Quench-type electrochemiluminescence immunosensor for detection of amyloid β-protein based on resonance energy transfer from luminol@SnS2-Pd to Cu doped WO3 nanoparticles.

A highly efficient quench-type electrochemiluminescence (ECL) immunosensor was proposed for the trace detection of amyloid β-protein (Aβ1-42). In this work, tin disulfide nanoflowers (SnS2 NFs) with large specific surface area, favorable catalytic property and chemical stability were prepared and used as substrate material. Taking advantage of the excellent catalytic ability and biocompatibility, palladium nanoparticles (Pd NPs) were in situ reduced on SnS2 NFs to obtain SnS2-Pd. Moreover it could combine with large amounts of luminol and achieve a strong ECL signal output. In addition, copper doped mesoporous tungsten trioxide (Cu:WO3) nanoparticles were selected to quench ECL emission of luminol@SnS2-Pd via resonance energy transfer, where luminol@SnS2-Pd was the donor and Cu:WO3 was the acceptor. On this basis, a quench-type ECL immunosensor was constructed for detection of Aβ1-42. Under optimum conditions, the fabricated ECL immunosensor showed sensitive response to Aβ1-42 concentration from 0.1 pg/mL to 50 ng/mL with a low detection limit of 5.4 fg/mL (S/N = 3). It is expected to be a promising analytical tool for the sensitive detection of Aβ1-42 and other biomarkers with high specificity, good reproducibility and long-term stability.