PubMed · 4172613
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O N Voskresenskiĭ. 1967. [A simple apparatus for microextraction].. https://pubmed.ncbi.nlm.nih.gov/4172613/
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Nanoscopic domains with different crystal structures have been induced in closed artificial membranes and have been directly imaged by atomic force microscopy at a spatial resolution better than 0.3 nm. These observations provide experimental evidence to the hydrophobic mismatching theory of lateral phase separation phenomena. Under oxidant conditions, the lipid-lipid assembly reorganizes into a new steady-state structure with disappearance of specific nanodomains. This finding may contribute to understanding the mechanism of peroxidative damage to membrane properties. In fact, alterations of specific modes of molecular conformation and packing may lead to perturbation of specific properties.
To prepare patterns of adsorption sites for alkanethiols with high lateral resolution, we used the scanning electrochemical microscopy (SECM) to etch masks into uniform layers of nickel coated on gold surfaces. The patterning of the nickel mask was accomplished in aqueous solutions by electrogenerating nitric acid out of nitrite at an ultramicroelectrode. Due to the sluggish kinetics of nickel etching in acidic media, the pattern generated by a 10-microm tip was about 50-microm wide, depending on the duration of the etching. As an alternative, applying the principle of the chemical lens by adding potassium hydroxide as a scavenger, the size of the adsorption sites had been reduced to 4 microm, independent of the duration of etching. In a follow-up step, monolayers of 11-mercaptoundecanoic acid were formed on the exposed gold areas of the surface by self-assembly. Fluorescent liposomes containing tetramethylrhodamine-labeled phospholipids were used to create solid-supported lipid layers (SSLLs). These fluorescent liposomes showed a selective binding affinity to the self-assembled monolayers (SAMs) modified areas, but not to the nickel surface. The patterns generated were imaged by the SECM itself, as well as by optical and fluorescence microscopy.
Oxidation of oil-in-water emulsion droplets is influenced by the properties of the interfacial membrane surrounding the lipid core. Previous work has shown that an important factor in the oxidation of oil-in-water emulsions is surfactant properties that impact interactions between water-soluble prooxidants and lipids in the emulsion droplet. The purpose of this research was to study the impact of surfactant hydrophobic tail group size on lipid oxidation in oil-in-water emulsions stabilized by polyoxyethylene 10 lauryl ether (Brij-lauryl) or polyoxyethylene 10 stearyl ether (Brij-stearyl). The ability of iron to decompose cumene peroxide was similar in hexadecane emulsions stabilized by Brij-stearyl and Brij-lauryl. Oxidation of methyl linoleate in hexadecane emulsions containing cumene peroxide was greater in droplets stabilized by Brij-lauryl than in those stabilized by Brij-stearyl at pH 3 with no differences observed at pH 7.0. Oxidation of salmon oil was greater in emulsions stabilized by Brij-lauryl than in those stabilized by Brij-stearyl as determined by both lipid peroxides and headspace propanal. These results suggest that surfactant hydrophobic tail group size may play a minor role in lipid oxidation in oil-in-water emulsions.