DNA cytosine methylation and its subsequent oxidation by ten-eleven translocation (TET) proteins to 5-hydroxymethylcytosine (5hmC) constitute a fundamental epigenetic modification in mammals. TET loss-of-function and the resulting reduction of 5hmC levels are recurrent in various cancers. Thus, the precise detection of 5hmC has great potential for early diagnosis and prognosis. Here, we show that 5hmC can be distinguished electrochemically, based on the inherent affinity of DNA bases to a gold surface. 5hmC-enriched DNA display less adsorption onto the gold surface, compared to those containing other cytosine analogs, and thereby, produce larger current response. We believe that this method will find broad application as a rapid, sensitive, and cost-effective biosensing technique for determining 5hmC levels in clinical samples, to expedite cancer diagnosis and prognosis evaluation.

DNA胞嘧啶甲基化及其随后的十一十一易位（TET）蛋白氧化为5-羟甲基胞嘧啶（5hmC）构成了哺乳动物的基本表观遗传修饰。TET功能丧失以及由此导致的5hmC水平降低在各种癌症中屡见不鲜。因此，精确检测5hmC具有早期诊断和预后的巨大潜力。在这里，我们显示5hmC可以电化学区分，基于DNA碱基对金表面的固有亲和力。与包含其他胞嘧啶类似物的DNA相比，富含5hmC的DNA在金表面上的吸附较少，从而产生更大的电流响应。我们相信，这种方法将作为一种快速，灵敏且经济高效的生物传感技术而得到广泛应用，可用于确定临床样品中的5hmC水平，