The virus
The SARS-CoV-2 was named because it shares 88% nucleotide similarity to two bat-derived severe acute respiratory syndrome (SARS)-like coronaviruses and 79% similarity to SARS-CoV that appeared in 2003 which affected 26 countries and killed about 800 people [3, 4]. There are 4 common types of human coronavirus that have been reported such as HKU1, NL63, 229E, and OC43 that cause the mild symptom of common flu, whereas SARS-CoV, Middle East respiratory syndrome-related coronavirus (MERS-CoV) and novel SARS-CoV-2 were reported that cause the severe or fatal symptom. The coronavirus is an enveloped, non-segmented positive-sense and single-stranded RNA virus with a crown-like appearance. Figure 1 shows the coronavirus structure that composes four types of protein, such as spike glycoprotein (S), envelope protein (E), membrane protein (M) and nucleocapsid protein (N). The S protein is playing an important role in invading into the host, by interacting with human receptor angiotensin-converting enzyme 2 (ACE2). The receptor-binding domain (RBD) of S protein contributed its immunogenic that attracted many neutralizing antibodies [5, 6]. They are all potential molecular targets for the identification of SARS-CoV-2 infection. Currently, there is no specific therapeutic drug or vaccine for COVID-19, therefore it is necessary to deploy a robust diagnostic methodology which is rapid, accurate and ultra-sensitive to isolate infected patients from the healthy population.