Alternating Current Spectroscopy of Biological Substances

The electrical properties of live matter are analyzed. The article first summarizes general principles which pertain to the frequency dependence of the electrical properties of any type of matter. It then states the particular mechanism which, at various parts of the total frequency spectrum, are predominantly responsible for observed data. They include time-dependent interface polarization, accumulation of charges due to inhomogeneous structure and orientation of polar molecules. The electrical properties of water and electrolytes, of protein suspensions, of subcellular and cellular structures are outlined in terms of previously mentioned mechanism. This, in turn, permits synthesis of the experimentally observed dielectric parameters of tissues. The treatment encompasses the total range of frequencies, from 1 cps to 100,000 mc. The article concludes with a chapter which outlines the application of the data and pertinent impedance techniques to a variety of basic and applied problems in biology and medicine.