Amplified electrochemical detection of circular RNA in breast cancer patients using ferrocene-capped gold nanoparticle/streptavidin conjugates

Abstract Circular RNAs (circRNAs) are a class of endogenous RNAs with a closed loop structure and extensively exist in mammalian cells. Evidence show that circRNA AHNAK was closely associated with triple-negative breast cancer and may serve as new biomarker. In this work, a sandwich structure with two complementary DNA probes were designed to recognize the target circRNA. Voltammetric quantification of circRNA was accomplished by the attachment of ferrocene (Fc)-capped gold nanoparticle/streptavidin conjugates to the biotinylated probe. The oxidation current of Fc was proportional to the concentration of circRNA between 0.5 pM and 10 pM with a detection limit of 0.22 pM. The feasibility of the method was demonstrated by detection of the circRNAs in PCR products amplified from blood of breast cancer patients and healthy donors. The sensing protocol is simple and sensitive, holds great potential for detection of circRNAs in clinical samples.