Characterizing Oscillatory and Excitability Regimes in a Protein-Free Lipid Membrane

Sandip Das, Matan Mussel

Research output: Contribution to journalArticlepeer-review

Abstract

Observations of electric potential oscillations in artificial lipid bilayers near the order-disorder transition indicate the existence of a stable limit cycle and, therefore, the possibility of producing excitable signals close to the bifurcation. We present a theoretical investigation of membrane oscillatory and excitability regimes induced by an increase in ion permeability at the order-disorder transition. The model accounts for the coupled effects of state-dependent permeability, membrane charge density, and hydrogen ion adsorption. A bifurcation diagram shows a transition between fixed-point and limit cycle solutions, enabling both oscillatory and excitability responses at different values of the acid association parameter. Oscillations are identified in terms of the membrane state, electric potential difference, and ion concentration near the membrane. The emerging voltage and time scales agree with measurements. Excitability is demonstrated by applying an external electric current stimulus, and the emerging signals display a threshold response and the appearance of repetitive signals upon using a long-lasting stimulus. The approach highlights the important role of the order-disorder transition, enabling membrane excitability in the absence of specialized proteins.

Original languageEnglish
Pages (from-to)5752-5760
Number of pages9
JournalLangmuir
Volume39
Issue number16
DOIs
StatePublished - 25 Apr 2023

Bibliographical note

Publisher Copyright:
© 2023 American Chemical Society.

ASJC Scopus subject areas

  • Condensed Matter Physics
  • General Materials Science
  • Spectroscopy
  • Surfaces and Interfaces
  • Electrochemistry

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