1 College of Food and Biological Engineering, Jimei University, Xiamen, China.
3 Xiamen Huaxia University, Xiamen, China.
Appl Spectrosc. 2019 Mar;73(3):294-303. doi: 10.1177/0003702818799100.
Fluorescence-based aptasensors possess high sensitivity but are complicated and usually require multistep labeling and modification in method design, which severely limit the practical applications. Here, a label-free fluorescence-based aptasensor, consisting of aptamer, gold nanoparticles (AuNPs), and cadmium telluride (CdTe) quantum dots (QDs), was developed for the detection of sulfadimethoxine (SDM) in water and fish based on the specific recognition of SDM-aptamer and the inner filter effect of QDs and AuNPs. In the absence of a target, AuNPs dispersed in salt solution because of the aptamer protection, which could effectively quench the fluorescence emission of QDs, while in the presence of SDM, AuNPs aggregated due to the specific recognition of SDM-aptamer to SDM, which resulted in fluorescence recovery. A linear response of SDM concentrations in the range of 10-250 ng mL ( R= 0.99) was obtained, and the detection limit was 1.54 ng mL (3σ, n = 9), far below the maximum residue limit (100 ng mL) of SDM in edible animal tissues regulated by China and the European Commission. The fluorescence-based aptasensor was applied to the detection of SDM in aquaculture water and fish samples with high accuracy, excellent precision, and ideal selectivity. The results indicated that the developed aptasensor was simple in design, easy to operate, and could be used to detect rapidly and accurately SDM in water and fish samples.
基于荧光的适体传感器具有高灵敏度，但方法设计通常较为复杂，且需要多步标记和修饰，这严重限制了其实际应用。在此，我们开发了一种无标记的基于荧光的适体传感器，由适体、金纳米粒子（AuNPs）和碲化镉（CdTe）量子点（QDs）组成，用于基于 SDM-适体的特异性识别和 QDs 和 AuNPs 的内滤效应，检测水中和鱼中的磺胺二甲氧嘧啶（SDM）。在不存在靶标时，由于适体的保护作用，AuNPs 分散在盐溶液中，这可以有效地猝灭 QDs 的荧光发射，而在存在 SDM 时，由于 SDM-适体对 SDM 的特异性识别，AuNPs 聚集，导致荧光恢复。SDM 浓度在 10-250ngmL（R=0.99）范围内呈线性响应，检测限为 1.54ngmL（3σ，n=9），远低于中国和欧盟委员会规定的食用动物组织中 SDM 的最大残留限量（100ngmL）。该荧光适体传感器在水产养殖用水和鱼类样品中的 SDM 检测中具有较高的准确性、优异的精密度和理想的选择性。结果表明，所开发的适体传感器设计简单、操作简便，可用于快速准确地检测水中和鱼类样品中的 SDM。
