2 research outputs found
Stabilization of Solid-Supported Phospholipid Multilayer against Water by Gramicidin Addition
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
Deposition of Metal Nanoparticles on Phospholipid Multilayer Membranes Modified by Gramicidin
A planar
dipalmitoyl phosphatidylcholine (DPPC) multilayer phospholipid
membrane was structurally modified by introducing a transmembrane
protein, gramicidin (up to 25 mol %), to study its effect on the metal
nanoparticles deposited on the membrane. Without gramicidin, when
3-nm-thick Ag, Sn, Al, and Au were deposited, the nanoparticles hardly
nucleated on the DPPC membrane in rigid gel state (except for Au);
however, the gramicidin addition dramatically enhanced the DPPC membrane
surface’s affinity for metal atoms so that a dense array of
metal (Ag, Sn, and Au) or metal-oxide (Al-oxide) nanoparticles was
produced on the membrane surface. The particle sizes ranged from 3
to 15 nm depending on the metal and gramicidin concentration, whereas
the particle density was strongly dictated by the gramicidin concentration.
The proposed method provides a convenient, generally applicable synthesis
route for preparing different metal or metal-oxide nanoparticles on
a relatively robust biocompatible membrane