ChemInform Abstract: Permeability Characteristics of Lipid Bilayers from Lipoic Acid Derived Phosphatidylcholines: Comparison of Monomeric, Cross‐Linked and Non‐Cross‐Linked Polymerized Membranes.

Abstract

Polymerized and monomeric forms of large unilamellar liposomes (ca.

Redox-Responsive Core-Cross-Linked Block Copolymer Micelles for Overcoming Multidrug Resistance in Cancer Cells

“…PEG-b-PLAHEMA block copolymer micelles were conveniently cross-linked by ring-opening of the 1,2dithiolane moiety based on thiol−disulfide exchange in PB (pH 7.4, 10 mM) by introducing 10 μM GSH, the concentration of GSH generally found in the blood plasma and extracellular environment. 57,58 Under the catalysis of GSH, few 1,2dithiolane rings present in the LAHEMA unit in the polymer opened to yield dihydrolipoyl (the reduced form of lipoyl) groups. Subsequently, the exchange reaction between the generated dihydrolipoyl groups and the disulfide bonds of other 1,2-dithiolane rings present in the PLAHEMA block resulted in the formation of linear disulfide bonds between the different lipoyl groups in the hydrophobic core of the micelles.…”

Polymerization of Preformed Self-Organized Assemblies

“…The formation of linear polymers in each leaflet of the bilayer reduces the permeability by factors of 2-5, whereas the formation of a cross-linked polymer network in the bilayer leaflets can decrease the permeability by at least 2 orders of magnitude. 29,30 The polymerization-induced decrease in membrane permeability is associated with a parallel increase in the chemical stability of vesicles, which is observed by resistance to dissolution by either surfactants or organic solvents; 22,23 e.g., cross-linked vesicles prepared from a bis-DenPC were not dissolved by excess Triton X-100. 31 Cross-linked vesicles of bis-SorbPC or bis-AcrylPC are also not disrupted by surfactants.…”

The Opening of 1,2‐Dithiolanes and 1,2‐Diselenolanes: Regioselectivity, Rearrangements, and Consequences for Poly(disulfide)s, Cellular Uptake and Pyruvate Dehydrogenase Complexes

“…The clarification of the regioselectivity between these isomers formed is relevant for the under-standing of functional systems in chemistry, biology, and the materials sciences. [2] [4 -22] It determines the tacticity of functional poly(disulfide)s prepared by ring-opening disulfide-exchange polymerization in vesicles, [5] on solid surfaces, [6] and in solution. [7 -13] Moreover, similar nucleophilic ring opening of lipoyl amide by acetyl thiamine 'Breslow intermediates' is believed to take place in the enzyme complex that transforms pyruvate into acetyl CoA.…”