The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is conducted for the emergence of the COVID-19 pandemic in Wuhan, China, which the initial symptoms of disease were warned in February 2019. To date, more than 16 million cases have been reported in 210 countries, of which 650,000 have died.
SARS-CoV-2 is a 60–140 nm spherical particle, with a crown-like shape glycoprotein coating. It belongs to the subgenus Sarbecovirus and genus Betacoronavirus within the family Coronaviridae .
SARS-CoV-2 is an enveloped virus with a very large positive-strand RNA genome, compromised of ~ 3 k nucleotides. Virus RNA polymerases have poor proofreading activity, leading to a high mutation rate. Consequently, RNA viruses are prone to evolving resistance to drugs and escaping from immune surveillance .
The coronaviral genome encodes four major structural proteins: the spike (S) protein, nucleocapsid (N) protein, membrane (M) protein, and the envelope (E) protein. The envelope bears club-shaped glycoprotein projections. Some coronaviruses also contain a hem agglutinin-esterase protein (HE). The lectin domain of HE protein helps attachment of virus-host cells, thus playing a key role in the production of infectious virions and the severity of the disease [3, 4].
CoV S protein is one of the key components in receptor binding and virus-host cell fusion, and it is also the main target for neutralizing antibodies and vaccine design [5–10]. The CoV E protein is a small integral membrane protein that involved in virus vital activity as assembly, budding, envelope formation, and pathogenesis. Studies have shown that SARS-CoV E protein is an important virulence factor that can contribute to therapeutic targets .
SARS-CoV-2 exhibits a high mutation rate during its interaction with the host population and transmission across the countries that are affected by its viral infections and high mortality rate. Recent studies have reported more than 40 mutations of SARS-CoV2 virus, and the strains grouped into aggressive form and milder types [12–15]. But different types of CoVs have highly similar surface chemical structures. The surface of the virus consists of the elements oxygen, sulfur, hydrogen and etc, that can also form strong bonds with other functional groups [16, 17].
The SARS-CoV-2 can attach to the human secretion that spread through air droplets and airborne. Infected people could expel pathogens during breathing, coughing, sneezing, and medical procedures which remain suspended particles in the air . Several factors may affect the droplet dispersion including the relative humidity, ventilation pattern, temperature, crowding and other environmental factors. Hospitals particularly intensive care units (ICU) or wards for COVID 19 patients need to critically improve their safety practices especially for medical staff [19, 20].
One of the most important ways to deal with microorganisms (SARS-CoV-19) is to take a commercial breathing mask to prevent the inhalation of airbornes, when going outdoors or staying indoors especially in the hospital, air quality is ensured by employing the air cleaners or modern ventilation systems. In general, the dimensions of aerosolized virus particles vary widely, ranging from nanometer to micrometer . It is very difficult to reduce air pollution problems, especially nanometer particles. Besides the complexity of the conventional air filter that mainly constitue of several layers of randomly oriented melt-blown micron-scale fibers showed unsatisfied yield. Conventional filter have sevral inherent functional obstacles of capturing fine particles . Electrospun nanofibers provided highly efficient, interconnected nanoscale pore structures and biocompatible nanofibrous filters for air purification. Nanofibrous filters based on their high porosity (physical barrier) and surface modification technologies (chemical barrier) could be a good choice for viral filtration .
Here, we present the synthesis of nanofiber of amid-MCM-41-SO3H via the electrospinning process, which will a significant step toward air filtration particularly hospital. In the process of air purification using the proposed filter, to ensure the removal of the virus from the air, in addition to creating a mechanical barrier (Amid nanofiber), a chemical barrier is embedded in this filter (MCM-41-SO3H) , which can be bond formed with functional groups on the virus surface (Fig. 1).