Electrochemical detection of microRNAs by graphene oxide modified disposable graphite electrodes

Graphene oxide (GO) modified disposable pencil graphite electrodes (PGEs) were developed for the first time in the present study for miRNA detection by measuring the guanine oxidation signal. GO modified PGEs were used as solid phase to immobilize amino linked DNA probe and then the complementary target RNA sequence (miRNA-34a) was recognized. The electrochemical behaviour of the GO modified electrodes was investigated by using electrochemical impedance spectroscopy (EIS) and microscopic characterization was performed by scanning electron microscopy (SEM). The optimization studies and detection of hybridization between miRNA-34a target and its complementary DNA probe was performed by differential pulse voltammetry (DPV). The selectivity of our assay was tested in the presence of non-complementary miRNA sequence. A good discrimination could be achieved compared to the results obtained with the full match hybridization of probe with its RNA target miRNA-34a target against other miRNA sequences; miRNA-16 and miRNA-155.