Response of A Saline Solution Containing A Macromolecule To An External Electric Field

The dynamical behavior of a model for body fluids in response to an external electric field is computationally investigated for communication frequencies. The effect of an applied potential difference between two electrodes in a saline solution containing a rodlike macromolecule is studied by solving the Poisson and ion continuity equations simultaneously using the finite element method (FEM). Examples of such macromolecules are stiff fragments of DNA or actin filaments. The electric field of 66 Vm-1 is considered to be applied along the symmetry axis of the system with a frequency of 1 GHz. For times larger than a few microseconds, the aggregation of the counter ions around the macromolecule decreases. This result is consistent with the experimental evidence reported in the literature. In order to reach sufficient accuracy of the model, the effect of the electroosmotic flow is investigated on the counter ion number density and on the permittivity of the system, which shows negligible effect. The real and imaginary parts of effective complex permittivity are obtained as 73.43 and 3.61, respectively, which is in agreement with the experimental limits obtained for protein solution. It is notable that the analysis is applicable to the Global System for Mobile communications (GSM) which operates in the GHz frequency band.