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

Abstract Lateral flow immunoassays (LFIAs) provide a powerful tool for rapid real-time assay of cancer biomarker, which is vital for cancer detection and treatment follow-up. Lanthanide-based LFIAs is one of the most widely used materials, especially Eu (III) chelates, which possess distinctive and attractive characteristics, such as time-resolved fluorescence and large Stokes-shift. Herein, we adopt a new one-step mini-emulsion polymerization method to synthesize carboxyl-modified fluorescent microspheres (OS-EuCM), which shows good stability, resistance to non-specific adhesion and uniform particle size distribution compared with traditional microsphere synthesized through swelling method. Benefit from the above advantages, OS-EuCMweresuccessfully used in LFIAs to detect tumor marker Alpha-fetoprotein (AFP) 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.