Triple signal-enhanced electrochemiluminescence strategy using iron-based metal-organic frameworks modified with Ru(II) complexes for carcino-embryonic antigen detection.

The development of a highly efficient electrochemiluminescence (ECL) emitter represents an effective strategy for enhancing the sensitivity and repeatability of ECL immunosensors. In this study, a sandwich-type ECL immunosensor with triple enhancement was developed to detect carcino-embryonic antigen (CEA). This sensor is based on a porous structure of iron-based metal-organic framework (NH-MIL-88(Fe)), encapsulating the luminescent tris(2,2'-bipyridine)ruthenium (II) (Ru (bpy)), Au@MoS with a 3D nanoflower structure as an enhanced substrate. In this system, the MOFs framework encapsulated luminophore was realized to solve its water solubility to reach stable luminescence, as well as the triple enhancement effect based on the principle of amino catalysis, Mo/Mo active site conversion, and gold nanoparticles (Au NPs) promotion, which significantly enhanced the detection sensitivity. Furthermore, the ECL immunosensor demonstrated successful application in the highly sensitive and selective detection of CEA, achieving a detection limit of 38.9 fg mL. The sensor demonstrates remarkable sensitivity, specificity, stability, repeatability, and practicality in the analysis of human serum samples. This investigation presents a highly effective approach for the ultrasensitive detection of trace proteins.