College of Chemistry, Chemical Engineering and Materials Science, Collaborative Innovation Center of Functionalized Probes for Chemical Imaging in Universities of Shandong, Key Laboratory of Molecular and Nano Probes, Ministry of Education, Shandong Provincial Key Laboratory of Clean Production of Fine Chemicals , Shandong Normal University , Jinan , Shandong 250014 , PR China.
Anal Chem. 2019 Jan 15;91(2):1232-1236. doi: 10.1021/acs.analchem.8b04663. Epub 2018 Dec 31.
DNA 5-hydroxymethylcytosine (5-hmC) is an important epigenetic biomarker for tumorigenesis, and the loss of 5-hmC levels is associated with leukemia and melanoma cancers. However, it is a great challenge to discriminate 5-hmC from 5-methylcytosine (5-mC) using the conventional bisulfite conversion methods. Herein, we report a label-free and immobilization-free electrochemical magnetobiosensor for sensitive quantification of 5-hmC in genomic DNA based on a dual signal amplification strategy coupled with terminal deoxynucleotidyl transferase (TDT) enzymatic amplification and Ru(III) redox cycling. This screen-printed carbon electrode (SPCE)-based electrochemical magnetobiosensor shows distinct advantages of having low cost and simple fabrication and being label-free, immobilization-free, PCR-free, and radioactive-free. It exhibits high sensitivity with a detection limit of as low as 9.06 fM and a large dynamic range from 0.01 to 1000 pM. Importantly, this biosensor can discriminate 5-hmC from cytosine and 5-mC, and it can successfully detect 5-hmC in live cells.
DNA 5-羟甲基胞嘧啶（5-hmC）是肿瘤发生的重要表观遗传生物标志物，5-hmC 水平的丧失与白血病和黑色素瘤癌症有关。然而，使用常规的亚硫酸氢盐转化方法将 5-hmC 与 5-甲基胞嘧啶（5-mC）区分开来具有很大的挑战性。在此，我们报道了一种无标记和无固定化的电化学磁生物传感器，用于基于双信号放大策略结合末端脱氧核苷酸转移酶（TDT）酶扩增和 Ru（III）氧化还原循环，灵敏地定量基因组 DNA 中的 5-hmC。这种基于丝网印刷碳电极（SPCE）的电化学磁生物传感器具有低成本、简单制造、无标记、无固定化、无 PCR 和无放射性等明显优势。它具有很高的灵敏度，检测限低至 9.06 fM，动态范围从 0.01 到 1000 pM 很宽。重要的是，该生物传感器可以区分 5-hmC 与胞嘧啶和 5-mC，并且可以成功地检测活细胞中的 5-hmC。
