Trimodal Multiplexed\nLateral Flow Test Strips Assisted\nwith a Portable Microfluidic Centrifugation Device

During the COVID-19\npandemic, the use of lateral flow\nassays (LFAs)\nexpanded significantly, offering testing beyond traditional health\ncare. Their appeal lies in the ease of use, affordability, and quick\nresults. However, LFAs often have lower sensitivity and specificity\ncompared with ELISA and PCR tests. Efforts to improve LFAs have increased\ndetection times and complexity, limiting their use in large-scale\npoint-of-care settings. To address this, we propose a novel approach\nusing probes that generate multiple signals to enhance the sensitivity\nand selectivity. This concept also allows multiplexed LFAs to detect\nmultiple analytes concurrently. We developed a trimodal probe that\nintegrates fluorescence, color, and magnetism into a single nanohybrid.\nThe strong plasmonic absorption and high fluorescence of Au nanoparticles\nand polymer dots enable qualitative and semiquantitative diagnosis,\nwhile the magnetic signal facilitates accurate quantitative measurements.\nAs proof-of-concept targets, we selected CYFRA 21-1 and CA15-3, biomarkers\nfor lung and breast cancer, respectively. This trimodal LFA demonstrated\na remarkable detection limit of 0.26 ng/mL for CYFRA 21-1 and 2.8\nU/mL for CA15-3. To the best of our knowledge, this is the first platform\nof a trimodal LFA with multiplexing ability. The platform’s\naccuracy and reliability were validated using clinical serum samples,\nshowing excellent consistency with electrochemiluminescence immunoassay\nresults. This universal concept can be applied to other targets, paving\nthe way for the next-generation LFAs.