Bimodal Electrochemiluminescence of Ru-MOFs in the Presence of Double Coreactants for CEA Detection

A dual-potential electrochemiluminescence (ECL) immunosensor, featuring simultaneous cathodic and anodic emission from ruthenium-based metal–organic frameworks (Ru-MOFs) as the sole luminophore and iron-monatomic catalysts (FeNC-SN SACs) with tunable sulfur functional groups and abundant Fe-N4 sites as a highly efficient coreactivity accelerant, is presented for the first time. Cathodic ECL emission originates from the Ru-MOFs/K2S2O8 system, whereas anodic ECL emission is achieved via the Ru-MOFs/polyethylene imine (PEI) system. The experimental results revealed a linear relationship between the variation in the ECL signal variation of the immunosensor and the concentration of CEA, which ranged from 0.1 pg/mL to 200 ng/mL. In addition, the detection limits were determined to be 0.028 pg/mL for the anodic system (S/N = 3) and 0.033 pg/mL for the cathodic system (S/N = 3). This study introduces reticulated hierarchical porous single-atom catalysts as coreaction accelerators for the catalysis of dual coreactants, enabling dual emission from a single luminophore for bioanalytical applications. These findings provide a novel approach for developing ECL biosensor platforms for biomarker detection.