The dynamic evolution of cell chaining in a biological suspension induced by an electrical field

The behaviour of biological cells in a suspension under the effect of an alternating electrical field was numerically simulated by solving the Langevin equation for each particle in the suspension. Cells were modelled as lossy dielectric shelled spheres and their interaction was treated in the dipole approximation. Using electrical parameters taken from the literature, viable and non-viable Saccharomices cerevisiae and Neurospora crassa cells immersed in a uniform field were studied. The aggregation into linear chains was effective only above a critical value of the external field. The obtained connectivity spectra matched the effective polarizability versus frequency curves, showing the possibility of using the study of aggregation patterns to investigate the physical properties of the various cellular components. A relevant difference among the types of cells studied was that we found very low connectivities for dead yeast compared with live yeast and Neurospora cells. For the last we could observe a two-regime aggregation: first, cells formed linear chains and then the chains condensed into columnar structures. These results demonstrate that the Brownian dynamics simulations can be used as a predictive tool in the study of the influences of various physical and biological conditions on the manipulation of cells using electrical fields.