CuS hollow nanocages with rough surface to enhanced photothermal property for ultra-sensitive detection of furazolidone metabolites

Signal tracers play a key role in the lateral flow immunoassay (LFIA) for improving sensitivity and signal output capability. Photothermal signal has sparked significant excitement in designing high-performance LFIAs. Herein, CuS hollow nanocages (CuS HNCs) were synthesized for building a dual signal LFIA. CuS HNCs show excellent photothermal conversion efficiency due to their unique morphology and superior localized surface plasmon resonance (LSPR) effect. Meanwhile, the hollow-cage structure endows CuS HNCs with high light absorption and suitable colorimetric property. Furazolidone (FZD) metabolite was used as a model target in the developed LFIA to demonstrate its superior comprehensive performances brought by CuS HNCs. The limit of detection is as low as 0.099 ng mL−1 (colorimetric mode) and 0.075ng mL−1 (photothermal mode), respectively. Furthermore, standard recovery test in honey and shrimp samples was performed and the recovery rates ranged from 86.33 % to 116.71 %. This study not only introduces a new type of nanolabel characterized by an abundance of high-energy hot carriers and pronounced thermal effects, enabling the development of exceptionally sensitive immunosensor platforms but also extends applications of hollow plasmonic photothermal material in the point-of-care (POC) diagnostic field.