The passive electrical properties of biological systems: their significance in physiology, biophysics and biotechnology.

There is much current interest in the electrical properties of biological materials, not least because of an increasing awareness of the possible physiological effects elicited by the absorption by tissues of non-ionising electromagnetic radiation (e.g. Presman 1970, Sheppard and Eisenbud 1977, Adey 1981, Illinger 1981, Konig et a1 1981, Becker and Marino 1982, Frohlich and Kremer 1983, Adey and Lawrence 1984, Chiabrera er a1 1985, Marino and Ray 1986, Polk and Postow 1986). Studies of the ways in which electromagnetic energy interacts with tissues are also of importance to the continuing development of the use of R F and microwave hyperthermia (Hahn 1982, Storm 1983), in impedance plethysmography (Hill 1979, Mohapatra 1981, Wheeler and Penney 1982, Brown 1983, Anderson 1984, Penney 1986) and pneumography (Henderson and Webster 1978, Baker 1979), in electrical impedance tomography (Pryce 1979, Barber and Brown 1984), in the gentle thawing of cryogenically preserved tissue (Burdette et a1 1980), in the use of pulsed electromagnetic fields to aid tissue and bone regeneration and healing (Barker and Lunt 1983, Pilla et a1 1983) and in a variety of existing or projected biosensing devices (Kell 1986a). The use of dielectric measurements as a tool for studying molecular and cellular parameters is a well established technique of continuing importance (e.g. Grant er a1 1978, Pethig 1979, 1984).