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Ušaj M, Pavlin M, Kandušer M. Feasibility Study for the Use of Gene Electrotransfer and Cell Electrofusion as a Single-Step Technique for the Generation of Activated Cancer Cell Vaccines. J Membr Biol 2024:10.1007/s00232-024-00320-5. [PMID: 39133276 DOI: 10.1007/s00232-024-00320-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2024] [Accepted: 07/20/2024] [Indexed: 08/13/2024]
Abstract
Cell-based therapies hold great potential for cancer immunotherapy. This approach is based on manipulation of dendritic cells to activate immune system against specific cancer antigens. For the development of an effective cell vaccine platform, gene transfer, and cell fusion have been used for modification of dendritic or tumor cells to express immune (co)stimulatory signals and to load dendritic cells with tumor antigens. Both, gene transfer and cell fusion can be achieved by single technique, a cell membrane electroporation. The cell membrane exposed to external electric field becomes temporarily permeable, enabling introduction of genetic material, and also fusogenic, enabling the fusion of cells in the close contact. We tested the feasability of combining gene electrotransfer and electrofusion into a single-step technique and evaluated the effects of electroporation buffer, pulse parameters, and cell membrane fluidity for single or combined method of gene delivery or cell fusdion. We determined the percentage of fused cells expressing green fluorescence protein (GFP) in a murine cell model of melanoma B16F1, cell line used in our previous studies. Our results suggest that gene electrotransfer and cell electrofusion can be applied in a single step. The percentage of viable hybrid cells expressing GFP depends on electric pulse parameters and the composition of the electroporation buffer. Furthermore, our results suggest that cell membrane fluidity is not related to the efficiency of the gene electrotransfer and electrofusion. The protocol is compatible with microfluidic devices, however further optimization of electric pulse parameters and buffers is still needed.
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Affiliation(s)
- Marko Ušaj
- Faculty of Health and Life Sciences, Department of Chemistry and Biomedical Sciences, Linnaeus University, 391 82, Kalmar, Sweden
| | - Mojca Pavlin
- Faculty of Medicine, Institute of Biophysics, University of Ljubljana, Vrazov Trg 2, 1000, Ljubljana, Slovenia
- Faculty of Electrical Engineering, Group for Nano and Biotechnological Applications, University of Ljubljana, Tržaška 25, 1000, Ljubljana, Slovenia
| | - Maša Kandušer
- Institute for Pharmacy, Faculty of Pharmacy, University of Ljubljana, Aškerčeva 7, 1000, Ljubljana, Slovenia.
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2
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Palepšienė R, Muralidharan A, Maciulevičius M, Ruzgys P, Chopra S, Boukany PE, Šatkauskas S. New insights into the mechanism of electrotransfer of small nucleic acids. Bioelectrochemistry 2024; 158:108696. [PMID: 38583283 DOI: 10.1016/j.bioelechem.2024.108696] [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: 12/28/2023] [Revised: 03/25/2024] [Accepted: 03/27/2024] [Indexed: 04/09/2024]
Abstract
RNA interference (RNAi) is a powerful and rapidly developing technology that enables precise silencing of genes of interest. However, the clinical development of RNAi is hampered by the limited cellular uptake and stability of the transferred molecules. Electroporation (EP) is an efficient and versatile technique for the transfer of both RNA and DNA. Although the mechanism of electrotransfer of small nucleic acids has been studied previously, too little is known about the potential effects of significantly larger pDNA on this process. Here we present a fundamental study of the mechanism of electrotransfer of oligonucleotides and siRNA that occur independently and simultaneously with pDNA by employing confocal fluorescence microscopy. In contrast to the conditional understanding of the mechanism, we have shown that the electrotransfer of oligonucleotides and siRNA is driven by both electrophoretic forces and diffusion after EP, followed by subsequent entry into the nucleus within 5 min after treatment. The study also revealed that the efficiency of siRNA electrotransfer decreases in response to an increase in pDNA concentration. Overall, the study provides new insights into the mechanism of electrotransfer of small nucleic acids which may have broader implications for the future application of RNAi-based strategies.
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Affiliation(s)
- Rūta Palepšienė
- Research Institute of Natural Sciences and Technology, Vytautas Magnus University, Universiteto str. 10, Akademija, Kaunas district LT-53361, Lithuania.
| | - Aswin Muralidharan
- Department of Bionanoscience, Delft University of Technology, Van der Maasweg 9 2629 HZ Delft, Netherlands; Kavli Institute of Nanoscience, Delft University of Technology, Van der Maasweg 9 2629 HZ Delft, Netherlands.
| | - Martynas Maciulevičius
- Research Institute of Natural Sciences and Technology, Vytautas Magnus University, Universiteto str. 10, Akademija, Kaunas district LT-53361, Lithuania.
| | - Paulius Ruzgys
- Research Institute of Natural Sciences and Technology, Vytautas Magnus University, Universiteto str. 10, Akademija, Kaunas district LT-53361, Lithuania.
| | - Sonam Chopra
- Research Institute of Natural Sciences and Technology, Vytautas Magnus University, Universiteto str. 10, Akademija, Kaunas district LT-53361, Lithuania.
| | - Pouyan E Boukany
- Department of Chemical Engineering, Delft University of Technology, Van der Maasweg 9 2629 HZ Delft, Netherlands.
| | - Saulius Šatkauskas
- Research Institute of Natural Sciences and Technology, Vytautas Magnus University, Universiteto str. 10, Akademija, Kaunas district LT-53361, Lithuania.
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Radzevičiūtė-Valčiukė E, Gečaitė J, Balevičiūtė A, Szewczyk A, Želvys A, Lekešytė B, Malyško-Ptašinskė V, Mickevičiūtė E, Malakauskaitė P, Kulbacka J, Novickij V. Effects of buffer composition and plasmid toxicity on electroporation-based non-viral gene delivery in mammalian cells using bursts of nanosecond and microsecond pulses. Front Bioeng Biotechnol 2024; 12:1430637. [PMID: 39050682 PMCID: PMC11266100 DOI: 10.3389/fbioe.2024.1430637] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2024] [Accepted: 06/17/2024] [Indexed: 07/27/2024] Open
Abstract
Gene electrotransfer (GET) is non-viral gene delivery technique, also known as electroporation-mediated gene delivery or electrotransfection. GET is a method used to introduce foreign genetic material (such as DNA or RNA) into cells by applying external pulsed electric fields (PEFs) to create temporary pores in the cell membrane. This study was undertaken to examine the impact of buffer composition on the efficiency of GET in mammalian cells Also, we specifically compared the effectiveness of high-frequency nanosecond (ns) pulses with standard microsecond (µs) pulses. For the assessment of cell transfection efficiency and viability, flow cytometric analysis, luminescent assays, and measurements of metabolic activity were conducted. The efficiency of electrotransfection was evaluated using two different proteins encoding plasmids (pEGFP-N1 and Luciferase-pcDNA3). The investigation revealed that the composition of the electroporation buffer significantly influences the efficacy of GET in CHO-K1 cell line. The different susceptibility of cell lines to the electric field and the plasmid cytotoxicity were reported. It was also shown that electroporation with nanosecond duration PEF protocols ensured equivalent or even better transfection efficiency than standard µsPEF. Additionally, we successfully performed long-term transfection of the murine 4T1 cell line using high-frequency nanosecond PEFs and confirmed its' applicability in an in vivo model. The findings from the study can be applied to optimize electrotransfection conditions.
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Affiliation(s)
- Eivina Radzevičiūtė-Valčiukė
- State Research Institute Centre for Innovative Medicine, Department of Immunology and Bioelectrochemistry, Vilnius, Lithuania
- Faculty of Electronics, Vilnius Gediminas Technical University, Vilnius, Lithuania
| | - Jovita Gečaitė
- State Research Institute Centre for Innovative Medicine, Department of Immunology and Bioelectrochemistry, Vilnius, Lithuania
| | - Austėja Balevičiūtė
- State Research Institute Centre for Innovative Medicine, Department of Immunology and Bioelectrochemistry, Vilnius, Lithuania
| | - Anna Szewczyk
- State Research Institute Centre for Innovative Medicine, Department of Immunology and Bioelectrochemistry, Vilnius, Lithuania
- Faculty of Pharmacy, Department of Molecular and Cellular Biology, Wroclaw Medical University, Wroclaw, Poland
| | - Augustinas Želvys
- State Research Institute Centre for Innovative Medicine, Department of Immunology and Bioelectrochemistry, Vilnius, Lithuania
- Faculty of Electronics, Vilnius Gediminas Technical University, Vilnius, Lithuania
| | - Barbora Lekešytė
- State Research Institute Centre for Innovative Medicine, Department of Immunology and Bioelectrochemistry, Vilnius, Lithuania
- Faculty of Electronics, Vilnius Gediminas Technical University, Vilnius, Lithuania
| | | | - Eglė Mickevičiūtė
- State Research Institute Centre for Innovative Medicine, Department of Immunology and Bioelectrochemistry, Vilnius, Lithuania
- Faculty of Electronics, Vilnius Gediminas Technical University, Vilnius, Lithuania
| | - Paulina Malakauskaitė
- State Research Institute Centre for Innovative Medicine, Department of Immunology and Bioelectrochemistry, Vilnius, Lithuania
- Faculty of Electronics, Vilnius Gediminas Technical University, Vilnius, Lithuania
| | - Julita Kulbacka
- State Research Institute Centre for Innovative Medicine, Department of Immunology and Bioelectrochemistry, Vilnius, Lithuania
- Faculty of Pharmacy, Department of Molecular and Cellular Biology, Wroclaw Medical University, Wroclaw, Poland
| | - Vitalij Novickij
- State Research Institute Centre for Innovative Medicine, Department of Immunology and Bioelectrochemistry, Vilnius, Lithuania
- Faculty of Electronics, Vilnius Gediminas Technical University, Vilnius, Lithuania
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Kiełbik A, Sowa PW, Pakhomov AG, Gudvangen E, Mangalanathan U, Kulbacka J, Pakhomova ON. Urine protects urothelial cells against killing with nanosecond pulsed electric fields. Bioelectrochemistry 2023; 149:108289. [DOI: 10.1016/j.bioelechem.2022.108289] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2022] [Revised: 10/01/2022] [Accepted: 10/05/2022] [Indexed: 11/07/2022]
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Sachdev S, Potočnik T, Rems L, Miklavčič D. Revisiting the role of pulsed electric fields in overcoming the barriers to in vivo gene electrotransfer. Bioelectrochemistry 2022; 144:107994. [PMID: 34930678 DOI: 10.1016/j.bioelechem.2021.107994] [Citation(s) in RCA: 19] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2021] [Revised: 10/15/2021] [Accepted: 11/02/2021] [Indexed: 12/21/2022]
Abstract
Gene therapies are revolutionizing medicine by providing a way to cure hitherto incurable diseases. The scientific and technological advances have enabled the first gene therapies to become clinically approved. In addition, with the ongoing COVID-19 pandemic, we are witnessing record speeds in the development and distribution of gene-based vaccines. For gene therapy to take effect, the therapeutic nucleic acids (RNA or DNA) need to overcome several barriers before they can execute their function of producing a protein or silencing a defective or overexpressing gene. This includes the barriers of the interstitium, the cell membrane, the cytoplasmic barriers and (in case of DNA) the nuclear envelope. Gene electrotransfer (GET), i.e., transfection by means of pulsed electric fields, is a non-viral technique that can overcome these barriers in a safe and effective manner. GET has reached the clinical stage of investigations where it is currently being evaluated for its therapeutic benefits across a wide variety of indications. In this review, we formalize our current understanding of GET from a biophysical perspective and critically discuss the mechanisms by which electric field can aid in overcoming the barriers. We also identify the gaps in knowledge that are hindering optimization of GET in vivo.
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Affiliation(s)
- Shaurya Sachdev
- University of Ljubljana, Faculty of Electrical Engineering, Tržaška cesta 25, 1000 Ljubljana, Slovenia
| | - Tjaša Potočnik
- University of Ljubljana, Faculty of Electrical Engineering, Tržaška cesta 25, 1000 Ljubljana, Slovenia
| | - Lea Rems
- University of Ljubljana, Faculty of Electrical Engineering, Tržaška cesta 25, 1000 Ljubljana, Slovenia
| | - Damijan Miklavčič
- University of Ljubljana, Faculty of Electrical Engineering, Tržaška cesta 25, 1000 Ljubljana, Slovenia.
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Meglič SH, Pavlin M. The impact of impaired DNA mobility on gene electrotransfer efficiency: analysis in 3D model. Biomed Eng Online 2021; 20:85. [PMID: 34419072 PMCID: PMC8379608 DOI: 10.1186/s12938-021-00922-3] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2020] [Accepted: 08/09/2021] [Indexed: 11/21/2022] Open
Abstract
Background Gene electrotransfer is an established method that enables transfer of DNA into cells with electric pulses. Several studies analyzed and optimized different parameters of gene electrotransfer, however, one of main obstacles toward efficient electrotransfection in vivo is relatively poor DNA mobility in tissues. Our aim was to analyze the effect of impaired mobility on gene electrotransfer efficiency experimentally and theoretically. We applied electric pulses with different durations on plated cells, cells grown on collagen layer and cells embedded in collagen gel (3D model) and analyzed gene electrotransfer efficiency. In order to analyze the effect of impaired mobility on gene electrotransfer efficiency, we applied electric pulses with different durations on plated cells, cells grown on collagen layer and cells embedded in collagen gel (3D model) and analyzed gene electrotransfer efficiency. Results We obtained the highest transfection in plated cells, while transfection efficiency of embedded cells in 3D model was lowest, similarly as in in vivo. To further analyze DNA diffusion in 3D model, we applied DNA on top or injected it into 3D model and showed, that for the former gene electrotransfer efficiency was similarly as in in vivo. The experimental results are explained with theoretical analysis of DNA diffusion and electromobility. Conclusion We show, empirically and theoretically that DNA has impaired electromobility and especially diffusion in collagen environment, where the latter crucially limits electrotransfection. Our model enables optimization of gene electrotransfer in in vitro conditions.
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Affiliation(s)
- Saša Haberl Meglič
- Faculty of Electrical Engineering, Laboratory of Biocybernetics, University of Ljubljana, Tržaška 25, 1000, Ljubljana, Slovenia
| | - Mojca Pavlin
- Faculty of Medicine, Institute of Biophysics, University of Ljubljana, Vrazov trg 2, 1000, Ljubljana, Slovenia. .,Faculty of Electrical Engineering, Group for Nano and Biotechnological Applications, University of Ljubljana, Tržaška 25, 1000, Ljubljana, Slovenia.
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7
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Potočnik T, Miklavčič D, Maček Lebar A. Gene transfer by electroporation with high frequency bipolar pulses in vitro. Bioelectrochemistry 2021; 140:107803. [PMID: 33975183 DOI: 10.1016/j.bioelechem.2021.107803] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2020] [Revised: 03/16/2021] [Accepted: 03/17/2021] [Indexed: 12/21/2022]
Abstract
High-frequency bipolar pulses (HF-BP) have been demonstrated to be efficient for membrane permeabilization and irreversible electroporation. Since membrane permeabilization has been achieved using HF-BP pulses we hypothesized that with these pulses we can also achieve successful gene electrotransfer (GET). Three variations of bursts of 2 µs bipolar pulses with 2 µs interphase delay were applied in HF-BP protocols. We compared transfection efficiency of monopolar micro and millisecond pulses and HF-BP protocols at various plasmid DNA (pDNA) concentrations on CHO - K1 cells. GET efficiency increased with increasing pDNA concentration. Overall GET obtained by HF-BP pulse protocols was comparable to overall GET obtained by longer monopolar pulse protocols. Our results, however, suggest that although we were able to achieve similar percent of transfected cells, the number of pDNA copies that were successfully transferred into cells seemed to be higher when longer monopolar pulses were used. Interestingly, we did not observe any direct correlation between fluorescence intensity of pDNA aggregates formed on cell membrane and transfection efficiency. The results of our study confirmed that we can achieve successful GET with bipolar microsecond i. e. HF-BP pulses, although at the expense of higher pDNA concentrations.
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Affiliation(s)
- Tjaša Potočnik
- University of Ljubljana, Faculty of Electrical Engineering, Tržaška 25, 1000 Ljubljana, Slovenia
| | - Damijan Miklavčič
- University of Ljubljana, Faculty of Electrical Engineering, Tržaška 25, 1000 Ljubljana, Slovenia
| | - Alenka Maček Lebar
- University of Ljubljana, Faculty of Electrical Engineering, Tržaška 25, 1000 Ljubljana, Slovenia.
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8
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Ates I, Rathbone T, Stuart C, Bridges PH, Cottle RN. Delivery Approaches for Therapeutic Genome Editing and Challenges. Genes (Basel) 2020; 11:E1113. [PMID: 32977396 PMCID: PMC7597956 DOI: 10.3390/genes11101113] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2020] [Revised: 09/16/2020] [Accepted: 09/18/2020] [Indexed: 02/07/2023] Open
Abstract
Impressive therapeutic advances have been possible through the advent of zinc-finger nucleases and transcription activator-like effector nucleases. However, discovery of the more efficient and highly tailorable clustered regularly interspaced short palindromic repeats (CRISPR) and associated proteins (Cas9) has provided unprecedented gene-editing capabilities for treatment of various inherited and acquired diseases. Despite recent clinical trials, a major barrier for therapeutic gene editing is the absence of safe and effective methods for local and systemic delivery of gene-editing reagents. In this review, we elaborate on the challenges and provide practical considerations for improving gene editing. Specifically, we highlight issues associated with delivery of gene-editing tools into clinically relevant cells.
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Affiliation(s)
- Ilayda Ates
- Department of Bioengineering, Clemson University, Clemson, SC 29634, USA; (I.A.); (T.R.); (C.S.)
| | - Tanner Rathbone
- Department of Bioengineering, Clemson University, Clemson, SC 29634, USA; (I.A.); (T.R.); (C.S.)
| | - Callie Stuart
- Department of Bioengineering, Clemson University, Clemson, SC 29634, USA; (I.A.); (T.R.); (C.S.)
| | - P. Hudson Bridges
- College of Medicine, Medical University of South Carolina, Charleston, SC 29425, USA;
| | - Renee N. Cottle
- Department of Bioengineering, Clemson University, Clemson, SC 29634, USA; (I.A.); (T.R.); (C.S.)
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9
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Sherba JJ, Hogquist S, Lin H, Shan JW, Shreiber DI, Zahn JD. The effects of electroporation buffer composition on cell viability and electro-transfection efficiency. Sci Rep 2020; 10:3053. [PMID: 32080269 PMCID: PMC7033148 DOI: 10.1038/s41598-020-59790-x] [Citation(s) in RCA: 55] [Impact Index Per Article: 13.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2019] [Accepted: 02/03/2020] [Indexed: 01/05/2023] Open
Abstract
Electroporation is an electro-physical, non-viral approach to perform DNA, RNA, and protein transfections of cells. Upon application of an electric field, the cell membrane is compromised, allowing the delivery of exogenous materials into cells. Cell viability and electro-transfection efficiency (eTE) are dependent on various experimental factors, including pulse waveform, vector concentration, cell type/density, and electroporation buffer properties. In this work, the effects of buffer composition on cell viability and eTE were systematically explored for plasmid DNA encoding green fluorescent protein following electroporation of 3T3 fibroblasts. A HEPES-based buffer was used in conjunction with various salts and sugars to modulate conductivity and osmolality, respectively. Pulse applications were chosen to maintain constant applied electrical energy (J) or total charge flux (C/m2). The energy of the pulse application primarily dictated cell viability, with Mg2+-based buffers expanding the reversible electroporation range. The enhancement of viability with Mg2+-based buffers led to the hypothesis that this enhancement is due to ATPase activation via re-establishing ionic homeostasis. We show preliminary evidence for this mechanism by demonstrating that the enhanced viability is eliminated by introducing lidocaine, an ATPase inhibitor. However, Mg2+ also hinders eTE compared to K+-based buffers. Collectively, the results demonstrate that the rational selection of pulsing conditions and buffer compositions are critical for the design of electroporation protocols to maximize viability and eTE.
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Affiliation(s)
- Joseph J Sherba
- Rutgers, The State University of New Jersey, Department of Biomedical Engineering, Piscataway, 08854, United States
| | - Stephen Hogquist
- Rutgers, The State University of New Jersey, Department of Biomedical Engineering, Piscataway, 08854, United States
| | - Hao Lin
- Rutgers, The State University of New Jersey, Department of Mechanical and Aerospace Engineering, Piscataway, 08854, United States
| | - Jerry W Shan
- Rutgers, The State University of New Jersey, Department of Mechanical and Aerospace Engineering, Piscataway, 08854, United States
| | - David I Shreiber
- Rutgers, The State University of New Jersey, Department of Biomedical Engineering, Piscataway, 08854, United States
| | - Jeffrey D Zahn
- Rutgers, The State University of New Jersey, Department of Biomedical Engineering, Piscataway, 08854, United States.
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10
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Enhancement of drug electrotransfer by extracellular plasmid DNA. Arch Biochem Biophys 2019; 666:156-160. [PMID: 30543787 DOI: 10.1016/j.abb.2018.12.010] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2018] [Revised: 12/05/2018] [Accepted: 12/07/2018] [Indexed: 10/27/2022]
Abstract
Electroporation is a widely established method for molecular delivery across electric field perturbed plasma membrane. It can be used as a non-viral DNA transfection method, or as a way to achieve small molecule delivery to or extraction from cells. We examined the possibility of combining the DNA delivery to the cells with small molecule transport across electroporated plasma membrane. The results show that the presence of DNA in electroporation medium increases the extraction of fluorescent dye calcein from calcein-AM loaded cells as well as the delivery of small-molecule drug bleomycin to the cells. We propose that these results may have implications in enhanced drug delivery using electroporation both in vivo and in clinics.
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11
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Hu X, Kang F, Yang B, Zhang W, Qin C, Gao Y. Extracellular Polymeric Substances Acting as a Permeable Barrier Hinder the Lateral Transfer of Antibiotic Resistance Genes. Front Microbiol 2019; 10:736. [PMID: 31057498 PMCID: PMC6479211 DOI: 10.3389/fmicb.2019.00736] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2019] [Accepted: 03/25/2019] [Indexed: 12/15/2022] Open
Abstract
Antibiotic resistance genes (ARGs) in bacteria are emerging contaminants as their proliferation in the environment poses significant threats to human health. It is well recognized that extracellular polymeric substances (EPS) can protect microorganisms against stress or damage from exogenous contaminants. However, it is not clear whether EPS could affect the lateral transfer of ARGs into bacteria, which is one of the major processes for the dissemination of ARGs. This study investigated the lateral transfer of ARGs carried by plasmids (pUC19, pHSG298, and pHSG396) into competent Escherichia coli cells with and without EPS. Transformant numbers and transformation efficiency for E. coli without EPS were up to 29 times of those with EPS at pH 7.0 in an aqueous system. The EPS removal further increased cell permeability in addition to the enhanced cell permeability by Ca2+, which could be responsible for the enhanced lateral transfer of ARGs. The fluorescence quenching experiments showed that EPS could strongly bind to plasmid DNA in the presence of Ca2+ and the binding strength (LogKA = 10.65–15.80 L mol-1) between EPS and plasmids was positively correlated with the enhancement percentage of transformation efficiency resulting from the EPS removal. X-ray photoelectron spectroscopy (XPS) analyses and model computation further showed that Ca2+ could electrostatically bind with EPS mainly through the carboxyl group, hydroxyl group, and RC-O-CR in glucoside, thus bridging the plasmid and EPS. As a result, the binding of plasmids with EPS hindered the lateral transfer of plasmid-borne ARGs. This study improved our understanding on the function of EPS in controlling the fate and transport of ARGs on the molecular and cellular scales.
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Affiliation(s)
- Xiaojie Hu
- Institute of Organic Contaminant Control and Soil Remediation, College of Resources and Environmental Sciences, Nanjing Agricultural University, Nanjing, China
| | - Fuxing Kang
- Institute of Organic Contaminant Control and Soil Remediation, College of Resources and Environmental Sciences, Nanjing Agricultural University, Nanjing, China
| | - Bing Yang
- Institute of Organic Contaminant Control and Soil Remediation, College of Resources and Environmental Sciences, Nanjing Agricultural University, Nanjing, China
| | - Wei Zhang
- Environmental Science and Policy Program, Department of Plant, Soil and Microbial Sciences, Michigan State University, East Lansing, MI, United States
| | - Chao Qin
- Institute of Organic Contaminant Control and Soil Remediation, College of Resources and Environmental Sciences, Nanjing Agricultural University, Nanjing, China
| | - Yanzheng Gao
- Institute of Organic Contaminant Control and Soil Remediation, College of Resources and Environmental Sciences, Nanjing Agricultural University, Nanjing, China
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12
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Ciobanu F, Golzio M, Kovacs E, Teissié J. Control by Low Levels of Calcium of Mammalian Cell Membrane Electropermeabilization. J Membr Biol 2017; 251:221-228. [PMID: 28823021 DOI: 10.1007/s00232-017-9981-y] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2017] [Accepted: 08/15/2017] [Indexed: 01/12/2023]
Abstract
Electric pulses, when applied to a cell suspension, induce a reversible permeabilization of the plasma membrane. This permeabilized state is a long-lived process (minutes). The biophysical molecular mechanisms supporting the membrane reorganization associated to its permeabilization remain poorly understood. Modeling the transmembrane structures as toroidal lipidic pores cannot explain why they are long-lived and why their resealing is under the control of the ATP level. Our results describe the effect of the level of free Calcium ions. Permeabilization induces a Ca2+ burst as previously shown by imaging of cells loaded with Fluo-3. But this sharp increase is reversible even when Calcium is present at a millimolar concentration. Viability is preserved to a larger extent when submillimolar concentrations are used. The effect of calcium ions is occurring during the resealing step not during the creation of permeabilization as the same effect is observed if Ca2+ is added in the few seconds following the pulses. The resealing time is faster when Ca2+ is present in a dose-dependent manner. Mg2+ is observed to play a competitive role. These observations suggest that Ca2+ is acting not on the external leaflet of the plasma membrane but due to its increased concentration in the cytoplasm. Exocytosis will be enhanced by this Ca2+ burst (but hindered by Mg2+) and occurs in the electropermeabilized part of the cell surface. This description is supported by previous theoretical and experimental results. The associated fusion of vesicles will be the support of resealing.
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Affiliation(s)
- Florin Ciobanu
- Institut de Pharmacologie et de Biologie Structurale, Université de Toulouse, CNRS, UPS, Toulouse, France.,University Carol Davila, Bucarest, Romania
| | - Muriel Golzio
- Institut de Pharmacologie et de Biologie Structurale, Université de Toulouse, CNRS, UPS, Toulouse, France
| | | | - Justin Teissié
- Institut de Pharmacologie et de Biologie Structurale, Université de Toulouse, CNRS, UPS, Toulouse, France.
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13
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Kang ML, Kim JE, Im GI. Vascular endothelial growth factor-transfected adipose-derived stromal cells enhance bone regeneration and neovascularization from bone marrow stromal cells. J Tissue Eng Regen Med 2017; 11:3337-3348. [DOI: 10.1002/term.2247] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2016] [Revised: 05/03/2016] [Accepted: 07/03/2016] [Indexed: 12/22/2022]
Affiliation(s)
- Mi-Lan Kang
- Department of Orthopedics; Dongguk University Ilsan Hospital; Goyang Korea
| | - Ji-Eun Kim
- Department of Orthopedics; Dongguk University Ilsan Hospital; Goyang Korea
| | - Gun-Il Im
- Department of Orthopedics; Dongguk University Ilsan Hospital; Goyang Korea
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Chafai DE, Mehle A, Tilmatine A, Maouche B, Miklavčič D. Assessment of the electrochemical effects of pulsed electric fields in a biological cell suspension. Bioelectrochemistry 2015; 106:249-57. [DOI: 10.1016/j.bioelechem.2015.08.002] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2014] [Revised: 08/10/2015] [Accepted: 08/10/2015] [Indexed: 11/25/2022]
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15
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Pavlin M, Kandušer M. New insights into the mechanisms of gene electrotransfer--experimental and theoretical analysis. Sci Rep 2015; 5:9132. [PMID: 25778848 PMCID: PMC5390920 DOI: 10.1038/srep09132] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2014] [Accepted: 02/11/2015] [Indexed: 01/14/2023] Open
Abstract
Gene electrotransfer is a promising non-viral method of gene delivery. In our in vitro study we addressed open questions about this multistep process: how electropermeabilization is related to electrotransfer efficiency; the role of DNA electrophoresis for contact and transfer across the membrane; visualization and theoretical analysis of DNA-membrane interaction and its relation to final transfection efficiency; and the differences between plated and suspended cells. Combinations of high-voltage and low-voltage pulses were used. We obtained that electrophoresis is required for the insertion of DNA into the permeabilized membrane. The inserted DNA is slowly transferred into the cytosol, and nuclear entry is a limiting factor for optimal transfection. The quantification and theoretical analysis of the crucial parameters reveals that DNA-membrane interaction (NDNA) increases with higher DNA concentration or with the addition of electrophoretic LV pulses while transfection efficiency reaches saturation. We explain the differences between the transfection of cell suspensions and plated cells due to the more homogeneous size, shape and movement of suspended cells. Our results suggest that DNA is either translocated through the stable electropores or enters by electo-stimulated endocytosis, possibly dependent on pulse parameters. Understanding of the mechanisms enables the selection of optimal electric protocols for specific applications.
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Affiliation(s)
- Mojca Pavlin
- Faculty of Electrical Engineering, University of Ljubljana, Tržaška 25, 1000 Ljubljana, Slovenia
| | - Maša Kandušer
- Faculty of Electrical Engineering, University of Ljubljana, Tržaška 25, 1000 Ljubljana, Slovenia
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16
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Marjanovič I, Kandušer M, Miklavčič D, Keber MM, Pavlin M. Comparison of flow cytometry, fluorescence microscopy and spectrofluorometry for analysis of gene electrotransfer efficiency. J Membr Biol 2014; 247:1259-67. [PMID: 25146882 DOI: 10.1007/s00232-014-9714-4] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2014] [Accepted: 07/25/2014] [Indexed: 10/24/2022]
Abstract
In this study, we compared three different methods used for quantification of gene electrotransfer efficiency: fluorescence microscopy, flow cytometry and spectrofluorometry. We used CHO and B16 cells in a suspension and plasmid coding for GFP. The aim of this study was to compare and analyse the results obtained by fluorescence microscopy, flow cytometry and spectrofluorometry and in addition to analyse the applicability of spectrofluorometry for quantifying gene electrotransfer on cells in a suspension. Our results show that all the three methods detected similar critical electric field strength, around 0.55 kV/cm for both cell lines. Moreover, results obtained on CHO cells showed that the total fluorescence intensity and percentage of transfection exhibit similar increase in response to increase electric field strength for all the three methods. For B16 cells, there was a good correlation at low electric field strengths, but at high field strengths, flow cytometer results deviated from results obtained by fluorescence microscope and spectrofluorometer. Our study showed that all the three methods detected similar critical electric field strengths and high correlations of results were obtained except for B16 cells at high electric field strengths. The results also demonstrated that flow cytometry measures higher values of percentage transfection compared to microscopy. Furthermore, we have demonstrated that spectrofluorometry can be used as a simple and consistent method to determine gene electrotransfer efficiency on cells in a suspension.
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Affiliation(s)
- Igor Marjanovič
- Laboratory of Biocybernetics, Faculty of Electrical Engineering, University of Ljubljana, Tržaška 25, 1000, Ljubljana, Slovenia
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17
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How medium osmolarity influences dielectrophoretically assisted on-chip electrofusion. Bioelectrochemistry 2014; 100:27-35. [PMID: 25012938 DOI: 10.1016/j.bioelechem.2014.05.004] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2013] [Revised: 05/23/2014] [Accepted: 05/27/2014] [Indexed: 12/11/2022]
Abstract
Cells submitted to an electric field gradient experience dielectrophoresis. Such a force is useful for pairing cells prior to electrofusion. The latter event is induced by the application of electric field pulses leading to membrane fusion while cells are in physical contact. Nevertheless, the efficiency of dielectrophoretic pairing and electrofusion of cells are highly dependent on medium properties (osmolarity and conductivity). In this paper, we examine the effect of medium osmolarity on volume, viability and electrical properties of cells. Then we characterize in real time the impact of electropermeabilization of cells on their dielectrophoretic response. To do so, a microfluidic device, inducing particular field topologies is used. These real time observations are correlated to numerical analysis of the Clausius-Mossotti factor. Taking into account the identified changes, an electrofusion protocol adequate to the optimal medium (100 mOsm, 0.03 S/m) is defined. Up to 75% simultaneous binuclear rapid electrofusions were achieved and monitored with average membrane fusion duration lower than 12s.
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18
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Nováková J, Izsáková A, Grivalský T, Ottmann C, Farkašovský M. Improved method for high-efficiency electrotransformation of Escherichia coli with the large BAC plasmids. Folia Microbiol (Praha) 2013; 59:53-61. [PMID: 23846555 DOI: 10.1007/s12223-013-0267-1] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2013] [Accepted: 06/28/2013] [Indexed: 11/28/2022]
Abstract
High transformation competency of Escherichia coli is one of the critical factors in the bacterial artificial chromosome (BAC)-based DNA library construction. Many electroporation protocols have been published until now, but the majority of them was optimized for transformation of small plasmids. Large plasmids with a size above 50 kbp display reduced transformation efficiency and thereby require specific conditions in the preparation and electroporation of electrocompetent cells. In the present work, we have optimized the parameters critical to the application of BAC DNA electrotransformation into E. coli. Systematic evaluation of electroporation variables has revealed several key factors like temperature of growth, media supplements, washing buffer, and cell concentration. Improvements made in the transformation protocol have led to electrocompetent cells with transformation efficiency up to 7 × 10(8) transformants per microgram of 120 kbp BAC plasmid DNA. We have successfully used in-house prepared competent cells, the quality of which is comparable with those produced by different companies, in the construction of metagenomic libraries from the soil. Our protocol can also be beneficial for other application with limited DNA source.
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Affiliation(s)
- Jana Nováková
- Department of Microbiology, Institute of Molecular Biology, Slovak Academy of Sciences, Dúbravská cesta 21, 84551, Bratislava, Slovakia
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19
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Chopinet L, Batista-Napotnik T, Montigny A, Rebersek M, Teissié J, Rols MP, Miklavčič D. Nanosecond electric pulse effects on gene expression. J Membr Biol 2013; 246:851-9. [PMID: 23831956 PMCID: PMC3825134 DOI: 10.1007/s00232-013-9579-y] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2012] [Accepted: 06/22/2013] [Indexed: 01/25/2023]
Abstract
Gene electrotransfection using micro- or millisecond electric pulses is a well-established method for safe gene transfer. For efficient transfection, plasmid DNA has to reach the nucleus. Shorter, high-intensity nanosecond electric pulses (nsEPs) affect internal cell membranes and may contribute to an increased uptake of plasmid by the nucleus. In our study, nsEPs were applied to Chinese hamster ovary (CHO) cells after classical gene electrotransfer, using micro- or millisecond pulses with a plasmid coding the green fluorescent protein (GFP). Time gaps between classical gene electrotransfer and nsEPs were varied (0.5, 2, 6 and 24 h) and three different nsEP parameters were used: 18 ns-10 kV/cm, 10 ns-40 kV/cm and 15 ns-60 kV/cm. Results analyzed by either fluorescence microscopy or flow cytometry showed that neither the percentage of electrotransfected cells nor the amount of GFP expressed was increased by nsEP. All nsEP parameters also had no effects on GFP fluorescence intensity of human colorectal tumor cells (HCT-116) with constitutive expression of GFP. We thus conclude that nsEPs have no major contribution to gene electrotransfer in CHO cells and no effect on constitutive GFP expression in HCT-116 cells.
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Affiliation(s)
- Louise Chopinet
- CNRS, IPBS - UMR 5089, 205 route de Narbonne, BP 64182, 31077 Toulouse Cedex 4, France
- UT1, UTM, LAAS, ITAV, UPS, INSA, INP, ISAE, Université de Toulouse, 31077 Toulouse Cedex 4, France
| | | | - Audrey Montigny
- CNRS, IPBS - UMR 5089, 205 route de Narbonne, BP 64182, 31077 Toulouse Cedex 4, France
- UT1, UTM, LAAS, ITAV, UPS, INSA, INP, ISAE, Université de Toulouse, 31077 Toulouse Cedex 4, France
| | - Matej Rebersek
- Faculty of Electrical Engineering, University of Ljubljana, Ljubljana, Slovenia
| | - Justin Teissié
- CNRS, IPBS - UMR 5089, 205 route de Narbonne, BP 64182, 31077 Toulouse Cedex 4, France
- UT1, UTM, LAAS, ITAV, UPS, INSA, INP, ISAE, Université de Toulouse, 31077 Toulouse Cedex 4, France
| | - Marie-Pierre Rols
- CNRS, IPBS - UMR 5089, 205 route de Narbonne, BP 64182, 31077 Toulouse Cedex 4, France
- UT1, UTM, LAAS, ITAV, UPS, INSA, INP, ISAE, Université de Toulouse, 31077 Toulouse Cedex 4, France
| | - Damijan Miklavčič
- Faculty of Electrical Engineering, University of Ljubljana, Ljubljana, Slovenia
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20
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Haberl S, Kandušer M, Flisar K, Hodžić D, Bregar VB, Miklavčič D, Escoffre JM, Rols MP, Pavlin M. Effect of different parameters used forin vitrogene electrotransfer on gene expression efficiency, cell viability and visualization of plasmid DNA at the membrane level. J Gene Med 2013; 15:169-81. [DOI: 10.1002/jgm.2706] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2012] [Revised: 03/29/2013] [Accepted: 04/01/2013] [Indexed: 11/09/2022] Open
Affiliation(s)
- Saša Haberl
- University of Ljubljana; Faculty of Electrical Engineering, Laboratory of Biocybernetics; Ljubljana; Slovenija
| | - Maša Kandušer
- University of Ljubljana; Faculty of Electrical Engineering, Laboratory of Biocybernetics; Ljubljana; Slovenija
| | - Karel Flisar
- University of Ljubljana; Faculty of Electrical Engineering, Laboratory of Biocybernetics; Ljubljana; Slovenija
| | - Duša Hodžić
- University of Ljubljana; Faculty of Electrical Engineering, Laboratory of Biocybernetics; Ljubljana; Slovenija
| | | | - Damijan Miklavčič
- University of Ljubljana; Faculty of Electrical Engineering, Laboratory of Biocybernetics; Ljubljana; Slovenija
| | - Jean-Michel Escoffre
- Inserm UMR 930 Imagerie et Cerveau, Université François-Rabelais de Tours, PRES Val de Loire Université; Tours; France
| | - Marie-Pierre Rols
- Institut de Pharmacologie et de Biologie Structurale, IPBS-CNRS UMR5089, Université de Toulouse III; Toulouse; France
| | - Mojca Pavlin
- University of Ljubljana; Faculty of Electrical Engineering, Group for Nano and Biotechnological Applications; Ljubljana; Slovenija
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21
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Tesic N, Cemazar M. In Vitro Targeted Gene Electrotransfer to Endothelial Cells with Plasmid DNA Containing Human Endothelin-1 Promoter. J Membr Biol 2013; 246:783-91. [DOI: 10.1007/s00232-013-9548-5] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2013] [Accepted: 04/17/2013] [Indexed: 01/03/2023]
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22
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Li J, Tan W, Yu M, Lin H. The effect of extracellular conductivity on electroporation-mediated molecular delivery. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2013; 1828:461-70. [DOI: 10.1016/j.bbamem.2012.08.014] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/15/2012] [Revised: 08/03/2012] [Accepted: 08/20/2012] [Indexed: 10/27/2022]
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23
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Physical non-viral gene delivery methods for tissue engineering. Ann Biomed Eng 2012; 41:446-68. [PMID: 23099792 DOI: 10.1007/s10439-012-0678-1] [Citation(s) in RCA: 116] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2012] [Accepted: 10/08/2012] [Indexed: 12/12/2022]
Abstract
The integration of gene therapy into tissue engineering to control differentiation and direct tissue formation is not a new concept; however, successful delivery of nucleic acids into primary cells, progenitor cells, and stem cells has proven exceptionally challenging. Viral vectors are generally highly effective at delivering nucleic acids to a variety of cell populations, both dividing and non-dividing, yet these viral vectors are marred by significant safety concerns. Non-viral vectors are preferred for gene therapy, despite lower transfection efficiencies, and possess many customizable attributes that are desirable for tissue engineering applications. However, there is no single non-viral gene delivery strategy that "fits-all" cell types and tissues. Thus, there is a compelling opportunity to examine different non-viral vectors, especially physical vectors, and compare their relative degrees of success. This review examines the advantages and disadvantages of physical non-viral methods (i.e., microinjection, ballistic gene delivery, electroporation, sonoporation, laser irradiation, magnetofection, and electric field-induced molecular vibration), with particular attention given to electroporation because of its versatility, with further special emphasis on Nucleofection™. In addition, attributes of cellular character that can be used to improve differentiation strategies are examined for tissue engineering applications. Ultimately, electroporation exhibits a high transfection efficiency in many cell types, which is highly desirable for tissue engineering applications, but electroporation and other physical non-viral gene delivery methods are still limited by poor cell viability. Overcoming the challenge of poor cell viability in highly efficient physical non-viral techniques is the key to using gene delivery to enhance tissue engineering applications.
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24
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Pavlin M, Haberl SA, Rebersek M, Miklavcic D, Kanduser M. Changing the direction and orientation of electric field during electric pulses application improves plasmid gene transfer in vitro. J Vis Exp 2011:3309. [PMID: 21931297 DOI: 10.3791/3309] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
Gene electrotransfer is a physical method used to deliver genes into the cells by application of short and intense electric pulses, which cause destabilization of cell membrane, making it permeable to small molecules and allows transfer of large molecules such as DNA. It represents an alternative to viral vectors, due to its safety, efficacy and ease of application. For gene electrotransfer different electric pulse protocols are used in order to achieve maximum gene transfection, one of them is changing the electric field direction and orientation during the pulse delivery. Changing electric field direction and orientation increase the membrane area competent for DNA entry into the cell. In this video, we demonstrate the difference in gene electrotransfer efficacy when all pulses are delivered in the same direction and when pulses are delivered by changing alternatively the electric field direction and orientation. For this purpose tip with integrated electrodes and high-voltage prototype generator, which allows changing of electric field in different directions during electric pulse application, were used. Gene electrotransfer efficacy is determined 24h after pulse application as the number of cells expressing green fluorescent protein divided with the number of all cells. The results show that gene transfection is increased when the electric field orientation during electric pulse delivery is changed.
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Affiliation(s)
- Mojca Pavlin
- Department of Fundamentals of Electrical Engineering, Mathematics and Physics, University of Ljubljana
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25
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Pavlin M, Pucihar G, Kandušer M. The role of electrically stimulated endocytosis in gene electrotransfer. Bioelectrochemistry 2011; 83:38-45. [PMID: 21907005 DOI: 10.1016/j.bioelechem.2011.08.005] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2011] [Revised: 08/12/2011] [Accepted: 08/15/2011] [Indexed: 01/08/2023]
Abstract
Gene electrotransfer is an established method for transfer of genes into cells, however, the mechanism of transfer of DNA across the cell membrane is still not known. Some studies suggest that DNA is translocated through membrane pores while others propose that DNA enters the cell via electro-endocytosis, but no direct observation was performed. In this paper we investigated the second hypothesis. Cells were stained with membrane dye FM 1-43FX, which is used for observation of endocytosis, and then exposed to electric pulses. We analyzed if endocytosis was stimulated by applying electric pulses with intensities below and above the threshold value for gene electrotransfer. No increase in endocytosis from 20 min or even up to 2h after the pulse delivery was observed, regardless of the electric field strength. These observations do not correlate with electrotransfer efficiency, which increases with field strength and is observed only above the threshold value. Our results suggest that electro-endocytosis is not a crucial mechanism for gene electrotransfer and that the hypothesis of DNA entry by translocation through permeabilized membrane is more plausible. The presented results are important for better understanding of the mechanisms of gene electrotransfer and for its optimization for clinical applications.
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Affiliation(s)
- Mojca Pavlin
- University of Ljubljana, Faculty of Electrical Engineering, Tržaška 25, SI-1000 Ljubljana, Slovenia.
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26
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Wu M, Yuan F. Membrane binding of plasmid DNA and endocytic pathways are involved in electrotransfection of mammalian cells. PLoS One 2011; 6:e20923. [PMID: 21695134 PMCID: PMC3113837 DOI: 10.1371/journal.pone.0020923] [Citation(s) in RCA: 58] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2011] [Accepted: 05/16/2011] [Indexed: 11/19/2022] Open
Abstract
Electric field mediated gene delivery or electrotransfection is a widely used method in various studies ranging from basic cell biology research to clinical gene therapy. Yet, mechanisms of electrotransfection are still controversial. To this end, we investigated the dependence of electrotransfection efficiency (eTE) on binding of plasmid DNA (pDNA) to plasma membrane and how treatment of cells with three endocytic inhibitors (chlorpromazine, genistein, dynasore) or silencing of dynamin expression with specific, small interfering RNA (siRNA) would affect the eTE. Our data demonstrated that the presence of divalent cations (Ca(2+) and Mg(2+)) in electrotransfection buffer enhanced pDNA adsorption to cell membrane and consequently, this enhanced adsorption led to an increase in eTE, up to a certain threshold concentration for each cation. Trypsin treatment of cells at 10 min post electrotransfection stripped off membrane-bound pDNA and resulted in a significant reduction in eTE, indicating that the time period for complete cellular uptake of pDNA (between 10 and 40 min) far exceeded the lifetime of electric field-induced transient pores (∼10 msec) in the cell membrane. Furthermore, treatment of cells with the siRNA and all three pharmacological inhibitors yielded substantial and statistically significant reductions in the eTE. These findings suggest that electrotransfection depends on two mechanisms: (i) binding of pDNA to cell membrane and (ii) endocytosis of membrane-bound pDNA.
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Affiliation(s)
- Mina Wu
- Department of Biomedical Engineering, Duke University, Durham, North Carolina, United States of America
| | - Fan Yuan
- Department of Biomedical Engineering, Duke University, Durham, North Carolina, United States of America
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