Highly sensitive electrochemical biosensor based on naturally reduced rGO/Au nanocomposite for the detection of miRNA-122 biomarker

Herein, we have developed a novel high-resolution electrochemical biosensor for the detection of the microRNA-122 (miRNA-122) using gold nanoparticles dotted reduced graphene oxide (rGO/Au) nanocomposite. The natural soapnut solution was used as a reducing agent for the synthesis of the nanocomposite. The naturally reduced rGO/Au nanocomposite was confirmed through various characterization techniques. When rGO/Au nanocomposite was coated on to the gold electrode and checked the electrochemical performance, the nanocomposite shows superior analytical performance. The probe DNA was anchored onto the binding sites of rGO/Au nanocomposite through thiol linker and recognized the target miRNA-122. The developed rGO/Au based electrochemical biosensor demonstrated a linear response for various target miRNA-122 concentrations with a range from 10 μM to 10 pM and, with a detection limit of 1.73 pM. The developed biosensor also shows good stability and reproducibility, could be used for the detection of miRNA-122 and, also can be used for the basic research and clinical studies. Besides, the demonstrated rGO/Au nanocomposite-based sensing strategy could be used to detect various miRNA and protein biomarkers. Furthermore, the green synthesis approach could also be useful for the synthesis of various nanomaterials and nanocomposites for various biomedical applications.