Design and fabrication of a novel nanobiosensor for early detection of breast cancer using signal amplification of the gold nanorods decorated on graphene oxide sheets

Biosensors are the attending class of miRNA quantification tools due to their great specificity and selectivity. The electrochemical biosensors are the most attractive method, because of their inexpensive, fast and precise detection. In addition, nanobiosensors are the biosensors which use nanomaterials for signal amplifying and improving the sensitivity of the detection system. Many of nanomaterials have been synthesized with different elements, shapes, structures, aspect-ratios and functionalization scheme, based on their goal application. In this research, graphene oxide and gold nanorods applied in an electrochemical nanobiosensor for miRNA quantification. The graphene oxide used for expanding the active area of the electrode surface, and the gold nanorods attached to the graphene oxide sheet to provide a plateau for attachment of thiolated single strand probes (SS-probe). The probe was designed to hybridize, specifically and selectively to the target miRNA (miR-155) and oracet blue (OB) used as an electroactive label. In our method, the reduction signal of OB is measured by differential pulse voltammetry (DPV). The results showed that application of graphene oxide and gold nanorods are very effective in signal amplification and the current for nanobiosensor is much higher compared to non-used nanomaterials method. The dynamic range of the nanobiosensor was from 2.0 fM to 8.0 pM, and the detection limit was 0.6 fM. Furthermore, the nanobiosensor showed high Specificity, and was able to discriminate sharply between complementary target miRNA, single-, three-base mismatch, and non-complementary miRNA.

کلیدواژه ها:

electrochemical ، nanobiosensor ، miRNA ، breast cancer ، graphene oxide ، gold nanorod