In this work, a brief electrochemical aptasensor was developed for highly sensitive detection of SARS-CoV-2 antigen utilizing an aptamer-binding induced multiple hairpin assembly strategy for signal amplification. In the presence of SARS-CoV-2, a pair of aptamers was brought in a close proximity according to the aptamer-protein antigen binding, which initiated strand displacement reaction thereby triggering a multiple hairpin assembly to obtain long linear DNA concatemers on the electrode surface. As the fabricated hairpin probes were labeled with biotin, massive streptavidin-alkaline phosphatases (ST-ALP) could be further introduced on the electrode interface via biotin-streptavidin interaction thus generating strong electrochemical signal in electrolyte solution containing 1-naphthol phosphate. Benefiting from the non-enzymatic multiple hairpin assembly signal amplification strategy, the designed aptasensor for SARS-CoV-2 spike protein detection exhibited the wide linear range from 50 fg·mL⁻¹ to 50 ng·mL⁻¹ and low detection limit of 9.79 fg·mL⁻¹. Meaningfully, this proposed electrochemical assay provided a potential application for the point of care analysis of viral diseases under ambient temperature.

在这项工作中，开发了一种简短的电化学适体传感器，利用适体结合诱导的多发夹组装策略进行信号放大，以高度灵敏地检测 SARS-CoV-2 抗原。在 SARS-CoV-2 存在的情况下，一对适体根据适体-蛋白抗原结合而靠得很近，引发链置换反应，从而引发多发夹组装，在电极表面获得长线性 DNA 串联体. 由于制造的发夹探针用生物素标记，大量的链霉亲和素-碱性磷酸酶 (ST-ALP) 可以通过以下方式进一步引入电极界面生物素-链霉亲和素相互作用，从而在含有 1-萘酚磷酸盐的电解质溶液中产生强烈的电化学信号。得益于非酶促多发夹组装信号放大策略，设计的用于 SARS-CoV-2 刺突蛋白检测的适体传感器表现出从 50 fg·mL ^-1到 50 ng·mL ^-1的宽线性范围和 9.79 的低检测限fg·mL ^-1。有意义的是，这种拟议的电化学测定法为环境温度下病毒性疾病的即时分析提供了潜在的应用。