▎ 摘　　要

A label-free DNA biosensor based on three-dimensional reduced graphene oxide (3D-rGO) and polyaniline (PANI) nanofibers modified glassy carbon electrode (GCE) was successfully developed for supersensitive detection of breast cancer BRCA1. The results demonstrated that 3D-rGO and PANI nanofibers had synergic effects for reducing the charge transfer resistance (R-ct), meaning a huge enhancement in electrochemical activity of 3D-rGO-PANI/GCE. Probe DNA could be immobilized on 3D-rGO-PANI/GCE for special and sensitive recognition of target DNA (1.0x10(-15)-1.0x10(-7) M) with a theoretical LOD of 3.01x10(-16) M (3S/m). Furthermore, this proposed nano-biosensor could directly detect BRCA1 in real blood samples.