Numerical evaluation of transmembrane potential in cell aggregates in presence of lipid droplets

In the paper, finite element analyses are used to study the effect of media inhomogeneity on the electric field distribution in a sample composed of extracellular matrix and cells, including cells with a lipid droplet in the cytoplasm. In the model, voltage pulses, typical of electrochemotherapy treatments, are considered. The electric field distribution around cells is computed numerically; moreover, the transmembrane potential at the cell membrane is evaluated. In order to study cell behavior in different conditions either the presence of the collagen or the lipid droplet inside the cell cytoplasm are considered. The conductivity of the extracellular medium varied between plain collagen to myxoid, i.e., a gel-like matrix; the combinations of the two cases (a collagen shell around cells immersed in a myxoid environment) is considered too. An increase in the transmembrane potential was found in the case of higher aggregate and collagen presence. However, it is already known that, increasing the cell aggregation, the transmembrane potential increases as well as in the case of the presence of the collagen shell. In the paper, the effect of a lipid droplet is studied too.