Hossain-Ali Rafiee-Pour - Department of Molecular and Cell Biology, Faculty of Chemistry, University of Kashan, Kashan, Iran
Nafiseh Sharifi - Department of Physics, University of Kashan, Kashan, Iran
Sedigheh Falahi - Institute of Nanoscience and Nanotechnology, University of Kashan, Kashan, Iran

Small noncoding microRNAs (miRNAs) have emerged as ideal noninvasive biomarkers for early-phase cancer detection. In this report, Through combining the advantages of electrochemical methods and nanomaterials with the selectivity of the oligo-hybridization-based biosensors, a novel, label-free and simple electrochemical nanobiosensor for miRNA-21 detection have demonstrated, based on carboxylated graphene oxidized and polyaniline (PANI) modified glassy carbon electrode. The successfully immobilization of the single strand DNA (ss-DNA) probe and hybridization with the target miRNA sequence were confirmed by electrochemical cyclic voltammetry (CV) method. The reduction signals of methylene blue (MB) as a redox indicator, were measured by differential pulse voltammetry (DPV) method, and an increase in the peak current was observed after hybridization. the nanobiosensor showed high Specificity, and was able to discriminate sharply between complementary target miRNA, single-base mismatch, and non-complementary miRNA. Consequently, this strategy will be valuable for sensitive, selective and label-free detection of miRNA. The performance of the assay developed here could satisfy the need for rapid, easy, sensitive and specific early cancer diagnosis in clinical diagnostics.

Early detection, Breast cancer, MicroRNA-21, Electrochemical nanobiosensor, Graphene oxide, Polyaniline