▎ 摘　　要

Here, we report on the preparation of a sensor platform that implies diphenylalanine based self-assembled peptide nanotubes (PNTs) with graphene oxide (GO) on pencil graphite electrodes (PGEs) and its evaluation for quantification of diabetic nephropathy and cancer-related microRNA-192. The PNT-GO structures were characterized and used to functionalize PGE for biosensor construction. The measured impedance was utilized for the first time as the signal to evaluate the hybridization between miRNA-192 and its corresponding ss-DNA probe owing to the features of PNT-GO. PNT-GO/PGE showed high sensitivity for electrochemical miRNA-192 analysis with a very wide dynamic detection range of 10 fM-1.0 nM and a low sensing limit of 8 fM. Evaluation of the developed impedimetric biosensor in peripheral serum samples revealed its potential for future clinical applications and diverse biomedical applications without the aid for extraction, sample pretreatment or amplification steps.