One-step polymerized lanthanide-based polystyrene microsphere for sensitive lateral flow immunoassay

Lateral flow immunoassays (LFIAs) provide a powerful tool for rapid real-time assay of cancer biomarkers, which is vital for cancer detection and treatment follow-up. Lanthanide-based LFIAs is one of the most widely used methods, especially Eu (III) chelates, which possess distinctive and attractive characteristics, such as time-resolved fluorescence and large Stokes shift. Herein, we adopted a new onestep mini-emulsion polymerization method to synthesize carboxyl-modified fluorescent microsphere (OS-EuCM), which shows good stability, resistance to non-specific adhesion and uniform particle size distribution compared with traditional microspheres synthesized through the swelling method. Benefiting from the above advantages, OS-EuCM was successfully used in LFIAs to detect tumor marker Alpha-fetoprotein with high sensitivity and selectivity in concentration as high as 320 ng/mL, as well as a detection limit of 0.683 ng/mL. This lanthanide-based microsphere holds great potential for rapid point of-care screening and clinical application. (c) 2021 Chinese Society of Rare Earths. Published by Elsevier B.V. All rights reserved.