Detection of FGFR2 : FAM76A Fusion Gene in Circulating Tumor RNA Based on Catalytic Signal Amplification of Graphene Oxide‐loaded Magnetic Nanoparticles

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 1.0 fM, high specificity and excellent reproducibility (% RSD=