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

Abstract

Aβ42 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 Aβ42 oligomers (Aβ42Os), the development of technologies for dynamically detecting changes in the blood or CSF levels of Aβ42 monomers (Aβ42Ms) and Aβ42Os is essential for the accurate diagnosis of AD. The currently commonly used Aβ42 ELISA test kits usually mis-detected the elevated Aβ42Os, leading to incomplete analysis and underestimation of soluble Aβ42, resulting in a comprised performance in AD diagnosis. Herein, we developed a dual-target lateral flow immunoassay (dLFI) using anti-Aβ42 monoclonal antibodies 1F12 and 2C6 for the rapid and point-of-care detection of Aβ42Ms and Aβ42Os in blood samples within 30 min for AD diagnosis. By naked eye observation, the visual detection limit of Aβ42Ms or/and Aβ42Os 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. Graphical Abstract

An In Situ Study on Nanozyme Performance to Optimize Nanozyme-Strip for Aβ Detection

“…There was a good correlation (R 2 = 0.9796) between the T line signal intensity and the detection concentration within the concentration range of 0.18–1820 ng/mL ( Figure 7 c). Previous studies have reported that the Aβ42Os levels in the blood of AD patients range from 0.1 to 1 ng/mL, as detected by sandwich ELISA [ 31 ]. The sensitivity of the nanozyme-strip for Aβ42Os detection needs to be improved.…”

Development of a Paper-based Hematocrit Test and a Lateral Flow Assay to Detect Critical Fibrinogen Concentrations Using a Bottom-Up Pyramid Workflow Approach

“…The first LFA, similar to those available today, was developed in the 1980s to detect the presence of human chorionic gonadotropin (hCG) in urine to confirm pregnancy . Since then, lateral flow tests have become successful analytical devices for PoC testing in various settings, ranging from detecting disease biomarkers, , pathogenic bacteria, viruses, and mycotoxins to chemical contaminants like veterinary drug residues or pesticides . Since the SARS-CoV-2 outbreak in 2019, LFAs have become one of the most abundant diagnostic tools for identification and monitoring of virus spread, needed to implement quarantine measures, despite their analytical drawbacks .…”

Microfluidic Device for Patient-Centric Multiplexed Assays with Readout in Centralized Laboratories

“…Especially immunoassays, when performed at the point of care (POC), could enable timely testing when a low turnaround time of analysis is highly needed, e.g., in first-aid settings (ambulance, physician offices, pharmacies). POC immunoassays also have great potential to assess time-critical and labile biomarkers, which are prone to degradation after sample collection. , Various lab-on-chip-type immunoassays, e.g., based on centrifugal − or paper-based − microfluidics, were proposed to realize POC applications. In these approaches, analyte capturing is typically achieved using immobilized antibodies, e.g., in porous matrices or on bead surfaces .…”