Abstract A novel bimetallic CoNi-based metal–organic framework (CoNi-MOF) was prepared using 2,2’-bipyridine-5,5’-dicarboxylic acid (dcbpy) as the building block and acted as an efficient sensing platform for detecting miRNA-126. As compared with its isostructrual monometallic counterpart Co-MOF or Ni-MOF, the bimetallic CoNi-MOF display superiorly electrochemical activity owing to the synergistic effect among diverse metal centers and electrochemically active ligand dcbpy. The complementary DNA probe (cDNA) of miRNA-126 is strongly immobilized over the CoNi-MOF via the combined interaction of hydrogen bonds, π-π stacking, metal binding with cDNA strands, and Van der Waals forces. In view of the complementary hybridization between cDNA and miRNA strands, the CoNi-MOF-based biosensor can be applied for the sensitive detection of miRNA, giving an amplified electrochemical response. Consequently, it leads to an ultralow detection limit of 0.14 fM, along with excellent selectivity, stability, and reproducibility. Furthermore, this electrochemical biosensor shows good applicability for the detection of miRNA-126 overexpressed in rat glioma cells (C6 cells). The proposed sensing strategy illustrates a promising method for the accurate detection of cancer biomarkers in living cancer cells, which could also be extended to construct other biosensors toward different targets.

中文翻译：

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CoNi双金属金属有机框架作为miRNA 126检测的有效生物传感平台

摘要 以 2,2'-联吡啶-5,5'-二羧酸 (dcbpy) 为基础制备了新型双金属 CoNi 基金属有机骨架 (CoNi-MOF)，并作为检测 miRNA 的有效传感平台。 -126。与其同构单金属对应物 Co-MOF 或 Ni-MOF 相比，双金属 CoNi-MOF 显示出优异的电化学活性，这是由于不同金属中心和电化学活性配体 dcbpy 之间的协同作用。miRNA-126 的互补 DNA 探针 (cDNA) 通过氢键、π-π 堆积、金属与 cDNA 链的结合和范德华力的组合相互作用牢固地固定在 CoNi-MOF 上。鉴于 cDNA 和 miRNA 链之间的互补杂交，基于 CoNi-MOF 的生物传感器可用于 miRNA 的灵敏检测，产生放大的电化学响应。因此，它导致 0.14 fM 的超低检测限，以及出色的选择性、稳定性和重现性。此外，该电化学生物传感器在检测大鼠神经胶质瘤细胞（C6 细胞）中过表达的 miRNA-126 方面表现出良好的适用性。所提出的传感策略说明了一种用于准确检测活癌细胞中癌症生物标志物的有前途的方法，该方法也可以扩展到构建针对不同目标的其他生物传感器。