1
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Zhang Y, Luo Z, Zhang Y, Guo F. Simulation study on electroporation of cancer cells in multicellular system. Bioelectrochemistry 2024; 160:108789. [PMID: 39128409 DOI: 10.1016/j.bioelechem.2024.108789] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2024] [Revised: 07/14/2024] [Accepted: 08/01/2024] [Indexed: 08/13/2024]
Abstract
Electroporation (EP) of the normal cell and cancer cell both in single-cell and multicellular models was investigated by the meshed transport network method (MTNM) in this paper. The simulation results suggest that the cancer cell undergoes faster and more significant local EP than that of the corresponding normal cell induced by nanosecond pulsed electric fields (nsPEFs) both in single-cell and multicellular models. Furthermore, the results of the multicellular model indicate that there is a unidirectional neighboring effect in the multicellular model, meaning that cells at the center are affected and their pore formation is significantly reduced, but this effect is very weak for cells at the edges of the system. This means that the electric field selectively kills cells in different distribution locations. This work can provide guidance for the selection of parameters for the cancer cell EP process.
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Affiliation(s)
- Yu Zhang
- Department of gynecology, Chongqing Traditional Chinese Medicine Hospital, Chongqing 400021, China.
| | - Zhijun Luo
- Institute of Ecological Safety, Chongqing University of Posts and Telecommunications, Chongqing 400065, China
| | - Yapeng Zhang
- Institute of Ecological Safety, Chongqing University of Posts and Telecommunications, Chongqing 400065, China
| | - Fei Guo
- Institute of Ecological Safety, Chongqing University of Posts and Telecommunications, Chongqing 400065, China.
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2
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Baker C, Willis A, Milestone W, Baker M, Garner AL, Joshi RP. Numerical assessments of geometry, proximity and multi-electrode effects on electroporation in mitochondria and the endoplasmic reticulum to nanosecond electric pulses. Sci Rep 2024; 14:23854. [PMID: 39394381 PMCID: PMC11470013 DOI: 10.1038/s41598-024-74659-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2023] [Accepted: 09/27/2024] [Indexed: 10/13/2024] Open
Abstract
Most simulations of electric field driven bioeffects have considered spherical cellular geometries or probed symmetrical structures for simplicity. This work assesses cellular transmembrane potential build-up and electroporation in a Jurkat cell that includes the endoplasmic reticulum (ER) and mitochondria, both of which have complex shapes, in response to external nanosecond electric pulses. The simulations are based on a time-domain nodal analysis that incorporates membrane poration utilizing the Smoluchowski model with angular-dependent changes in membrane conductivity. Consistent with prior experimental reports, the simulations show that the ER requires the largest electric field for electroporation, while the inner mitochondrial membrane (IMM) is the easiest membrane to porate. Our results suggest that the experimentally observed increase in intracellular calcium could be due to a calcium induced calcium release (CICR) process that is initiated by outer cell membrane breakdown. Repeated pulsing and/or using multiple electrodes are shown to create a stronger poration. The role of mutual coupling, screening, and proximity effects in bringing about electric field modifications is also probed. Finally, while including greater geometric details might refine predictions, the qualitative trends are expected to remain.
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Affiliation(s)
- C Baker
- Department of Electrical and Computer Engineering, Texas Tech University, Lubbock, TX, 79409, USA
| | - A Willis
- Department of Electrical and Computer Engineering, Texas Tech University, Lubbock, TX, 79409, USA
- Texas Tech University Health Sciences Center, Lubbock, TX, 79430, USA
| | - W Milestone
- Nanohmics, Inc, 6201 E Oltorf St, Austin, TX, 78717, USA
| | - M Baker
- Department of Electrical and Computer Engineering, Texas Tech University, Lubbock, TX, 79409, USA
| | - A L Garner
- School of Nuclear Engineering, Purdue University, West Lafayette, IN, 47907, USA
- Elmore Family School of Electrical and Computer Engineering, West Lafayette, IN, 47907, USA
| | - R P Joshi
- Department of Electrical and Computer Engineering, Texas Tech University, Lubbock, TX, 79409, USA.
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3
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Bougandoura O, Achour Y, Zaoui A. Electroporation in Cancer Therapy: A Simplified Model Derived from the Hodgkin-Huxley Model. Bioelectricity 2024; 6:181-195. [PMID: 39372085 PMCID: PMC11447485 DOI: 10.1089/bioe.2023.0045] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/08/2024] Open
Abstract
Cancer remains a global health challenge, necessitating effective treatments with fewer side effects. Traditional methods such as chemotherapy and surgery often have complications. Pulsed electric fields and electroporation have emerged as promising approaches to mitigate these challenges. This study presents a comprehensive overview of electroporation as an innovative tool in cancer therapy, encompassing critical elements such as pulse generators and delivery devices. Furthermore, it introduces a simplified reversible electroporation model grounded in the Hodgkin-Huxley model. This model ensures resting potential stability by regulating ionic currents. When membrane charges reach the electroporation threshold, the model swiftly increases the fraction of open pores, resulting in a rapid rise in electroporation current. Conversely, as the transmembrane potential drops below the threshold, the model gradually reduces the fraction of open pores, leading to a gradual decline in electroporation current, indicating pore resealing. This model contributes to easier modeling and implementation of reversible electroporation dynamics, providing a valuable tool for further exploration of electroporation for cancer therapy.
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Affiliation(s)
| | - Yahia Achour
- UER-ELT, Ecole Militaire Polytechnique, Algiers, Algeria
| | - Abdelhalim Zaoui
- Department of Electrical Engineering and Industrial Computing, Ecole Nationale Supérieure des Technologies Avancées, Algiers, Algeria
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4
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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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5
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Novickij V, Rembiałkowska N, Szlasa W, Kulbacka J. Does the shape of the electric pulse matter in electroporation? Front Oncol 2022; 12:958128. [PMID: 36185267 PMCID: PMC9518825 DOI: 10.3389/fonc.2022.958128] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2022] [Accepted: 08/15/2022] [Indexed: 11/13/2022] Open
Abstract
Electric pulses are widely used in biology, medicine, industry, and food processing. Numerous studies indicate that electroporation (EP) is a pulse-dependent process, and the electric pulse shape and duration strongly determine permeabilization efficacy. EP protocols are precisely planned in terms of the size and charge of the molecules, which will be delivered to the cell. In reversible and irreversible EP applications, rectangular or sine, polar or bipolar pulses are commonly used. The usage of pulses of the asymmetric shape is still limited to high voltage and low voltage (HV/LV) sequences in the context of gene delivery, while EP-based applications of ultra-short asymmetric pulses are just starting to emerge. This review emphasizes the importance and role of the pulse shape for membrane permeabilization by EP.
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Affiliation(s)
- Vitalij Novickij
- Faculty of Electronics, Vilnius Gediminas Technical University (Vilnius TECH), Vilnius, Lithuania
- *Correspondence: Vitalij Novickij, ; Julita Kulbacka,
| | - Nina Rembiałkowska
- Department of Molecular and Cellular Biology, Faculty of Pharmacy, Wroclaw Medical University, Wroclaw, Poland
| | - Wojciech Szlasa
- Faculty of Medicine, Wroclaw Medical University, Wroclaw, Poland
| | - Julita Kulbacka
- Department of Molecular and Cellular Biology, Faculty of Pharmacy, Wroclaw Medical University, Wroclaw, Poland
- *Correspondence: Vitalij Novickij, ; Julita Kulbacka,
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6
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Ruiz-Fernández AR, Campos L, Gutierrez-Maldonado SE, Núñez G, Villanelo F, Perez-Acle T. Nanosecond Pulsed Electric Field (nsPEF): Opening the Biotechnological Pandora’s Box. Int J Mol Sci 2022; 23:ijms23116158. [PMID: 35682837 PMCID: PMC9181413 DOI: 10.3390/ijms23116158] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2022] [Revised: 05/23/2022] [Accepted: 05/23/2022] [Indexed: 02/04/2023] Open
Abstract
Nanosecond Pulsed Electric Field (nsPEF) is an electrostimulation technique first developed in 1995; nsPEF requires the delivery of a series of pulses of high electric fields in the order of nanoseconds into biological tissues or cells. They primary effects in cells is the formation of membrane nanopores and the activation of ionic channels, leading to an incremental increase in cytoplasmic Ca2+ concentration, which triggers a signaling cascade producing a variety of effects: from apoptosis up to cell differentiation and proliferation. Further, nsPEF may affect organelles, making nsPEF a unique tool to manipulate and study cells. This technique is exploited in a broad spectrum of applications, such as: sterilization in the food industry, seed germination, anti-parasitic effects, wound healing, increased immune response, activation of neurons and myocites, cell proliferation, cellular phenotype manipulation, modulation of gene expression, and as a novel cancer treatment. This review thoroughly explores both nsPEF’s history and applications, with emphasis on the cellular effects from a biophysics perspective, highlighting the role of ionic channels as a mechanistic driver of the increase in cytoplasmic Ca2+ concentration.
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Affiliation(s)
- Alvaro R. Ruiz-Fernández
- Computational Biology Lab, Centro Científico y Tecnológico de Excelencia Ciencia & Vida, Fundación Ciencia & Vida, Santiago 7780272, Chile; (L.C.); (S.E.G.-M.); (G.N.); (F.V.)
- Facultad de Ingeniería y Tecnología, Universidad San Sebastian, Bellavista 7, Santiago 8420524, Chile
- Correspondence: (A.R.R.-F.); (T.P.-A.)
| | - Leonardo Campos
- Computational Biology Lab, Centro Científico y Tecnológico de Excelencia Ciencia & Vida, Fundación Ciencia & Vida, Santiago 7780272, Chile; (L.C.); (S.E.G.-M.); (G.N.); (F.V.)
- Facultad de Ingeniería y Tecnología, Universidad San Sebastian, Bellavista 7, Santiago 8420524, Chile
| | - Sebastian E. Gutierrez-Maldonado
- Computational Biology Lab, Centro Científico y Tecnológico de Excelencia Ciencia & Vida, Fundación Ciencia & Vida, Santiago 7780272, Chile; (L.C.); (S.E.G.-M.); (G.N.); (F.V.)
- Facultad de Ingeniería y Tecnología, Universidad San Sebastian, Bellavista 7, Santiago 8420524, Chile
| | - Gonzalo Núñez
- Computational Biology Lab, Centro Científico y Tecnológico de Excelencia Ciencia & Vida, Fundación Ciencia & Vida, Santiago 7780272, Chile; (L.C.); (S.E.G.-M.); (G.N.); (F.V.)
| | - Felipe Villanelo
- Computational Biology Lab, Centro Científico y Tecnológico de Excelencia Ciencia & Vida, Fundación Ciencia & Vida, Santiago 7780272, Chile; (L.C.); (S.E.G.-M.); (G.N.); (F.V.)
- Facultad de Ingeniería y Tecnología, Universidad San Sebastian, Bellavista 7, Santiago 8420524, Chile
| | - Tomas Perez-Acle
- Computational Biology Lab, Centro Científico y Tecnológico de Excelencia Ciencia & Vida, Fundación Ciencia & Vida, Santiago 7780272, Chile; (L.C.); (S.E.G.-M.); (G.N.); (F.V.)
- Facultad de Ingeniería y Tecnología, Universidad San Sebastian, Bellavista 7, Santiago 8420524, Chile
- Correspondence: (A.R.R.-F.); (T.P.-A.)
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7
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Li Z, Xuan Y, Ghatak S, Guda PR, Roy S, Sen CK. Modeling the gene delivery process of the needle array-based tissue nanotransfection. NANO RESEARCH 2022; 15:3409-3421. [PMID: 36275042 PMCID: PMC9581438 DOI: 10.1007/s12274-021-3947-1] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/12/2021] [Revised: 10/17/2021] [Accepted: 10/24/2021] [Indexed: 05/14/2023]
Abstract
Hollow needle array-based tissue nanotransfection (TNT) presents an in vivo transfection approach that directly translocate exogeneous genes to target tissues by using electric pulses. In this work, the gene delivery process of TNT was simulated and experimentally validated. We adopted the asymptotic method and cell-array-based model to investigate the electroporation behaviors of cells within the skin structure. The distribution of nonuniform electric field across the skin results in various electroporation behavior for each cell. Cells underneath the hollow microchannels of the needle exhibited the highest total pore numbers compared to others due to the stronger localized electric field. The percentage of electroporated cells within the skin structure, with pore radius over 10 nm, increases from 25% to 82% as the applied voltage increases from 100 to 150 V/mm. Furthermore, the gene delivery behavior across the skin tissue was investigated through the multilayer-stack-based model. The delivery distance increased nonlinearly as the applied voltage and pulse number increased, which mainly depends on the diffusion characteristics and electric conductivity of each layer. It was also found that the skin is required to be exfoliated prior to the TNT procedure to enhance the delivery depth. This work provides the foundation for transition from the study of murine skin to translation use in large animals and human settings.
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Affiliation(s)
- Zhigang Li
- Indiana Center for Regenerative Medicine and Engineering, Indiana University Health Comprehensive Wound Center, Department of Surgery, Indiana University School of Medicine, Indianapolis, IN 46202, USA
- Birck Nanotechnology Center and Weldon School of Biomedical Engineering, Purdue University, West Lafayette, IN 47907, USA
| | - Yi Xuan
- Indiana Center for Regenerative Medicine and Engineering, Indiana University Health Comprehensive Wound Center, Department of Surgery, Indiana University School of Medicine, Indianapolis, IN 46202, USA
- Birck Nanotechnology Center and Weldon School of Biomedical Engineering, Purdue University, West Lafayette, IN 47907, USA
| | - Subhadip Ghatak
- Indiana Center for Regenerative Medicine and Engineering, Indiana University Health Comprehensive Wound Center, Department of Surgery, Indiana University School of Medicine, Indianapolis, IN 46202, USA
| | - Poornachander R. Guda
- Indiana Center for Regenerative Medicine and Engineering, Indiana University Health Comprehensive Wound Center, Department of Surgery, Indiana University School of Medicine, Indianapolis, IN 46202, USA
| | - Sashwati Roy
- Indiana Center for Regenerative Medicine and Engineering, Indiana University Health Comprehensive Wound Center, Department of Surgery, Indiana University School of Medicine, Indianapolis, IN 46202, USA
| | - Chandan K. Sen
- Indiana Center for Regenerative Medicine and Engineering, Indiana University Health Comprehensive Wound Center, Department of Surgery, Indiana University School of Medicine, Indianapolis, IN 46202, USA
- Birck Nanotechnology Center and Weldon School of Biomedical Engineering, Purdue University, West Lafayette, IN 47907, USA
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8
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Rems L, Tang X, Zhao F, Pérez-Conesa S, Testa I, Delemotte L. Identification of electroporation sites in the complex lipid organization of the plasma membrane. eLife 2022; 11:e74773. [PMID: 35195069 PMCID: PMC8912918 DOI: 10.7554/elife.74773] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2021] [Accepted: 02/22/2022] [Indexed: 11/13/2022] Open
Abstract
The plasma membrane of a biological cell is a complex assembly of lipids and membrane proteins, which tightly regulate transmembrane transport. When a cell is exposed to strong electric field, the membrane integrity becomes transiently disrupted by formation of transmembrane pores. This phenomenon termed electroporation is already utilized in many rapidly developing applications in medicine including gene therapy, cancer treatment, and treatment of cardiac arrhythmias. However, the molecular mechanisms of electroporation are not yet sufficiently well understood; in particular, it is unclear where exactly pores form in the complex organization of the plasma membrane. In this study, we combine coarse-grained molecular dynamics simulations, machine learning methods, and Bayesian survival analysis to identify how formation of pores depends on the local lipid organization. We show that pores do not form homogeneously across the membrane, but colocalize with domains that have specific features, the most important being high density of polyunsaturated lipids. We further show that knowing the lipid organization is sufficient to reliably predict poration sites with machine learning. Additionally, by analysing poration kinetics with Bayesian survival analysis we show that poration does not depend solely on local lipid arrangement, but also on membrane mechanical properties and the polarity of the electric field. Finally, we discuss how the combination of atomistic and coarse-grained molecular dynamics simulations, machine learning methods, and Bayesian survival analysis can guide the design of future experiments and help us to develop an accurate description of plasma membrane electroporation on the whole-cell level. Achieving this will allow us to shift the optimization of electroporation applications from blind trial-and-error approaches to mechanistic-driven design.
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Affiliation(s)
- Lea Rems
- KTH Royal Institute of Technology, Dept. Applied Physics, Science for Life LaboratorySolnaSweden
- University of Ljubljana, Faculty of Electrical EngineeringLjubljanaSlovenia
| | - Xinru Tang
- KTH Royal Institute of Technology, Dept. Applied Physics, Science for Life LaboratorySolnaSweden
- University of Chinese Academy of SciencesBeijingChina
| | - Fangwei Zhao
- KTH Royal Institute of Technology, Dept. Applied Physics, Science for Life LaboratorySolnaSweden
- University of Chinese Academy of SciencesBeijingChina
| | - Sergio Pérez-Conesa
- KTH Royal Institute of Technology, Dept. Applied Physics, Science for Life LaboratorySolnaSweden
| | - Ilaria Testa
- KTH Royal Institute of Technology, Dept. Applied Physics, Science for Life LaboratorySolnaSweden
| | - Lucie Delemotte
- KTH Royal Institute of Technology, Dept. Applied Physics, Science for Life LaboratorySolnaSweden
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9
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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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10
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Hu Q, Joshi RP. Continuum analysis to assess field enhancements for tailoring electroporation driven by monopolar or bipolar pulsing based on nonuniformly distributed nanoparticles. Phys Rev E 2021; 103:022402. [PMID: 33736030 DOI: 10.1103/physreve.103.022402] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2020] [Accepted: 01/15/2021] [Indexed: 11/07/2022]
Abstract
Recent reports indicate that nanoparticle (NP) clusters near cell membranes could enhance local electric fields, leading to heightened electroporation. This aspect is quantitatively analyzed through numerical simulations whereby time dependent transmembrane potentials are first obtained on the basis of a distributed circuit mode, and the results then used to calculate pore distributions from continuum Smoluchowski theory. For completeness, both monopolar and bipolar nanosecond-range pulse responses are presented and discussed. Our results show strong increases in TMP with the presence of multiple NP clusters and demonstrate that enhanced poration could be possible even over sites far away from the poles at the short pulsing regime. Furthermore, our results demonstrate that nonuniform distributions would work to enable poration at regions far away from the poles. The NP clusters could thus act as distributed electrodes. Our results were roughly in line with recent experimental observations.
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Affiliation(s)
- Q Hu
- School of Engineering, Eastern Michigan University, Ypsilanti, Michigan 48197, USA
| | - R P Joshi
- Department of Electrical and Computer Engineering, Texas Tech University, Lubbock, Texas 79409, USA
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11
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Nonlinear dispersive cell model for microdosimetry of nanosecond pulsed electric fields. Sci Rep 2020; 10:19456. [PMID: 33173132 PMCID: PMC7655951 DOI: 10.1038/s41598-020-76642-w] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2020] [Accepted: 10/30/2020] [Indexed: 01/07/2023] Open
Abstract
For applications based on nanosecond pulsed electric fields (nsPEFs), the underlying transmembrane potential (TMP) distribution on the plasma membrane is influenced by electroporation (EP) of the plasma membrane and dielectric dispersion (DP) of all cell compartments which is important for predicting the bioelectric effects. In this study, the temporal and spatial distribution of TMP on the plasma membrane induced by nsPEFs of various pulse durations (3 ns, 5 ns unipolar, 5 ns bipolar, and 10 ns) is investigated with the inclusion of both DP and EP. Based on the double-shelled dielectric spherical cell model, the Debye equation describing DP is transformed into the time-domain form with the introduction of polarization vector, and then we obtain the time course of TMP by solving the combination of Laplace equation and time-domain Debye equation. Next, the asymptotic version of the Smoluchowski equation is included to characterize the EP of plasma membrane in order to observe more profound electroporation effects with larger pore density and electroporated areas in consideration of both DP and EP. Through the simulation, it is clearer to understand the relationship between the applied nsPEFs and the induced bioelectric effects.
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12
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Nathamgari SSP, Pathak N, Lemaitre V, Mukherjee P, Muldoon JJ, Peng CY, McGuire T, Leonard JN, Kessler JA, Espinosa HD. Nanofountain Probe Electroporation Enables Versatile Single-Cell Intracellular Delivery and Investigation of Postpulse Electropore Dynamics. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2020; 16:e2002616. [PMID: 33006271 PMCID: PMC7646188 DOI: 10.1002/smll.202002616] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/25/2020] [Revised: 07/27/2020] [Indexed: 05/13/2023]
Abstract
Introducing exogenous molecules into cells with high efficiency and dosage control is a crucial step in basic research as well as clinical applications. Here, the capability of the nanofountain probe electroporation (NFP-E) system to deliver proteins and plasmids in a variety of continuous and primary cell types with appropriate dosage control is reported. It is shown that the NFP-E can achieve fine control over the relative expression of two cotransfected plasmids. Finally, the dynamics of electropore closure after the pulsing ends with the NFP-E is investigated. Localized electroporation has recently been utilized to demonstrate the converse process of delivery (sampling), in which a small volume of the cytosol is retrieved during electroporation without causing cell lysis. Single-cell temporal sampling confers the benefit of monitoring the same cell over time and can provide valuable insights into the mechanisms underlying processes such as stem cell differentiation and disease progression. NFP-E parameters that maximize the membrane resealing time, which is essential for increasing the sampled volume and in meeting the challenge of monitoring low copy number biomarkers, are identified. Its application in CRISPR/Cas9 gene editing, stem cell reprogramming, and single-cell sampling studies is envisioned.
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Affiliation(s)
- Samba Shiva Prasad Nathamgari
- Department of Mechanical Engineering, Northwestern University, Evanston, IL, 60208, USA
- Theoretical and Applied Mechanics Program, Northwestern University, Evanston, IL, 60208, USA
| | - Nibir Pathak
- Department of Mechanical Engineering, Northwestern University, Evanston, IL, 60208, USA
- Theoretical and Applied Mechanics Program, Northwestern University, Evanston, IL, 60208, USA
| | | | - Prithvijit Mukherjee
- Department of Mechanical Engineering, Northwestern University, Evanston, IL, 60208, USA
- Theoretical and Applied Mechanics Program, Northwestern University, Evanston, IL, 60208, USA
| | - Joseph J Muldoon
- Department of Chemical and Biological Engineering and Interdisciplinary Biological Sciences Program, Northwestern University, Evanston, IL, 60208, USA
| | - Chian-Yu Peng
- Department of Neurology, Northwestern University Feinberg School of Medicine, Chicago, IL, 60611, USA
| | - Tammy McGuire
- Department of Neurology, Northwestern University Feinberg School of Medicine, Chicago, IL, 60611, USA
| | - Joshua N Leonard
- Department of Chemical and Biological Engineering and Interdisciplinary Biological Sciences Program, Northwestern University, Evanston, IL, 60208, USA
- Center for Synthetic Biology, Northwestern University, Evanston, IL, 60208, USA
| | - John A Kessler
- Department of Neurology, Northwestern University Feinberg School of Medicine, Chicago, IL, 60611, USA
| | - Horacio Dante Espinosa
- Department of Mechanical Engineering, Northwestern University, Evanston, IL, 60208, USA
- Theoretical and Applied Mechanics Program, Northwestern University, Evanston, IL, 60208, USA
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13
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Actin networks regulate the cell membrane permeability during electroporation. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2020; 1863:183468. [PMID: 32882211 DOI: 10.1016/j.bbamem.2020.183468] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 05/30/2020] [Revised: 08/14/2020] [Accepted: 08/26/2020] [Indexed: 01/08/2023]
Abstract
Transient physical disruption of cell membranes by electric pulses (or electroporation) has significance in biomedical and biological applications requiring the delivery of exogenous (bio)molecules to living cells. We demonstrate that actin networks regulate the cell membrane permeability during electroporation. Disruption of actin networks increases the uptake of membrane-impermeable molecules such as propidium iodide during electroporation. Our experiments at different temperatures ranging from 11 °C to 37 °C show that molecular uptake during electroporation increases with temperature. Furthermore, by examining the temperature-dependent kinetics of propidium iodide uptake, we infer that the activation energy barrier of electroporation is lowered when the actin networks are disrupted. Our numerical calculations of transmembrane voltage show that the reduced activation energy barrier for the cells with disrupted actin is not a consequence of the changes in transmembrane voltage associated with changes in the cell shape due to the disruption of actin, indicating that this could be due to changes in membrane mechanical properties. Our results suggest that the current theoretical models of electroporation should be advanced further by including the contributions of the cytoskeletal networks on the cell membrane permeability during the delivery of exogenous materials.
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14
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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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15
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Aycock KN, Davalos RV. Irreversible Electroporation: Background, Theory, and Review of Recent Developments in Clinical Oncology. Bioelectricity 2019; 1:214-234. [PMID: 34471825 PMCID: PMC8370296 DOI: 10.1089/bioe.2019.0029] [Citation(s) in RCA: 77] [Impact Index Per Article: 15.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Abstract
Irreversible electroporation (IRE) has established a clinical niche as an alternative to thermal ablation for the eradication of unresectable tumors, particularly those near critical vascular structures. IRE has been used in over 50 independent clinical trials and has shown clinical success when used as a standalone treatment and as a single component within combinatorial treatment paradigms. Recently, many studies evaluating IRE in larger patient cohorts and alongside other novel therapies have been reported. Here, we present the basic principles of reversible electroporation and IRE followed by a review of preclinical and clinical data with a focus on tumors in three organ systems in which IRE has shown great promise: the prostate, pancreas, and liver. Finally, we discuss alternative and future developments, which will likely further advance the use of IRE in the clinic.
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Affiliation(s)
- Kenneth N Aycock
- Department of Biomedical Engineering and Mechanics, Virginia Tech-Wake Forest University, Blacksburg, Virginia
| | - Rafael V Davalos
- Department of Biomedical Engineering and Mechanics, Virginia Tech-Wake Forest University, Blacksburg, Virginia
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16
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Stirke A, Celiesiute-Germaniene R, Zimkus A, Zurauskiene N, Simonis P, Dervinis A, Ramanavicius A, Balevicius S. The link between yeast cell wall porosity and plasma membrane permeability after PEF treatment. Sci Rep 2019; 9:14731. [PMID: 31611587 PMCID: PMC6791849 DOI: 10.1038/s41598-019-51184-y] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2019] [Accepted: 09/17/2019] [Indexed: 01/17/2023] Open
Abstract
An investigation of the yeast cell resealing process was performed by studying the absorption of the tetraphenylphosphonium (TPP+) ion by the yeast Saccharomyces cerevisiae. It was shown that the main barrier for the uptake of such TPP+ ions is the cell wall. An increased rate of TPP+ absorption after treatment of such cells with a pulsed electric field (PEF) was observed only in intact cells, but not in spheroplasts. The investigation of the uptake of TPP+ in PEF treated cells exposed to TPP+ for different time intervals also showed the dependence of the absorption rate on the PEF strength. The modelling of the TPP+ uptake recovery has also shown that the characteristic decay time of the non-equilibrium (PEF induced) pores was approximately a few tens of seconds and this did not depend on the PEF strength. A further investigation of such cell membrane recovery process using a florescent SYTOX Green nucleic acid stain dye also showed that such membrane resealing takes place over a time that is like that occurring in the cell wall. It was thus concluded that the similar characteristic lifetimes of the non-equilibrium pores in the cell wall and membrane after exposure to PEF indicate a strong coupling between these parts of the cell.
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Affiliation(s)
- Arunas Stirke
- Center for Physical Sciences and Technology, Sauletekio ave. 3, LT-10257, Vilnius, Lithuania
| | | | - Aurelijus Zimkus
- Department of Biochemistry and Biophysics, Life Sciences Center, Sauletekio ave. 7, LT-10257, Vilnius, Lithuania
| | - Nerija Zurauskiene
- Center for Physical Sciences and Technology, Sauletekio ave. 3, LT-10257, Vilnius, Lithuania
| | - Povilas Simonis
- Center for Physical Sciences and Technology, Sauletekio ave. 3, LT-10257, Vilnius, Lithuania
| | - Aldas Dervinis
- Center for Physical Sciences and Technology, Sauletekio ave. 3, LT-10257, Vilnius, Lithuania
| | - Arunas Ramanavicius
- Center for Physical Sciences and Technology, Sauletekio ave. 3, LT-10257, Vilnius, Lithuania.,Department of Physical Chemistry, Faculty of Chemistry and Geosciences, Vilnius University, Naugarduko st. 24, LT-03225, Vilnius, Lithuania
| | - Saulius Balevicius
- Center for Physical Sciences and Technology, Sauletekio ave. 3, LT-10257, Vilnius, Lithuania
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17
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Pulsed electric field inactivation of microorganisms: from fundamental biophysics to synergistic treatments. Appl Microbiol Biotechnol 2019; 103:7917-7929. [DOI: 10.1007/s00253-019-10067-y] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2019] [Revised: 07/25/2019] [Accepted: 07/26/2019] [Indexed: 12/15/2022]
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18
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Kotnik T, Rems L, Tarek M, Miklavčič D. Membrane Electroporation and Electropermeabilization: Mechanisms and Models. Annu Rev Biophys 2019; 48:63-91. [PMID: 30786231 DOI: 10.1146/annurev-biophys-052118-115451] [Citation(s) in RCA: 342] [Impact Index Per Article: 68.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Exposure of biological cells to high-voltage, short-duration electric pulses causes a transient increase in their plasma membrane permeability, allowing transmembrane transport of otherwise impermeant molecules. In recent years, large steps were made in the understanding of underlying events. Formation of aqueous pores in the lipid bilayer is now a widely recognized mechanism, but evidence is growing that changes to individual membrane lipids and proteins also contribute, substantiating the need for terminological distinction between electroporation and electropermeabilization. We first revisit experimental evidence for electrically induced membrane permeability, its correlation with transmembrane voltage, and continuum models of electropermeabilization that disregard the molecular-level structure and events. We then present insights from molecular-level modeling, particularly atomistic simulations that enhance understanding of pore formation, and evidence of chemical modifications of membrane lipids and functional modulation of membrane proteins affecting membrane permeability. Finally, we discuss the remaining challenges to our full understanding of electroporation and electropermeabilization.
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Affiliation(s)
- Tadej Kotnik
- Faculty of Electrical Engineering, University of Ljubljana, SI-1000 Ljubljana, Slovenia; ,
| | - Lea Rems
- Science for Life Laboratory, Department of Applied Physics, KTH Royal Institute of Technology, 17165 Solna, Sweden;
| | - Mounir Tarek
- Université de Lorraine, CNRS, LPCT, F-54000 Nancy, France;
| | - Damijan Miklavčič
- Faculty of Electrical Engineering, University of Ljubljana, SI-1000 Ljubljana, Slovenia; ,
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19
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Beier HT, Roth CC, Bixler JN, Sedelnikova AV, Ibey BL. Visualization of Dynamic Sub-microsecond Changes in Membrane Potential. Biophys J 2018; 116:120-126. [PMID: 30579565 DOI: 10.1016/j.bpj.2018.11.3129] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2017] [Revised: 11/08/2018] [Accepted: 11/20/2018] [Indexed: 02/07/2023] Open
Abstract
Direct observation of rapid membrane potential changes is critical to understand how complex neurological systems function. This knowledge is especially important when stimulation is achieved through an external stimulus meant to mimic a naturally occurring process. To enable exploration of this dynamic space, we developed an all-optical method for observing rapid changes in membrane potential at temporal resolutions of ∼25 ns. By applying a single 600-ns electric pulse, we observed sub-microsecond, continuous membrane charging and discharging dynamics. Close agreement between the acquired results and an analytical membrane-charging model validates the utility of this technique. This tool will deepen our understanding of the role of membrane potential dynamics in the regulation of many biological and chemical processes within living systems.
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Affiliation(s)
- Hope T Beier
- Bioeffects Division, Air Force Research Laboratory, JBSA Fort Sam Houston, Texas.
| | - Caleb C Roth
- Bioeffects Division, Air Force Research Laboratory, JBSA Fort Sam Houston, Texas
| | - Joel N Bixler
- Bioeffects Division, Air Force Research Laboratory, JBSA Fort Sam Houston, Texas
| | | | - Bennett L Ibey
- Bioeffects Division, Air Force Research Laboratory, JBSA Fort Sam Houston, Texas
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20
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Gowrishankar TR, Stern JV, Smith KC, Weaver JC. Nanopore occlusion: A biophysical mechanism for bipolar cancellation in cell membranes. Biochem Biophys Res Commun 2018; 503:1194-1199. [DOI: 10.1016/j.bbrc.2018.07.024] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2018] [Accepted: 07/06/2018] [Indexed: 12/21/2022]
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21
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Gupta R, Rai B. Electroporation of Skin Stratum Corneum Lipid Bilayer and Molecular Mechanism of Drug Transport: A Molecular Dynamics Study. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2018; 34:5860-5870. [PMID: 29708340 DOI: 10.1021/acs.langmuir.8b00423] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
The electroporation technique has been used significantly to increase drug permeation through the skin. This technique relies on the application of short-timed (microseconds to millisecond) electric fields (generally, order of 50--300 V) on the skin to create microscopic pores. However, the molecular mechanism of pore formation, resulting in an enhanced flux of active molecules through the skin, remains poorly understood. In this study, extensive atomistic molecular dynamics simulation of skin lipids [made up of ceramide (CER), cholesterol (CHOL), and free fatty acid (FFA)] has been performed at various external electric fields. We show for the first time the pore formation in the skin lipid bilayer during electroporation. We show the effect of the applied external electrical field (0.6-1.0 V/nm) on the pore formation dynamics in the lipid bilayer of different sizes (154, 616, and 2464 lipids) and compositions (CER/CHOL/FFA, 1:0:0, 1:0:1, 1:1:0, 1:1:1). The pore formation and resealing kinetics were different and were found to be highly dependent on the composition of the skin lipid bilayer. The pore formation time decreased with increase in the bilayer size. The pore sustaining electric field was found to be in the range of 0.20-0.25 V/nm for equimolar CER, CHOL, and FFA lipid bilayers. The skin lipid bilayer (1:1:1) sealed itself within 20 ns after the removal of the external electric field. We also present the molecular mechanism of enhancement of drug permeation in the presence of external field as compared to the passive diffusion. The molecular-level understanding obtained here could help in optimizing/designing the electroporation experiments for effective drug delivery. For a given skin composition and size of the drug molecule, the combination of pore formation time and pore growth model can be used to know a priori the desired electric field and time for the application of the electric field.
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Affiliation(s)
- Rakesh Gupta
- Physical Science Research Area, Tata Research Development & Design Centre, TCS Innovation Labs , Pune 411013 , India
| | - Beena Rai
- Physical Science Research Area, Tata Research Development & Design Centre, TCS Innovation Labs , Pune 411013 , India
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22
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Core-shell magnetoelectric nanorobot - A remotely controlled probe for targeted cell manipulation. Sci Rep 2018; 8:1755. [PMID: 29379076 PMCID: PMC5788862 DOI: 10.1038/s41598-018-20191-w] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2017] [Accepted: 01/16/2018] [Indexed: 01/16/2023] Open
Abstract
We have developed a remotely controlled dynamic process of manipulating targeted biological live cells using fabricated core-shell nanocomposites, which comprises of single crystalline ferromagnetic cores (CoFe2O4) coated with crystalline ferroelectric thin film shells (BaTiO3). We demonstrate them as a unique family of inorganic magnetoelectric nanorobots (MENRs), controlled remotely by applied a.c. or d.c. magnetic fields, to perform cell targeting, permeation, and transport. Under a.c. magnetic field excitation (50 Oe, 60 Hz), the MENR acts as a localized electric periodic pulse generator and can permeate a series of misaligned cells, while aligning them to an equipotential mono-array by inducing inter-cellular signaling. Under a.c. magnetic field (40 Oe, 30 Hz) excitation, MENRs can be dynamically driven to a targeted cell, avoiding untargeted cells in the path, irrespective of cell density. D.C. magnetic field (−50 Oe) excitation causes the MENRs to act as thrust generator and exerts motion in a group of cells.
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23
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Perrier DL, Rems L, Boukany PE. Lipid vesicles in pulsed electric fields: Fundamental principles of the membrane response and its biomedical applications. Adv Colloid Interface Sci 2017; 249:248-271. [PMID: 28499600 DOI: 10.1016/j.cis.2017.04.016] [Citation(s) in RCA: 43] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2017] [Revised: 04/24/2017] [Accepted: 04/25/2017] [Indexed: 01/04/2023]
Abstract
The present review focuses on the effects of pulsed electric fields on lipid vesicles ranging from giant unilamellar vesicles (GUVs) to small unilamellar vesicles (SUVs), from both fundamental and applicative perspectives. Lipid vesicles are the most popular model membrane systems for studying biophysical and biological processes in living cells. Furthermore, as vesicles are made from biocompatible and biodegradable materials, they provide a strategy to create safe and functionalized drug delivery systems in health-care applications. Exposure of lipid vesicles to pulsed electric fields is a common physical method to transiently increase the permeability of the lipid membrane. This method, termed electroporation, has shown many advantages for delivering exogenous molecules including drugs and genetic material into vesicles and living cells. In addition, electroporation can be applied to induce fusion between vesicles and/or cells. First, we discuss in detail how research on cell-size GUVs as model cell systems has provided novel insight into the basic mechanisms of cell electroporation and associated phenomena. Afterwards, we continue with a thorough overview how electroporation and electrofusion have been used as versatile methods to manipulate vesicles of all sizes in different biomedical applications. We conclude by summarizing the open questions in the field of electroporation and possible future directions for vesicles in the biomedical field.
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24
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Adrenal Chromaffin Cells Exposed to 5-ns Pulses Require Higher Electric Fields to Porate Intracellular Membranes than the Plasma Membrane: An Experimental and Modeling Study. J Membr Biol 2017; 250:535-552. [PMID: 28840286 DOI: 10.1007/s00232-017-9983-9] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2017] [Accepted: 08/19/2017] [Indexed: 12/17/2022]
Abstract
Nanosecond-duration electric pulses (NEPs) can permeabilize the endoplasmic reticulum (ER), causing release of Ca2+ into the cytoplasm. This study used experimentation coupled with numerical modeling to understand the lack of Ca2+ mobilization from Ca2+-storing organelles in catecholamine-secreting adrenal chromaffin cells exposed to 5-ns pulses. Fluorescence imaging determined a threshold electric (E) field of 8 MV/m for mobilizing intracellular Ca2+ whereas whole-cell recordings of membrane conductance determined a threshold E-field of 3 MV/m for causing plasma membrane permeabilization. In contrast, a 2D numerical model of a chromaffin cell, which was constructed with internal structures representing a nucleus, mitochondrion, ER, and secretory granule, predicted that exposing the cell to the same 5-ns pulse electroporated the plasma and ER membranes at the same E-field amplitude, 3-4 MV/m. Agreement of the numerical simulations with the experimental results was obtained only when the ER interior conductivity was 30-fold lower than that of the cytoplasm and the ER membrane permittivity was twice that of the plasma membrane. A more realistic intracellular geometry for chromaffin cells in which structures representing multiple secretory granules and an ER showed slight differences in the thresholds necessary to porate the membranes of the secretory granules. We conclude that more sophisticated cell models together with knowledge of accurate dielectric properties are needed to understand the effects of NEPs on intracellular membranes in chromaffin cells, information that will be important for elucidating how NEPs porate organelle membranes in other cell types having a similarly complex cytoplasmic ultrastructure.
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25
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Poellmann MJ, Lee RC. Repair and Regeneration of the Wounded Cell Membrane. REGENERATIVE ENGINEERING AND TRANSLATIONAL MEDICINE 2017. [DOI: 10.1007/s40883-017-0031-1] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
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26
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Labarbera N. Uncertainty Quantification in Irreversible Electroporation Simulations. Bioengineering (Basel) 2017; 4:bioengineering4020041. [PMID: 28952520 PMCID: PMC5590475 DOI: 10.3390/bioengineering4020041] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2017] [Revised: 05/02/2017] [Accepted: 05/04/2017] [Indexed: 12/18/2022] Open
Abstract
One recent area of cancer research is irreversible electroporation (IRE). Irreversible electroporation is a minimally invasive procedure where needle electrodes are inserted into the body to ablate tumor cells with electricity. The aim of this paper is to investigate how uncertainty in tissue and tumor conductivity propagate into final ablation predictions used for treatment planning. Two dimensional simulations were performed for a circular tumor surrounded by healthy tissue, and electroporated from two monopolar electrodes. The conductivity values were treated as random variables whose distributions were taken from published literature on the average and standard deviation of liver tissue and liver tumors. Three different Monte Carlo setups were simulated each at three different voltages. Average and standard deviation data was reported for a multitude of electrical field properties experienced by the tumor. Plots showing the variability in the electrical field distribution throughout the tumor are also presented.
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Affiliation(s)
- Nicholas Labarbera
- Engineering Science & Mechanics, The Pennsylvania State University, State College, PA 16801, USA.
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27
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Investigation of the morphological transition of a phospholipid bilayer membrane in an external electric field via molecular dynamics simulation. J Mol Model 2017; 23:113. [PMID: 28289956 DOI: 10.1007/s00894-017-3292-1] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2016] [Accepted: 02/20/2017] [Indexed: 12/12/2022]
Abstract
Elucidating the mechanisms for morphological transitions of the phospholipid bilayer membrane during cellular activity should lead to greater understanding of these membrane transitions and allow us to optimize biotechnologies such as drug delivery systems in organisms. To investigate the mechanism for and the dynamics of morphological changes in the phospholipid membrane, we performed molecular dynamics simulation of a phospholipid membrane with and without membrane protein under the influence of electric fields with different strengths. In the absence of membrane protein, it was possible to control the transition from one lamellar membrane morphology to another by applying a strong electric field. The strong electric field initially disordered the lipid molecules in the membrane, leading to the formation of a hydrophilic pore. The lipid molecules then spontaneously fused into a new lamellar membrane morphology. In the presence of membrane protein, a morphological transition from lamellar membrane to vesicle under the influence of a strong electric field was observed. Studying the complex transition dynamics associated with these changes in membrane morphology allowed us to gain deep insight into the electrofusion and electroporation that occur in the presence or absence of membrane protein, and the results obtained here should prove useful in work aimed at controlling membrane morphology. Graphical Abstract Memebrane morphological transition under the electric field of 0.6 V/nm with the membrane protein (down) and without membrane protein (up).
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28
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Ding X, Stewart M, Sharei A, Weaver JC, Langer RS, Jensen KF. High-throughput Nuclear Delivery and Rapid Expression of DNA via Mechanical and Electrical Cell-Membrane Disruption. Nat Biomed Eng 2017; 1. [PMID: 28932622 PMCID: PMC5602535 DOI: 10.1038/s41551-017-0039] [Citation(s) in RCA: 125] [Impact Index Per Article: 17.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/03/2022]
Abstract
Nuclear transfection of DNA into mammalian cells is challenging yet critical for many biological and medical studies. Here, by combining cell squeezing and electric-field-driven transport in a device that integrates microfluidic channels with constrictions and microelectrodes, we demonstrate nuclear delivery of plasmid DNA within 1 hour after treatment, the most rapid DNA expression in a high-throughput setting (up to millions of cells per minute per device). Passing cells at high speed through microfluidic constrictions smaller than the cell diameter mechanically disrupts the cell membrane, allowing a subsequent electric field to further disrupt the nuclear envelope and drive DNA molecules into the cytoplasm and nucleus. By tracking the localization of the ESCRT-III (endosomal sorting complexes required for transport) protein CHMP4B, we show that the integrity of the nuclear envelope is recovered within 15 minutes of treatment. We also provide insight into subcellular delivery by comparing the performance of the disruption-and-field-enhanced method with those of conventional chemical, electroporation, and manual-injection systems.
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Affiliation(s)
- Xiaoyun Ding
- Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139, USA.,The David Koch Institute for Integrative Cancer Research, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Martin Stewart
- Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139, USA.,The David Koch Institute for Integrative Cancer Research, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Armon Sharei
- Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139, USA.,The David Koch Institute for Integrative Cancer Research, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - James C Weaver
- Harvard-MIT Division of Health Sciences and Technology, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Robert S Langer
- Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139, USA.,The David Koch Institute for Integrative Cancer Research, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Klavs F Jensen
- Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
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29
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Rems L. Applicative Use of Electroporation Models. ADVANCES IN BIOMEMBRANES AND LIPID SELF-ASSEMBLY 2017. [DOI: 10.1016/bs.abl.2017.06.001] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
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30
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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] [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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31
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Betal S, Shrestha B, Dutta M, Cotica LF, Khachatryan E, Nash K, Tang L, Bhalla AS, Guo R. Magneto-elasto-electroporation (MEEP): In-vitro visualization and numerical characteristics. Sci Rep 2016; 6:32019. [PMID: 27562291 PMCID: PMC4999954 DOI: 10.1038/srep32019] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2015] [Accepted: 07/19/2016] [Indexed: 11/09/2022] Open
Abstract
A magnetically controlled elastically driven electroporation phenomenon, or magneto-elasto-electroporation (MEEP), is discovered while studying the interactions between core-shell magnetoelectric nanoparticles (CSMEN) and biological cells in the presence of an a.c. magnetic field. In this paper we report the effect of MEEP observed via a series of in-vitro experiments using core (CoFe2O4)-shell (BaTiO3) structured magnetoelectric nanoparticles and human epithelial cells (HEP2). The cell electroporation phenomenon and its correlation with the magnetic field modulated CSMEN are described in detail. The potential application of CSMEN in electroporation is confirmed by analyzing crystallographic phases, multiferroic properties of the fabricated CSMEN, influences of d.c. and a.c. magnetic fields on the CSMEN and cytotoxicity tests. The mathematical formalism to quantitatively describe the phenomena is also reported. The reported findings provide insights into the underlying MEEP mechanism and demonstrate the utility of CSMEN as an electric pulse-generating nano-probe in electroporation experiments with a potential application toward accurate and efficient targeted cell permeation.
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Affiliation(s)
- Soutik Betal
- Department of Electrical and Computer Engineering, University of Texas at San Antonio, San Antonio, TX 78249, USA
| | - Binita Shrestha
- Department of Biomedical Engineering, University of Texas at San Antonio, San Antonio, TX 78249, USA
| | - Moumita Dutta
- Department of Electrical and Computer Engineering, University of Texas at San Antonio, San Antonio, TX 78249, USA
| | - Luiz F Cotica
- Department of Physics, State University of Maringá, Maringá, PR - 87020-900, Brazil
| | - Edward Khachatryan
- Department of Physics and Astronomy, University of Texas at San Antonio, San Antonio, TX 78249, USA
| | - Kelly Nash
- Department of Physics and Astronomy, University of Texas at San Antonio, San Antonio, TX 78249, USA
| | - Liang Tang
- Department of Biomedical Engineering, University of Texas at San Antonio, San Antonio, TX 78249, USA
| | - Amar S Bhalla
- Department of Electrical and Computer Engineering, University of Texas at San Antonio, San Antonio, TX 78249, USA
| | - Ruyan Guo
- Department of Electrical and Computer Engineering, University of Texas at San Antonio, San Antonio, TX 78249, USA
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Moen EK, Ibey BL, Beier HT, Armani AM. Quantifying pulsed electric field-induced membrane nanoporation in single cells. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2016; 1858:2795-2803. [PMID: 27535877 DOI: 10.1016/j.bbamem.2016.08.007] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/19/2016] [Revised: 08/11/2016] [Accepted: 08/12/2016] [Indexed: 12/21/2022]
Abstract
Plasma membrane disruption can trigger a host of cellular activities. One commonly observed type of disruption is pore formation. Molecular dynamic (MD) simulations of simplified lipid membrane structures predict that controllably disrupting the membrane via nano-scale poration may be possible with nanosecond pulsed electric fields (nsPEF). Until recently, researchers hoping to verify this hypothesis experimentally have been limited to measuring the relatively slow process of fluorescent markers diffusing across the membrane, which is indirect evidence of nanoporation that could be channel-mediated. Leveraging recent advances in nonlinear optical microscopy, we elucidate the role of pulse parameters in nsPEF-induced membrane permeabilization in live cells. Unlike previous techniques, it is able to directly observe loss of membrane order at the onset of the pulse. We also develop a complementary theoretical model that relates increasing membrane permeabilization to membrane pore density. Due to the significantly improved spatial and temporal resolution possible with our imaging method, we are able to directly compare our experimental and theoretical results. Their agreement provides substantial evidence that nanoporation does occur and that its development is dictated by the electric field distribution.
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Affiliation(s)
- Erick K Moen
- Ming Hsieh Department of Electrical Engineering - Electrophysics, University of Southern California, 920 Bloom Walk, SSC, 502 Los Angeles, CA, USA.
| | - Bennett L Ibey
- Bioeffects Division, 711 Human Performance Wing, Air Force Research Laboratory, 4141 Petroleum Rd., JBSA Fort Sam, Houston, TX 78234, USA
| | - Hope T Beier
- Bioeffects Division, 711 Human Performance Wing, Air Force Research Laboratory, 4141 Petroleum Rd., JBSA Fort Sam, Houston, TX 78234, USA
| | - Andrea M Armani
- Ming Hsieh Department of Electrical Engineering - Electrophysics, University of Southern California, 920 Bloom Walk, SSC, 502 Los Angeles, CA, USA
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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: 48] [Impact Index Per Article: 6.0] [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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Son RS, Gowrishankar TR, Smith KC, Weaver JC. Modeling a Conventional Electroporation Pulse Train: Decreased Pore Number, Cumulative Calcium Transport and an Example of Electrosensitization. IEEE Trans Biomed Eng 2016; 63:571-80. [DOI: 10.1109/tbme.2015.2466234] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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Bhonsle SP, Arena CB, Sweeney DC, Davalos RV. Mitigation of impedance changes due to electroporation therapy using bursts of high-frequency bipolar pulses. Biomed Eng Online 2015; 14 Suppl 3:S3. [PMID: 26355870 PMCID: PMC4565149 DOI: 10.1186/1475-925x-14-s3-s3] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
BACKGROUND For electroporation-based therapies, accurate modeling of the electric field distribution within the target tissue is important for predicting the treatment volume. In response to conventional, unipolar pulses, the electrical impedance of a tissue varies as a function of the local electric field, leading to a redistribution of the field. These dynamic impedance changes, which depend on the tissue type and the applied electric field, need to be quantified a priori, making mathematical modeling complicated. Here, it is shown that the impedance changes during high-frequency, bipolar electroporation therapy are reduced, and the electric field distribution can be approximated using the analytical solution to Laplace's equation that is valid for a homogeneous medium of constant conductivity. METHODS Two methods were used to examine the agreement between the analytical solution to Laplace's equation and the electric fields generated by 100 µs unipolar pulses and bursts of 1 µs bipolar pulses. First, pulses were applied to potato tuber tissue while an infrared camera was used to monitor the temperature distribution in real-time as a corollary to the electric field distribution. The analytical solution was overlaid on the thermal images for a qualitative assessment of the electric fields. Second, potato ablations were performed and the lesion size was measured along the x- and y-axes. These values were compared to the analytical solution to quantify its ability to predict treatment outcomes. To analyze the dynamic impedance changes due to electroporation at different frequencies, electrical impedance measurements (1 Hz to 1 MHz) were made before and after the treatment of potato tissue. RESULTS For high-frequency bipolar burst treatment, the thermal images closely mirrored the constant electric field contours. The potato tissue lesions differed from the analytical solution by 39.7 ± 1.3 % (x-axis) and 6.87 ± 6.26 % (y-axis) for conventional unipolar pulses, and 15.46 ± 1.37 % (x-axis) and 3.63 ± 5.9 % (y-axis) for high- frequency bipolar pulses. CONCLUSIONS The electric field distributions due to high-frequency, bipolar electroporation pulses can be closely approximated with the homogeneous analytical solution. This paves way for modeling fields without prior characterization of non-linear tissue properties, and thereby simplifying electroporation procedures.
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Bullmann T, Arendt T, Frey U, Hanashima C. A transportable, inexpensive electroporator for in utero electroporation. Dev Growth Differ 2015; 57:369-377. [PMID: 25988525 DOI: 10.1111/dgd.12216] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2015] [Revised: 03/31/2015] [Accepted: 04/08/2015] [Indexed: 01/14/2023]
Abstract
Electroporation is a useful technique to study gene function during development but its broad application is hampered due to the expensive equipment needed. We describe the construction of a transportable, simple and inexpensive electroporator delivering square pulses with varying length and amplitude. The device was successfully used for in utero electroporation in mouse with a performance comparable to that of commercial products.
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Affiliation(s)
- Torsten Bullmann
- Frey Initiative Research Unit, RIKEN Quantitative Biology Center, 2-2-3 Minatojima-minamimachi, Chuo-ku, Kobe, 650-0047, Japan.,Laboratory for Neocortical Development, RIKEN Center for Developmental Biology, 2-2-3 Minatojima-minamimachi, Chuo-ku, Kobe, 650-0047, Japan.,Department of Molecular and Cellular Mechanisms of Neurodegeneration, Paul Flechsig Institute of Brain Research, University of Leipzig, Liebigstraβe 19, 04103, Leipzig, Germany
| | - Thomas Arendt
- Department of Molecular and Cellular Mechanisms of Neurodegeneration, Paul Flechsig Institute of Brain Research, University of Leipzig, Liebigstraβe 19, 04103, Leipzig, Germany
| | - Urs Frey
- Frey Initiative Research Unit, RIKEN Quantitative Biology Center, 2-2-3 Minatojima-minamimachi, Chuo-ku, Kobe, 650-0047, Japan
| | - Carina Hanashima
- Laboratory for Neocortical Development, RIKEN Center for Developmental Biology, 2-2-3 Minatojima-minamimachi, Chuo-ku, Kobe, 650-0047, Japan
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Hoiles W, Krishnamurthy V, Cranfield CG, Cornell B. An engineered membrane to measure electroporation: effect of tethers and bioelectronic interface. Biophys J 2015; 107:1339-51. [PMID: 25229142 DOI: 10.1016/j.bpj.2014.07.056] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2014] [Revised: 06/27/2014] [Accepted: 07/30/2014] [Indexed: 01/19/2023] Open
Abstract
This article reports on the construction and predictive models for a platform comprised of an engineered tethered membrane. The platform provides a controllable and physiologically relevant environment for the study of the electroporation process. The mixed self-assembled membrane is formed via a rapid solvent exchange technique. The membrane is tethered to the gold electrode and includes an ionic reservoir separating the membrane and gold surface. Above the membrane, there is an electrolyte solution, and a gold counterelectrode. A voltage is applied between the gold electrodes and the current measured. The current is dependent on the energy required to form aqueous pores and the conductance of each pore. A two-level predictive model, consisting of a macroscopic and a continuum model, is developed to relate the pore dynamics to the measured current. The macroscopic model consists of an equivalent circuit model of the tethered membrane, and asymptotic approximations to the Smoluchowski-Einstein equation of electroporation that is dependent on the pore conductance and the energy required to form aqueous pores. The continuum model is a generalized Poisson-Nernst-Planck (GPNP) system where an activity coefficient to account for steric effects of ions is added to the standard PNP system. The GPNP is used to evaluate the conductance of aqueous pores, and the electrical energy required to form the pores. As an outcome of the setup of the device and the two-level model, biologically important variables can be estimated from experimental measurements. To validate the accuracy of the two-level model, the predicted current is compared with experimentally measured current for different tethering densities.
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Affiliation(s)
- William Hoiles
- Department of Electrical and Computer Engineering, University of British Columbia, Vancouver, British Columbia, Canada
| | - Vikram Krishnamurthy
- Department of Electrical and Computer Engineering, University of British Columbia, Vancouver, British Columbia, Canada.
| | - Charles G Cranfield
- School of Medical and Molecular Biosciences, University of Technology Sydney, Broadway, New South Wales, Australia; Victor Chang Cardiac Research Institute, Darlinghurst, New South Wales, Australia
| | - Bruce Cornell
- Surgical Diagnostics, Roseville, New South Wales, Australia
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38
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Effects of nanosecond pulse electric fields on cellular elasticity. Micron 2015; 72:15-20. [PMID: 25732004 DOI: 10.1016/j.micron.2015.01.004] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2014] [Revised: 01/26/2015] [Accepted: 01/26/2015] [Indexed: 11/22/2022]
Abstract
We investigated the effects of a single 60 nanosecond pulsed electric field (nsPEF) of low (15 kV/cm) and high (60 kV/cm) field strengths on cellular morphology and membrane elasticity in Jurkat cells using fluorescent microscopy and atomic force microscopy (AFM). We performed force displacement measurements on cells using AFM and calculated the Young's modulus for membrane elasticity. Differential effects were observed depending upon pulsing conditions. We found that a single nsPEF of low field strength did not induce any apparent cytoskeletal breakdown and had minor morphological changes. Interestingly, force measurements and calculation of Young's modulus showed a significant decrease in membrane elasticity. A single nsPEF of high field strength induced stark morphological changes due to disruption of the actin cytoskeleton and a marked decrease in elasticity likely caused by irreversible membrane damage. We suggest that the cellular morphology is mainly dependent on stabilization by the actin cytoskeleton, while the elasticity changes are partially dependent on the cytoskeletal integrity.
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Smith KC, Son RS, Gowrishankar T, Weaver JC. Emergence of a large pore subpopulation during electroporating pulses. Bioelectrochemistry 2014; 100:3-10. [DOI: 10.1016/j.bioelechem.2013.10.009] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2013] [Revised: 10/21/2013] [Accepted: 10/31/2013] [Indexed: 11/25/2022]
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40
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Son RS, Smith KC, Gowrishankar TR, Vernier PT, Weaver JC. Basic features of a cell electroporation model: illustrative behavior for two very different pulses. J Membr Biol 2014; 247:1209-28. [PMID: 25048527 PMCID: PMC4224743 DOI: 10.1007/s00232-014-9699-z] [Citation(s) in RCA: 67] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2014] [Accepted: 06/07/2014] [Indexed: 12/23/2022]
Abstract
Science increasingly involves complex modeling. Here we describe a model for cell electroporation in which membrane properties are dynamically modified by poration. Spatial scales range from cell membrane thickness (5 nm) to a typical mammalian cell radius (10 μm), and can be used with idealized and experimental pulse waveforms. The model consists of traditional passive components and additional active components representing nonequilibrium processes. Model responses include measurable quantities: transmembrane voltage, membrane electrical conductance, and solute transport rates and amounts for the representative "long" and "short" pulses. The long pulse--1.5 kV/cm, 100 μs--evolves two pore subpopulations with a valley at ~5 nm, which separates the subpopulations that have peaks at ~1.5 and ~12 nm radius. Such pulses are widely used in biological research, biotechnology, and medicine, including cancer therapy by drug delivery and nonthermal physical tumor ablation by causing necrosis. The short pulse--40 kV/cm, 10 ns--creates 80-fold more pores, all small (<3 nm; ~1 nm peak). These nanosecond pulses ablate tumors by apoptosis. We demonstrate the model's responses by illustrative electrical and poration behavior, and transport of calcein and propidium. We then identify extensions for expanding modeling capability. Structure-function results from MD can allow extrapolations that bring response specificity to cell membranes based on their lipid composition. After a pulse, changes in pore energy landscape can be included over seconds to minutes, by mechanisms such as cell swelling and pulse-induced chemical reactions that slowly alter pore behavior.
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Affiliation(s)
- Reuben S. Son
- />Harvard-MIT Division of Health Sciences and Technology, Massachusetts Institute of Technology, 77 Massachusetts Avenue, E25-213A, Cambridge, MA 02139 USA
| | - Kyle C. Smith
- />Harvard-MIT Division of Health Sciences and Technology, Massachusetts Institute of Technology, 77 Massachusetts Avenue, E25-213A, Cambridge, MA 02139 USA
- />Department of Electrical Engineering and Computer Science, Massachusetts Institute of Technology, Cambridge, MA USA
- />Center for Engineering in Medicine, Massachusetts General Hospital, 114 16th Street, Charlestown, MA 02129 USA
| | - Thiruvallur R. Gowrishankar
- />Harvard-MIT Division of Health Sciences and Technology, Massachusetts Institute of Technology, 77 Massachusetts Avenue, E25-213A, Cambridge, MA 02139 USA
| | - P. Thomas Vernier
- />Frank Reidy Research Center for Bioelectrics, Old Dominion University, Norfolk, VA 23508 USA
| | - James C. Weaver
- />Harvard-MIT Division of Health Sciences and Technology, Massachusetts Institute of Technology, 77 Massachusetts Avenue, E25-213A, Cambridge, MA 02139 USA
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41
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Peter EK, Pivkin IV. A polarizable coarse-grained water model for dissipative particle dynamics. J Chem Phys 2014; 141:164506. [DOI: 10.1063/1.4899317] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Affiliation(s)
- Emanuel K. Peter
- Institute of Computational Science, Faculty of Informatics, University of Lugano, Lugano, Switzerland
| | - Igor V. Pivkin
- Institute of Computational Science, Faculty of Informatics, University of Lugano, Lugano, Switzerland
- Swiss Institute of Bioinformatics, Lausanne, Switzerland
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42
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Ion transport into cells exposed to monopolar and bipolar nanosecond pulses. Bioelectrochemistry 2014; 103:44-51. [PMID: 25212701 DOI: 10.1016/j.bioelechem.2014.08.015] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2014] [Revised: 07/21/2014] [Accepted: 08/12/2014] [Indexed: 02/06/2023]
Abstract
Experiments with CHO cells exposed to 60 and 300 ns pulsed electric fields with amplitudes in the range from several kV/cm to tens of kV/cm showed a decrease of the uptake of calcium ions by more than an order of magnitude when, immediately after a first pulse, a second one of opposite polarity was applied. This effect is assumed to be due to the reversal of the electrophoretic transport of ions through the electroporated membrane during the second phase of the bipolar pulse. This assumption, however, is only valid if electrophoresis is the dominant transport mechanism, rather than diffusion. Comparison of calculated calcium ion currents with experimental results showed that for nanosecond pulses, electrophoresis is at least as important as diffusion. By delaying the second pulse with respect to the first one, the effect of reverse electrophoresis is reduced. Consequently, separating nanosecond pulses of opposite polarity by up to approximately hundred microseconds allows us to vary the uptake of ions from very small values to those obtained with two pulses of the same polarity. The measured calcium ion uptake obtained with bipolar pulses also allowed us to determine the membrane pore recovery time. The calculated recovery time constants are on the order of 10 μs.
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43
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Cell electrofusion using nanosecond electric pulses. Sci Rep 2013; 3:3382. [PMID: 24287643 PMCID: PMC3843160 DOI: 10.1038/srep03382] [Citation(s) in RCA: 69] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2013] [Accepted: 11/13/2013] [Indexed: 12/21/2022] Open
Abstract
Electrofusion is an efficient method for fusing cells using short-duration high-voltage electric pulses. However, electrofusion yields are very low when fusion partner cells differ considerably in their size, since the extent of electroporation (consequently membrane fusogenic state) with conventionally used microsecond pulses depends proportionally on the cell radius. We here propose a new and innovative approach to fuse cells with shorter, nanosecond (ns) pulses. Using numerical calculations we demonstrate that ns pulses can induce selective electroporation of the contact areas between cells (i.e. the target areas), regardless of the cell size. We then confirm experimentally on B16-F1 and CHO cell lines that electrofusion of cells with either equal or different size by using ns pulses is indeed feasible. Based on our results we expect that ns pulses can improve fusion yields in electrofusion of cells with different size, such as myeloma cells and B lymphocytes in hybridoma technology.
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44
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Sridhara V, Joshi RP. Numerical study of lipid translocation driven by nanoporation due to multiple high-intensity, ultrashort electrical pulses. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2013; 1838:902-9. [PMID: 24239610 DOI: 10.1016/j.bbamem.2013.11.003] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/28/2013] [Revised: 11/01/2013] [Accepted: 11/05/2013] [Indexed: 11/16/2022]
Abstract
The dynamical translocation of lipids from one leaflet to another due to membrane permeabilization driven by nanosecond, high-intensity (>100kV/cm) electrical pulses has been probed. Our simulations show that lipid molecules can translocate by diffusion through water-filled nanopores which form following high voltage application. Our focus is on multiple pulsing, and such simulations are relevant to gauge the time duration over which nanopores might remain open, and facilitate continued lipid translocations and membrane transport. Our results are indicative of a N(½) scaling with pulse number for the pore radius. These results bode well for the use of pulse trains in biomedical applications, not only due to cumulative behaviors and in reducing electric intensities and pulsing hardware, but also due to the possibility of long-lived thermo-electric physics near the membrane, and the possibility for pore coalescence.
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Affiliation(s)
- Viswanadham Sridhara
- Center for Computational Biology and Bioinformatics, College of Natural Sciences, University of Texas, 2415 Speedway, C4500, Austin, TX 78712, USA
| | - Ravindra P Joshi
- Dept. of Electrical & Computer Engineering, Frank Reidy Center for Bio-Electrics, Old Dominion University, Norfolk, VA 23529-0246, USA.
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45
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Liu C, Xie X, Zhao W, Liu N, Maraccini PA, Sassoubre LM, Boehm AB, Cui Y. Conducting nanosponge electroporation for affordable and high-efficiency disinfection of bacteria and viruses in water. NANO LETTERS 2013; 13:4288-93. [PMID: 23987737 DOI: 10.1021/nl402053z] [Citation(s) in RCA: 83] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
High-efficiency, affordable, and low energy water disinfection methods are in great need to prevent diarrheal illness, which is one of the top five leading causes of death over the world. Traditional water disinfection methods have drawbacks including carcinogenic disinfection byproducts formation, energy and time intensiveness, and pathogen recovery. Here, we report an innovative method that achieves high-efficiency water disinfection by introducing nanomaterial-assisted electroporation implemented by a conducting nanosponge filtration device. The use of one-dimensional (1D) nanomaterials allows electroporation to occur at only several volts, which is 2 to 3 orders of magnitude lower than that in traditional electroporation applications. The disinfection mechanism of electroporation prevents harmful byproduct formation and ensures a fast treatment speed of 15,000 L/(h·m(2)), which is equal to a contact time of 1 s. The conducting nanosponge made from low-cost polyurethane sponge coated with carbon nanotubes and silver nanowires ensures the device's affordability. This method achieves more than 6 log (99.9999%) removal of four model bacteria, including Escherichia coli, Salmonella enterica Typhimirium, Enterococcus faecalis, and Bacillus subtilis, and more than 2 log (99%) removal of one model virus, bacteriophage MS2, with a low energy consumption of only 100 J/L.
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Affiliation(s)
- Chong Liu
- Department of Materials Science and Engineering, Stanford University , Stanford, California 94305, United States
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46
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Romeo S, Wu YH, Levine ZA, Gundersen MA, Vernier PT. Water influx and cell swelling after nanosecond electropermeabilization. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2013; 1828:1715-22. [DOI: 10.1016/j.bbamem.2013.03.007] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/10/2012] [Revised: 02/20/2013] [Accepted: 03/01/2013] [Indexed: 10/27/2022]
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Huerfano S, Ryabchenko B, Forstová J. Nucleofection of expression vectors induces a robust interferon response and inhibition of cell proliferation. DNA Cell Biol 2013; 32:467-79. [PMID: 23745681 DOI: 10.1089/dna.2012.1950] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
The interferon (IFN) response, induced as a side effect after transfection of nucleic acids into mammalian cells, is known but inadequately described. We followed the IFN response, the fate of cells, and the possible mechanisms leading to this response in NIH3T3 mouse fibroblasts after DNA nucleofection. The gateway destination vector, phGf, and its derivatives encoding toxic and non-toxic variants of the minor structural proteins of polyomaviruses, VP2 and VP3, were used. DNA vector sequences induced in cells the production of high levels of IFN and the upregulation of the IFN-inducible genes, Mx-1, STAT1, IRF1, and IRF7. The IFN response was not restricted to phGf-derived plasmids. In nucleofected cells, upregulation of the modified γ-histone 2A.X indicating DNA damage and inhibition of cell proliferation were also observed. Although 3T3 cells expressed the Toll-like receptor-9 (TLR9) and vectors used for nucleofection contained unmethylated CpGs, signaling leading to IFN induction was found to be TLR9 independent. However, the early activation of nuclear factor-kappa B suggested the participation of this transcription factor in IFN induction. Surprisingly, in contrast to nucleofection, transfection using a cationic polymer induced only a poor IFN response. Together, the results point to a strong side effect of nucleofection.
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Affiliation(s)
- Sandra Huerfano
- Department of Genetics and Microbiology, Charles University in Prague, Prague, Czech Republic
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48
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Frey W, Gusbeth C, Schwartz T. Inactivation of Pseudomonas putida by pulsed electric field treatment: a study on the correlation of treatment parameters and inactivation efficiency in the short-pulse range. J Membr Biol 2013; 246:769-81. [PMID: 23660812 DOI: 10.1007/s00232-013-9547-6] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2012] [Accepted: 04/17/2013] [Indexed: 01/19/2023]
Abstract
An important issue for an economic application of the pulsed electric field treatment for bacterial decontamination of wastewater is the specific treatment energy needed for effective reduction of bacterial populations. The present experimental study performed in a field amplitude range of 40 > E > 200 kV/cm and for a suspension conductivity of 0.01 = κ(e) > 0.2 S/m focusses on the application of short pulses, 25 ns > T > 10 μs, of rectangular, bipolar and exponential shape and was made on Pseudomonas putida, which is a typical and widespread wastewater microorganism. The comparison of inactivation results with calculations of the temporal and azimuthal membrane charging dynamics using the model of Pauly and Schwan revealed that for efficient inactivation, membrane segments at the cell equator have to be charged quickly and to a sufficiently high value, on the order of 0.5 V. After fulfilling this basic condition by an appropriate choice of pulse field strength and duration, the log rate of inactivation for a given suspension conductivity of 0.2 S/m was found to be independent of the duration of individual pulses for constant treatment energy expenditure. Moreover, experimental results suggest that even pulse shape plays a minor role in inactivation efficiency. The variation of the suspension conductivity resulted in comparable inactivation performance of identical pulse parameters if the product of pulse duration and number of pulses was the same, i.e., required treatment energy can be linearly downscaled for lower conductivities, provided that pulse amplitude and duration are selected for entire membrane surface permeabilization.
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Affiliation(s)
- Wolfgang Frey
- Institute for Pulsed Power and Microwave Technology, Karlsruhe Institute of Technology, Hermann-von-Helmholtz-Platz 1, Eggenstein-Leopoldshafen, 76344, Germany,
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Retelj L, Pucihar G, Miklavcic D. Electroporation of intracellular liposomes using nanosecond electric pulses--a theoretical study. IEEE Trans Biomed Eng 2013; 60:2624-35. [PMID: 23674414 DOI: 10.1109/tbme.2013.2262177] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Nanosecond (ns) electric pulses of sufficient amplitude can provoke electroporation of intracellular organelles. This paper investigates whether such pulses could provide a method for controlled intracellular release of a content of small internalized artificial lipid vesicles (liposomes). To estimate the pulse parameters needed to selectively electroporate liposomes while keeping the plasma and nuclear membranes intact, we constructed a numerical model of a biological cell containing a nucleus and liposomes of different sizes (with radii from 50 to 500 nm), which were placed in various sites in the cytoplasm. Our results show that under physiological conditions selective electroporation is only possible for the largest liposomes and when using very short pulses (few ns). By increasing the liposome interior conductivity and/or decreasing the cytoplasmic conductivity, selective electroporation of even smaller liposomes could be achieved. The location of the liposomes inside the cell does not play a significant role, meaning that liposomes of similar size could all be electroporated simultaneously. Our results indicate the possibility of using ns pulse treatment for liposomal drug release.
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Affiliation(s)
- Lea Retelj
- Faculty of Electrical Engineering, University of Ljubljana, Ljubljana SI-1000, Slovenia.
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Thresholds for phosphatidylserine externalization in Chinese hamster ovarian cells following exposure to nanosecond pulsed electrical fields (nsPEF). PLoS One 2013; 8:e63122. [PMID: 23658665 PMCID: PMC3639203 DOI: 10.1371/journal.pone.0063122] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2012] [Accepted: 03/29/2013] [Indexed: 11/19/2022] Open
Abstract
High-amplitude, MV/m, nanosecond pulsed electric fields (nsPEF) have been hypothesized to cause nanoporation of the plasma membrane. Phosphatidylserine (PS) externalization has been observed on the outer leaflet of the membrane shortly after nsPEF exposure, suggesting local structural changes in the membrane. In this study, we utilized fluorescently-tagged Annexin V to observe the externalization of PS on the plasma membrane of isolated Chinese Hamster Ovary (CHO) cells following exposure to nsPEF. A series of experiments were performed to determine the dosimetric trends of PS expression caused by nsPEF as a function of pulse duration, τ, delivered field strength, ED, and pulse number, n. To accurately estimate dose thresholds for cellular response, data were reduced to a set of binary responses and ED50s were estimated using Probit analysis. Probit analysis results revealed that PS externalization followed the non-linear trend of (τ*ED2)−1 for high amplitudes, but failed to predict low amplitude responses. A second set of experiments was performed to determine the nsPEF parameters necessary to cause observable calcium uptake, using cells preloaded with calcium green (CaGr), and membrane permeability, using FM1-43 dye. Calcium influx and FM1-43 uptake were found to always be observed at lower nsPEF exposure parameters compared to PS externalization. These findings suggest that multiple, higher amplitude and longer pulse exposures may generate pores of larger diameter enabling lateral diffusion of PS; whereas, smaller pores induced by fewer, lower amplitude and short pulse width exposures may only allow extracellular calcium and FM1-43 uptake.
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