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

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.