Abstract

A novel electrochemical nanobiosensor for the detection of miR-155 (as breast cancer biomarker) is introduced . Fe(3)O(4)NPs@Ag core-shell nanoparticles were synthesized and their shape and characteristics were confirmed by scanning electron microscope (SEM) imaging, Fourier-transform infrared spectroscopy (FTIR), and X-ray diffraction (XRD) methods. Synthesized nanoparticles were applied onto the magnetic bar carbon paste electrode and then the amine-modified anti-miR-155 (single-stranded probes) was applied on the modified electrode surface and upon hybridization with target miR-155, resveratrol (RSV) was eventually applied as an electrochemical label on the double-strand oligonucleotide. Differential pulse voltammetry (DPV) of the oxidation peak of RSV was assumed as the final signal by sweeping potential from 0 to 0.6 V (vs. Ag/AgCl). The fabrication process was optimized through a series of experiments and the optimized process was confirmed using cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). The linear range of the fabricated nanobiosensor was 0.5 fM to 1.0 nM and the detection limit was 0.15 fM. The nanobiosensor was able to pass reproducibility and specificity tests using different types of mismatched target sequences.Spiked real samples of human serum were used to confirm that the nanobiosensor enables detection of miR-155 without any significant interferences from other moieties and molecules. Finally, the molecular dynamics simulation of the RSV interaction with single- and double-stranded oligonucleotide was performed and confirmed the preferential binding of RSV to double-stranded DNA; therefore, it can be used as the electrochemical label of DNA and/or miRNA hybridization-based biosensors.