A ratiometric surface-enhanced Raman scattering (SERS) aptasensor based on internal standard (IS) methods was proposed for the ultrasensitive and reproducible quantitative detection of silver ion (Ag⁺) with [email protected] core-shell nanoparticle ([email protected] NP) substrate. In principle, the thiolated 5′-Rox C-containing labeled aptamer probe (Rox-aptamer) is firstly immobilized on the SERS substrate surface and then hybridizes with the complementary DNA (cDNA) to form a rigid double-stranded DNA (dsDNA), in which the Rox Raman labels is used to produce the Raman signal. Furthermore, the pyridine is employed as an IS element to provide the ratiometric determination of target. In the presence of Ag⁺, the Rox-aptamer is turned into the cytosine (C)-Ag⁺-C mediated hairpin structure, which remarkably reduces the distance between the Rox labels and the [email protected] NP surface responsible for a measurable ‘turn-on’ signal change of Rox. This IS-based ratiometric SERS aptasensor exhibits a limit of detection of 50 pM for Ag⁺ with a linear detection range from 0.1 to 100 nM and the shortcoming of irreproducibility of SERS signal could be overcome. The proposed method provides a simple, robust, and rapid approach for the sensitive and reproducible quantitative detection of Ag⁺, and it could also be used for the detection of other metal ions which exhibits specific interactions with natural or synthetic bases.

提出了一种基于内标（IS）方法的比例表面增强拉曼散射（SERS）适体传感器，用于具有[电子邮件保护的]核壳纳米粒子（[电子邮件保护的] NP的超灵敏和可重复的定量检测银离子（Ag ⁺）。 ） 基质。原则上，首先将含硫醇化5'-Rox C的标记适体探针（Rox-aptamer）固定在SERS底物表面，然后与互补DNA（cDNA）杂交形成刚性双链DNA（dsDNA），其中Rox拉曼标签用于产生拉曼信号。此外，吡啶被用作IS元素以提供目标的比例测定。在存在Ag ⁺的情况下，Rox适体变成胞嘧啶（C）-Ag ⁺-C介导的发夹结构，可显着减小Rox标签与负责Rox的“开启”信号变化的[受电子邮件保护的] NP表面之间的距离。这种基于IS的比例SERS适体传感器对Ag ⁺的检测限为50 pM，线性检测范围为0.1至100 nM，可以克服SERS信号不可重复性的缺点。所提出的方法为灵敏和可重复的Ag ⁺定量检测提供了一种简单，可靠且快速的方法，它还可以用于检测其他与天然或合成碱发生特定相互作用的金属离子。