A highly sensitive electrochemiluminescence immunosensor for h-FABP determination based on self-enhanced luminophore coupled with ultrathin 2D nickel metal-organic framework nanosheets

Abstract

In this work, a novel ECL immunosensor based on self-enhanced luminophore and ultrathin 2D nickel MOF nanosheets was fabricated for sensitive and specific detection of h-FABP. Initially, the porous ultrathin Ni-TCPP (Fe) nanosheets with high specific surface area and plentiful active sites were newly synthesized, which could enhance ECL signal of luminol by the superior peroxidase mimics activity towards H₂O₂ decomposition. Then, PEI and luminol were simultaneously immobilized on Ni-TCPP (Fe) nanosheets to construct self-enhanced solid state luminophore (Ni-TCPP (Fe)-PEI-Lum), possessing desirable stability and high ECL efficiency. Furthermore, poly (indole-5-carboxylic acid) (PICA) worked as substrate with outstanding conductivity and abundant binding sites to improve sensitivity. Under optimal conditions, the designed ECL immunosensor exhibited a wide dynamic range from 100 fg mL^-1 to 100 ng mL^-1 and a low detection limit of 44.5 fg mL^-1. In addition, the ECL immunosensor behaved excellent specificity and was successfully applied to detect target h-FABP protein in complex physiological matrix. Therefore, this work may provide an alternative method for biomarker detection in clinical diagnosis and expand the application potential of 2D MOF nanosheets in ECL technique.

Keywords: Electrochemiluminescence; Ni-TCPP (Fe) -PEI-Lum; Self-enhanced; Solid-state luminophore; h-FABP.