Conducting polymers as model biological membranes

Andrzej Lewenstam 

Abo Akademi University, Center for Process Analytical Chemistry and Sensor Technology ProSens (PROSENS), Biskopsgatan 8, Turku 00410, Finland
AGH University of Science and Technology, Faculty of Materials Science and Ceramics (AGH UST), Mickiewicza 30, Kraków 30-059, Poland

Abstract

Conducting polymers (CPs) films, poly(3,4-ethylene- dioxythiophene) (PEDOT) and poly(pyrrole), doped with adenosine triphosphate, heparin, asparagine or glutamine and made sensitive to calcium and magnesium are used to study the influence of a competitive magnesium and calcium ion-exchange on a membrane potential formation.

The films are analyzed by X-ray Photoelectron Spectroscopy (XPS) and Energy Dispersive Analysis of X-rays (EDAX) to show how their topography and morphology is influenced by the conditions during electrodeposition and post-deposition soaking. Atomic Force Microscopy (AFM) and Scanning Electron Microscopy (SEM) are used to prove that the topography and morphology of the films determines the quality of their open-circuit (potentiometric) response. More smooth and less rough films result in better potentiometric characteristics, particularly in a faster response, which is a prerequisite for using the CPs films as model biological membranes.

Membrane potential transients provoked by a competitive calcium and magnesium ion-exchange at the sites (dopants) dispersed in the films, and the mechanism of activation of calcium channels blocked by magnesium-site interaction are investigated. Theoretical interpretation in time domain is obtained by the numerical resolution of Nernst-Planck-Poisson (NPP) coupled equations or simpler diffusion-layer model, deduced from the NPP.

 

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Presentation: Tutorial lecture at SMCBS'2005 Workshop, by Andrzej Lewenstam
See On-line Journal of SMCBS'2005 Workshop

Submitted: 2005-07-20 10:57
Revised:   2009-06-07 00:44