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Surface Functionalization of a Polymeric Lipid Bilayer for Coupling a Model Biological Membrane with Molecules, Cells, and Microstructures
journal contribution
posted on 2013-02-26, 00:00 authored by Kenichi Morigaki, Kazuyuki Mizutani, Makoto Saito, Takashi Okazaki, Yoshihiro Nakajima, Yoshiro Tatsu, Hiromasa ImaishiWe describe a stable and functional model biological
membrane based
on a polymerized lipid bilayer with a chemically modified surface.
A polymerized lipid bilayer was formed from a mixture of two diacetylene-containing
phospholipids, 1,2-bis(10,12-tricosadiynoyl)-sn-glycero-3-phosphocholine
(DiynePC) and 1,2-bis(10,12-tricosadiynoyl)-sn-glycero-3-phosphoethanolamine
(DiynePE). DiynePC formed a stable bilayer structure, whereas the
ethanolamine headgroup of DiynePE enabled functional molecules to
be grafted onto the membrane surface. Copolymerization of DiynePC
and DiynePE resulted in a robust bilayer. Functionalization of the
polymeric bilayer provided a route to a robust and biomimetic surface
that can be linked with biomolecules, cells, and three-dimensional
(3D) microstructures. Biotin and peptides were grafted onto the polymeric
bilayer for attaching streptavidin and cultured mammalian cells by
molecular recognition, respectively. Nonspecific adsorption of proteins
and cells on polymeric bilayers was minimum. DiynePE was also used
to attach a microstructure made of an elastomer (polydimethylsiloxan:
PDMS) onto the membrane, forming a confined aqueous solution between
the two surfaces. The microcompartment enabled us to assay the activity
of a membrane-bound enzyme (cyochrome P450). Natural (fluid) lipid
bilayers were incorporated together with membrane-bound proteins by
lithographically polymerizing DiynePC/DiynePE bilayers. The hybrid
membrane of functionalized polymeric bilayers and fluid bilayers offers
a novel platform for a wide range of biomedical applications including
biosensor, bioassay, cell culture, and cell-based assay.