Guizhou Province Key Laboratory of Fermentation Engineering and Biopharmacy, School of Liquor and Food Engineering, Guizhou University, Guiyang 550025, Huaxi District, Guizhou Province, China.
Analyst. 2018 Oct 22;143(21):5151-5160. doi: 10.1039/c8an01166d.
This paper reports a novel fluorescent aptasensor for the detection of acetamiprid pesticide with high sensitivity and selectivity based on the inner filter effect (IFE) of gold nanoparticles (AuNPs) toward fluorescent carbon dots (CDs). The aptasensor employs S-18 aptamer as the specific target recognition molecule and CDs as the signal transmission element. Free S-18 aptamer sequences can wrap the surfaces of AuNPs and enable their dispersion state even in the presence of high amounts of Tris-HCl salt, which can effectively quench the fluorescence of the CDs through the IFE. Upon adding acetamiprid pesticide, the free S-18 aptamer sequences are firstly exhausted to form some complexes; thus, the AuNPs tend to aggregate and their absorption spectrum no longer overlaps with the fluorescence emission spectrum of the CDs, which leads to obvious fluorescence recovery of the aptasensor. The properties of the CDs were extensively characterized, and the fluorescence quenching effects of the AuNPs toward the CDs were fully investigated. Additionally, the effects of some vital parameters, such as the type and amount of AuNPs, on the fluorescent aptasensor were also investigated. The proposed aptasensor has a detection limit as low as 1.08 μg L-1 with a linear range of 5 to 100 μg L-1 and shows high selectivity for acetamiprid over other control pesticides. Moreover, the aptasensor displays excellent accuracy and recovery in the detection of spiked real samples, suggesting that this fluorescent aptasensor can play important roles in the fields of food analysis and environmental detection.
本文报道了一种基于金纳米粒子（AuNPs）对荧光碳点（CDs）的内滤效应（IFE）的新型荧光适体传感器，用于高灵敏度和选择性检测乙虫腈农药。该适体传感器采用 S-18 适体作为特定目标识别分子，CDs 作为信号传输元件。游离的 S-18 适体序列可以包裹 AuNPs 的表面，即使在存在大量 Tris-HCl 盐的情况下，也能使它们处于分散状态，通过 IFE 有效地猝灭 CDs 的荧光。当添加乙虫腈农药时，游离的 S-18 适体序列首先被耗尽，形成一些复合物；因此，AuNPs 趋于聚集，其吸收光谱不再与 CDs 的荧光发射光谱重叠，导致适体传感器的荧光恢复明显。广泛表征了 CDs 的性质，并充分研究了 AuNPs 对 CDs 的荧光猝灭效应。此外，还研究了一些重要参数（如 AuNPs 的类型和数量）对荧光适体传感器的影响。该提出的适体传感器的检测限低至 1.08 μg L-1，线性范围为 5 至 100 μg L-1，对乙虫腈的选择性高于其他对照农药。此外，该适体传感器在实际样品的加标检测中表现出优异的准确性和回收率，表明该荧光适体传感器在食品分析和环境检测领域具有重要作用。
