Abstract
In December 2019, China experienced an unexpected outbreak of an unknown respiratory disease. Shortly after that, the disease was reported in many other countries across the world. Molecular analysis revealed that severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) was the causative agent of the disease. SARS-CoV-2 is an enveloped virus containing single-stranded, positive-sense RNA about 30 kilobases long. The genome is characterized by four primary proteins: spike glycoprotein (S), envelope glycoprotein (E), membrane protein (M), and nucleocapsid protein (N). The spike protein is the most important amongst the four proteins, as it facilitates viral entry into the host cell by binding its receptor-binding domain (RBD) to the ACE2 receptor on human host cells. SARS-CoV-2 belongs to the beta coronavirus family. Due to the rapid spread of the virus, there was a dire need to develop a reliable detection assay with a short turnaround time to control its transmission. The World Health Organization (WHO) recommended RT-PCR as the preferred diagnostic method for SARS-CoV-2. However, the fast spread of the virus created a demand for alternative detection methods that could be used outside of laboratory settings, such as a rapid point-of-need (POC) test. Gold nanoparticle (AuNP)-based dipstick assays, fabricated with DNA probes specific for the SARS-CoV-2 RBD, could serve as an effective POC diagnostic tool. The good thing about this assay is in their speed and simplicity. The results are often ready in few minutes. However, like all tests, these AuNPs-based dipstick assay are not perfect, they can not detect low concentration of the virus. Key words: ACE2, AuNPs, Dipstick assay, POC, RBD, RT-PCR, SARS-CoV-2, Spike protein