Guo Jiajia, Li Ying, Wang Luokai, Xu Jingyue, Huang Yanjun, Luo Yeli, Shen Fei, Sun Chunyan, Meng Rizeng
Department of Food Quality and Safety, Jilin University, Changchun, 130062, China.
Laboratory of Nutrition and Functional Food, Jilin University, Changchun, 130062, China.
Anal Bioanal Chem. 2016 Jan;408(2):557-66. doi: 10.1007/s00216-015-9132-1. Epub 2015 Oct 31.
This paper reports a novel aptamer-based fluorescent detection method for small molecules represented by acetamiprid based on the specific binding of aptamers with acetamiprid, and the inner filter effect (IFE) of gold nanoparticles (AuNPs) on the fluorescence of CdTe quantum dots (CdTe QDs). When CdTe QDs were mixed with AuNPs, the fluorescence of CdTe QDs was significantly quenched via IFE. The IFE efficiency could be readily modulated by the absorption and the aggregation state of AuNPs. The presence of salt could easily induce the aggregation of AuNPs, resulting in the fluorescence recovery of the quenched QDs. Acetamiprid-binding aptamer (ABA) could adsorb on the negatively charged AuNPs through the coordination interaction to protect AuNPs from salt-induced aggregation, so the fluorescence of CdTe QDs would be quenched by the IFE of AuNPs. However, the specific binding of ABA with acetamiprid could release the ABA from the surfaces of AuNPs and decrease the salt tolerance of AuNPs, so the IFE-decreased fluorescence of CdTe QDs was regained with the presence of acetamiprid, and the fluorescence enhancement efficiency was driven by the concentration of acetamiprid. Based on this principle, the aptamer-based fluorescent method for acetamiprid has been established and optimized. The assay exhibited excellent selectivity towards acetamiprid over its analogues and other pesticides which may coexist with acetamiprid. Under the optimum experiment conditions, the established method could be applied for the determination of acetamiprid with a wide linear range from 0.05 to 1.0 μM, and a low detection limit of 7.29 nM (3σ). Furthermore, this IFE-based method has been successfully utilized to detect acetamiprid in six types of vegetables, and the results were in full agreement with those from HPLC and LC-MS. The proposed method displays remarkable advantages of high sensitivity, rapid analysis, excellent selectivity, and would be suitable for the practical application of target screening in real samples.
本文报道了一种基于适体的新型小分子荧光检测方法，该方法以啶虫脒为代表，基于适体与啶虫脒的特异性结合，以及金纳米颗粒（AuNPs）对碲化镉量子点（CdTe QDs）荧光的内滤效应（IFE）。当CdTe QDs与AuNPs混合时，CdTe QDs的荧光通过IFE显著猝灭。IFE效率可通过AuNPs的吸收和聚集状态轻松调节。盐的存在可轻易诱导AuNPs聚集，导致猝灭的量子点荧光恢复。啶虫脒结合适体（ABA）可通过配位相互作用吸附在带负电荷的AuNPs上，保护AuNPs免受盐诱导的聚集，因此CdTe QDs的荧光会被AuNPs的IFE猝灭。然而，ABA与啶虫脒的特异性结合可使ABA从AuNPs表面释放，并降低AuNPs的耐盐性，因此在啶虫脒存在的情况下，CdTe QDs的IFE降低的荧光得以恢复，荧光增强效率受啶虫脒浓度驱动。基于此原理，建立并优化了基于适体的啶虫脒荧光检测方法。该检测方法对啶虫脒相对于其类似物和其他可能与啶虫脒共存的农药具有优异的选择性。在最佳实验条件下，所建立的方法可用于测定啶虫脒，线性范围宽，为0.05至1.0 μM，检测限低至7.29 nM（3σ）。此外，这种基于IFE的方法已成功用于检测六种蔬菜中的啶虫脒，结果与高效液相色谱（HPLC）和液相色谱 - 质谱联用（LC - MS）的结果完全一致。所提出的方法具有高灵敏度、快速分析、优异选择性等显著优点，适用于实际样品中目标物筛选的实际应用。
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