School of Environment and Natural Resources, Renmin University of China, Beijing, 100872, China.
Research Institute of Chemical Defense, Academy of Military Sciences PLA China, Beijing, 102205, China.
Mikrochim Acta. 2018 Oct 3;185(10):491. doi: 10.1007/s00604-018-3020-2.
A SERS-based aptasensor for ochratoxin A (OTA) is described. It is making use of FeO@Au magnetic nanoparticles (MGNPs) and of Au@Ag nanoprobes modified with the Raman reporter 5,5-dithiobis-(2-nitrobenzoic acid; DTNB). Au-DTNB@Ag NPs were modified with the OTA aptamer (aptamer-GSNPs) and used as Raman signal probes. The SERS peak of DTNB at 1331 cm was used for quantitative analysis. MGNPs modified with cDNA (cDNA-MGNPs) were used as capture probes and reinforced substrates. When the Au-DTNB@Ag-FeO@Au complexes are formed through oligonucleotide hybridization, the Raman signal intensity of the Raman probe is significantly enhanced. If the OTA concentration in samples increases, more Raman signal probes (aptamer-GSNPs) will dissociate from the cDNA-MGNPs because more OTA aptamer is bound by OTA. This leads to a lower Raman signal after magnetic separation. Under the optimal conditions, the detection limit for OTA is 0.48 pg·mL based on 3σ criterion. This is attributed to the multiple Raman signal enhancement and the good performance of the OTA aptamer. The good recovery and accuracy of the assay was confirmed by evaluating spiked samples of wine and coffee. Graphical abstract Schematic of an aptamer based SERS assay for OTA by integrating FeO@AuNPs (MGNPs) with Au-DTNB@Ag NPs with multiple signal enhancement. Aptamer modified Au-DTNB@Ag NPs are used as Raman probes, and MGNPs modified with cDNA are used as capture probes and reinforced substrates.
一种基于 SERS 的赭曲霉毒素 A（OTA）适体传感器被描述。它利用了 FeO@Au 磁性纳米粒子（MGNPs）和修饰有拉曼报告分子 5,5-二硫代双（2-硝基苯甲酸；DTNB）的 Au@Ag 纳米探针。Au-DTNB@Ag NPs 被 OTA 适体（适体-GSNPs）修饰，并用作拉曼信号探针。DTNB 的 SERS 峰在 1331 cm 处用于定量分析。修饰有 cDNA（cDNA-MGNPs）的 MGNPs 被用作捕获探针和增强基底。当通过寡核苷酸杂交形成 Au-DTNB@Ag-FeO@Au 复合物时，拉曼探针的拉曼信号强度显著增强。如果样品中 OTA 浓度增加，更多的拉曼信号探针（适体-GSNPs）将从 cDNA-MGNPs 上解离，因为更多的 OTA 适体与 OTA 结合。这导致磁分离后拉曼信号降低。在最佳条件下，基于 3σ 准则，OTA 的检测限为 0.48 pg·mL。这归因于多重拉曼信号增强和 OTA 适体的良好性能。通过评估葡萄酒和咖啡的加标样品，验证了该测定法的良好回收率和准确性。示意图基于整合 FeO@AuNPs（MGNPs）与 Au-DTNB@Ag NPs 的适体基于 SERS 的 OTA 测定法，通过多重信号增强。修饰有适体的 Au-DTNB@Ag NPs 用作拉曼探针，修饰有 cDNA 的 MGNPs 用作捕获探针和增强基底。
