A Novel Engineered Membrane to Measure Electroporation: Effect of Tethers and Bioelectronic Interface

This paper reports on the construction and predictive models for an engineered tethered membrane. A key feature of the engineered membrane is that it provides a controllable and physiologically relevant environment for the study of the electroporation process. The mixed self-assembled membrane is formed via a rapid solvent exchange technique. The membrane is tethered to the gold electrode and includes an ionic reservoir separating the membrane and gold surface. Above the membrane there is an electrolyte solution, and a counter gold electrode. A voltage is applied between the gold electrodes and the current measured. The current is dependent on the energy required to form aqueous pores and the conductance of each pore. Modelling the membrane as a dielectric and elastic continuum, we construct a free energy model for pores in the membrane. The free energy model is constructed using the Poisson-Nernst-Planck (PNP) system of equations with an activity coefficient to model the steric effects of ions in the electrolyte. The electrical energy required to form a pore is estimated using the PNP system of equations coupled to the Maxwell stress tensor. The tethers are modelled as Hookean spring anchors to the membrane surface. The conductance of pores in the membrane are estimated using the generalized PNP equations to account for the finite size of ions, multiple ionic species, and the Stern and diffuse layers present. The population and radii of pores in the membrane are estimated using asymptotic approximations to the Smoluchowski-Einstein equation that are dependent on the energy required to form the pores. Using an equivalent circuit model of the tethered membrane, the current is predicted using the estimated pore population, radii, and the conductance of the pores, and compared with experimentally measured current for different tethering densities. *Correspondence: [email protected]