LAUSR

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.