Detection of miR-155 Using Two Types of Electrochemical Approaches

Abstract

We present electrochemical biosensors for the analysis of a target miR-155 that work through the formation of miRNA-DNA hybrid duplexes by hybridization of miR-155 with its complementary DNA and through the subsequent intercalation of appropriate intercalating agents on gold electrodes. In the first method, the electrochemical behavior of methylene blue intercalated to the miRNA-DNA hybrid duplex, formed between miR-155 and its complementary DNA, on the gold electrode was measured. In the second method, the miRNA-DNA hybrid duplex formed between ferrocene-labeled DNA and miR-155 in solution is intercalated to the pyrenes immobilized on the electrode surface. This lead to an electrochemical signal being generated from the oxidized ferrocene accumulated on the electrode surface. For each method, the limit of detections for the detection of miR-155 were determined to be 0.96 and 2.22 pM, respectively. In addition, the developed electrochemical biosensors were effective in the quantitation of miR-155 in serum sample.