Wetenschappelijk nieuws

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Cell membrane electroporation- Part 1: The phenomenon

Kotnik, T. ; Kramar, P. ; Pucihar, G. ; Miklavcic, D. ; Tarek, M. Cell membrane electroporation- Part 1: The phenomenon. Electrical Insulation Magazine, IEEE. 28(5): 14-23. 2012.

Abstract

Each biological cell, trillions of which build our bodies, is enveloped by its plasma membrane. Composed largely of a bilayer (double layer) of lipids just two molecules thick (about 5 nm), and behaving partly as a liquid and partly as a gel, the cell plasma membrane nonetheless separates and protects the cell from its surrounding environment very reliably and stably. Embedded within the lipid bilayer, also quite stably, are a number of different proteins, some of which act as channels and pumps, providing a pathway for transporting specific molecules across the membrane. Without these proteins, the membrane would be a largely impenetrable barrier. Electrically, the cell plasma membrane can be viewed as a thin insulating sheet surrounded on both sides by aqueous electrolyte solutions. When exposed to a sufficiently strong electric field, the membrane will undergo electrical breakdown, which renders it permeable to molecules that are otherwise unable to cross it. The process of rendering the membrane permeable is called membrane electroporation. Unlike solid insulators, in which an electrical breakdown generally causes permanent structural change, the membrane, with its lipids behaving as a two-dimensional liquid, can spontaneously return to its prebreakdown state. If the exposure is sufficiently short and the membrane recovery sufficiently rapid for the cell to remain viable, electroporation is termed reversible; otherwise, it is termed irreversible. Since its discovery [1-3}, electroporation has steadily gained ground as a useful tool in various areas of medicine and biotechnology. Today, reversible electroporation is an established method for introducing chemotherapeutic drugs into tumor cells (electrochemotherapy) [4]. It also offers great promise as a technique for gene therapy without the risks caused by viral vectors (DNA electrotransfer) [5]. In clinical medicine, irreversible electroporation is being investigated as a method for tissue ablation (n- nthermal electroablation) [6], whereas in biotechnology, it is useful for extraction of biomolecules [7] and for microbial deactivation, particularly in food preservation [8]. This article, the first in a series of three focusing on electroporation, describes the phenomenon at the molecular level of the lipid bilayer, and then proceeds to the cellular level, explaining how exposure of a cell as a whole to an external electric field results in an inducement of voltage on its plasma membrane, its electroporation, and transport thorough the electroporated membrane. The second article will review the most important and promising applications of electroporation, and the third article will focus on the hardware for electroporation (pulse generators and electrodes) and on the need for standards, safety, and certification.

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Cell membrane electroporation- Part 2: the applications

Haberl, S.; Miklavcic, D. Sersa, G.  Frey, W.  Rubinsky B. Cell membrane electroporation-Part 2: the applications. Electrical Insulation Magazine, IEEE , 29:1,:29-37. 2013. DOI: 10.1109/MEI.2013.6410537.

Electroporation can be used as a tool for extracting or introducing molecules from or into a cell. The most important and promising applications of electroporation in medicine and biotechnology are described.

http://bit.ly/1k8qahu

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Cell membrane electroporation-Part 3: the equipment

Rebersek, M. ; Miklavcic, D. ; Bertacchini, C. ; Sack, M. Cell membrane electroporation-Part 3: the equipment. Electrical Insulation Magazine, IEEE. 30(3):8-18. 2014.

As described in Part 1, a cell membrane can be made permeable to various molecules by carrying out a procedure called electroporation [1]. This procedure is being successfully used in biology, biotechnology, and medicine [2], [3]. It requires electroporators and electrodes. An electroporator generates short HV pulses of specific shape, amplitude, duration, number, and repetition frequency [4], and the pulses are applied to the target cells or load through the electrodes [5]. The energy delivered to the load is governed by the number of pulses and the pulse voltage, current, and duration. In biomedical applications that energy can be several joules; in biotechnology, where electroporation is used for treatment of agricultural products and water, it can be several kilojoules.

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