A highly sensitive lateral flow immunoassay (LFIA) is developed for the enzyme-catalyzed and double-reading determination of clenbuterol (CLE), in which a new type of probe was adopted through the direct electrostatic adsorption of ultra-small copper–gold bimetallic enzyme mimics (USCGs) and monoclonal antibodies. In the assay, based on the peroxidase activity of USCG, the chromogenic substrate TMB–H₂O₂ was introduced to trigger its color development, and the results were compared with those before catalysis. The detection sensitivity after catalysis is 0.03 ng mL⁻¹ under optimal circumstances, which is 6-fold better than that of the traditional Au NPs-based LFIA and 2-fold greater than that before catalysis. This approach was successfully applied to the detection of CLE in milk, pork and mutton samples with an optimum assay time of 7 min and best catalytic time of 80 s, after which satisfactory recoveries of 98.53–117.79% were obtained. Cu–Au nanoparticles as a signal tag and the use of their nanozyme properties are the first applications in the field of LFIA. This work can be a promising exhibition for the application of a cheaper substitute for HRP, ultra-small bimetallic enzyme mimics, in LFIAs.

中文翻译：

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HRP 的更便宜替代品：超小 Cu-Au 双金属酶模拟物，具有极小的空间位阻，可促进克伦特罗的催化侧流免疫检测

开发了一种用于酶催化双读测定克仑特罗（CLE）的高灵敏侧流免疫分析法（LFIA），采用新型探针，通过超小型铜金双金属酶的直接静电吸附模拟物（USCG）和单克隆抗体。实验中，根据USCG的过氧化物酶活性，引入显色底物TMB–H ₂ O ₂引发其显色，并将结果与​​催化前进行比较。在最佳情况下，催化后的检测灵敏度为0.03 ng mL ^-1，比传统的基于Au NPs的LFIA提高了6倍，比催化前提高了2倍。该方法成功应用于牛奶、猪肉和羊肉样品中CLE的检测，最佳检测时间为7 min，最佳催化时间为80 s，回收率达到98.53%~117.79%。Cu-Au 纳米颗粒作为信号标签及其纳米酶特性的利用是 LFIA 领域的首次应用。这项工作对于 HRP 的更便宜的替代品（超小型双金属酶模拟物）在 LFIA 中的应用来说是一个很有前途的展览。