Karami Abbas, Hasani Masoumeh, Azizi Jalilian Farid, Ezati Razieh
Faculty of Chemistry, Bu-Ali Sina University, Hamedan, 65174, Iran.
Department of Medical Virology, Faculty of Medicine, Hamedan University of Medical Sciences, Hamedan, Iran.
Sens Actuators B Chem. 2021 Feb 1;328:128971. doi: 10.1016/j.snb.2020.128971. Epub 2020 Sep 28.
Continuous identification of suspected infectious cases is crucial to control the recent pandemic caused by the novel human coronavirus SARS-CoV-2 (severe acute respiratory syndrome coronavirus 2). Real-time polymerase chain reaction (real-time PCR) technology cannot be implemented easily and in large scale in some communities due to lack of resources and infrastructures. Here, we report a simple colorimetric strategy derived from linker-based single-component assembly of gold nanoparticle-core spherical nucleic acids (AuNP-core SNAs) for visual detection of PCR products of SARS-CoV-2 ribonucleic acid (RNA) template. A palindromic linker is designed based on SARS-CoV-2 specific E gene to program the identical colloidal SNAs into large assemblies along with a distinct red-to-purple color change. The linker acts as a probe of SARS-CoV-2 RNA in conventional PCR reaction. In the presence of the correct template the palindromic linker, which is complementary to a short region within the target amplicon, is cleaved by 5'-exonuclease activity of deoxyribonucleic acid (DNA) polymerase. Cleavage of the palindromic linker during the amplification process inhibits the single-component assembly formation of SNAs. So, positive and negative viral samples produce simply red and purple colors in the post PCR colorimetric test, respectively. Evaluation of the samples obtained from cases with laboratory-confirmed SARS-CoV-2 infection revealed that our assay can rival with real-time PCR method in sensitivity.
持续识别疑似感染病例对于控制由新型人类冠状病毒SARS-CoV-2（严重急性呼吸综合征冠状病毒2）引起的近期大流行至关重要。由于缺乏资源和基础设施，实时聚合酶链反应（实时PCR）技术在一些社区难以轻松大规模实施。在此，我们报告了一种简单的比色策略，该策略源自基于连接子的金纳米颗粒核心球形核酸（AuNP-core SNA）单组分组装，用于可视化检测SARS-CoV-2核糖核酸（RNA）模板的PCR产物。基于SARS-CoV-2特异性E基因设计了一个回文连接子，以将相同的胶体SNA编程为大型组装体，并伴随明显的从红色到紫色的颜色变化。该连接子在常规PCR反应中充当SARS-CoV-2 RNA的探针。在存在正确模板的情况下，与目标扩增子内短区域互补的回文连接子会被脱氧核糖核酸（DNA）聚合酶的5'-外切核酸酶活性切割。扩增过程中回文连接子的切割会抑制SNA的单组分组装形成。因此，在PCR后的比色测试中，阳性和阴性病毒样本分别简单地产生红色和紫色。对实验室确诊的SARS-CoV-2感染病例获得的样本进行评估发现，我们的检测方法在灵敏度上可与实时PCR方法相媲美。
