The understanding of the interaction between the membrane of neurons and amyloid-β peptides is of crucial importance to shed light on the mechanism of toxicity in Alzheimer's disease. This paper describes how supercritical angle fluorescence spectroscopy was applied to monitor in real-time the interaction between a supported lipid bilayer (SLB) and the peptide. Different forms of amyloid-β (40 and 42 amino acids composition) were tested, and the interfacial fluorescence was measured to get information about the lipid integrity and mobility. The results show a concentration-dependent damaging process of the lipid bilayer. Prolonged interaction with the peptide up to 48 h lead to an extraction and clustering of lipid molecules from the surface and a potential disruption of the bilayer, correlated with the formation of peptide aggregates. The natural diffusion of the lipid was slightly hindered by the interaction with amyloid-β(1-42) and closely related to the oligomerization of the peptide. The adsorption and desorption of Amyloid-β was also characterized in terms of affinity. Amyloid-β(1-42) exhibited a slightly higher affinity than amyloid-β(1-40). The former was also more prone to aggregate and to adsorb on the bilayer as oligomer.

中文翻译：

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通过超临界角荧光研究淀粉样蛋白-β肽-脂质双层相互作用。

了解神经元膜与淀粉样β肽之间的相互作用对于阐明阿尔茨海默氏病的毒性机制至关重要。本文介绍了如何应用超临界角荧光光谱法实时监测支持的脂质双层（SLB）与肽之间的相互作用。测试了不同形式的淀粉样蛋白β（40和42个氨基酸组成），并测量了界面荧光以获取有关脂质完整性和迁移率的信息。结果显示脂质双层的浓度依赖性破坏过程。与肽的延长相互作用长达48小时会导致脂质分子从表面提取和聚集，并可能破坏双层分子，这与肽聚集体的形成有关。与淀粉样蛋白-β（1-42）的相互作用略微阻碍了脂质的自然扩散，并且与肽的寡聚密切相关。淀粉样蛋白-β的吸附和解吸也以亲和力为特征。淀粉样蛋白-β（1-42）表现出比淀粉样蛋白-β（1-40）略高的亲和力。前者也更易于聚集并且以低聚物的形式吸附在双层上。