▎ 摘　　要

In our study, graphene oxide (GO) modified graphite electrodes were used for sensitive and selective impedimetric detection of miRNA. After chemical activation of pencil graphite electrode (PGE) surface using covalent agents (CA), GO modification was performed at the surface of chemically activated PGE. Then, CA-GO-PGEs were applied for impedimetric miRNA detection. The microscopic and electrochemical characterization of CA-GO-PGEs was performed by scanning electron microscopy (SEM) and electrochemical impedance spectroscopy (EIS). The optimization of experimental conditions; such as GO concentration, DNA probe concentration and miRNA target concentration was performed by using EIS technique. After the hybridization occurred between miRNA-34a RNA target and its complementary DNA probe, the hybrid was immobilized onto the surface of CA-GO-PGEs. Then, the impedimetric detection of miRNA-DNA hybridization was performed by EIS. The selectivity of our assay was also tested under the optimum experimental conditions.