The aim of the project is to theoretically model the effects of fluctuations in Structured Coulomb fluids (SCF’s) and to develop the computational means to apply implicit solvent models to biological systems. SCF’s are composed of solvated ions, charged molecules like DNA, proteins or protein complexes, or larger biomolecular structures such as membranes. Since often such biological systems are highly charged, both fluctuations of the electrostatic potential or electric field and the nature of the polarizable surrounding medium, water, need to be taken into account in order to describe these systems in a proper way. In the first part of the project we will extend an established generalization of the mean-field Poisson-Boltzmann theory of SCF’s based on the electrostatic potential to include fluctuations. The second part of the project will see the development a Poisson-Boltzmann theory for an SCF in terms of a local constrained functional of the electric field, which due to its convexity property has an essential computational advantage and will allow applications of our approach to still larger systems.