Electrochemical competitive immunodetection of messenger RNA modified with N6-methyladenosine by using DNA-modified...

N⁶-Methyladenosine (m⁶A) is the most abundant RNA modification in eukaryotic messenger RNA (mRNA). A highly sensitive electrochemical immunosensor is described for the determination of m⁶A-RNA. The method is based on the use of antibody (anti-m⁶A) and PtCo mesoporous nanospheres (MPNs). The analogously modified probe of type m⁶A-DNA-PtCo competes with m⁶A-RNA for antibodies on the gold electrode as an electrical signal probe. The electrical signal, best acquired at a working potential of -0.37 V (vs. Ag/AgCl) reflects the concentration of m⁶A. The PtCo MPNs catalyze the reduction of H₂O₂, and this amplifies the current and enhances sensitivity. The detection time of the assay is <1.5 h. Under optimal conditions, response is linear in the 0.005 to 100 nM m⁶A RNA concentration range, and the detection limit is 2.1 pM. The results obtained by this immunoassay with human cell lines are comparable to those obtained with a commercial kit. Graphical abstractSchematic representation of a method for electrochemical determination of m⁶A-modified mRNA. Anti-m⁶A Ab: antibody against m⁶A; BSA: bovine serum albumin; PtCo: PtCo mesoporous nanospheres; SH-m⁶A-DNA: DNA modified with both m⁶A and thiol groups; DPV: differential pulse voltammetry.