Highly selective and sensitive electrochemical biosensor based on electrochemically reduced graphene oxide for detection of miRNA as a cancer biomarker

Nowadays, cancer is one of the most outrageous diseases affecting millions of people throughout the world. In this study, the sensitive biosensor for miRNA-21 detection was developed. Through a facile sulfonamide coupling reaction a miRNA-21 specific DNA hybridization probe was immobilized onto a glassy carbon electrode (GCE) modified with electrochemical reduced graphene oxide (erGO). miRNA is a small non-coding RNA molecule which plays an important role in gene expression. The level of miRNA in extracellular fluids varying in the presence of cancer and it can serve as potential biomarker for early detection of cancer. An elevated level of miRNA-21 represents a common feature of pathological cell growth or cell stress and is connected with almost all types of cancer and with cardiovascular diseases, as well. The aim of this study was improve the electrochemical properties by using erGO as a modification for better sensitivity of the developed biosensor. After the modification with erGO, 1-amino-2-naphthol-4-sulfonic acid (AN-SO3-) was electrodeposited on the GCE surface. --Finally, the amino terminated capture probe was immobilized on the GCE via the sulfonamide coupling reaction. The developed biosensor for the detection of specific miRNA sequence was optimized and modified for using in further experiments.