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.