Combining hybrid nanoflowers with hybridization chain reaction for highly sensitive detection of SARS-CoV-2 nucleocapsid protein

• Published in: Analytica chimica acta 2023-10, Vol.1279, p.341838-341838, Article 341838
• Main Authors: Yin, Wen, Hu, Ji, Chen, Fang, Zhu, Li, Ma, Yingxin, Wang, Nuo, Wei, Hongping, Yang, Hang, Chou, Shan-Ho, He, Jin
• Format: Article
• Language: English
• Subjects: Aptamer; Hybrid nanoflower; Hybridization chain reaction (HCR); Nucleocapsid protein; Portable glucometer detection; SARS-CoV-2
• ISSN: 0003-2670; 1873-4324
• DOI: 10.1016/j.aca.2023.341838

COVID-19 (coronavirus disease 2019) pandemic has had enormous social and economic impacts so far. The nucleocapsid protein (N protein) is highly conserved and is a key antigenic marker for the diagnosis of early SARS-CoV-2 infection. In this study, the N protein was first captured by an aptamer (Aptamer 58) coupled to magnetic beads (MBs), which in turn were bound to another DNA sequence containing the aptamer (Aptamer 48-Initiator). After adding 5′-biotinylated hairpin DNA Amplifier 1 and Amplifier 2 with cohesive ends for complementary hybridization, the Initiator in the Aptamer 48-Initiator began to trigger the hybridization chain reaction (HCR), generating multiple biotin-labeled DNA concatamers. When incubated with synthetic streptavidin-invertase-Ca3(PO4)2 hybrid nanoflower (SICa), DNA concatamers could specifically bind to SICa through biotin-streptavidin interaction with high affinity. After adding sucrose, invertase in SICa hydrolyzed sucrose to glucose, whose concentration could be directly read with a portable glucometer, and its concentration was positively correlated with the amount of captured N protein. The method is highly sensitive with a detection limit as low as 1 pg/mL. We believe this study provided a practical solution for the early detection of SARS-CoV-2 infection, and offered a new method for detecting other viruses through different target proteins. [Display omitted] •Aptamer 58 was used to specifically capture SARS-CoV-2 N protein in samples.•Aptamer 48-Initiator was used to bind the captured N protein and trigger HCR.•HCR was used to generate multiple biotin-modified DNA concatamers.•DNA concatamers specifically bound to SICa enclosing streptavidin and invertase.•Invertase activity that reflects N protein amount was detected by a glucometer.