An Insight Into Detection Pathways/Biosensors of Highly Infectious Coronaviruses.

The outbreak of COVID-19 pandemic and its consequences have inflicted a substantial damage on the world. In this study, it was attempted to review the recent coronaviruses appeared among the human being and their epidemic/pandemic spread throughout the world. Currently, there is an inevitable need for the establishment of a quick and easily available biosensor for tracing COVID-19 in all countries. It has been known that the incubation time of COVID-19 lasts about 14 days and 25% of the infected individuals are asymptomatic. To improve the ability to determine SARS-CoV-2 precisely and reduce the risk of eliciting false-negative results produced by mutating nature of coronaviruses, many researchers have established a real-time reverse transcriptase-polymerase chain reaction (RT-PCR) assay using mismatch-tolerant molecular beacons as multiplex real-time RT-PCR to distinguish between pathogenic and non-pathogenic strains of coronaviruses. The possible mechanisms and pathways for the detection of coronaviruses by biosensors have been reviewed in this study.

In silico Investigation on the Inhibiting Role of Nicotine/Caffeine by Blocking the S Protein of SARS-CoV-2 Versus ACE2 Receptor.

In this paper, we studied the in silico interaction of angiotensin-converting enzyme 2 (ACE2) human receptor with two bioactive compounds, i.e., nicotine and caffeine, via molecular dynamic (MD) simulations. The simulations reveal the efficient blocking of ACE2 by caffeine and nicotine in the exposure to the spike (S) protein of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). We have selected the two most important active sites of ACE2-S protein, i.e., 6LZG and 6VW1, which are critically responsible in the interaction of S protein to the receptor and thus, we investigated their interaction with nicotine and caffeine through MD simulations. Caffeine and nicotine are interesting structures for interactions because of their similar structure to the candidate antiviral drugs. Our results reveal that caffeine or nicotine in a specific molar ratio to 6LZG shows a very strong interaction and indicate that caffeine is more efficient in the interaction with 6LZG and further blocking of this site against S protein binding. Further, we investigated the interaction of ACE2 receptor- S protein with nicotine or caffeine when mixed with candidate or approved antiviral drugs for SARS-CoV-2 therapy. Our MD simulations suggest that the combination of caffeine with ribavirin shows a stronger interaction with 6VW1, while in case of favipiravir+nicotine, 6LZG shows potent efficacy of these interaction, proposing the potent efficacy of these combinations for blocking ACE2 receptor against SARS-CoV-2.

Covalently bonded pancreatic lipase onto the dithiocarbamate/chitosan-based magnetite: Stepwise fabrication of Fe3O4@CS/NHCS-Lip as a novel and promising nanobiocatalyst.

In the present paper, porcine pancreas lipase (PPL) was immobilized to a new version of magnetite via a novel stepwise dithiocarbamate/chitosan-based method in alternation to glutaraldehyde. Magnetic chitosan nanocomposite was post-modified to produce dithiocarbamate moieties on the surface through amine functions. Then, immobilization of lipase was successfully achieved on the surface of magnetically separable Fe3O4@CS/NHCS2H via a post-modification. Each step of immobilization was carefully monitored by characterization and all were successfully proved. Comparison of immobilized enzyme with free enzyme showed that the method of immobilization is efficient.

Dithiocarbamate to modify magnetic graphene oxide nanocomposite (Fe3O4-GO): A new strategy for covalent enzyme (lipase) immobilization to fabrication a new nanobiocatalyst for enzymatic hydrolysis of PNPD.

Immobilization of lipase was successfully achieved on the surface of magnetically separable Fe3O4/graphene oxide (GO) via a post-modification. This post modification was achieved in alternation to glutaraldehyde post-modification. The activity of immobilized lipase had not a significant loss in the activity while on the other hand, it is simply extractable (by keeping its major activity) from reaction crude by a magnet. Each step of immobilization was carefully monitored by characterization and all were successfully proved. SEM, TEM, XRD, EDX, and FTIR were used to characterize the support and immobilization process.