Surface-Enhanced Raman Scattering-Based Lateral Flow Assay Strips Using Highly Symmetric Gold Nanostars
Yixuan Wu, Qian Yang, Jiadong Chen, Liyan Bi, Zhiyang Zhang, Na Zhou, Abbas Ostovan, Maryam Arabi, Lingxin Chen, Jaebum Choo
Abstract
The applications for lateral flow assay (LFA) strips in point-of-care testing have been significantly constrained by their insufficient sensitivity and reproducibility. To address these inherent issues, we developed surface-enhanced Raman scattering (SERS)-based LFA strips, in which highly symmetric Au nanostars (Sym-AuNS) were employed as the sensing element. Due to the uniform tip-sharp nanostructure and a certain number of branches on the surface of Sym-AuNS, it generates a uniform hotspot distribution, thus producing a strong and stable SERS signal. As a proof of concept, human IgG was chosen as the target to evaluate the performance of the proposed SERS-LFA strips. In human serum spiked samples, the limit of detection for human IgG detection was achieved as low as 38 ng/mL, which exhibited a 2-fold, 3-fold, and 13-fold sensitivity improvement compared with the SERS-LFA strips using conventional gold nanostars (AuNS), enzyme-linked immunosorbent assays (ELISA), and the conventional LFA strips, respectively. Furthermore, the SERS-LFA strips demonstrated high assay reproducibility, with a relative standard deviation of 7.75% for five repeated tests, much lower than those of SERS-LFA strips using AuNS (24.6%), ELISA (12.42%), and conventional LFA strips (31.32%). These results demonstrate that the construction of sensitive and reproducible SERS-LFA strips was obtained, and this platform using Sym-AuNS as SERS nanoparticles paves the way for a promising approach in immunoassay technology.