Detection of Aβ Monomers and Oligomers: Early Diagnosis of Alzheimer's Disease

Alzheimer's disease (AD), as the most common progressive neurodegenerative disorder, is pathologically characterized by deposition of extracellular plaque composed of amyloid‐β peptide (Aβ). Different assembled states of Aβ have been considered as both important biomarkers and drug targets for the diagnosis and therapy of AD. Recent studies demonstrate that small, diffusible Aβ oligomers formed by aggregation of Aβ monomers are the major toxic agents in AD. Therefore, the development of reliable assays for Aβ (both monomers and oligomers) will be important for the early differential diagnosis of dementia, predicting the progression of AD, as well as monitoring the effectiveness of novel anti‐Aβ drugs for AD. In this review, we summarize the recent progress made in the development of techniques for detection of Aβ monomers and oligomers. In particular, the principles governing the design of these sensors are classified and summarized. Moreover, the advantages and disadvantages of the assays are evaluated. This review also discusses the improvements and challenges for application of these assays in the early diagnosis of AD.