1 research outputs found
Amphiphobic Septa Enhance the Mechanical Stability of Free-Standing Bilayer Lipid Membranes
Artificial
bilayer lipid membranes (BLMs) provide well-defined
systems for investigating the fundamental properties of membrane proteins,
including ion channels, and for screening the effect of drugs that
act on them. However, the application of this technique is limited
due to the low stability and low reconstitution efficiency of the
process. We previously reported on improving the stability of BLM
based on the fabrication of microapertures having a tapered edge in
SiO<sub>2</sub>/Si<sub>3</sub>N<sub>4</sub> septa and efficient ion
channel incorporation based on vesicle fusion accelerated by a centrifugal
force. Although the BLM stability and incorporation probability were
dramatically improved when these approaches were used, some BLMs were
ruptured when subjected to a centrifugal force. To further improve
the BLM stability, we investigated the effect of modifying the surface
of the SiO<sub>2</sub>/Si<sub>3</sub>N<sub>4</sub> septa on the stability
of BLM suspended in the septa. The modified surfaces were characterized
in terms of hydrophobicity, lipophobicity, and surface roughness.
Diffusion coefficients of the lipid monolayers formed on the modified
surfaces were also determined. Highly fluidic lipid monolayers were
formed on the amphiphobic substrates that had been modified with long-chain
perfluorocarbons. Free-standing BLMs formed in amphiphobic septa showed
a much higher mechanical stability, including tolerance to water movement
and applied centrifugal forces with and without proteoliposomes, than
those formed in the septa that had been modified with a short alkyl
chain. These results demonstrate that highly stable BLMs are formed
when the surface of the septa has amphiphobic properties. Because
highly fluidic lipid monolayers that are formed on the septa seamlessly
connect with BLMs in a free-standing region, the high fluidity of
the lipids contributes to decreasing potential damage to BLMs when
mechanical stresses are applied. This approach to improve the BLM
stability increases the experimental efficiency of the BLM systems
and will contribute to the development of high-throughput platforms
for functional assays of ion channel proteins