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

Gorgannezhad, Lena; Umer, Muhammad; Masud, Mostafa Kamal; Hossain, Md. Shahriar A.; Tanaka, S.; Yamauchi, Y.; Salomon, Carlos; Kline, Richard; Nguyen, Nam-Trung; Shiddiky, Muhammad J. A.

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.

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