Performance comparison of single and mixed-sized gold nanoparticles on straightforward lateral flow assay for albumin detection

The sensitivity of the lateral flow assay can be influenced by multiple factors, such as the size of gold nanoparticles (GNPs) employed, which affect the sensitivity and reproducibility of the assay testing procedure. Here, we evaluated the analytical performance of single-sized and mixed-sized GNPs using a simple lateral flow assay (LFA) platform. This platform was used as a model assay to diagnose albumin levels and demonstrate the analytical performance of single-sized and mixed-sized GNPs in LFA tests. Two sizes of GNPs@anti-bovine serum albumin (BSA) conjugate proteins were mixed at different ratios. The unique optical properties of the GNPs induced a distinguishing color-shedding effect on the single and mixed-sized GNPs@anti-BSA conjugates interacting with the target analyte BSA spotted on the test line. The use of mixed-sized GNPs@anti-BSA conjugates enhanced signal amplification, and provided superior stability compared with solely employing the large GNPs (50 nm). The proposed platform in this study could provide an efficient BSA detection mechanism that can be utilized as a biomarker for confronting chronic kidney disease.