Photocatalytic DNA chemiluminescent biosensor via cooperative hybridization for miR-21 assay with both good sensitivity and selectivity

Cervical cancer is one common cause of cancer relative death in women worldwide, while microRNA-21 (miR-21) can serve as one upregulated miRNA in cervical cancer for early diagnosis. Chemiluminescence is a powerful assaying method, but balancing the sensitivity and selectivity is often difficult at present. For this problem, a photocatalytic chemiluminescent biosensor was developed to homogeneously assay miR-21 with good performances. Based on a base stacking principle, cooperative hybridization is employed in double DNA probes for biosensor design. After DNA probe hybridization, photocatalytic DNA-dye complex can induce luminol’s chemiluminescence signals via several processes. Here the double-probe design results in the high sensitivity to assay miR-21 with a detection limit in pM level. Meanwhile, the short probe design and cooperative principle guarantee a good selectivity to discriminate other nucleotide variants. For comparison, both a single short and long probes were also studied to show the advantages of our biosensor in assay performances. So this photocatalytic chemiluminescent biosensor via cooperative hybridization is an ideal method to assay miR-21, showing a good potential for cancer early diagnosis.