Ion-channel-like behavior in lipid bilayer membranes at the melting transition

TL;DR

This paper investigates ion-channel-like behavior in lipid bilayer membranes at melting transition, revealing power-law open time distributions and proposing a pore freezing model to explain ion permeability and noise characteristics.

Contribution

It introduces a pore freezing model that explains quantized currents and 1/f noise in lipid membranes at phase transition, linking physical state to ion channel behavior.

Findings

Open time histogram follows a -3/2 power law.

Open-closed transition rate decreases as t^{-1}.

Model accounts for observed 1/f noise.

Abstract

It is well known that at the gel-liquid phase transition temperature a lipid bilayer membrane exhibits an increased ion permeability. We analyze the quantized currents in which the increased permeability presents itself. The open time histogram shows a "-3/2" power law which implies an open-closed transition rate that decreases like $k(t) \propto t^{-1}$ as time evolves. We propose a "pore freezing" model to explain the observations. We discuss how this model also leads to the $1/f^{\alpha}$ noise that is commonly observed in currents across biological and artificial membranes.