The development of graphene oxide modified electrodes and its application to voltametric detection of miRNA

microRNAs (miRNA) are small RNA molecules, that contains 19-25 nucleotides. The abnormal expression of miRNA causes different type of cancer and neurodegenerative diseases such as Alzheimer, and metabolic diseases as diabetes. Therefore, the studies have been performed in order to investigate practical, easy-to-prepare, miniaturize biosensor platforms which can detect miRNAs rapidly, sensitively and selectively. Graphene is a crystalline allotrope of carbon with 2-dimensional properties. Graphene was discovered in the recent past and it has perfect physical, chemical, electrical, thermal and optic properties. Graphene oxide (GO) is a form of chemically active graphene that can be produced cost effectively. Due to its large surface area, GO also increases the immobilization and adsorption capasity of the surfaces. GO modified disposable electrodes were used in our study for sensitive and selective voltametric detection of miRNAs. Disposable pencil graphite electrode (PGE) surfaces were modified by GO and used as a platform for analyzing of miRNA. The detection of specific recognition of miRNA-34a, which has been related to Alzheimer disease, was performed according to DNA-RNA hybridization by using GO-PGEs. The characterization of the GO-PGEs was investigated by using electrochemical impedance spectroscopy (EIS), cyclic voltammetry (CV), and scanning electron microscopy (SEM) techniques. The effect of the changes at GO concentration, DNA probe concentration, miRNA-34a concentration upon to biosensor response on detection of hybridization between miRNA-34a target and its complementary DNA probe was explored and optimized, and then, the selectivity of miRNA-34a biosensor was tested under the optimum conditions. GO-PGEs were developed in our study that presented important advantages such as, being cost-effective, easy to use without requiring any extra chemicals, and surface modification in a short time. In this study selective and sensitive GO modified electrochemical biosensor was developed for miRNA analysis by using voltametric techniques without using any electrochemical indicator.