Diffusion in Low-Dimensional Lipid Membranes

• Published in: Nano letters Vol. 14; no. 10; pp. 5984 - 5988
• Main Authors: Heath, George R, Roth, Johannes, Connell, Simon D, Evans, Stephen D
• Format: Journal Article
• Language: English
• Published: Washington, DC American Chemical Society 08.10.2014
• Subjects: Atomic force microscopy; Condensed matter: structure, mechanical and thermal properties; Cross-disciplinary physics: materials science; rheology; Diffusion; Diffusion in nanoscale solids; Diffusion in solids; Electron, ion, and scanning probe microscopy; Exact sciences and technology; High speed; Humans; Influenza A virus - chemistry; Influenza, Human - virology; Lipid Bilayers - chemistry; Lipids; Materials science; Membranes; Methods of nanofabrication; Microscopy, Atomic Force; Models, Molecular; Nanolithography; Nanostructure; Nanotechnology; Phosphatidylcholines - chemistry; Phosphatidylethanolamines - chemistry; Physics; Proteins; Scanning probe microscopy: scanning tunneling, atomic force, scanning optical, magnetic force, etc; Structure of solids and liquids; crystallography; Transport properties of condensed matter (nonelectronic); Viral Matrix Proteins - chemistry; lipid diffusion; Lipid membranes; nanolithography; high-speed AFM; molecular crowding; Atomic force microscopy; Dimensionality; Macromolecules; Lipids; Diffusion; Nanolithography; Physical properties; Energy transfer; Lipid bilayers; Membrane proteins
• DOI: 10.1021/nl503024v
• ISSN: 1530-6984

The diffusion behavior of biological components in cellular membranes is vital to the function of cells. By collapsing the complexity of planar 2D membranes down to one dimension, fundamental investigations of bimolecular behavior become possible in one dimension. Here we develop lipid nanolithography methods to produce membranes, under fluid, with widths as low as 6 nm but extending to microns in length. We find reduced lipid mobility, as the width is reduced below 50 nm, suggesting different lipid packing in the vicinity of boundaries. The insertion of a membrane protein, M2, into these systems, allowed characterization of protein diffusion using high-speed AFM to demonstrate the first membrane protein 1D random walk. These quasi-1D lipid bilayers are ideal for testing and understanding fundamental concepts about the roles of dimensionality and size on physical properties of membranes from energy transfer to lipid packing.