Xiong Xiaohui, Luo Yun, Lu Yichen, Xiong Xiong, Li Yi, Liu Yuanjian, Lu Lixia
Coll. Food Sci. & Light Ind., Nanjing Tech University Nanjing 211816 China
RSC Adv. 2019 Dec 20;9(72):42423-42429. doi: 10.1039/c9ra08869e. eCollection 2019 Dec 18.
A rapid and ultrasensitive method is described for the detection of Staphylococcal enterotoxin B (SEB). It is based on the formation of the flower like nucleic acid nanostructure by integrating (a) target-induced triggering of DNA release with (b) signal amplification by a hybridization chain reaction (HCR). Firstly, partially complementary pairing of aptamer and trigger DNA forms a duplex structure. The capture DNA (cpDNA) is then placed on the surface of gold electrode through gold-thiol chemistry. In the presence of SEB, the aptamer-target conjugate is compelled to form. This causes the release of trigger DNA owing to a strong competition between aptamer and SEB. Then, the trigger DNA is subsequently hybridized with the partial complementary sequences of the cpDNA to trigger HCR with three auxiliary DNA sequences (referred to as MB1, MB2, MB3). Finally, the flower like nucleic acid nanostructures are formed and allow numerous hexaammineruthenium(iii) chloride ([Ru(NH)], RuHex) to be absorbed on the DNA by electrostatic interaction, and thus amplify electrochemical signal. Under optimal conditions, the chronocoulometry charge difference increases linearly with the logarithm of the SEB concentrations in the range from 5 pg mL to 100 ng mL with a detection limit as low as 3 pg mL (S/N = 3).
描述了一种用于检测葡萄球菌肠毒素B（SEB）的快速且超灵敏的方法。它基于以下原理：通过将（a）靶标诱导的DNA释放触发与（b）杂交链式反应（HCR）的信号放大相结合，形成花状核酸纳米结构。首先，适配体与触发DNA的部分互补配对形成双链结构。然后，捕获DNA（cpDNA）通过金-硫醇化学方法放置在金电极表面。在SEB存在的情况下，迫使适配体-靶标共轭物形成。这由于适配体与SEB之间的强烈竞争而导致触发DNA的释放。然后，触发DNA随后与cpDNA的部分互补序列杂交，以用三个辅助DNA序列（称为MB1、MB2、MB3）触发HCR。最后，形成花状核酸纳米结构，并允许大量氯化六氨合钌（III）（[Ru(NH)]，RuHex）通过静电相互作用吸附在DNA上，从而放大电化学信号。在最佳条件下，计时电量法电荷差与SEB浓度的对数在5 pg/mL至100 ng/mL范围内呈线性增加，检测限低至3 pg/mL（S/N = 3）。
