Abstract
β-amyloid1-42 (Aβ1-42) is a humoral biomarker for early diagnosis of Alzheimer's disease (AD), and exists at a low level in human body. Its sensitive detection is very valuable. The electrochemiluminescence (ECL) assay of Aβ1-42 has attracted special attention owing to high sensitivity and simple operation. However, currently reported ECL assays for Aβ1-42 usually required the introduction of exogenous coreactants to improve the detection sensitivity. Introducing exogenous coreactants will lead to non-negligible repeatability and stability problems. This work exploited poly [(9,9-dioctylfluorenyl-2,7-diyl)-co-(1,4-benzo-{2,1',3}-thiadazole)] nanoparticles (PFBT NPs) as coreactant-free ECL emitters for detecting Aβ1-42. The PFBT NPs, first antibody (Ab1) and antigen Aβ1-42 were successively assembled on glassy carbon electrode (GCE). Silica nanoparticles served as a carrier to grow polydopamine (PDA) in situ, and further assembled Au nanoparticles (Au NPs) and second antibody (Ab2), producing the secondary antibody complex (SiO2@PDA-Au NPs-Ab2). With its assembly on the biosensor, the ECL signal decreased since both PDA and Au NPs could quench ECL emission from PFBT NPs. The limit of detection (LOD) of 0.55fg/mL and limit of quantification (LOQ) of 37.45fg/mL for Aβ1-42 were obtained. PFBT NPs coupling dual-quencher PDA-Au NPs created an excellent ECL system for bioassays, and constructed a sensitive analytical method for Aβ1-42.
Published Version
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