▎ 摘　　要

Circulating tumor nucleic acids (ctNAs) are promising biomarkers for minimally invasive cancer assessment. The FGFR2:FAM76A fusion gene is one of the highly promising ovarian cancer biomarkers detectable in ctNAs. Herein, we introduce a new amplification-free electrochemical assay for the detection of FGFR2:FAM76A fusion gene in ctNAs extracted from ovarian cancer patients. The assay relies on the electrocatalytic activity of a new class of superparamagnetic graphene-loaded iron oxide nanoparticles (GO-NPFe2O3). After isolation and purification, the target RNA was directly adsorbed onto the GO-NPFe2O3 surface through graphene-RNA affinity interaction. The electrocatalytic signal was achieved by the reduction of surface-attached ruthenium hexaammine(III) chloride which was further amplified by using the ferricyanide redox system. Our assay depicted an excellent detection sensitivity down to 1.0fM, high specificity and excellent reproducibility (%RSD=<5%, for n=3). The analytical performance of our method was validated with standard qRT-PCR analysis. We believe that this newly developed assay would be practically applicable in clinical research.