Electrofusion, also known as cell-cell electrofusion or electrically mediated cell-cell fusion, is the fusion of two cells, mediated by electrical stimulation. Dr. Mitsugi Senda first reported this technique in 1979 when he fused two plant protoplasts by using capillary microelectrodes and applying electric current. In 1981, Dr. Ulrich Zimmerman built upon Dr. Senda’s study and introduced a more efficient method in which he used parallel electrodes to fuse multiple cells. Although the technology has changed greatly, the basic concept of cell-cell electrofusion has remained unaltered since the early days of its discovery.

There are variety methods for performing cell-cell electrofusion experiments, most of which involve three basic steps: initiation, fusion and recovery. During the initiation phase, the cells of interest are placed in a low-conductive medium and brought in close proximity to one another by applying uneven electrical currents, known as dielectrophoresis. This creates dipole-dipole forces between the cells, drawing them closer in preparation for fusion. In the next step, square electric pulses are delivered to initiate fusion. During the recovery phase, the fused cells are nurtured in an environment that allows them to mature and recover. Typically, the experiment is verified chemically through the use of dyes, stains or markers. Alternatively, the results may be verified by flow cytometry.

The applications of cell-cell electrofusion are numerous and include monoclonal antibody and hybrid creation, transfer of cell materials and immunotherapy. Immunotherapy applications involve the fusion of a healthy cell with a tumor cell, so that the healthy cell masks the effects of its counterpart.

The instrumentation used to perform cell-cell electrofusion is fairly basic, and includes general laboratory instruments such as titrators, centrifuges and balances, as well as media, reagents and fusion-specific electric pulse generators. There are only a handful of vendors that offer electric pulse generators. Cyto Pulse Sciences sells the Hybrimune, which is primarily designed for monocolonal antibody creation and immunotherapy. BTX, a subsidiary of Havard Bioscience, offers the ECM 830 and 2021 electrofusion generators. Both models are square wave generators, but the ECM 2021 can accommodate a variety of cell types.

The market for cell-cell electrofusion was at its peak in the 1990s. Advances in genomics during the past decade, such as the human genome project and genome mapping of a variety of organisms, have led to the growth of other cell analysis technologies that have taken market share from electrofusion. Electroporation, in particular, has enjoyed tremendous growth in recent years. Nevertheless, the electrofusion market, although a minute part of the $300 million transfection business, is not expected to disappear, as the technology continues to be used for a variety of applications, particularly in academic laboratories.

Electrofusion at a Glance:

Leading Suppliers

• Cyto Pulse Sciences

• Harvard Apparatus

• Eppendorf

Largest Markets

• Academia

• Agriculture

• Clinical

Instrument Cost

• $500–$15,000