Characterization of Interfaces between Graphene Films and Support Substrates by Observation of Lipid Membrane Formation

2013 ◽  
Vol 117 (37) ◽  
pp. 18913-18918 ◽  
Author(s):  
Kenji Yamazaki ◽  
Syunsuke Kunii ◽  
Toshio Ogino
Keyword(s):  
Lipid Membrane ◽  
Membrane Formation ◽  
Graphene Films

Electrophysiological Characterization of Transport Across Outer Membrane Channels from Gram-Negative Bacteria in Their Native Environment

2019 ◽  
Author(s):  
Jiajun Wang ◽  
Rémi Terrasse ◽  
Jayesh Arun Bafna ◽  
Lorraine Benier ◽  
Mathias Winterhalter
Keyword(s):  
Outer Membrane ◽  
Lipid Membrane ◽  
Membrane Vesicles ◽  
Outer Membrane Vesicles ◽  
Multi Drug Resistance ◽  
Gram Negative Bacteria ◽  
Membrane Channels ◽  
Gram Negative ◽  
Electrophysiological Characterization

Multi-drug resistance in Gram-negative bacteria is often associated with low permeability of the outer membrane. To investigate the role of membrane channels in the uptake of antibiotics, we extract, purify and reconstitute them into artificial planar membranes. To avoid this time-consuming procedure, here we show a robust approach using fusion of native outer membrane vesicles (OMV) into planar lipid bilayer which moreover allows also to some extend the characterization of membrane protein channels in their native environment. Two major membrane channels from <i>Escherichia coli</i>, OmpF and OmpC, were overexpressed from the host and the corresponding OMVs were collected. Each OMV fusion revealed surprisingly single or only few channel activities. The asymmetry of the OMV´s translates after fusion into the lipid membrane with the LPS dominantly present at the side of OMV addition. Compared to conventional reconstitution methods, the channels fused from OMVs containing LPS have similar conductance but a much broader distribution. The addition of Enrofloxacin on the LPS side yields somewhat higher association (<i>k<sub>on</sub></i>) and lower dissociation (<i>k<sub>off</sub></i>) rates compared to LPS-free reconstitution. We conclude that using outer membrane vesicles is a fast and easy approach for functional and structural studies of membrane channels in the native membrane.

scholarly journals Electrochemical Properties of Lipid Membranes Self-Assembled from Bicelles

Membranes ◽  
2020 ◽  
Vol 11 (1) ◽  
pp. 11
Author(s):  
Damian Dziubak ◽  
Kamil Strzelak ◽  
Slawomir Sek
Keyword(s):  
Electrochemical Properties ◽  
Self Assembly ◽  
Lipid Membranes ◽  
Lipid Membrane ◽  
Membrane Resistance ◽  
Electrochemical Characteristics ◽  
Freeze Thaw ◽  
Lipid Films ◽  
Supported Lipid Membranes

Supported lipid membranes are widely used platforms which serve as simplified models of cell membranes. Among numerous methods used for preparation of planar lipid films, self-assembly of bicelles appears to be promising strategy. Therefore, in this paper we have examined the mechanism of formation and the electrochemical properties of lipid films deposited onto thioglucose-modified gold electrodes from bicellar mixtures. It was found that adsorption of the bicelles occurs by replacement of interfacial water and it leads to formation of a double bilayer structure on the electrode surface. The resulting lipid assembly contains numerous defects and pinholes which affect the permeability of the membrane for ions and water. Significant improvement in morphology and electrochemical characteristics is achieved upon freeze–thaw treatment of the deposited membrane. The lipid assembly is rearranged to single bilayer configuration with locally occurring patches of the second bilayer, and the number of pinholes is substantially decreased. Electrochemical characterization of the lipid membrane after freeze–thaw treatment demonstrated that its permeability for ions and water is significantly reduced, which was manifested by the relatively high value of the membrane resistance.

Synthesis and characterization of nitrogen-doped graphene films using C5NCl5

2015 ◽  
Vol 106 (25) ◽  
pp. 253105 ◽  
Author(s):  
Wei Cai ◽  
Cong Wang ◽  
Xiaohong Fang ◽  
Liyou Yang ◽  
Xiaoyuan Chen
Keyword(s):  
Synthesis And Characterization ◽  
Nitrogen Doped ◽  
Graphene Films ◽  
Nitrogen Doped Graphene ◽  
Doped Graphene

Characterization of Photophysics and Mobility of Single Molecules in a Fluid Lipid Membrane

1995 ◽  
Vol 99 (49) ◽  
pp. 17662-17668 ◽  
Author(s):  
Th. Schmidt ◽  
G. J. Schuetz ◽  
W. Baumgartner ◽  
H. J. Gruber ◽  
H. Schindler
Keyword(s):  
Lipid Membrane ◽  
Single Molecules

Characterizing the Supported Lipid Membrane Formation from Cholesterol-Rich Bicelles

Langmuir ◽  
2019 ◽  
Vol 35 (47) ◽  
pp. 15063-15070 ◽  
Author(s):  
Tun Naw Sut ◽  
Soohyun Park ◽  
Younghwan Choe ◽  
Nam-Joon Cho
Keyword(s):  
Lipid Membrane ◽  
Membrane Formation
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