We discuss various models of ion transport through cell membrane channels. Recent experimental data shows that sizes of ion channels are compared to those of ions and that only few ions may be simultaneously in any single channel. Theoretical description of ion transport in such channels should therefore take into account interactions between ions and between ions and channel proteins. This is ...

We report here new electrical laws, derived from nonlinear electro-diffusion theory, about the effect of the local geometrical structure, such as curvature, on the electrical properties of a cell. We adopt the Poisson-Nernst-Planck (PNP) equations for charge concentration and electric potential as a model of electro-diffusion. In the case at hand, the entire boundary is impermeable to ions and ...

Presence of wall at the vicinity of a moving particle through a flowing or stationary fluid hindered the motion of the particle by implying more drag on it. Presence of charge on the particle alone or on both the wall and particle hinders the motion more due to electrokinetic effect like relaxation and EDL overlap. Presence of charged surface heterogeneity make the scenario worse. A 3D finite e...

We present a theoretical study of ion transport in microchannels containing nanoporous ion-selective membranes. The developed model includes the effect of water splitting as well as reactions between the liquid and the surface groups on the walls. By numerically solving the full PNP (Poisson–Nernst–Planck) problem coupled with the flow problem, results are obtained both in the simple non-advect...

The Poisson-Nernst-Planck (PNP) equation provides a continuum description of electrostatic-driven diffusion and is used here to model the diffusion and reaction of acetylcholine (ACh) with acetylcholinesterase (AChE) enzymes. This study focuses on the effects of ion and substrate concentrations on the reaction rate and rate coefficient. To this end, the PNP equations are numerically solved with...

We demonstrate the role of selectivity variation in the structure of the nonequilibrium extended space charge using one-dimensional analytic and two-dimensional numerical Poisson-Nernst-Planck models for the electro-diffusive transport of a symmetric electrolyte. This provides a deeper understanding of the underlying mechanism behind a previously observed maximum in the resistance-voltage curve...

A self-consistent solution is derived for the Poisson-Nernst-Planck (PNP) equation, valid both inside a biological ion channel and in the adjacent bidk fliud. An iterative procedure is used to match the two solutions together at the channel mouth. Charge fluctuations at the mouth are modeled as shot noise flipping the height of the potential barrier at the selectivity site. The residtant estima...

BACKGROUND It has been proposed that in the absence of a blood supply, the ocular lens operates an internal microcirculation system. This system delivers nutrients, removes waste products and maintains ionic homeostasis in the lens. The microcirculation is generated by spatial differences in membrane transport properties; and previously has been modelled by an equivalent electrical circuit and ...

This study established a reactive transport model (RTM) for saturated cement-based materials based on multi-ionic through an uncharged, ‘free water’ and charged, ‘the electrical double layer’ coupled with chemical equilibrium interaction between pore solution solid phase. A set of modified Poisson-Nernst-Planck equations, including the effect temperature, property, structure changes, have been ...

In this paper, an improved Poisson-Nernst-Planck ion channel (PNPic) model is presented, along with its effective finite element solver and software package for protein in a solution of multiple ionic species. Numerical studies are then done on the effects boundary value conditions, membrane charges, bulk concentrations electrostatics protein, gramicidin A (gA), five different solvents up to fo...