Surface-Enhanced\nRaman Scattering-Based Lateral Flow\nAssay Strips Using Highly Symmetric Gold Nanostars

The applications for lateral flow assay (LFA) strips\nin point-of-care\ntesting have been significantly constrained by their insufficient\nsensitivity and reproducibility. To address these inherent issues,\nwe developed surface-enhanced Raman scattering (SERS)-based LFA strips,\nin which highly symmetric Au nanostars (Sym-AuNS) were employed as\nthe sensing element. Due to the uniform tip-sharp nanostructure and\na certain number of branches on the surface of Sym-AuNS, it generates\na uniform hotspot distribution, thus producing a strong and stable\nSERS signal. As a proof of concept, human IgG was chosen as the target\nto evaluate the performance of the proposed SERS-LFA strips. In human\nserum spiked samples, the limit of detection for human IgG detection\nwas achieved as low as 38 ng/mL, which exhibited a 2-fold, 3-fold,\nand 13-fold sensitivity improvement compared with the SERS-LFA strips\nusing conventional gold nanostars (AuNS), enzyme-linked immunosorbent\nassays (ELISA), and the conventional LFA strips, respectively. Furthermore,\nthe SERS-LFA strips demonstrated high assay reproducibility, with\na relative standard deviation of 7.75% for five repeated tests, much\nlower than those of SERS-LFA strips using AuNS (24.6%), ELISA (12.42%),\nand conventional LFA strips (31.32%). These results demonstrate that\nthe construction of sensitive and reproducible SERS-LFA strips was\nobtained, and this platform using Sym-AuNS as SERS nanoparticles paves\nthe way for a promising approach in immunoassay technology.