Energetic variational approaches in calcium and sodium<br/><br/>channels

Wednesday, December 9, 2009 - 2:10pm - 2:50pm
EE/CS 3-180
Chun Liu (University of Minnesota, Twin Cities)
Keywords: Energetic Variational Approaches, ion channels, complex fluids

Abstract: Ion channels are key components in a wide variety of biological processes, such as nerve impulse,
cardiac and muscle contraction, regulating the secretion of hormones into the bloodstream.
Ion channels are a frequent target in the search of new drugs.

Ion channels, like enzymes, have their specific properties: potassium, sodium, calcium, and chloride
channels allow only that type of ions to move through the pores. This selectivity is the key to
all those biological process mentioned above.

Selectivities in both calcium and sodium channels can be described
by the reduced models, taking into consideration of
dielectric coefficient and ion particle sizes, as well as their
very different primary structure and properties.
The side-chains are represented only as charged spheres
(calcium channel EEEA/EEEE; sodium channel DEKA).
These self-organized systems will be modeled and analyzed
with energetic variational approaches (EnVarA)
that were motivated by classical works of Rayleigh and Onsager.
The resulting/derived multiphysics-multiscale systems automatically satisfy
the Second Laws of Thermodynamics and the basic physics that are involved in the system,
such as the microscopic diffusion, the electrostatics
and the macroscopic conservation of momentum, as well as the physical boundary conditions.

In this talk, I will discuss the some of the related biological, physics, chemistry and mathematical issues.

This is a joint work with Bob Eisenberg (Rush) and Yunkyong Hyon (IMA).