Formation of cell protrusions by an electric field: a thermodynamic analysis.

This work gives a thermodynamic analysis of outgrowth extraction from the cell body by a pulling force. The results are applied for a case when the pulling force is generated by an external high-frequency electric field. Two equilibrium conditions are analyzed: internal equilibrium of an outgrowth and equilibrium between the outgrowth and the cell body. In both cases the stability of feasible equilibrium states was studied. The work shows that the curvature of an outgrowth equilibrated with a pulling electric force depends on the squared amplitude of the electric field E0(2), on the outgrowth length l and on the transmembrane pressure differential delta P, and that at a sufficiently large transmembrane pressure differential the cylindrical form of the outgrowth loses its stability. Long outgrowths are more stable than short ones. The minimal value of critical pressure differential was estimated. The work also shows that outgrowth extraction from the cell body requires that the applied force exceeds a critical value below which no outgrowth is formed. The value of the electric field at which outgrowth formation is feasible was estimated.