Several neurodegenerative diseases have been linked to proteins or peptides that are prone to aggregate in different brain regions. Aggregation of amyloid-β (Aβ) peptides is recognized as the main cause of Alzheimer’s disease (AD) progression, leading to the formation of toxic Aβ oligomers and amyloid fibrils. The molecular mechanism of Aβ aggregation is complex and still not fully understood. Nanopore technology provides a new way to obtain kinetic and morphological aspects of Aβ aggregation at a single-molecule scale without labeling by detecting the electrochemical signal of the peptides when they pass through the hole. Here, we investigate the influence of nanoscale geometry (conical and bullet-like shape) of a track-etched nanopore pore and the effect of molecular crowding (polyethylene glycol-functionalized pores) on Aβ fibril sensing and analysis. Various Aβ fibril samples that differed by their length were produced by sonication of fibrils obtained in the presence of epigallocatechin gallate. The conical nanopore functionalized with polyethylene glycol (PEG) 5 kDa is suitable for discrimination of the fibril size from relative current blockade. The bullet-like-shaped nanopore enhances the amplitude of the current and increases the dwell time, allowing us to well discern the fibrils. Finally, the nanopore crowded with PEG 20 kDa enhances the relative current blockade and increases the dwell time; however, the discrimination is not improved compared to the “bullet-shaped” nanopore.

中文翻译：

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使用径迹蚀刻纳米孔检测淀粉样蛋白 β 原纤维：几何形状和拥挤的影响

几种神经退行性疾病与易于在不同大脑区域聚集的蛋白质或肽有关。淀粉样蛋白-β (Aβ) 肽的聚集被认为是阿尔茨海默病 (AD) 进展的主要原因，导致有毒 Aβ 寡聚体和淀粉样蛋白原纤维的形成。Aβ 聚集的分子机制很复杂，目前仍未完全了解。纳米孔技术提供了一种新方法，通过检测肽通过孔时的电化学信号，无需标记即可在单分子尺度上获得 Aβ 聚集的动力学和形态方面。这里，我们研究了径迹蚀刻纳米孔的纳米级几何形状（锥形和子弹状形状）的影响以及分子拥挤（聚乙二醇功能化的孔）对 Aβ 原纤维传感和分析的影响。通过对在表没食子儿茶素没食子酸酯存在下获得的原纤维进行超声处理，产生了长度不同的各种 Aβ原纤维样品。用聚乙二醇 (PEG) 5 kDa 功能化的锥形纳米孔适用于区分原纤维大小相对电流封锁。子弹状的纳米孔增强了电流的幅度并增加了停留时间，使我们能够很好地辨别原纤维。最后，充满 PEG 20 kDa 的纳米孔增强了相对电流阻断并增加了停留时间；然而，与“子弹形”纳米孔相比，辨别力并没有提高。