Title: Reversible Lifting of Surface Supported Lipid Bilayers with a Membrane-Spanning Nonionic Triblock Copolymer

Abstract

Neutron reflectometry was used to monitor structural variations in surface supported DMPC bilayers induced by the addition of Triton X-100, a surfactant commonly used to aid solubilization of membrane proteins, and the co-addition of a membrane spanning non-ionic amphiphilic triblock copolymer, (PEO₁₁₇-PPO₄₇-PE_O117, Pluronic F98). Surfactant addition causes slight compression of the bilayer thickness and the creation of a distinct EO layer that increases the hydrophilic layer proximal to the supporting substrate (i.e., a water and EO gap between the lipid bilayer and quartz) to 6.8 ± 0.4 Å. Addition of the triblock copolymer into the DMPC: Triton X-100 bilayer increases the complexity (broadens) the lipid phase transition, further compresses the bilayer, and continues to expand the proximal hydrophilic layer thickness. The observed structural changes are temperature dependent with transmembrane polymer insertion achieved at 37 °C leading to a compressed membrane thickness of 39.2 ± 0.2 Å and proximal gap of 45.2 ± 0.2 Å. Temperature driven exclusion of the polymer at 15 °C causes partitioning of the polymer into the proximal space generating a large hydrogel cushion 162 ± 16 Å thick. An intermediate gap width (10 – 27 Å) is achieved at room temperature (22 – 25 °C). Themore » temperature-driven changes in the proximal hydrophilic gap dimensions are shown to be reversible but thermal history causes variation in magnitude. Temperature-driven changes in polymer association with a supported lipid bilayer offer a facile means to reversibly control both the membrane characteristics as well as the separation between membrane and solid substrate.« less

Authors:

Hayden, Steven C. ^[1]; Junghans, Ann ^[1]; Majewski, Jaroslaw ^[2]; Firestone, Millicent A.  ^[1]

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• Search DOE PAGES for ORCID "0000-0002-8671-1502"

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+ Show Author Affiliations

1. Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
2. Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Univ. of California, Davis, CA (United States)

Publication Date:

Wed Feb 22 00:00:00 EST 2017

Research Org.:

Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

Sponsoring Org.:

USDOE Office of Science (SC). Basic Energy Sciences (BES) (SC-22)

OSTI Identifier:

1414103

Report Number(s):

LA-UR-17-21430
Journal ID: ISSN 1525-7797

Grant/Contract Number:  

AC52-06NA25396

Resource Type:

Accepted Manuscript

Journal Name:

Biomacromolecules

Additional Journal Information:

Journal Volume: 18; Journal Issue: 4; Journal ID: ISSN 1525-7797

Publisher:

American Chemical Society

Country of Publication:

United States

Language:

English

Subject:

36 MATERIALS SCIENCE; Material Science