State Key Laboratory of Food Science and Technology, Jiangnan University, Wuxi, 214122, PR China; School of Food Science and Technology, Jiangnan University, Wuxi, 214122, PR China; International Joint Laboratory on Food Safety, Jiangnan University, Wuxi, 214122, PR China; Collaborative Innovation Center of Food Safety and Quality Control in Jiangsu Province, Jiangnan University, Wuxi, 214122, PR China.
State Key Laboratory of Food Science and Technology, Jiangnan University, Wuxi, 214122, PR China; School of Food Science and Technology, Jiangnan University, Wuxi, 214122, PR China.
Anal Chim Acta. 2021 Dec 15;1188:339189. doi: 10.1016/j.aca.2021.339189. Epub 2021 Oct 19.
Here, a plasmonic nanogap structure was fabricated with its specific surface enhanced Raman spectroscopy (SERS) effect to construct an aptasensor for the sensitive detection of ochratoxin A (OTA). Gold nanorod (AuNR) were synthesized first by seed-mediated method. Then, silver was reduced and grown on its surface. In the presence of glycine, Ag was preferred to grow at both ends of AuNR to form gold@silver nanodumbbell (Au@AgND). The thiolated OTA aptamer and its complementary sequence were modified on Au@AgND respectively using Ag-SH bond. Under the base complementary pairing principle, Au@AgND assembly formed with certain inter distances. The inter-nanogap structure generated more hot spots which enhanced the Raman signal of 4-hydroxybenzoic acid (4-MBA) immobilized on Au@AgND. When OTA was present, the aptamer preferentially combined to OTA and the Au@AgND assembly disintegrated. Thus, the SERS signal of 4-MBA decreased. Under the optimal conditions, the OTA concentrations were inversely proportional to SERS signal. The linear range was 0.01 ng/mL-50 ng/mL and the limit of detection (LOD) was 0.007 ng/mL. The method can be successfully applied to the detection of real sample (beer/peanut oil).
在这里，我们构建了一种等离子体纳米间隙结构，并利用其表面增强拉曼光谱（SERS）效应，构建了一种适体传感器，用于灵敏检测赭曲霉毒素 A（OTA）。首先，采用种子介导法合成了金纳米棒（AuNR）。然后，在其表面还原并生长银。在甘氨酸存在的情况下，Ag 优先在 AuNR 的两端生长，形成金@银纳米哑铃（Au@AgND）。巯基化 OTA 适体及其互补序列分别通过 Ag-SH 键修饰在 Au@AgND 上。根据碱基互补配对原理，Au@AgND 组装体形成具有一定间隔距离的结构。所产生的纳米间隙结构产生了更多的热点，增强了固定在 Au@AgND 上的 4-羟基苯甲酸（4-MBA）的拉曼信号。当 OTA 存在时，适体优先与 OTA 结合，Au@AgND 组装体解体。因此，4-MBA 的 SERS 信号降低。在最佳条件下，OTA 浓度与 SERS 信号呈反比。线性范围为 0.01ng/mL-50ng/mL，检测限（LOD）为 0.007ng/mL。该方法可成功应用于实际样品（啤酒/花生油）的检测。
