Faculty of material science and chemical engineering, Ningbo University, Ningbo 315211, China.
Faculty of material science and chemical engineering, Ningbo University, Ningbo 315211, China.
Talanta. 2019 Jul 1;199:491-498. doi: 10.1016/j.talanta.2019.03.005. Epub 2019 Mar 2.
It's important to eliminate matrix interference for accurate detecting antibiotic residues in complex food samples. In this study, we designed a zero-backgrounded fluorescence aptasensor to achieve on-site detection of antibiotic residues, with chloramphenicol (CAP) as representative analyte. Moreover, a three stir-bars assisted target recycling system (TSBTR) was designed to achieve triple signal amplification and increase the sensitivity. The bars included one magnetic stir-bar modified with two kinds of long DNA chains, and two gold stir-bars modified with Y shape-duplex DNA probes respectively. In the presence of CAP, the target could recurrently react with the probes on the bars and replace a large amount of long DNA chains into supernatant. After then, the bars were taken out and SYBR green dye was added to the solution. The dye can specifically intercalate into the duplex structures of DNA chains to emit fluorescence while not emitting a signal in its free state. Under the optimized experimental conditions, a wide linear response range of 5 orders of magnitude from 0.001 ng mL to 10 ng mL was achieved with a detection limit of 0.033 pg mL CAP. The assay was successfully employed to detect CAP in food samples (milk & fish) with consistent results with ELISA's. High selectivity and sensitivity were attributed to the zero background signal and triple signal-amplification strategy. Moreover, the detection time can be shortened to 40 min due to that three signal amplified process can occur simultaneously. The fluorescent aptasensor was also label- and enzyme-free. All these ensure the platform to be rapid, cost-effective, easily-used, and is especially appropriate for detection antibiotics in food safety.
消除基质干扰对于准确检测复杂食品样品中的抗生素残留非常重要。在本研究中，我们设计了一种零背景荧光适体传感器，以实现抗生素残留的现场检测，以氯霉素（CAP）为代表性分析物。此外，设计了一种三搅拌棒辅助目标循环系统（TSBTR），以实现三重信号放大，提高灵敏度。搅拌棒包括一个修饰有两种长 DNA 链的磁性搅拌棒，以及两个分别修饰有 Y 形双链 DNA 探针的金搅拌棒。在 CAP 的存在下，靶标可以与棒上的探针反复反应，并将大量长 DNA 链替换到上清液中。然后，取出搅拌棒并向溶液中加入 SYBR 绿色染料。该染料可以特异性地插入 DNA 链的双链结构中，在自由状态下不发出信号而发出荧光。在优化的实验条件下，实现了从 0.001ng/mL 到 10ng/mL 的 5 个数量级的宽线性响应范围，检测限为 0.033pg/mL CAP。该测定法成功用于检测食品样品（牛奶和鱼）中的 CAP，与 ELISA 的结果一致。高选择性和灵敏度归因于零背景信号和三重信号放大策略。此外，由于三个信号放大过程可以同时发生，检测时间可以缩短至 40 分钟。荧光适体传感器还无需标记和酶。所有这些都确保了该平台具有快速、经济高效、易于使用的特点，特别适合食品安全中抗生素的检测。
