A sensitive photoelectrochemical immunoassay of N6-methyladenosine based on dual-signal amplification strategy: Ru doped in SiO2 nanosphere and carboxylated g-C3N4.

A novel, simple and sensitive photoelectrochemical (PEC) immunosensing platform was constructed for detecting N6-methyladenosine (m6A) based on the carboxylated CN and avidin functionalized Ru@SiO2 (ARS) nanocomposite. Herein, the N6-methyladenosine-5'-triphosphate (m6ATP) was selected as the detection target molecule, m6A antibody was used as recognition unit for m6A, the carboxylated g-C3N4 (CN) was not only used as the photoactive substance, but the substrate for the m6A antibody immobilization, ARS was synthesized and used as signal amplification unit to improve the photocurrent of CN, Phos-tag-biotin was employed as bridge of m6ATP and Ru@SiO2 through the specific interaction between phosphate group of m6ATP and Phos-tag, biotin and avidin, respectively. Under the optimal condition, the fabricated PEC biosensor showed a linear range of 0.01-10nM and high detection sensitivity with low detection limit of 3.23pM for m6ATP. Besides, the developed strategy was also successfully applied to evaluate the content of m6A in human serum samples.