Ionic Membranes
Channel proteins or ion channels are
a class of proteins that in nature play a key role in the control of ion
transport across the barriers that define cells and organelles. The
proteins form water-filled nanotubes of
varying dimension that connect both sides of a lipid
bilayer membrane, and provide in this way a pathway for ions to
flow through. They are however not mere open pores or molecular sieves,
since they exhibit both selectivity (meaning that some ions are allowed to
pass whereas others are not) and gating (switching transitions between
open and closed states, often dependant on stimuli from the environment).
Since ion channels are current conducting proteins they are ideally suited
to form the basis of functional devices that combine the stability and
strength of solid-state materials with the functionality of soft
biological materials. This is the general goal towards which the Biomade
Ionic Membranes program is aimed
For the successful application of
channel proteins in functional devices two specific requirements have to
be met:
·
the channel proteins must be
embedded in a robust, non-leaky membrane and
·
the
functionality (selectivity, gating) of the channel protein must be under
control.
Using a combination of molecular
biology, protein biochemistry, electrophysiology, physical and
computational methods (the latter in collaboration with Prof. Eisenberg
and Nonner at Rush Medical College (Chicago)
and the University of Miami, respectively) we are working towards a
fundamental understanding of ion channel function as well as the ability
to manipulate these functionalities in our favour,
using the OmpF channel protein shown at the
left. In parallel, efforts are directed towards developing stable
membranes that are suitable for ion channel incorporation, both in
freestanding and supported format. These membranes will find application
in (bio-) sensors and highly (ion-) selective filters, for example in the
fields of medicine and homeland defence.
