Metal self-reducing triggered green etching for the CuO@Ag composite synthesis and its application in high-sensitive lateral flow immunoassay
Jiaqi Ma, Xuechi Yin, Yuanyuan Cheng, Chaoying Wang, Qiaoying Wu, Qingzhe Zhang, Lei Zhao, Jing Zhou, Jianlong Wang, Daohong Zhang
Abstract
Photothermal materials has aroused extensive attention for building multi-signal immunosensors. Herein, a metal self-reducing triggered green etching strategy was employed for the synthesis of CuO@Ag nanoparticles (NPs) with high photothermal conversion efficiency and better antibody coupling efficiency. The flower-like morphology of the CuO@Ag NPs has improved its binding ability with antibodies, which enables them to serve as the multifunctional signal label of the lateral flow immunoassay (LFIA). Then, a colorimetric-photothermal dual-mode LFIA (CuO@Ag-based LFIA) was designed for the highly sensitive detection of clenbuterol hydrochloride (CLE). After direct, the CuO@Ag NPs endowed T-line to be irradiated by an 808 nm laser to obtain photothermal signal owing to their strong photothermal conversion efficiency of CuO@Ag. Under optimal conditions, the detection limits of the CuO@Ag-based LFIA are 0.205 ng mL −1 and 0.131 ng mL −1 under colorimetric and photothermal modes, respectively, which are 13 and 20 times sensitive than that of the conventional AuNP-based LFIA. Additionally, the LFIA was assessed by measuring CLE in food samples with recovery rates ranging from 86.37 % to 103.72 % and coefficient of variations (CVs) ranging from 2.52 % to 9.64 %. Consequently, this work provides qualitative-quantitative point-of-care testing (POCT) approach and has important reference value for other facile, green, and low-cost synthesis of composite signal labels in the LFIA system.