Department of Chemistry, Faculty of Sciences, Ilam University, P. O. BOX. 69315-516, Ilam, Iran.
Department of Virology, Faculty of Medical Sciences, Tarbiat Modares University, Tehran, Iran.
Mikrochim Acta. 2021 Mar 2;188(3):105. doi: 10.1007/s00604-021-04762-9.
Severe acute respiratory syndrome SARS-CoV-2 has caused a global pandemic starting in 2020. Accordingly, testing is crucial for mitigating the economic and public health effects. In order to facilitate point-of-care diagnosis, this study aims at presenting a label-free electrochemical biosensor as a powerful nanobiodevice for SARS-CoV-2 spike protein detection. Utilizing the IgG anti-SARS-CoV-2 spike antibody onto the electrode surface as a specific platform in an ordered orientation through staphylococcal protein A (ProtA) is highly significant in fabricating the designed nanobiodevice. In this sense, the screen-printed carbon electrode modified with CuO nanocubes (CuO NCs), which provide a large surface area in a very small space, was applied in order to increase the ProtA loading on the electrode surface. Accordingly, the sensitivity and stability of the sensing platform significantly increased. The electrochemical evaluations proved that there is a very good linear relationship between the charge transfer resistance (R) and spike protein contents via a specific binding reaction in the range 0.25 fg mL to 1 μg mL. Moreover, the assay when tested with influenza viruses 1 and 2 was performed in 20 min with a low detection limit of 0.04 fg mL for spike protein without any cross-reactivity. The designed nanobiodevice exhibited an average satisfactory recovery rate of ~ 97-103% in different artificial sample matrices, i.e., saliva, artificial nasal, and universal transport medium (UTM), illustrating its high detection performance and practicability. The nanobiodevice was also tested using real patients and healthy samples, where the results had been already obtained using the standard polymerase chain reaction (PCR) procedure, and showed satisfactory results. Graphical abstract.
严重急性呼吸系统综合症（SARS）冠状病毒 2 型（SARS-CoV-2）自 2020 年以来引发了全球大流行。因此，检测对于减轻其对经济和公共卫生的影响至关重要。为了便于即时护理诊断，本研究旨在提出一种无标签的电化学生物传感器，作为一种强大的纳米生物器件，用于检测 SARS-CoV-2 的刺突蛋白。通过金黄色葡萄球菌蛋白 A（ProtA）将 IgG 抗 SARS-CoV-2 刺突抗体定向有序地固定在电极表面上，这对于构建设计的纳米生物器件非常重要。从这个意义上说，应用修饰有氧化铜纳米立方体（CuO NCs）的丝网印刷碳电极，它在非常小的空间内提供了较大的表面积，以增加电极表面上 ProtA 的负载量。因此，传感平台的灵敏度和稳定性显著提高。电化学评估证明，通过特定的结合反应，在 0.25 fg mL 至 1 μg mL 的范围内，电荷转移电阻（R）与刺突蛋白含量之间存在非常好的线性关系。此外，当与流感病毒 1 和 2 进行测试时，该测定在 20 分钟内完成，检测限低至 0.04 fg mL，对刺突蛋白无任何交叉反应。设计的纳米生物器件在不同的人工样本基质（即唾液、人工鼻和通用运输介质）中表现出平均令人满意的回收率约为 97-103%，表明其具有高检测性能和实用性。该纳米生物器件还使用真实患者和健康样本进行了测试，结果已经使用标准聚合酶链反应（PCR）程序获得，结果令人满意。
