Electrochemiluminescence immunosensor based on a novel heterostructured Fe-MIL-88@1T-MoS2 dual-nanozyme with high peroxidase-like activity for the sensitive detection of NT-proBNP

Abstract

In this work, an efficient Fe-MIL-88@1T-MoS₂ dual-nanozyme and hollow CeO₂ mono-nanozyme were synthesized as coreaction accelerators to fabricate an electrochemiluminescence (ECL) immunosensor for the detection of the N-terminal pro-brain natriuretic peptide (NT-proBNP). First, the peroxidase-like activity of the proposed Fe-MIL-88@1T-MoS₂ dual-nanozyme was found to be superior to that of individual Fe-MIL-88 and MoS₂, owing to the synergistic catalytic effect caused by the heterostructure. Therefore, it could be utilized as an ideal coreaction accelerator to boost H₂O₂ decomposition and subsequently generate abundant reactive oxygen species, which could promote electrical oxidation of ABEI and obtain a high ECL signal. Second, the rough surface of Fe-MIL-88@1T-MoS₂ facilitated the mass capture of luminescent ABEI-modified silver nanoparticles (Ag-ABEI), which could further enhance the ECL signal of the immunosensor. Finally, hollow CeO₂ also exhibited excellent catalytic performance toward H₂O₂ decomposition owing to its facile redox-active Ce³⁺/Ce⁴⁺ and abundant surface oxygen vacancies, resulting in a further enhancement in the ECL signal of the immunosensor. Therefore, the ECL immunosensor based on Fe-MIL-88@1T-MoS₂ and hollow CeO₂ exhibited an extremely strong ECL signal and realized the ultra-sensitive detection of NT-proBNP with a detection limit as low as 0.21 fg mL⁻¹. Thus, these results demonstrate that the proposed strategy may afford an efficient means for the sensitive detection of trace proteins.