marina del Rey, California 90292-6695, and Ming Hsieh Department of Electrical Engineering-Electrophysics, Viterbi School of Engineering, University of Southern California, Los Angeles, California 90089-0271
| | - P. Thomas Vernier
- Mork Family Department of Chemical Engineering and Materials Science, Viterbi School of Engineering, University of Southern California, Los Angeles, California 90089-0271, MOSIS, Information Sciences Institute, Viterbi School of Engineering, University of Southern California, Marina del Rey, California 90292-6695, and Ming Hsieh Department of Electrical Engineering-Electrophysics, Viterbi School of Engineering, University of Southern California, Los Angeles, California 90089-0271
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49
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Kinetics, statistics, and energetics of lipid membrane electroporation studied by molecular dynamics simulations. Biophys J 2008; 95:1837-50. [PMID: 18469089 DOI: 10.1529/biophysj.108.129437] [Citation(s) in RCA: 194] [Impact Index Per Article: 12.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Membrane electroporation is the method to directly transfer bioactive substances such as drugs and genes into living cells, as well as preceding electrofusion. Although much information on the microscopic mechanism has been obtained both from experiment and simulation, the existence and nature of possible intermediates is still unclear. To elucidate intermediates of electropore formation by direct comparison with measured prepore formation kinetics, we have carried out 49 atomistic electroporation simulations on a palmitoyl-oleoyl-phosphatidylcholine bilayer for electric field strengths between 0.04 and 0.7 V/nm. A statistical theory is developed to facilitate direct comparison of experimental (macroscopic) prepore formation kinetics with the (single event) preporation times derived from the simulations, which also allows us to extract an effective number of lipids involved in each pore formation event. A linear dependency of the activation energy for prepore formation on the applied field is seen, with quantitative agreement between experiment and simulation. The distribution of preporation times suggests a four-state pore formation model. The model involves a first intermediate characterized by a differential tilt of the polar lipid headgroups on both leaflets, and a second intermediate (prepore), where a polar chain across the bilayer is formed by 3-4 lipid headgroups and several water molecules, thereby providing a microscopic explanation for the polarizable volume derived previously from the measured kinetics. An average pore radius of 0.47 +/- 0.15 nm is seen, in favorable agreement with conductance measurements and electrooptical experiments of lipid vesicles.
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50
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Joshi R, Mishra A, Jiahui Song, Pakhomov A, Schoenbach K. Simulation Studies of Ultrashort, High-Intensity Electric Pulse Induced Action Potential Block in Whole-Animal Nerves. IEEE Trans Biomed Eng 2008; 55:1391-8. [DOI: 10.1109/tbme.2007.912424] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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