Herein, a light-up nonthiolated aptasensor was developed for low-mass, soluble amyloid-β₄₀ oligomers (LS-Aβ_40-O). Au nanoparticles (AuNP) were employed as colorimetric probes, and the nonthiolated aptamers (Apt) were adsorbed on AuNP surfaces, acting as binding elements for LS-Aβ_40-O. The aggregation of AuNPs was induced when Apt-modified AuNPs ([email protected]) were under high-salt conditions. However, upon the addition of LS-Aβ_40-O into the [email protected] solution, the salt tolerance of the AuNPs was greatly enhanced. Further studies confirmed that the formed LS-Aβ_40-O–Apt complex attached onto the AuNP surfaces via interactions between LS-Aβ_40-O and Au, which led to electrostatic and steric stabilization of the AuNPs under high-salt conditions. On the basis of this outcome, a sensitive light-up nonthiolated aptasensor for LS-Aβ_40-O was achieved with a detection limit of 10.0 nM and a linear range from 35.0 to 700 nM in a 175 mM NaCl solution. Cerebrospinal-fluid (CSF) samples from healthy persons and Alzheimer’s disease (AD) patients were successfully distinguished by using this proposed method. The concentrations of LS-Aβ_40-O in the CSF of AD patients were of nanomolar grade, but there was no detectable LS-Aβ_40-O in those of the healthy persons. This work provides a new insight into the interaction between [email protected] and Aβ_40-O and also develops a simple, rapid, highly selective and sensitive, and applicable method for LS-Aβ_40-O detection in real CSF samples, which is significant for the diagnosis of AD.

中文翻译：

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亮灯Nonthiolated适体传感器的低质量，可溶性淀粉样β _40个在高盐浓度低聚物

在此，点亮nonthiolated适体传感器被用于低质量，可溶性淀粉样蛋白β开发_40个低聚物（LS-Aβ _40-O ）。将金纳米颗粒（AuNP）用作比色探针，并且将非硫醇化的适体（Apt）吸附在AuNP表面上，充当LS- _Aβ40-O的结合元件。当Apt修饰的AuNPs（[受电子邮件保护]）处于高盐条件下时，会诱导AuNPs聚集。但是，在[电子邮件保护的]溶液中添加LS- _Aβ40-O后，AuNP的耐盐性大大提高。进一步的研究证实，形成的LS- _Aβ40-O –Apt复合物通过LS- _Aβ40-O之间的相互作用附着在AuNP表面上和金，导致在高盐条件下AuNPs的静电和位阻稳定。基于此结果，在175 mM NaCl溶液中获得了灵敏的LS- _Aβ40-O点亮非硫醇化适体传感器，检测限为10.0 nM，线性范围为35.0至700 nM。使用该方法可以成功地区分来自健康人和阿尔茨海默氏病（AD）患者的脑脊液（CSF）样品。AD患者脑脊液中的LS- _Aβ40-O浓度为纳摩尔级，但健康人中未检测到LS- _Aβ40-O。这项工作为[受电子邮件保护]与_Aβ40-O之间的相互作用提供了新的见解并开发了一种简单，快速，高度选择性和灵敏且适用的方法用于实际CSF样品中LS- _Aβ40-O的检测，这对AD的诊断具有重要意义。