Department of Food Science & Technology, School of Agriculture and Biology, Shanghai Jiao Tong University, 800 Dongchuan Road, Minhang District, Shanghai 200240, China.
Yunnan Dali Research Institute of Shanghai Jiao Tong University, Yunnan 671000, China.
Anal Methods. 2024 Aug 29;16(34):5826-5834. doi: 10.1039/d4ay01333f.
Cadmium (Cd) is a highly toxic heavy metal that can accumulate in the human body through contaminated food and water, posing great health risks. In this study, a label-free fluorescent aptasensor based on SYBR Green I (SGI) for the rapid and sensitive detection of Cd in food samples was designed. The aptasensor utilizes a Cd-specific aptamer (Cd-(21)) and its complementary strand (CS) to form a double-stranded DNA (dsDNA) structure in the absence of Cd. SGI intercalates into the dsDNA, resulting in a strong fluorescence signal. In the presence of Cd, the aptamer undergoes a conformational change, preventing the formation of dsDNA and leading to a decrease in fluorescence intensity. Under optimized conditions, the aptasensor exhibited a linear response to Cd concentrations ranging from 0.11 to 157.37 ng mL, with a limit of detection (LOD) of 0.07 ng mL. The aptasensor demonstrated high specificity and was successfully applied to detect Cd in fruits and vegetables, with satisfactory recovery rates (95-111%). The proposed aptasensor provides a promising tool for the rapid and sensitive detection of Cd in food.
镉 (Cd) 是一种剧毒重金属，可通过受污染的食物和水在人体内积累，对健康构成极大威胁。在本研究中，设计了一种基于 SYBR Green I (SGI) 的无标记荧光适体传感器，用于快速灵敏地检测食品样品中的 Cd。该适体传感器利用 Cd 特异性适体 (Cd-(21)) 和其互补链 (CS) 在没有 Cd 的情况下形成双链 DNA (dsDNA) 结构。SGI 嵌入 dsDNA 中，导致荧光信号增强。在存在 Cd 的情况下，适体发生构象变化，阻止 dsDNA 的形成，导致荧光强度降低。在优化条件下，该适体传感器对 Cd 浓度在 0.11 至 157.37ng mL 范围内表现出线性响应，检测限 (LOD) 为 0.07ng mL。该适体传感器表现出高特异性，并成功应用于水果和蔬菜中 Cd 的检测，回收率令人满意（95-111%）。该适体传感器为食品中 Cd 的快速灵敏检测提供了一种有前途的工具。
