Quantitative assessment of AD markers using naked eyes: point-of-care testing with paper-based lateral flow immunoassay.

Aβ ₄₂ is one of the most extensively studied blood and Cerebrospinal fluid (CSF) biomarkers for the diagnosis of symptomatic and prodromal Alzheimer's disease (AD). Because of the heterogeneity and transient nature of Aβ ₄₂ oligomers (Aβ ₄₂ Os), the development of technologies for dynamically detecting changes in the blood or CSF levels of Aβ ₄₂ monomers (Aβ ₄₂ Ms) and Aβ ₄₂ Os is essential for the accurate diagnosis of AD. The currently commonly used Aβ ₄₂ ELISA test kits usually mis-detected the elevated Aβ ₄₂ Os, leading to incomplete analysis and underestimation of soluble Aβ ₄₂ , resulting in a comprised performance in AD diagnosis. Herein, we developed a dual-target lateral flow immunoassay (dLFI) using anti-Aβ ₄₂ monoclonal antibodies 1F12 and 2C6 for the rapid and point-of-care detection of Aβ ₄₂ Ms and Aβ ₄₂ Os in blood samples within 30 min for AD diagnosis. By naked eye observation, the visual detection limit of Aβ ₄₂ Ms or/and Aβ ₄₂ Os in dLFI was 154 pg/mL. The test results for dLFI were similar to those observed in the enzyme-linked immunosorbent assay (ELISA). Therefore, this paper-based dLFI provides a practical and rapid method for the on-site detection of two biomarkers in blood or CSF samples without the need for additional expertise or equipment.
(© 2021. The Author(s).)