This work describes the preparation of an immunoplatform for the sensitive and selective determination of
N6-methyladenosine (m6A). The simple and fast protocol involves for the first time the use of micromagnetic
immunoconjugates to establish a direct competitive assay between the
m6A target and a biotinylated
RNA oligomer bearing a single
m6A enzymatically labelled with a commercial conjugate of
streptavidin-
peroxidase (Strep-HRP) as tracer. The cathodic current change measured in the presence of H2O2/
hydroquinone (HQ) at screen-printed
carbon electrodes (SPCEs) upon surface capturing the magnetic bioconjugates is inversely proportional to the
m6A target concentration. After evaluating the effect of key variables, the analytical characteristics were established for the determination of three different targets: the N6-methyladenosine-5'-triphosphate (m6ATP)
ribonucleotide, a short synthetic
RNA oligomer bearing a single
m6A and the positive control provided in a commercial colorimetric kit for m6A-RNA quantification. The obtained results show that this immunoplatform is competitive with other methods reported to date, achieving an improved sensitivity (limit of detection of 0.9 pM for the short synthetic oligomer) using a much simpler and faster protocol (~1 h) and disposable
electrodes for the transduction. Furthermore, the applicability for discriminating the metastatic potential of
cancer cells by directly analyzing a small amount of raw total
RNA without enriching or fragmenting was also preliminary assessed.