Zhejiang Key Laboratory of Silkworm Bioreactor and Biomedicine, College of Life Sciences and Medicine, Zhejiang Sci-Tech University, Hangzhou 310018, China.
Zhejiang Key Laboratory of Silkworm Bioreactor and Biomedicine, College of Life Sciences and Medicine, Zhejiang Sci-Tech University, Hangzhou 310018, China.
Food Chem. 2024 Sep 1;451:139390. doi: 10.1016/j.foodchem.2024.139390. Epub 2024 Apr 15.
The DNA-based biosensor utilises a thymine/guanine(T/G)-rich ODN-4 scaffold with 4',6-diamidino-2-phenylindole(DAPI) as a fluorescent emissary to monitor mercury/lead(Hg(II)/Pb(II)) ions simultaneously. Key to its bifocal detection capability is the twin unbound cytosine(C) bases strategically bridging the G-quadruplex and T-rich sequences, enabling their synergistic interplay. It facilitates the recognition of Hg(II)/Pb(II) ions, characterised by high specificity, and effectively mitigates interference from silver(Ag(I)). The G-quadruplex, guided by the C bases, induces a conformational transition in T-Hg(II)-T complexes, resulting in intense fluorescence. Pb(II) causes a spatial shift in the G-quadruplex, relaxing the T-Hg(II)-T base pairs and attenuating the fluorescence signal. The ODN-4 exhibits a robust, linear correlation with Hg(II) concentration (4.09 nmol/L to 1000 nmol/L) and Pb(II) concentration (3.22 nmol/L to 5 μmol/L). Recovery rates in milk, tap water, and rice water specimens with both ions validate method accuracy (Hg(II): 95.19% to 104.68%, Pb(II): 98.20% to 103.46%). It holds promising prospects for practical food analysis.
基于 DNA 的生物传感器利用富含胸腺嘧啶/鸟嘌呤（T/G）的 ODN-4 支架和 4'，6-二脒基-2-苯基吲哚（DAPI）作为荧光发射体，同时监测汞/铅（Hg(II)/Pb(II)）离子。其双焦点检测能力的关键是双未结合的胞嘧啶（C）碱基策略性地桥接 G-四链体和富含 T 的序列，使其协同作用。它促进了 Hg(II)/Pb(II)离子的识别，具有高特异性，并有效减轻了银（Ag(I)）的干扰。G-四链体在 C 碱基的引导下，诱导 T-Hg(II)-T 复合物发生构象转变，导致强烈的荧光。Pb(II)导致 G-四链体的空间移位，松弛 T-Hg(II)-T 碱基对并减弱荧光信号。ODN-4 与 Hg(II)浓度（4.09 nmol/L 至 1000 nmol/L）和 Pb(II)浓度（3.22 nmol/L 至 5 μmol/L）呈稳健的线性相关性。在牛奶、自来水和米饭水中两种离子的回收率验证了方法的准确性（Hg(II)：95.19%至 104.68%，Pb(II)：98.20%至 103.46%）。它为实际的食品分析提供了有前途的前景。
