In this work, a novel MXene-Au nanoparticle (Ti₃C₂@Au) was synthesized with a high molar extinction coefficient, strong fluorescence quenching ability, ultrahigh antibody affinity, high stability, and good dispersibility, and it was used to develop a colorimetric-fluorescence dual-mode lateral flow immunoassay (LFIA). The detection limits of this method for the detection of dexamethasone in milk, beef, and pork were 0.0018, 0.12, and 0.084 μg/kg in the “turn-off” mode (colorimetric signal), and 0.0013, 0.080, and 0.070 μg/kg in the “turn-on” mode (fluorescent signal), respectively, which was up to 231-fold more sensitive compared with that of the reported LFIAs. The recovery rates ranged from 81.1–113.7%, and 89.2–115.4%, with the coefficients of variation ranging from 1.4–15.0%, and 1.9–14.8%, respectively. The results of the LC-MS/MS confirmation test on 30 real samples had a good correlation with that of our established method (R² > 0.97). This work not only developed novel nanocarriers for antibody-based LFIA but also ensured high-performance detection.

中文翻译：

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高密度 Au 锚定于基于 Ti3C2 的比色荧光双模式横向流动免疫分析，用于全域增强性能和信号相互校准

本工作合成了一种新型MXene-Au纳米粒子（Ti ₃ C ₂ @Au），具有高摩尔消光系数、强荧光猝灭能力、超高抗体亲和力、高稳定性和良好分散性，并用于开发比色荧光双模式侧流免疫分析（LFIA）。该方法检测牛奶、牛肉和猪肉中地塞米松的检出限在“关闭”模式（比色信号）下分别为 0.0018、0.12 和 0.084 μg/kg，在“关闭”模式下（比色信号）为 0.0013、0.080 和 0.070 μg/kg。 kg 分别在“开启”模式（荧光信号）下，其灵敏度比报道的 LFIA 高 231 倍。回收率范围为81.1-113.7%和89.2-115.4%，变异系数范围分别为1.4-15.0%和1.9-14.8%。 30个实际样品的LC-MS/MS确证试验结果与我们建立的方法有很好的相关性（R ² > 0.97）。这项工作不仅开发了用于基于抗体的 LFIA 的新型纳米载体，而且还确保了高性能检测。