Nanozymes have drawn much attention as an enzyme mimetic with low cost and stability in enhancing analytical performance. Herein, a peroxidase-mimicking nanozyme-improved enzyme-linked immunosorbent assay (ELISA) was developed employing the bimetallic PdRu nanozyme to replace the natural enzymes as a catalytic carrier for the sensing of Escherichia coli O157:H7 (E. coli O157:H7). The PdRu nanozyme displayed ultrahigh catalytic activity, possessing a catalytic rate that was 5-fold higher than horseradish peroxidase (HRP). In addition, PdRu exhibited great biological affinity with antibody (affinity constant was about 6.75 × 10¹² M) and high stability. All those advantages ensure the successful establishment and the construction of a novel colorimetric biosensor for E. coli O157:H7 detection. PdRu-based ELISA not only achieved an ultrasensitive detection sensitivity (8.7 × 10² CFU/mL) by approximately 288-fold as compared to the traditional HRP-based ELISA and also possessed satisfactory specificity and reproducibility (relative standard deviation (RSD) < 10%). Furthermore, the feasibility of PdRu-ELISA was further evaluated by detecting E. coli O157:H7 in actual samples with satisfactory recoveries, indicating its potential for applications in bioassays and clinical diagnostics.

中文翻译：

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用于高灵敏大肠杆菌 O157:H7 检测的多功能 PdRu 双金属纳米酶集成酶联免疫吸附测定

纳米酶作为一种低成本且稳定的酶模拟物，在提高分析性能方面备受关注。在此，开发了一种模拟过氧化物酶的纳米酶改进的酶联免疫吸附测定（ELISA），采用双金属PdRu纳米酶代替天然酶作为催化载体用于传感大肠杆菌O157：H7（E.coli O157：H7） 。PdRu纳米酶表现出超高的催化活性，其催化速率比辣根过氧化物酶（HRP）高5倍。此外，PdRu与抗体表现出良好的生物亲和力（亲和常数约为6.75×10 ¹²M) 稳定性高。所有这些优势确保了用于大肠杆菌O157:H7检测的新型比色生物传感器的成功建立和构建。基于 PdRu 的 ELISA 不仅实现了超灵敏的检测灵敏度（8.7 × 10 ² CFU/mL），是传统基于 HRP 的 ELISA 的约 288 倍，而且还具有令人满意的特异性和重现性（相对标准偏差 (RSD) < 10 %）。此外，通过检测实际样品中的大肠杆菌O157:H7，进一步评估了PdRu-ELISA的可行性，回收率令人满意，表明其在生物测定和临床诊断中的应用潜力。