A sensitive photoelectrochemical immunoassay of N-methyladenosine based on dual-signal amplification strategy: Ru doped in SiO nanosphere and carboxylated g-CN.

A novel, simple and sensitive photoelectrochemical (PEC) immunosensing platform was constructed for detecting N-methyladenosine (mA) based on the carboxylated CN and avidin functionalized Ru@SiO (ARS) nanocomposite. Herein, the N-methyladenosine-5'-triphosphate (mATP) was selected as the detection target molecule, mA antibody was used as recognition unit for mA, the carboxylated g-CN (CN) was not only used as the photoactive substance, but the substrate for the mA 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 mATP and Ru@SiO through the specific interaction between phosphate group of mATP 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 mATP. Besides, the developed strategy was also successfully applied to evaluate the content of mA in human serum samples.