Cortisol, a corticosteroid hormone as a primary stress hormone response to internal and external stress, has been regarded as a gold standard reliable biomarker to evaluate human mental stress. The double enzymes strategy, using nanozyme and enzyme amplifying the electrochemical signal, has been widely used to improve the performance of electrochemical biosensors. An ultra-sensitive electrochemical cortisol sensor based on Au single-atom nanozymes had been fabricated through HRP labeled anti-cortisol antibody binding with Au by Au-S bond. Based on the high catalytic activity of Au single-atom nanozymes and the high selectivity of HRP-labeled anti-cortisol antibodies, the cortisol electrochemical sensor-based Au single-atom nanozymes had an excellent response to cortisol, such as high electrochemical activity, high sensitivity, high selectivity, and wide linear range (0.15–300 ng mL) and low detection (0.48 pg mL) through the four-parameter logistic model with 95% confidence. The electrochemical cortisol sensor was used to determine the cortisol concentration of human saliva at different times.

中文翻译：

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Au单原子纳米酶和HRP酶放大的超灵敏皮质醇电化学免疫传感器

皮质醇是一种皮质类固醇激素，作为对内部和外部压力的主要应激激素反应，已被视为评估人类精神压力的金标准可靠生物标志物。使用纳米酶和酶放大电化学信号的双酶策略已被广泛用于提高电化学生物传感器的性能。通过HRP标记的抗皮质醇抗体通过Au-S键与Au结合，制备了基于Au单原子纳米酶的超灵敏电化学皮质醇传感器。基于Au单原子纳米酶的高催化活性和HRP标记的抗皮质醇抗体的高选择性，基于Au单原子纳米酶的皮质醇电化学传感器对皮质醇具有优异的响应，例如高电化学活性、高通过四参数 Logistic 模型，具有 95% 的置信度，具有高灵敏度、高选择性、宽线性范围 (0.15–300 ng mL) 和低检出率 (0.48 pg mL)。利用电化学皮质醇传感器测定不同时间人体唾液的皮质醇浓度。