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-NPFeO). After isolation and purification, the target RNA was directly adsorbed onto the GO-NPFeO 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