Lateral Flow Immunosensor for Ferritin Based on Dual Signal-Amplified Strategy by Rhodium Nanoparticles

Lateral flow immunoassay (LFIA) is one of the most widely used tools for analysis and field measurement and has the advantages of high efficiency, simple operation, portability, and low cost. Therefore, in this study, we designed a proof-of-concept of LFIA based on rhodium nanoparticles and investigated its improvement by further introducing the tetramethyl benzidine and H₂O₂ mixture as the substrate to trigger the color reaction. The proposed methods were qualitative research by the naked eye and quantitative measurement by a smartphone and software. Under the optimal condition, the detection of ferritin was successfully established with the limit of detection of 0.3 ng/mL. The lowest visually detectable amount was 0.05 ng/mL. To verify the performance of the RhNPs-LFIA, three spiked serum samples were tested, and the recovery rate increased from 88.9 to 129.9%, revealing that the proposed methods were applicable and practically reliable for testing serum samples. The developed RhNP-based LFIA is highly sensitive and convenient, which provides a promising technology for accurate, rapid, high sensitivity, and high screening detection of ferritin in clinical diagnosis.