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Formation and disruption of vesicles could be photochemically controlled in aqueous mixtures of a “photo-switchable” azobenzene-modified cationic surfactant (4-butylazobenzene-4‘-(oxyethyl)trimethylammonium bromide; AZTMA) and an anionic surfactant (sodium dodecylbenzenesulfonate; SDBS). Vesicles were formed spontaneously in a wide composition range in aqueous trans-AZTMA/SDBS mixtures. AZTMA molecules constituting vesicles underwent reversible trans−cis photoisomerization upon alternate UV and visible-light irradiation. Transmission electron microscopic observations via freeze replica technique demonstrated the disruption of the vesicles into larger aggregates (precipitate) with UV-light irradiation (cis formation) and the following visible-light irradiation (trans formation) resulted in vesicle reformation. Furthermore, the release rate of aqueous compounds encapsulated in vesicles was shown to be photochemically controllable in the present AZTMA/SDBS mixed system.

Oligomerization, conformational changes, and the consequent neurodegeneration of Alzheimer's β-amyloid protein (AβP) play crucial roles in the pathogenesis of Alzheimer's disease (AD). Mounting evidence suggests that oligomeric AβPs cause the disruption of calcium homeostasis, eventually leading to neuronal death. We have demonstrated that oligomeric AβPs directly incorporate into neuronal membranes, form cation-sensitive ion channels (“amyloid channels”), and cause the disruption of calcium homeostasis via the amyloid channels. Other disease-related amyloidogenic proteins, such as prion protein in prion diseases or α-synuclein in dementia with Lewy bodies, exhibit similarities in the incorporation into membranes and the formation of calcium-permeable channels. Here, based on our experimental results and those of numerous other studies, we review the current understanding of the direct binding of AβP into membrane surfaces and the formation of calcium-permeable channels. The implication of composition of membrane lipids and the possible development of new drugs by influencing membrane properties and attenuating amyloid channels for the treatment and prevention of AD is also discussed.