Homogeneous hybrid droplet interface bilayers assembled from binary mixtures of DPhPC phospholipids and PB-b-PEO diblock copolymers

Subhadeep Koner; Joseph Tawfik; Farzin Mashali; Kristen B Kennison; William T McClintic; Frederick A Heberle; Yu-Ming Tu; Manish Kumar; Stephen A Sarles

doi:10.1016/j.bbamem.2022.183997

Homogeneous hybrid droplet interface bilayers assembled from binary mixtures of DPhPC phospholipids and PB-b-PEO diblock copolymers

Biochim Biophys Acta Biomembr. 2022 Oct 1;1864(10):183997. doi: 10.1016/j.bbamem.2022.183997. Epub 2022 Jun 16.

Authors

Subhadeep Koner¹, Joseph Tawfik¹, Farzin Mashali¹, Kristen B Kennison², William T McClintic², Frederick A Heberle², Yu-Ming Tu³, Manish Kumar⁴, Stephen A Sarles⁵

Affiliations

¹ Department of Mechanical Aerospace and Biomedical Engineering, University of Tennessee, Knoxville, TN 37996, USA.
² Department of Chemistry, University of Tennessee, Knoxville, TN 37996, USA.
³ Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, MA, USA.
⁴ McKetta Department of Chemical Engineering, The University of Texas at Austin, Austin, TX 78712, USA; Department of Civil, Architectural and Environmental Engineering, The University of Texas at Austin, Austin, TX 78712, USA.
⁵ Department of Mechanical Aerospace and Biomedical Engineering, University of Tennessee, Knoxville, TN 37996, USA. Electronic address: ssarles@utk.edu.

PMID: 35718208
DOI: 10.1016/j.bbamem.2022.183997

Abstract

Hybrid membranes built from phospholipids and amphiphilic block copolymers seek to capitalize on the benefits of both constituents for constructing biomimetic interfaces with improved performance. However, hybrid membranes have not been formed or studied using the droplet interface bilayer (DIB) method, an approach that offers advantages for revealing nanoscale changes in membrane structure and mechanics and offers a path toward assembling higher-order tissues. We report on hybrid droplet interface bilayers (hDIBs) formed in hexadecane from binary mixtures of synthetic diphytanoyl phosphatidylcholine (DPhPC) lipids and low molecular weight 1,2 polybutadiene-b-polyethylene oxide (PBPEO) amphiphilic block copolymers and use electrophysiology measurements and imaging to assess the effects of PBPEO in the membrane. This work reveals that hDIBs containing up to 15 mol% PBPEO plus DPhPC are homogeneously mixtures of lipids and polymers, remain highly resistive to ion transport, and are stable-including under applied voltage. Moreover, they exhibit hydrophobic thicknesses similar to DPhPC-only bilayers, but also have significantly lower values of membrane tension. These characteristics coincide with reduced energy of adhesion between droplets and the formation of alamethicin ion channels at significantly lower threshold voltages, demonstrating that even moderate amounts of amphiphilic block copolymers in a lipid bilayer provide a route for tuning the physical properties of a biomimetic membrane.

Keywords: Alamethicin; Diblock copolymer; Diphythanoyl phosphatidylcholine (DPhPC); Droplet interface bilayer; Hybrid membrane; Polybutadiene-b-polyethylene oxide (PBPEO).

Publication types

Research Support, Non-U.S. Gov't
Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

Alamethicin
Lipid Bilayers / chemistry
Phosphatidylcholines* / chemistry
Phospholipids* / chemistry

Substances

Lipid Bilayers
Phosphatidylcholines
Phospholipids
Alamethicin