A sandwich electrochemiluminescence immunosensor for highly sensitive detection of alpha fetal protein based on MoS2-PEI-Au nanocomposites and Au@BSA core/shell nanoparticles

In this work, a novel and universal sandwich-type electrochemiluminescence (ECL) immunosensor was constructed for the sensitive and specific detection of alpha fetal protein (AFP), in which the MoS2 nanosheets surface was modified using polyethylenimine (PEI) polymer with plentiful amino-groups (MoS2-PEI) for warranting their positively charged interface and thereby a large amount of negatively charged gold nanoparticles (AuNPs) were electrostatically adsorbed to form MoS2-PEI-Au nanocomposites. Meanwhile, the synthesized Au@BSA nanoparticles were utilized to immobilize molecule recognition probe secondary antibodies (Ab2) and signal probe numerous luminol molecules, respectively. Upon the optimization of assay conditions, the proposed immunosensor displayed wide linear range from 0.0001 ng/mL to 200.0 ng/mL with limit of detection of 1.0 × 10−5 ng/mL. Moreover, this immunosensor was employed to analyze AFP in real human serum samples with favorable results. The presented immunosensing strategy may provide great potential in the assay of other clinically biomarkers.