Stabilization
of Solid-Supported Phospholipid Multilayer against Water by Gramicidin
Addition
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Abstract
It was demonstrated that hydrophobicity
of solid supported planar
dipalmitoyl phosphatidylcholine (DPPC) phospholipid multilayer can
be greatly increased by incorporating a transmembrane protein, gramicidin,
into the DPPC membrane. The contact angle of deionized water droplet
on the gramicidin-modified DPPC membrane increased from 0° (complete
wetting) without gramicidin to 55° after adding 15 mol % gramicidin.
The increased hydrophobicity of the gramicidin-modified DPPC membrane
allowed the membrane to remain stable at the air/water interface as
well as underwater. The Au nanoparticles deposited on the gramicidin-modified
DPPC membrane reproduced the characteristic surface plasmon resonance
peak after being kept underwater or in phosphate-buffered saline solution
for 5 days, attesting to the membrane stability in an aqueous environment.
The enhanced underwater stability of the lipid multilayer substantially
broadens the potential application of the lipid multilayer which includes
biosensing, enzymatic fuel cell, surface enhanced Raman spectroscopy
substrate