The goal of this research project is to investigate the dynamical behavior of ion flow through membrane channels in living cells. The membrane channels are three-dimensional tubular-like structures whose radii are much smaller than their lengths. The ion flow is modeled by the Poisson-Nernst-Planck (PNP) system, which consists of at least two nonlinear parabolic equations for ion concentrations, coupled with an elliptic equation for the electric potential. The PNP system is singularly perturbed by the presence of small physical parameters multiplying the highest-order derivatives. This project focuses on the effects of the singular parameters on the global dynamics of the PNP model. It combines approaches from the theory of singular perturbations, dynamical systems, and partial differential equations. The PI will (i) identify the one-dimensional limiting system of the original three-dimensional PNP system when the radius of the membrane channel approaches zero; (ii) justify the limiting system by examining the relationship between the dynamics of the limiting system and the perturbed system; (iii) study the existence and stability of the steady state solutions of the systems; and (iv) explore the dynamics of the perturbed three-dimensional system based on the dynamical information of the one-dimensional limiting system.
Publications
Preprints
Publications Listed in Mathematical Reviews