A novel Ag/Zn bimetallic MOF as a superior sensitive biosensing platform for HCV-RNA electrochemical detection

• A novel Ag/Zn bimetallic MOF was synthesized using nanolinker as building blocks. • A novel HCV-RNA biosensor based on Ag/Zn bimetallic MOF was successfully constructed. • The biosensor shows a remarkable selectivity, stability, reproducibility, and sensitivity. • The designed biosensor could be a promising analytical tool for RNA detection in real human samples. A new label-free electrochemical biosensor was progressed for direct detection of unamplified HCV nucleic acid based on silver/zinc bimetallic metal–organic framework (Ag/Zn-MOF). Several physico-chemical techniques were used to confirm the structure and morphology. The prepared bimetallic-MOF was cast on the glassy carbon electrode (GCE) and treated with the capture probe of HCV. Then, treated with bovine serum albumin (BSA) to passivate the surface, which is ready for hybridization process once the HCV target nucleic acid was added. Cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) were used as an evidence for the successful stepwise formation of the desired biosensor. In addition, a differential pulse voltammetry (DPV) measurement was used in the presence of glucose as an electrochemical catalytic indicator. The results confirmed that the bimetallic MOF's catalytic activity stimulated glucose oxidation to gluconolactone, resulting in electrochemical signal amplification. The proposed HCV electrochemical biosensor has several advantages ease of use; low cost; high selectivity and sensitivity; a linear detection ranges from 1 fM to 100 nM; and ultra-low detection limit (0.64 fM). To date, this is the first electrochemical HCV-biosensor report based on bimetallic-MOF. Consequently, this assay opens the door for designing more electrochemical biosensors regarding the electrical and catalytic activity of bimetallic-MOF.