A sensitive photoelectrochemical immunoassay of N-6-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 N-6-methyladenosine (m(6)A) based on the carboxylated CN and avidin functionalized Ru@SiO2 CARS) nanocomposite. Herein, the N-6-methyladenosine-5'-triphosphate (m(6)ATP) was selected as the detection target molecule, m6A antibody was used as recognition unit for m(6)A, the carboxylated g-C3N4 (CN) was not only used as the photoactive substance, but the substrate for the m(6)A 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 m(6)ATP and Phos-tag, biotin and avidin, respectively. Under the optimal condition, the fabricated PEC biosensor showed a linear range of 0.01-10 nM and high detection sensitivity with low detection limit of 3.23 pM for m(6)ATP. Besides, the developed strategy was also successfully applied to evaluate the content of m(6)A in human serum samples.