ABSTRACT
Experimental measurements of the electrical characteristics of cellular and synthetic membranes have been used widely in investigations of membrane structure, function and the relationship between these. In cellular as well as synthetic membranes, the electrical response time of the system is limited by diffusion time constants as well as dielectric charging time constants of the membrane and its substructure. Such systems display characteristic dispersions with frequency of the capacitance and conductance. The diffusion limited processes can be analyzed in terms of generalized Nernst-Planck-Poisson equations for electrodiffusion. A review is presented of the various mechanisms and membrane attributes that contribute to the dispersion of the impedance. The expected impedance dispersions are compared to experimental measurements for a variety of systems and illustrate the scope of the impedance spectroscopy technique in the study of membrane systems.
