Dual-signal amplified photoelectrochemical biosensor for detection of N-methyladenosine based on BiVO-110-TiO heterojunction, Ag-mediated cytosine pairs.

Herein, a novel dual-signal amplified photoelectrochemical (PEC) biosensor was successfully developed for the highly selective detection of N-methyladenosine (mA) methylated RNA. The PEC biosensor comprised BiVO-110-TiO heterojunction and gold nanoparticle decorated MoS (MoS-AuNPs) as the photoactive materials, horseradish peroxidase conjugated biotin (HRP-Biotin) as the enzymatic unit, Ag-mediated cytosine pairs (C-Ag-C) as the signal amplification unit, and the anti-mA antibody as the mA methylated RNA recognition unit. Following immunoreaction between mA and the anti-mA antibody, the C-Ag-C structure of the hairpin DNA unfolded, yielding the duplex strand DNA (dsDNA) and releasing Ag ions. Superoxide ions (O) generated by the action of HRP on HO then served as an electron donor, resulting in the deposition of Ag on AuNPs surface and resulting in an increased photocurrent. Based on this change f the photocurrent, mA could be accurately assayed using this dual-signal amplified PEC biosensor. The biosensor showed high selectivity and a very low detection limit of 1.665 pM for mA, and was successfully applied to evaluate the content change of mA in leaves of maize seedling and chicken fetal hepatocytes samples after treatment with chemical mutagen of ethylmethane sulfonate and hormone of insulin, respectively.