Fabrication of an antibody-aptamer sandwich assay for electrochemical evaluation of levels of ?-amyloid oligomers.

ABSTRACT: Amyloid ?-peptide (A?) in its oligomeric form is often considered as the most toxic species in Alzheimer's disease (AD), and thus A? oligomer is a potentially promising candidate biomarker for AD diagnosis. The development of a sensitive and reliable method for monitoring the A? oligomer levels in body fluids is an urgent requirement in order to predict the severity and progression at early or preclinical stages of AD. Here, we show a proof of concept for a sensitive and specific detection of A? oligomers by an antibody-aptamer sandwich assay. The antibodies of A? oligomers and a nanocomposite of gold nanoparticles with aptamer and thionine (aptamer-Au-Th) were used as the recognition element and the detection probe for specifically binding to A? oligomers, respectively. The electrochemical signal of Th reduction could provide measurable electrochemical signals, and a low limit of detection (100?pM) was achieved due to the signal amplification by high loading of Th on the gold nanoparticles. The feasibility of the assay was verified by test of A? oligomers in artificial cerebrospinal fluid. The proposed strategy presents valuable information related to early diagnosis of AD process.

SUBMITTER: Zhou Y 

PROVIDER: S-EPMC5057102 | biostudies-literature | 2016 Oct

REPOSITORIES: biostudies-literature