Abstract

A dielectric boundary in a biomolecular system is a solute-solvent (e.g., protein-water) interface that defines the dielectric coefficient to be one value in the solute region and another in solvent. The inhomogeneous dielectric medium gives rise to an effective dielectric boundary force that is crucial to the biomolecular conformation and dynamics. This lecture presents a precise definition and explicit formula of the dielectric boundary force based on the classical Poisson-Boltzmann theory of electrostatic interactions. These results are used to study the motion of a cylindrical dielectric boundary driven by the competition between the surface tension, dielectric boundary force, and solvent viscous force. Implications of the mathematical findings to biomolecular conformational stabilities are discussed.