Abstract：
We have developed a powerful biosensing strategy for immobilizing histidine-tagged (His-Tag)-oriented recombinant nano-protein immobilization on a chemically modified glassy carbon electrode (GCE) surfaces via (S)-N-(5-amino-1-carboxypentyl)iminodiacetic acid (ANTA) acting as a chelating Ni2+ centered interaction. Here, we introduce a label-free electro-sensor to quantify cortisol levels in saliva samples for point-of-care testing (POCT). The high specificity of the chemically modified GCE was established by genetically bio-engineered metal-binding sites on the selected recombinant apoferritin (R-AFTN) nano-protein to impart functionality to its surface and by coating the carbon surface with the self-assembled monolayers of 4-aminobenzoic acid (4-ABA) attached to ANTA groups complexed with Ni2+ transition metal ions. Despite the variety of conventional assays available to monitor cortisol levels, they require bulky exterior outfits, which hinders use in the healthcare systems. Therefore, we performed a rapid, easy-to-implement, and low-cost quantitative electro-sensor to enable the real-time detection of cortisol levels in saliva samples. As a result, the cortisol electro-sensor fabricated with high specificity utilizing a GCE could measure cortisol levels with a detection limit of 0.95 ng/ml and sensitivity of 7.91 μA/(ng/mL), which is a practical approach in human saliva. Thus, protein nanoprobe-based cortisol biosensing showed high sensitivity and selectivity for the direct electro-sensing of cortisol for POCT.
摘要：
我们已经开发了一种强大的生物传感策略，用于通过（S）-N-（5-氨基-1-羧基戊基）亚氨基二乙酸（ANTA）作为螯合Ni2中心相互作用，将组氨酸标记（His-Tag）定向的重组纳米蛋白固定在化学修饰的玻碳电极（GCE）表面上。这里,我们引入了一种无标签的电传感器来量化唾液样本中的皮质醇水平,用于即时检测(POCT).化学修饰的GCE的高特异性是通过在选定的重组脱铁铁蛋白（R-AFTN）纳米蛋白上进行基因工程化的金属结合位点以赋予其表面功能性，并通过用自组装的单层覆盖碳表面来建立的。4-氨基苯甲酸（4-ABA）连接到与Ni2过渡金属离子络合的ANTA基团。尽管有多种常规检测方法可用于监测皮质醇水平，他们需要笨重的外部服装，这阻碍了医疗保健系统的使用。因此,我们表演了一个快速的，易于实现，和低成本的定量电传感器，使唾液样本中的皮质醇水平的实时检测。因此,利用GCE制造的高特异性皮质醇电传感器可以测量皮质醇水平，检出限为0.95ng/ml，灵敏度为7.91μA/（ng/mL），这是人类唾液中的一种实用方法。因此，基于蛋白质纳米探针的皮质醇生物传感对POCT的皮质醇直接电传感具有很高的灵敏度和选择性。
