The function and mode of action of curcumin in modulating the formation of lipid raft domains were investigated by microscopic observation using model membranes. Curcumin induces fusion of lipid raft domains at extremely low concentrations through the alteration of the boundary between the ordered and disordered phases.
Well-defined hybrid nanodiscs were produced by employing bicelle formation of a binary lipid mixture in water. The resulting nanoparticles have a lipid bilayer coated with ceramic layers, which are formed by the sol–gel reaction among the alkoxysilyl headgroups of the hybrid lipid. The hybrid bicelles displayed significant morphological stability against dry environments and surfactant addition, in stark contrast to conventional phospholipid bicelles.
In this study, we investigated the aggregation behaviors of amphiphilic poly(vinyl ether)s with antimicrobial activity. We synthesized a di-block poly(vinyl ether), B3826, composed of cationic primary amine and hydrophobic isobutyl (iBu) side chains, which previously showed antimicrobial activity against Escherichia coli. B3826 showed similar uptake behaviors as those for a hydrophobic fluorescent dye, 1,6-diphenyl-1,3,5-hexatriene, to counterpart polymers including homopolymer H44 and random copolymer R4025, indicating that the iBu block does not form strong hydrophobic domains. The cryo-TEM observations also indicated that the polymer aggregate of B3826 appears to have low-density polymer chains without any defined microscopic structures. We speculate that B3826 formed large aggregates by liquid-liquid separation due to the weak association of polymer chains. The fluorescence microscopy images showed that B3826 bonds to E. coli cell surfaces, and these bacterial cells were stained by propidium iodide, indicating that the cell membranes were significantly damaged. The results suggest that block copolymers may provide a new platform to design and develop antimicrobial materials that can utilize assembled structures and properties.