Institute for Chemical Biology & Biosensing, College of Life Sciences, Qingdao University, 308 Ningxia Road, Qingdao 266071, China.
School of Pharmacy, Medical College, Qingdao University, 308 Ningxia Road, Qingdao 266071, China.
Anal Chem. 2023 Aug 22;95(33):12532-12540. doi: 10.1021/acs.analchem.3c02821. Epub 2023 Aug 8.
Rapid and sensitive antigen detection using a lateral flow immunoassay (LFIA) is crucial for diagnosing infectious diseases due to its simplicity, speed, and user-friendly features. However, it remains a critical issue to explore specific biorecognition elements and powerful signal amplification. In this study, taking SARS-CoV-2 as a proof of concept, a specific peptide, WFLNDSELIML, binding to the SARS-CoV-2 spike (S) antigen was identified by a nonamplified biopanning method, which exhibited high affinity to the target, with a dissociation constant of 9.29 ± 1.55 nM. Molecular docking analysis reveals that this peptide binds to the N-terminal domain of the SARS-CoV-2 S antigen. Then, using this peptide as a capture probe and angiotensin-converting enzyme 2 as a detection probe, a peptide-based lateral flow immunoassay (pLFIA) for the sensitive detection of the SARS-CoV-2 S antigen without any antibody was developed, for which a polydopamine nanosphere (PDA)@MnO nanocomposite with excellent oxidase-like activity was used as a colorimetric label, exhibiting dual-mode remarkable signal amplification of natural melanin and on-demand nanozyme catalytic enhancement. The PDA@MnO-based pLFIA is capable of detecting the SARS-CoV-2 S antigen with a limit of detection of 8.01 pg/mL, which is 18.7 times lower than that of a conventional pLFIA tagged with gold nanoparticles. Additionally, the as-proposed PDA@MnO-based pLFIA can detect up to 150 transduction units/mL SARS-CoV-2 pseudoviruses spiked in saliva samples. Given the outstanding analytical performance, the proposed PDA@MnO-based pLFIA may offer a reliable option for the rapid diagnosis of SARS-CoV-2.
采用侧向流免疫分析（LFIA）快速灵敏地检测抗原对于诊断传染病至关重要，因为它具有简单、快速和用户友好的特点。然而，探索特定的生物识别元件和强大的信号放大仍然是一个关键问题。在这项研究中，以 SARS-CoV-2 为概念验证，通过非扩增的生物淘选方法鉴定出与 SARS-CoV-2 刺突（S）抗原结合的特异性肽 WFLNDSELIML，该肽对靶标具有高亲和力，解离常数为 9.29 ± 1.55 nM。分子对接分析表明，该肽结合 SARS-CoV-2 S 抗原的 N 端结构域。然后，使用该肽作为捕获探针，血管紧张素转化酶 2 作为检测探针，开发了一种无抗体的基于肽的侧向流免疫分析（pLFIA）用于灵敏检测 SARS-CoV-2 S 抗原，其中使用具有优异过氧化物酶样活性的聚多巴胺纳米球（PDA）@MnO 纳米复合材料作为比色标记，显示出天然黑色素和按需纳米酶催化增强的双重模式显著信号放大。基于 PDA@MnO 的 pLFIA 能够检测 SARS-CoV-2 S 抗原，检测限为 8.01 pg/mL，比标记金纳米颗粒的传统 pLFIA 低 18.7 倍。此外，所提出的基于 PDA@MnO 的 pLFIA 可以检测到唾液样本中高达 150 转导单位/mL 的 SARS-CoV-2 假病毒。鉴于其出色的分析性能，所提出的基于 PDA@MnO 的 pLFIA 可能为 SARS-CoV-2 的快速诊断提供可靠选择。
