Prospects for the use of macrocyclic photosensitizers for inactivation of SARS-CoV-2: selection of compounds leaders based on the molecular docking data.

The treatment of coronavirus COVID-19, like other viral diseases, is currently underdeveloped. This fact necessitates the search for new drugs and treatment methods that will effectively disrupt the life cycle of the virus. A big problem in the therapy of viral diseases is the ability of viruses to evade the host's immune response. We suppose that the search for drugs that can change the evasiveness of the virus from the immune response of the host is a very promising strategy, as it can help the body to cope with the infection. Protein SARS-CoV-2 ORF8 is one of the key proteins that can suppress antiviral immunity. This paper considers the available information on the structure and functioning of ORF8, as well as the results of molecular docking of ORF8 to a wide range of tetrapyrrole macroheterocyclic compounds capable of generating reactive oxygen species upon photoirradiation. This principle of photoinactivation of biosubstrates underlies the methods of photodynamic therapy of cancer. Application of photoinactivation of drug-resistant forms of bacteria and some viruses can be useful in the fight against COVID-19 and other viral infections. In this work, the structure of ORF8 complexes with macrocyclic compounds is considered in detail, the dependence of their binding affinity on the nature of macrocycles and the nature of peripheral substituents is analyzed and spectral studies of the binding of ORF8 to chlorin is performed. This paper is a part of a large project to investigate the possibility of using macrocyclic compounds for the treatment of viral diseases.Communicated by Ramaswamy H. Sarma.

DFT, molecular docking and ADME prediction of tenofovir drug as a promising therapeutic inhibitor of SARS-CoV-2 M-pro

In the present work, at first, DFT calculations were carried out to study the molecular structure of the tenofovir at B3LYP/MidiX level of theory and in the water as solvent. The HOMO/LUMO molecular orbitals, excitation energies and oscillator strengths of investigated drug were also calculated and presented. NBO analysis was performed to illustrate the intramolecular rehybridization and electron density delocalization. In the following, a molecular docking study was performed for screening of effective available tenofovir drug which may act as an efficient inhibitor for the SARS-CoV-2 M-pro. The binding energy value showed a good binding affinity between the tenofovir and SARS-CoV-2 Mpro with binding energy of-47.206 kcal/mol. Therefore, tenofovir can be used for possible application against the SARS-CoV-2 M-pro.

Textile Functionalization Using LTA and FAU Zeolitic Materials.

COVID-19 has drawn worldwide attention to the need for personal protective equipment. Face masks can be transformed from passive filters into active protection. For this purpose, it is sufficient to apply materials with oligodynamic effect to the fabric of the masks, which makes it possible to destroy infectious agents that have fallen on the mask with aerosol droplets from the air stream. Zeolites themselves are not oligodynamic materials, but can serve as carriers for nanoparticles of metals and/or compounds of silver, zinc, copper, and other materials with biocidal properties. Such a method, when the particles are immobilized on the surface of the substrate, will increase the lifetime of the active oligodynamic material. In this work, we present the functionalization of textile materials with zeolites to obtain active personal protective equipment with an extended service life. This is done with the aim to extend the synthesis of zeolitic materials to polymeric fabrics beyond cotton. The samples were characterized using XRD, SEM, and UV-Vis spectroscopy. Data of physicochemical studies of the obtained hybrid materials (fabrics with crystals grown on fibers) will be presented, with a focus on the effect of fabrics in the growth process of zeolites.

DFT and Molecular Docking Study of 1-(2´-Thiophen)-2-propen-1-one-3-(2,3,5-trichlorophenyl) (TTCP) Molecule as Antiviral to Covid-19 Main Protease.

Thiophene-containing compounds have antiviral properties and may be among the drugs tested for the treatment of COVID-19 diseases. In order to better understand the molecular definition of the 1-(2´-Thiophen)-2-propen-1-one-3-(2,3,5-trichlorophenyl) molecule from thiophene-containing compounds, the physico-chemical (molecular structure analysis, spectroscopic properties, boundary orbital analysis) mechanisms underlying the protein-ligand interaction should be examined in detail. For this reason, geometric parameters, IR and UV-vis spectra, conformational analysis, electronic, NBO and NLO properties, molecular electrostatic potential map and Mulliken charge distributions of the TTCP molecule were investigated theoretically using DFT theory in the Gaussian program. Accordingly, molecular docking calculations with COVID-19 main protease (PDB 5R7Y) were performed to determine the pharmaceutical activities of the TTCP molecule against coronavirus diseases.

Favipiravir-Tautomeric and Complexation Properties in Solution.

The tautomeric properties of favipiravir were investigated experimentally for the first time by using molecular spectroscopy (UV-Vis absorption, fluorescence and NMR), as well as DFT quantum-chemical calculations. According to the obtained results, the enol tautomer is substantially more stable in most of the organic solvents. In the presence of water, a keto form appears to be favored due to the specific solute-solvent interactions. Upon the addition of alkaline-earth-metal ions, deprotonation and complexation occurred simultaneously, giving the formation of 2 : 1 ligand : metal complexes. According to the theoretical simulations, the metal ion is captured between the carbonyl groups as a result of the size-fit effect.

Development and Application of an SPR Nanobiosensor Based on AuNPs for the Detection of SARS-CoV-2 on Food Surfaces.

A new transmission route of SARS-CoV-2 through food was recently considered by the World Health Organization (WHO), and, given the pandemic scenario, the search for fast, sensitive, and low-cost methods is necessary. Biosensors have become a viable alternative for large-scale testing because they overcome the limitations of standard techniques. Herein, we investigated the ability of gold spherical nanoparticles (AuNPs) functionalized with oligonucleotides to detect SARS-CoV-2 and demonstrated their potential to be used as plasmonic nanobiosensors. The loop-mediated isothermal amplification (LAMP) technique was used to amplify the viral genetic material from the raw virus-containing solution without any preparation. The detection of virus presence or absence was performed by ultraviolet-visible (UV-Vis) absorption spectroscopy, by monitoring the absorption band of the surface plasmonic resonance (SPR) of the AuNPs. The displacement of the peak by 525 nm from the functionalized AuNPs indicated the absence of the virus (particular region of gold). On the other hand, the region ~300 nm indicated the presence of the virus when RNA bound to the functionalized AuNPs. The nanobiosensor system was designed to detect a region of the N gene in a dynamic concentration range from 0.1 to 50 × 103 ng·mL-1 with a limit of detection (LOD) of 1 ng·mL-1 (2.7 × 103 copy per µL), indicating excellent sensitivity. The nanobiosensor was applied to detect the SARS-CoV-2 virus on the surfaces of vegetables and showed 100% accuracy compared to the standard quantitative reverse transcription polymerase chain reaction (RT-qPCR) technique. Therefore, the nanobiosensor is sensitive, selective, and simple, providing a viable alternative for the rapid detection of SARS-CoV-2 in ready-to-eat vegetables.

Study of the Electronic and Spectrum Properties for a Medication Hydroxychloroquine

Calculated the electronics and vibrational properties of the medicine hydroxy-chloroquine nanoparticles based on the fitting of their UV-vis spectra, transmittable, IR, Raman spectrum, Electronic circular dichroism (ECD) and HOMO and LUMO, These properties were theoretically studied using Gaussian 09 program. The result shows the stability of hydroxy-chloroquine. The longer wavelength that (500 nm) means high absorbance and less energy. Transmittable, the highest transmittable value in the region is (0 - 3000cm-1) and (2600-1250 cm-1) is offset by the lowest absorption here, the sample has good transparency characteristics at this region. Infrared spectrum, the area (2900 cm-1) it is for the carbon and hydrogen Single bond C-H, and hybridization type sp3. Raman scattering, electronic effect on bond C-H in the area (2800 cm-1) is very large and this bond type stretch. Electronic circular dichroism (ECD), when finding the sign of one or more bands can be an AC limitation. A positive skew angle is foretelling to become connected CD of the low-lying p-p∗ move at about 600 nm;certainly, for a negative CD, can find a negative angle is expected. © Published under licence by IOP Publishing Ltd.

Characterization of Carotenoids from Pineapples: An Integrated andModular Experiment for Practical Learning of UV-vis Spectroscopy,Chromatography, Mass Spectrometry, and Chemometrics br

In the past few decades, chemistry has evolved to interact withvarious disciplines to synergistically help tackle global challenges. This, in turn,requires that newer generations of chemistry students are trained to be moreflexible in accepting and coordinating new concepts. In this experiment, pineapplewas used as a key model to allow for the incorporation of multiple importantconcepts into the laboratory. Using carotenoid separation as a main goal, columnchromatography, UV-vis spectroscopy, thin-layer chromatography, high-perform-ance liquid chromatography, mass spectrometry, and principal component analysiscan be included in a cohesive laboratory experiment. On the other hand, theseactivities were also designed to be modular, thus allowing instructors to add,remove, or modify the contents in a highly customizable manner. This makes ithighly versatile and amenable to uncertain situations like unexpected universityclosure due to COVID-19 related lockdown. Overall, this laboratory experimentserves as a practical example of how chemistry can help solve real-world problems while also allowing highflexibility in teaching management

Selective Detection of F– ion and SO2 Molecule: An Experimental and DFT Study

A novel Schiff base was synthesized from acenocoumarol and aniline in gram scale in ∼95% yield. Highly selective detection of SO2 molecule and F– ion was confirmed by experiments, DFT, and TD-DFT calculations. A detection limit of 0.01 ppm, within the permissible limit of F– concentration in drinking water was achieved as mandated by WHO. The mechanism studies show that the first H-transfer is the rate determine step for the overall reaction process. The reversibility study shows the potential applicability and reusability of our sensor. An excellent binding activity was observed with SARS-CoV-2 and the binding energy was found to be -1.9 kcal/mol.

Two Green Micellar HPLC and Mathematically Assisted UV Spectroscopic Methods for the Simultaneous Determination of Molnupiravir and Favipiravir as a Novel Combined COVID-19 Antiviral Regimen.

Following the spread of the COVID-19 pandemic crisis, a race was initiated to find a successful regimen for postinfections. Among those trials, a recent study declared the efficacy of an antiviral combination of favipiravir (FAV) and molnupiravir (MLP). The combined regimen helped in a successful 60% eradication of the SARS-CoV-2 virus from the lungs of studied hamster models. Moreover, it prevented viral transmission to cohosted sentinels. Because both medications are orally bioavailable, the coformulation of FAV and MLP can be predicted. The developed study is aimed at developing new green and simple methods for the simultaneous determination of FAV and MLP and then at their application in the study of their dissolution behavior if coformulated together. A green micellar HPLC method was validated using an RP-C18 core-shell column (5 µm, 150 × 4.6 mm) and an isocratic mixed micellar mobile phase composed of 0.1 M SDS, 0.01 M Brij-35, and 0.02 M monobasic potassium phosphate mixture and adjusted to pH 3.1 at 1.0 mL min-1 flow rate. The analytes were detected at 230 nm. The run time was less than five minutes under the optimized chromatographic conditions. Four other multivariate chemometric model methods were developed and validated, namely, classical least square (CLS), principal component regression (PCR), partial least squares (PLS-1), and genetic algorithm-partial least squares (GA-PLS-1). The developed models succeeded in resolving the great similarity and overlapping in the FAV and MLP UV spectra unlike the traditional univariate methods. All methods were organic solvent-free, did not require extraction or derivatization steps, and were applied for the construction of the simultaneous dissolution profile for FAV tablets and MLP capsules. The methods revealed that the amount of the simultaneously released cited drugs increases up until reaching a plateau after 15 and 20 min for FAV and MLP, respectively. The greenness was assessed on GAPI and found to be in harmony with green analytical chemistry concepts.

At-Home Laboratory Experiments for the Analytical Chemistry Curriculum

In this communication, we describe five at-home laboratory experiments and demonstrations that complement a semester-long analytical chemistry curriculum. The experiments were successfully carried out by remote undergraduate students enrolled in a hybrid analytical chemistry course during the COVID19 pandemic. Students used their personal smartphones to perform the spectrophotometric analyses and all other materials needed to carry out the experiments were assembled in a homemade laboratory kit with a total cost of 265 USD (with the potential for additional cost savings). The experiments centered on the analysis of a single analyte, Allura Red food dye, and spanned quantitative analysis by absorption spectroscopy, reverse-phase liquid chromatography, fluorescence quenching, and Brownian motion. Students used external calibration and the method of standard additions to determine the concentration of Allura Red in maraschino cherry juice to be 140 +/- 40 and 130 +/- 40 ppm, respectively. Students' results were within the expected concentration range of 100-150 ppm. Qualitative spectroscopic and chromatographic analyses spurred robust discussion of the chemical principles underpinning the analytical techniques. Independent remote laboratory instruction was supported through weekly laboratory group meetings involving the remote students and course instructor. Group meetings enabled remote students to make connections with other students in the course, troubleshoot their data analysis in real-time with peer and instructor support, and reflect more deeply on their experimental work. Details about the kit contents, experimental results, best practices for implementation, and recommendations for future adaptation are described.

Gold-Oligonucleotide Nanoconstructs Engineered to Detect Conserved Enteroviral Nucleic Acid Sequences.

Enteroviruses are ubiquitous mammalian pathogens that can produce mild to life-threatening disease. We developed a multimodal, rapid, accurate and economical point-of-care biosensor that can detect nucleic acid sequences conserved amongst 96% of all known enteroviruses. The biosensor harnesses the physicochemical properties of gold nanoparticles and oligonucleotides to provide colourimetric, spectroscopic and lateral flow-based identification of an exclusive enteroviral nucleic acid sequence (23 bases), which was identified through in silico screening. Oligonucleotides were designed to demonstrate specific complementarity towards the target enteroviral nucleic acid to produce aggregated gold-oligonucleotide nanoconstructs. The conserved target enteroviral nucleic acid sequence (≥1 × 10-7 M, ≥1.4 × 10-14 g/mL) initiates gold-oligonucleotide nanoconstruct disaggregation and a signal transduction mechanism, producing a colourimetric and spectroscopic blueshift (544 nm (purple) > 524 nm (red)). Furthermore, lateral-flow assays that utilise gold-oligonucleotide nanoconstructs were unaffected by contaminating human genomic DNA, demonstrated rapid detection of conserved target enteroviral nucleic acid sequence (<60 s), and could be interpreted with a bespoke software and hardware electronic interface. We anticipate that our methodology will translate in silico screening of nucleic acid databases to a tangible enteroviral desktop detector, which could be readily translated to related organisms. This will pave the way forward in the clinical evaluation of disease and complement existing strategies to overcome antimicrobial resistance.

Comparative Analysis of Commercial Colloidal Silver Products.

PURPOSE: The public fear associated with the novel coronavirus (SARS-CoV-2) pandemic has triggered recently a significant proliferation of supplements touted as potential cures against bacteria and viruses. Colloidal silver has particularly benefited from this rush given its empirically and scientifically documented anti-bacterial and anti-viral actions. The lack of standards in the unregulated supplements industry remains a major roadblock in evaluating the quality and consistency of marketed products or assessing the accuracy of the information provided by manufacturers. This study is the first scientifically rigorous attempt to evaluate commercial silver colloidal products offered for sale on the internet. METHODS: Fourteen of the most popular colloidal silver products purchased from Amazon (www.amazon.com) were evaluated using state-of-the-art analytical techniques widely accepted as gold standards for investigating the properties (size, shape) and the dispersion of silver nanoparticles. RESULTS: Commercial samples were analysed using UV-Vis, FE-SEM and AAS techniques. In general, the Ag concentration was very close to those claimed by the manufacturer. The colorless product shows no absorbance in the UV-Vis analysis. The FESEM and STEM images confirmed the conclusions of the UV-Vis analysis. CONCLUSION: The results of this evaluation show clearly that 70% of the commercial products evaluated contain only ionic silver. Despite the evidence showing that silver nanoparticles are not present, eight of these products are promoted by the manufacturers as 'colloidal silver'. Considering the extensive scientific research showing major differences between silver ionic and silver nanoparticles in terms of mechanisms of action, efficacy and safety, it is clear that this misrepresentation impacts the consumers and must be addressed. This study serves as blueprint for a scientific protocol to be followed by manufacturers for characterizing their silver supplements.

Simulating Absorption Spectra of Flavonoids in Aqueous Solution: A Polarizable QM/MM Study.

We present a detailed computational study of the UV/Vis spectra of four relevant flavonoids in aqueous solution, namely luteolin, kaempferol, quercetin, and myricetin. The absorption spectra are simulated by exploiting a fully polarizable quantum mechanical (QM)/molecular mechanics (MM) model, based on the fluctuating charge (FQ) force field. Such a model is coupled with configurational sampling obtained by performing classical molecular dynamics (MD) simulations. The calculated QM/FQ spectra are compared with the experiments. We show that an accurate reproduction of the UV/Vis spectra of the selected flavonoids can be obtained by appropriately taking into account the role of configurational sampling, polarization, and hydrogen bonding interactions.