Chemistry-based research from the laboratory to industries are progressing their efforts towards discovering more about the virus, developing improved testing technologies, and eventually discovering drugs to treat the disease. Chemistry as the subject of practice in every step of life is essential at every step of our response to contain the virus. Scientists throughout the world are involved in evolving new diagnostic methods to be deployed for the SARS-CoV-2 identification including optical biosensors and point-of-care diagnostics. 

In spite of an immensely disrupted class routine, there will surely be thousands of students going on to study and work in chemistry in the years to come. Through this blog, we are trying to document the chemical science community’s role in response to the recent outbreak of coronavirus. 

COVID-19 disease transmission route inspired by Gas-Phase Chemistry: 

The person-to-person spread of infectious respiratory diseases like COVID-19 occurs primarily due to the transference of virus-laden fluid particles from the diseased person. The infectious fluid particles instigate from the respiratory tract of the person and are ejected from the nose and the mouth during breathing, speaking, whistling, sneezing, and coughing etc. These particles have been broadly classified into two types: aerosols (aerodynamic particle size <5 μm) and droplets (aerodynamic particle size ≥5 μm–10 μm). The outcomes indicated that the transmission phenomena of these virus particles ejected by patients would be dependent on droplet sizes. Once expelled from the mouth or nose, bigger respiratory droplets endure gravitational subsiding before evaporation; in contrast, the smaller droplet particles evaporate faster than they settle down, afterwards forming the aerosolized droplet nuclei that can be deferred for prolonged periods and foldaway in the air over long distances. Investigations by Bourouiba et al. have shown that these droplets can travel rather large distances initially within a turbulent jet, which later transition to a puff or a cloud due to the lack of a continuous momentum source. Depending on the ambient conditions and droplet size, these droplets evaporate at different times. Chemical kinetics-based model i.e. the application of Lattice Boltzmann Method with Brownian dynamics to access the effects of nanoparticles at the liquid-vapour interface of an evaporating sessile droplet can be coupled with of evaporation, dispersion and precipitation to devise a hitherto new methodology to predict the infection spread in the context of COVID-19. 

All most all investigations have found that SARS-CoV-2 virus stability monotonically decreases with an increase in temperature. It has also been found that the enveloped viruses like SARS-CoV-2 survive well in droplets far from their dried state, as well as in the desiccated residue where the virus remains in a frozen state, these shreds of evidence prove that virus survivability within desiccated nuclei enables the virus to be airborne. To prove these, chemists have used 1% (w/w) NaCl aqueous solution as a substitute respiratory fluid and 100nm fluorescent particles as a stand-in virus, whose concentration was controlled from 0.005 to 0.1%. Featured basic mechanism in particle deposition in water-based solutions explained in these studies can be extended to pathogens, the dynamics in respiratory droplets are more involved due to the physicochemical complexities and the resulting variation in thermo-physical properties. 

Role of synthetic chemists in the development of drugs  

The development of antibiotics was one of the most important scientific innovations of the twentieth century, as it drastically reduced the threat of bacterial infections. Though the early antibiotics era was characterized by fully synthetic compounds (e.g., sulfonamides and organoarsenicals) and was largely pioneered by industrial chemists, the modern era of natural product-based antibiotics witnessed significant contributions from academia. Penicillin V  and vancomycin provide two examples where synthetic chemists have made impactful, translational contributions by pursuing fundamental research interests. In this time of pandemic caused by the SARS-CoV-2 virus, chemists from worldwide are trying their best to delineate different drugs to annihilate this virus.  the antiviral drugs commonly used in clinical practice to treat viral infections are not applicable to SARS-Cov-2. Thus, it is very necessary to identify new drugs suitable for the treatment of the 2019-nCoV outbreak 

Nanotrap: Chemists from the Pritzker School of Molecular Engineering have designed an entirely novel potential treatment for COVID-19: nanoparticles that apprehend SARS-CoV-2 viruses within the body and then use the body’s own immune system to annihilate it. 

These “Nanotraps” entice the virus by imitating the marked cells the virus infects. When the virus muddles to the Nanotraps, the traps then impound the virus from other cells and target it for annihilation by the immune system. 

In theory, these Nanotraps could also be used on variants of the virus, leading to a potential new way to constrain the virus moving forward. Though the therapy remains in the early stages of testing, the researchers envision it could be administered via a nasal spray as a treatment for COVID-19. 

HTCC: An antiviral potential of the polymer HTCC [N-(2-hydroxypropyl)-3-trimethylammonium chitosan chloride], which efficiently hampered infection of all low-pathogenicity human coronaviruses in vitro and ex vivo.  The hydrophobically-modified derivative (HM-HTCC) acts as potent inhibitors of the coronavirus HCoV-NL63.  we show It has been investigated as that HTCC inhibits interaction of a virus with its receptor and thus blocks the entry. Synthetic chemists are trying to delineate the process through which the HTCC interferes with the virus replication. The photophysical study of HTCC labelled with FITC in water were measured in the absence and in the presence of various concentrations of SARS-CoV-2 spike protein S1 domains to understand the effectivity of HTCC. 

Application of polymer chemistry to contain SARS-CoV 2: 

Polyelectrolytes: The surface of such envelope virus is found to be rich in amino acid residues. Therefore, polyanions may be used to electrostatically bind to the spike (S) glycoprotein, which binds to the ACE2 protein as an important step in host cell invasion and prevent the virus from interacting with the host cell’s surface. Thus, polyanions and polycations can be used to potentially interrupt the binding between the virus and host cell. As examples, Poly(propylacrylic acid), poly(vinylbenzoic acid) (PVBzA), poly(vinylphosphonic acid) (PVPA), and poly(2-acrylamidoethyl)phosphate may be developed as bio-compatible to exhibit this inhibitory effect. 

Dendritic Polymer: Dendritic or highly branched polymers that possess greater solubilities, larger surface areas, and tuneable shapes are being investigated to hinder the virus and cell binding. These types of polymers are being designed to be non-toxic and bio-compatible thus they can act as co-receptor and subsequently, mediate the entry of the SARS-CoV2 virus to the host cells. 

Natural Polymer: Natural polymers like  polysaccharides, cyclodextrins (CDs) and chitosan are reported to inhibit the attachment of coronavirus to host cells because of their ability to remove cholesterol from cell membranes. These polymers can inhibit the replication of the virus in the host cell.  Moreover, polysaccharides can activate T lymphocytes, B lymphocytes, and other immune cells to improvise an advantageous immune response to inhibit the virulent effect. It is worthy to mention here that natural polymers inherently possess greater biocompatibility compared to synthetic polymers, which serves as one of the major factor for their applicability as potential drugs. 

Conclusions: SARS-CoV-2 virus has caused a global health crisis with high rates of infection and mortality. However, in existing treatment programmes, there are latent drawbacks such as they are time-consuming and full proof. It is hoped that the chemists along with scientists & technologists from interdisciplinary branches throughout the world will develop better model and drugs in the near future and move toward clinical treatment as soon as possible. More clinical trials with these suitable drugs should be performed on patients affected by SARS-CoV-2 of different mutant strains to prove their efficacy and safety. Not only chemists, but it’s a team’s of scientists of all spheres and philosophers’ activity towards investigation how the system can be used to help medical professionals treat patients more effectively.  

As a chemist, we have learned that we are very resilient and have discovered our extra efficacies in terms of serving the people, we may not have found had this pandemic not happened. 

References: 

1. KuritzkesD.R. Drug resistance in HIV-1. Curr. Opin. Virol. 2011;1:582–589. doi: 10.1016/j.coviro.2011.10.020. 
2. TannockG.A., Kim H., Xue L. Why are vaccines against many human viral diseases still unavailable; an historic perspective? J. Med. Virol. 2020;92:129–138. 
3. KC GB, Bocci G, Verma S. et al. A machine learning platform to estimate anti-SARS-CoV-2 activities.
4. ToturaA.L., Bavari S. Broad-spectrum coronavirus antiviral drug discovery. Expet Opin. Drug Discov. 2019;14(4):397–412. 
5. LiowS.S., Chee P.L., Owh C., Zhang K., Zhou Y., Gao F., Lakshminarayanan R., Loh X.J. Cationic poly ([R]-3-hydroxybutyrate) copolymers as antimicrobial agents. Macromol. Biosci.  
6. Lin Q., Lim J.Y.,Xue K., Yew P.Y.M., Owh C., Chee P.L., Loh X.J. Sanitizing agents for virus inactivation and disinfection. View. 2020