Dual-signal immunosensor based on aggregation-induced electrochemiluminescence resonance energy transfer of La-MOF and low cathodic excitation potential of g-C3N4@AuNPs for the quantitation of human serum amyloid A

We report on the development of a dual-signal electrochemiluminescence (ECL) immunosensor for the quantitation of human serum amyloid A (SAA). The immunosensor comprises g-C₃N₄@AuNPs as the cathode and a lanthanum-based metal organic framework (La-MOF) as the anode, the latter of which utilizes aggregation-induced electrochemiluminescence (AIECL) to overcome the otherwise poor ECL intensity of H₄TBAPy ligands at the electrode surface. Furthermore, the rigid MOF structure significantly improved the fluorescence quantum yield, as well as the fluorescence and ECL emission, of the La-MOF compared to H₄TBAPy. The g-C₃N₄@AuNPs exhibits an ultrathin nanosheet structure with a low cathodic excitation potential of −0.72 V. When the dual-signal ECL immunosensor was employed to detect SAA, the difference between the anodic and cathodic ECL signals exhibited a strong linear relationship with the logarithm of the SAA concentration in the range of 100 fg/mL–200 ng/mL, with a detection limit of 24.5 fg/mL.