Electric field-induced cell-to-cell fusion

Abstract

Cell-to-cell fusion has great potential in membrane research, membrane reconstitution and genetic mapping [25,34,49]. Furthermore, both somatic hybridization and genetic engineering offer a way of modifying plant cells and, in turn, of improving crops [49,53]. If lymphocyte cells are fused with a permanent cell line so-called hybridoma cells are produced [32] which are capable of producing monoclonal antibodies of predetermined antigenic specificity. These hybridoma cells (antibody-producing hybrids) can be envisaged as important tools in future clinical diagnosis and therapy as well as in the purification and enrichment of compounds of cell-biological and medical interest [18,65, 72]. However, despite many promising results and considerable efforts, fusion still seems to be something of an art rather than a precise science.Phenomenologically, cell-to-cell fusion is achieved presently in vitro by chemicals or inactivated virus [2,30,31,33,34,48,64]. Fusion can usually only be achieved by using membrane-disrupting agents and procedures and/or unphysiological conditions (e.g., high Ca/+ concentrations, high or low pH values, hypotonic conditions, etc.)The field of chemically and virus-induced fusion has been excellently reviewed by several authors over the last years [17,34,45,47,48]. In view of the bewildering array of data on chemically and virusinduced fusion we are obliged to conclude that we are still far from solving the molecular mechanism underlying the fusion process.Any progress in this field and in the development of novel fusion techniques will have to be evaluated by comparison with the inherent limitations of the current fusion procedures, which are listed below:

Multiplex Polymerase Chain Reaction Used for Bovine Embryo Sex Determination

“…Complete enucleation was confirmed by staining with Hoechst 33342 (Sigma). An individual bovine fibroblast was injected into the perivitelline space of the enucleated oocyte, and fusion was initiated by placing the couplets into Zimmermann fusion medium [19] followed by electrical stimulation using two DC pulses at 24 V for 15 μsec using a fusion machine (SUT F-1, Suranaree University of Technology). The reconstructed embryos were activated with 7% ethanol (Sigma) at room temperature for 5 min following by 10 μg/ml cycloheximide (Sigma) and 1.25 μg/ml cytochalasin D (Sigma) at 38.5 C under a humidified atmosphere of 5% CO2 in air for 5 h. After activation, the embryos were cultured in modified synthetic oviduct fluid (mSOF) supplemented with 3 mg/ml BSA [20] under a humidified atmosphere of 5% CO2, 5% O2, and 90% N2 at 38.5 C for 2 days.…”

Microfluidic cell fusion under continuous direct current voltage

“…In comparison, electrofusion, which is based on the application of high-voltage electric pulses, can be applied to a wide range of cell types with high efficiency and high postfusion viability. 3,4 Electrofusion typically requires specialized equipment which generates both low-voltage alternating current ͑ac͒ for cell alignment/contact and high-voltage direct current ͑dc͒ pulses for cell fusion. 5 Due to the complexity and cost associated with the instrumentation, very few studies have explored realizing this important technique on a microfluidic platform.…”

Fusion of Plant Protoplasts by Electric Fields

“…Recently, the list of methods available for protoplast fusion has been expanded by the development of techniques for fusing cells electrically (8,14 …”