Membrane applications Electroporation

Transdermal iontophoresis involves the application of an electric field across the skin to facilitate (primarily) ionic transport across the membrane. Iontophoresis, it is important to point out, is differentiated from electroporation [14], another electrical approach to enhance transdermal transport, by the low fields employed. Whereas iontophoresis has achieved commercialization, there is (to our knowledge) no active development in progress of a transdermal delivery system employing electroporation. 

Application of an electric field to lipid bilayers such as those found in cellular membranes causes short-term depolarization of the membrane and formation of pores and other structural changes [17]. These so-called electropores allow the uptake of hydrophilic macromolecules such as plasmid DNA, siRNA, or proteins that are otherwise unable to diffuse passively through this highly regulated barrier. The use of high-voltage electrical pulses to permeabilize cell membranes was first described as a tool to deliver DNA into mammalian cells in 1982 (Wong and Neumann 1982 Neumann et al. 1982). In cuvette-based methods, cells are... 

Transfection efficacy of naked DNA can be increased by physical methods such as electroporation and sonication. Electroporation employs electric pulses to punch holes in the cell membrane, usually smaller than 10 nm but larger than oligonucleotides. With the use of electroporation, DNA was delivered into the cytosol of cells by diffusion. Since its introduction in 1982, in vivo transfection has been achieved in skeletal muscle, fiver, skin, tumors, testis, and the kidney. Tsujie et al. (2001) developed a method to target glomeruli using electroporation in vivo wherein injection of plasmid DNA via the renal artery was followed by application of electric fields. The kidney was electroporated by sandwiching the organ... 

Cell lysis under a high electric field is referred to as electroporation [6], Under these conditions, the cell membrane experiences dramatic changes in permeability to macromolecules. The main applications of the electroporation include the electrotransformation of cells and the electroporative gene transfer by the uptake of foreign DNA or RNA (in plants, animals, bacteria, and yeast). The electric field generates permeable microspores at the cell membrane, so that the nucleic acid can be introduced by electroosmosis or diffusion. 

Figure 6.35. Electroporation. Foreign DNA can be introduced into plant cells by electroporation, the application of intense electric fields to make their plasma membranes transiently permeable.

The continuous interest and growth of the various new industrial processes related to the life sciences will also require significant contributions from membrane engineering. It is hoped that future research would provide deeper insight on the precise mechanisms involved, which would show new direction for research in membrane science and applications. It is, however, important to recognize that applicability of electroporation has been demonstrated in a variety of bacteria, yeast, and mammalian cells and some applications are ready for exploitation while many new technologies seem potentially possible. 

One of the striking applications of electroporation is incorporation of externally added protein into plasma membrane. Protein molecules with amphipathic nature can be stably entrapped in electroporated membrane when they reseal. This phenomenon called electroinsertion has been demonstrated in a number of investigations. For example, electroinsertion of transmembrane protein CD4 receptors [60] and glycophorin [61] was demonstrated, which may prove valuable in surface engineering and studies on transmembrane proteins. In addition, a number of exogenous peptides and protein enzymes have been introduced... 

Chapter 26 Membrane Electroporation and Emerging Biomedical Applications.741... 

The phenomenon of membrane electrofusion is of particular interest, because of its widespread use in cell biology and biotechnology (e.g., [162-164] and the references cited therein). The application of electrofusion to cells can lead to the creation of multinucleated viable cells with new properties (this phenomenon is also known as hybridization) (e.g., [164]). In addition, electroporation and electrofusion are often used to introduce molecules like proteins, foreign genes (plasmids), antibodies, and drugs into cells. 

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