Accurate dielectric modelling of shelled particles and cells

Dielectric modelling of shelled particles is usually based on analytical solutions of Laplaceʹs equation, assuming a simplified spherical or ellipsoidal geometry. We propose a boundary element method, derived from an integral equation for the charge density at the interfaces, to overcome the limitations of the analytical approach. It can be applied to a variety of situations involving stress effects or dielectric response of individual particles and colloidal suspensions, with particular reference to biological cells. Effects of particle shape and membrane structure, are analyzed. Polarizabilities of a spheroid with a layer defined by confocal surfaces and different elongated particles with a layer of uniform thickness, are compared. Numerical stability and efficiency of the proposed method are shown to be excellent.