Molecular docking, molecular dynamics simulation and MM-GBSA studies of the activity of glycyrrhizin relevant substructures on SARS-CoV-2 RNA-dependent-RNA polymerase.

SARS-CoV-2 is the causative agent of Coronavirus Disease (COVID-19), which is a life-threatening disease. The World Health Organization has classified COVID-19 as a severe worldwide public health pandemic due to its high death rate, quick transmission, and lack of medicines. To counteract the recurrence of the severe acute respiratory syndrome, active antiviral medications are urgently required. Glycyrrhizin was documented with activity on different viral proteins, including SARS-CoV-2; in this study, the activity of glycyrrhizin and its substructures (604 molecules) were screened on SARS-CoV-2 RNA-dependent-RNA polymerase using molecular docking, molecular dynamic (MD) simulation, and MM/GBSA. Sixteen molecules exhibited docking energy higher than -7 kcal/mol; four compounds (10772603, 101088272, 154730753 and glycyrrhizin) showed the highest binding energy, and good stability during MD simulation. The glycyrrhizin compound exhibited favorable docking energy (-7.9 kcal/mol), and it was the most stable complex during MD simulation. The predicted binding free energy of the glycyrrhizin complex was -57 ± 8 kcal/mol. These findings suggest that this molecule, after more validation, could become a good candidate for developing and manufacturing an anti-SARS-CoV-2 medication.Communicated by Ramaswamy H. Sarma.

Fabrication and characterization of field effect transistor based on single walled carbon nanotubes

Objectives Sensor Biology and sensor devices have been advancing since its inceptions. In this work, we report fabrication of carbon nanotubes filed-effect transistor (CNT-FET) sensor and its characterization. CNT intensively has been used in the construction of sensing layers due to their exceptional features, large surface area, stability, high mechanical strength, adaptability, and functional behavior. Methods Carbon nanotubes (CNTs) as semiconductor were fabricated as an active nanomaterial between the source-drain electrodes. The fabrication of CNT-FETs performed by following conventional photolithography method and lift-off techniques. Results The structural morphology of deposited CNT was confirmed by the scanning electron micrograph (SEM) imaging. The transfer curves between drain-source were considered as a function of the drain-source voltage (VDS) and gate-source voltage (VGS) from individual CNT-FET fabricated wafer. The characterized Ion/Ioff ratio was calculated for every CNT-FET device. The semiconductor properties of the fabricated CNT-FET device characterized by the source-drain current (IDS) versus gate voltage (VGS). Conclusions CNT-FET based device have advantages of low cost fabrication, quick response, increased sensitivity, small size, and high flexibility. CNT-FETs have been used comprehensively in the biosensing of chemicals, proteins, nucleic acids, bacteria, and virus etc. This device could be used for SARS-CoV-2 and related variant detection in current scenario.

Carbon nanotube field-effect transistor (CNT-FET)-based biosensor for rapid detection of SARS-CoV-2 (COVID-19) surface spike protein S1.

The large-scale diagnosis of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is important for traceability and treatment during pandemic outbreaks. We developed a fast (2-3 min), easy-to-use, low-cost, and quantitative electrochemical biosensor based on carbon nanotube field-effect transistor (CNT-FET) that allows digital detection of the SARS-CoV-2 S1 in fortifited saliva samples for quick and accurate detection of SARS-CoV-2 S1 antigens. The biosensor was developed on a Si/SiO2 surface by CNT printing with the immobilization of a anti-SARS-CoV-2 S1. SARS-CoV-2 S1 antibody was immobilized on the CNT surface between the S-D channel area using a linker 1-pyrenebutanoic acid succinimidyl ester (PBASE) through non-covalent interaction. A commercial SARS-CoV-2 S1 antigen was used to characterize the electrical output of the CNT-FET biosensor. The SARS-CoV-2 S1 antigen in the 10 mM AA buffer pH 6.0 was effectively detected by the CNT-FET biosensor at concentrations from 0.1 fg/mL to 5.0 pg/mL. The limit of detection (LOD) of the developed CNT-FET biosensor was 4.12 fg/mL. The selectivity test was performed by using target SARS-CoV-2 S1 and non-target SARS-CoV-1 S1 and MERS-CoV S1 antigens in the 10 mM AA buffer pH 6.0. The biosensor showed high selectivity (no response to SARS-CoV-1 S1 or MERS-CoV S1 antigen) with SARS-CoV-2 S1 antigen detection in the 10 mM AA buffer pH 6.0. The biosensor is highly sensitive, saves time, and could be a helpful platform for rapid detection of SARS-CoV-2 S1 antigen from the patients saliva.

COVID-19: Prospective Challenges and Potential Vaccines

ContextRNA viruses exhibit an extraordinary ability to evolve in a changing environment and to switch from animal hosts to humans. The ongoing COVID-19 pandemic, recognized as a respiratory disease, is an example of zoonotic transmission of the RNA virus known as SARS-CoV-2. The development and regulatory approval of a vaccine against SARS-CoV-2 pose multiple preventive and therapeutic challenges, especially during an ongoing pandemic.ObjectiveThe review intended to examine the challenges and recent achievements in the development of vaccine candidates against COVID-19.DesignThe research team performed a literature review, searching relevant and up to date information from the literature. The sources of data included Google Scholar, PubMed, NCBI, and Yahoo. The search terms used were COVID-19 challenges, SARS-CoV-2 prospective challenges, RNA viruses adoptability, host switching by RNA viruses, COVID-19 vaccines.SettingThe study took place at the digital libraries of contributing institutions. The data was combined, selected for further analysis and manuscript preparation at King Abdulaziz University.ResultsRNA viruses with high rate of genome alterations and evolution have better chances to survive in the adverse environmental conditions by adopting the alternate host species. The recent epidemics such as SARS, MERS, and COVID-19 are examples of zoonotic transmission of RNA viruses from animal species to the humans. However, the mechanisms involved in the switching-on to new host species need further investigations to control the zoonotic transmissions in near future. As of April 2020, 115 candidate vaccines were being evaluated;78 of them had been found to be active, and a few of them are in Phase I trials. In the development of different types of vaccine candidates against COVID-19, multiple international pharmaceutical and biotechnology companies are involved.ConclusionsEmerging and re-emerging pathogenic RNA viruses pose a serious threat to human health. Little is known about the human-host adoptive mechanism for zoonotic transmission. Deep insights into the molecular mechanism responsible for the switching of animal or bird viruses to humans could provide target molecules or events to prevent such transmissions in the near future. Fast development and approval of efficacious and safe vaccines is key to the effort to provide preventive measures against COVID-19 and future viruses. However, the development and availability of a vaccine candidate is a time-consuming process and often can't be completed during an epidemic. Currently, several types of vaccines are under development, and most of them won't realistically be available in time for the present COVID-19 pandemic.

Origin, Potential Therapeutic Targets and Treatment for Coronavirus Disease (COVID-19).

The ongoing episode of coronavirus disease 19 (COVID-19) has imposed a serious threat to global health and the world economy. The disease has rapidly acquired a pandemic status affecting almost all populated areas of the planet. The causative agent of COVID-19 is a novel coronavirus known as SARS-CoV-2. The virus has an approximate 30 kb single-stranded positive-sense RNA genome, which is 74.5% to 99% identical to that of SARS-CoV, CoV-pangolin, and the coronavirus the from horseshoe bat. According to available information, SARS-CoV-2 is inferred to be a recombinant virus that originated from bats and was transmitted to humans, possibly using the pangolin as the intermediate host. The interaction of the SARS-CoV-2 spike protein with the human ACE2 (angiotensin-converting enzyme 2) receptor, and its subsequent cleavage by serine protease and fusion, are the main events in the pathophysiology. The serine protease inhibitors, spike protein-based vaccines, or ACE2 blockers may have therapeutic potential in the near future. At present, no vaccine is available against COVID-19. The disease is being treated with antiviral, antimalarial, anti-inflammatory, herbal medicines, and active plasma antibodies. In this context, the present review article provides a cumulative account of the recent information regarding the viral characteristics, potential therapeutic targets, treatment options, and prospective research questions.