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Lipid Bilayer Membrane (lipid + bilayer_membrane)

Distribution by Scientific Domains

Chemistry	80%

Selected Abstracts

Electroreduction of Oxygen by Cytochrome,c Oxidase Immobilized in Electrode-Supported Lipid Bilayer Membranes

CHEMISTRY & BIODIVERSITY, Issue 9 2004
Lianyong Su
Cytochrome c oxidase is the terminal enzyme in mammalian respiration, and one of its main functions is to catalyze the reduction of oxygen under physiological conditions. Direct reduction of oxygen at electrodes requires application of substantial overpotentials. In this work, bovine cytochrome c oxidase has been immobilized in electrode-supported lipid bilayer membranes to investigate the electroreduction of oxygen under flow conditions. The effect that temperature, solution pH, and solution composition have on the reduction of oxygen by this novel enzyme-modified electrode is reported. Results indicate that the electroreduction of oxygen is most pronounced at low pH (6.4) and elevated temperature (38°). At an applied potential of ,350,mV vs. Ag/AgCl (1M KCl), a current density of ca. 7,,A/cm2 was obtained. The current responses obtained at these electrodes are stable over a period of ca. 10,14 days (10,15% decrease in response). The cytochrome c oxidase-modified electrodes described here could potentially be used for the direct electroreduction of oxygen to water in a biofuel cell. [source]

Novel Engineered Ion Channel Provides Controllable Ion Permeability for Polyelectrolyte Microcapsules Coated with a Lipid Membrane

ADVANCED FUNCTIONAL MATERIALS, Issue 2 2009
Andrew R. Battle
Abstract The development of nanostructured microcapsules based on a biomimetic lipid bilayer membrane (BLM) coating of poly(sodium styrenesulfonate) (PSS)/poly(allylamine hydrochloride) (PAH) polyelectrolyte hollow microcapsules is reported. A novel engineered ion channel, gramicidin (bis-gA), incorporated into the lipid membrane coating provides a functional capability to control transport across the microcapsule wall. The microcapsules provide transport and permeation for drug-analog neutral species, as well as positively and negatively charged ionic species. This controlled transport can be tuned for selective release biomimetically by controlling the gating of incorporated bis-gA ion channels. This system provides a platform for the creation of "smart" biomimetic delivery vessels for the effective and selective therapeutic delivery and targeting of drugs. [source]

Anion,, Slides for Transmembrane Transport

CHEMISTRY - A EUROPEAN JOURNAL, Issue 1 2009
Jiri Mareda Dr.
Abstract The recognition and transport of anions is usually accomplished by hydrogen bonding, ion pairing, metal coordination, and anion,dipole interactions. Here, we elaborate on the concept to use anion,, interactions for this purpose. Different to the popular cation,, interactions, applications of the complementary ,-acidic surfaces do not exist. This is understandable because the inversion of the aromatic quadrupole moment to produce ,-acidity is a rare phenomenon. Here, we suggest that ,-acidic aromatics can be linked together to produce an unbendable scaffold with multiple binding sites for anions to move along across a lipid bilayer membrane. The alignment of multiple anion,, sites is needed to introduce a cooperative multi-ion hopping mechanism. Experimental support for the validity of the concept comes from preliminary results with oligonaphthalenediimide (O-NDI) rods. Predicted by strongly positive facial quadrupole moments, the cooperativity and chloride selectivity found for anion transport by O-NDI rods were consistent with the existence of anion,, slides. The proposed mechanism for anion transport is supported by DFT results for model systems, as well as MD simulations of rigid O-NDI rods. Applicability of anion,, slides to achieve electroneutral photosynthesis is elaborated with the readily colorizable oligoperylenediimide (O-PDI) rods. To clarify validity, scope and limitations of these concepts, a collaborative research effort will be needed to address by computer modeling and experimental observations the basic questions in simple model systems and to design advanced multifunctional anion,, architectures. [source]

Two-Component Membrane Lithography via Lipid Backfilling

CHEMPHYSCHEM, Issue 3 2005
Seung-Yong Jung Dr.
A novel lithographic technique to pattern artificial lipid bilayer microdomains has been developed which exploits the limited mobility of gel-phase phospholipids. With this technique, fluid microdomains could be patterned into a solid gel-like matrix or gel-like lipids could be patterned in a sea of fluid lipids. In both cases, the patterned areas form a cohesive and contiguous supported lipid bilayer membrane (see picture). [source]