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An accurate and efficient characterization of the polyelectrolyte properties for cytoskeleton filaments are key to the molecular understanding of electrical signal propagation, bundle and network formation, as well as other relevant physicochemical processes associated with biological functions in eukaryotic cells and their potential nanotechnological applications. In this article, we introduce an innovative multi-scale approach able to account for the atomistic details of a proteins molecular structure, its biological environment, and their impact on electrical impulses propagating along wild type Actin filaments. The approach provides a novel, simple, accurate, approximate analytic expression for the characterization of electrical impulses in the shape of soliton waveforms. It has been successfully used to determine the effects of electrolyte conditions and voltage stimulus on the electrical impulse shape, attenuation and kern propagation velocity in these systems. Our results predict the propagation of electrical signal impulses in the form of solitons for the range of voltage stimulus and electrolyte solutions typically present in intracellular and in-vitro conditions. This multi-scale theory may also be applicable to other highly charged rod-like polyelectrolytes with relevance in biomedicine and biophysics. It is also able to account for molecular structure conformation (mutation) and biological environment (protonations/deprotonations) changes often present in pathological conditions.

The accurate characterization of electrical double layer properties of nanoparticles is of fundamental importance for optimizing their physicochemical properties for specific biotechnological and biomedical applications. In this article, we use classical solvation density functional theory and a surface complexation model to investigate the effects of pH and nanoparticle size on the structural and electrostatic properties of an electrolyte solution surrounding a spherical silica oxide nanoparticle. The formulation has been particularly useful for identifying dominant interactions governing the ionic driving force under a variety of pH levels and nanoparticle sizes. As a result of the energetic interplay displayed between electrostatic potential, ion-ion correlation and particle crowding effects on the nanoparticle surface titration, rich, non-trivial ion density profiles and mean electrostatic potential behavior have been found., Comment: 21 pages, 7 figures, submitted for publication to PCCP