Evaluation of action of steroid molecules on SARS-CoV-2 by inhibiting NSP-15, an endoribonuclease.

Many countries in the world have recently experienced an outbreak of COVID-19, turned out to be a pandemic which significantly affected the world economy. Among many attempts to treat/control infection or to modulate host immunity, many small molecules including steroids were prescribed based on their use against other viral infection or inflammatory conditions. A recent report established the possibility of usage of a corticosteroid against the virus through inhibiting NSP-15; an mRNA endonuclease of SARS-CoV-2 and thereby viral replication. This study aimed to identify potential anti-viral agents for the virus through computational approaches and to validate binding properties with the protein target through molecular dynamics simulation. Unlike the conventional approaches, dedicated data base of steroid like compounds was used for initial screening along with dexamethasone and cortisone, which are used in the treatment of COVID-19 affected population in some countries. Molecular docking was performed for three compounds filtered from data base in addition to dexamethasone and Cortisone followed by molecular dynamics simulation analysis to validate the dynamics of binding at the active site. In addition, analysis of ADME properties established that these compounds have favorable drug-like properties. Based on docking, molecular dynamics simulation studies and various other trajectory analyses, compounds that are identified could be suggested as therapeutics or precursors towards designing new anti-viral agents against SARS-CoV-2, to combat COVID-19. Also, this is an attempt to study the impact of steroid compounds on NSP-15 of SARS-CoV-2, since many steroid like compounds are used during the treatment of COVID-19 patients.

Growth optimization of single-phase novel colloidal perovskite Cs3Bi2I9 nanocrystals and Cs3Bi2I9@SiO2 core-shell nanocomposites for bio-medical application.

Lead-free halide perovskites have gained attention in recent years as viable materials with more distinctive characteristics than conventional semiconductor materials. Lead-free Cs3Bi2I9 colloidal perovskite nanocrystal is chosen to eliminate its single-phase synthesis difficulty and implement the material in bioimaging applications. Nanostructured Cs3Bi2I9 perovskite composites were coated with a thin coating of SiO2 by an in situ tetraethyl orthosilicate/(3-aminopropyl)trimethoxysilane injection growth method to enhance their stability in aqueous medium and biocompatibility. Single-phase novel Cs3Bi2I9 colloidal perovskite nanocrystal synthesis was successfully developed and optimized by adopting different synthetic conditions with varied experimental parameters. Characterization studies, including X-ray diffractometry and transmission electron microscopy, confirm the hexagonal structure of Cs3Bi2I9 crystals and their cubic morphology. A broad emission peak in the red region was captured for pure and composite perovskite under different excitation wavelengths and was observed using a UV-visible spectrophotometer. Bioimaging of Cs3Bi2I9@SiO2 composites incorporated with L929 cells was conducted using an inverted fluorescence microscope under blue and green excitation. The results obtained from bioimaging studies indicated that the Cs3Bi2I9@SiO2 nanocomposites entered the cell field and exhibited an emission under excitation. The non-toxic behavior of the synthesized Cs3Bi2I9@SiO2 composites was demonstrated using MTT cytotoxicity assay in L929 fibroblast mouse cells, showing better cell compatibility.

Structure-based pharmacophore modeling, virtual screening approaches to identifying the potent hepatitis C viral protease and polymerase novel inhibitors.

Hepatitis C is an infectious disease that leads to acute and chronic liver illnesses. Currently, there are no effective vaccines against this deadly virus. Direct acting antiviral (DAA) drugs are given in the combination with ribavirin and pegylated interferon which lead to adverse effects. Through in silico analysis, the structure-based docking study was performed against NS3/4A protease and NS5B polymerase proteins of HCV. In the current study, multiple e-pharmacophore-based virtual screening methods such as HTVS, SP, and XP were carried out to screen natural compounds and enamine databases. Our result outcomes revealed that CID AE-848/13196185 and CID AE-848/36959205 compounds show good binding interactions with protease protein. In addition, CID 15081408 and CID 173568 show better binding interactions with the polymerase protein. Further to validate the docking results, we performed molecular dynamics simulation for the top hit compounds bound with protease and polymerase proteins to illustrate conformational differences in the stability compared with the active site of the cocrystal inhibitor. Thus, the current study emphasizes these compounds could be an effective drug to treat HCV.

Surface Modification of Decellularized Natural Cellulose Scaffolds with Organosilanes for Bone Tissue Regeneration.

The utility of plant tissues as scaffolding materials has been gaining significant interest in recent years owing to their unique material characteristics that are ideal for tissue regeneration. In this study, the degradation and biocompatibility of natural cellulosic scaffolds derived from Borassus flabellifer (Linn.) (BF) immature endosperm was improved by chemical oxidation and surface functionalization processes. Briefly, thus obtained cellulosic scaffolds were sequentially processed via a detergent exchange decellularization process followed by sodium periodate mediated oxidation and organosilane-based surface modification using amino (NH2)-terminated 3-aminopropyltriethoxysilane (APTES) and methyl (CH3)-terminated octadecyltrichlorosilane (OTS). Post oxidation and surface functionalization, the scaffolds showed improved physiochemical, morphological, and mechanical properties. Especially, the swelling capacity, total porosity, surface area, degradation kinetics, and mechanical behavior of scaffold were significantly higher in modified scaffold groups. The biocompatibility analysis demonstrated excellent cellular adhesion, proliferation and differentiation of osteoblasts with an evident upregulation of mineralization. Subcutaneous implantation of these scaffolds in a rat model demonstrated active angiogenesis, enhanced degradation, and excellent biocompatibility with concomitant deposition of a collagen matrix. Taken together, the native cellulosic scaffolds post chemical oxidation and surface functionalization can exclusively integrate the potential properties of native soft tissue with ameliorated in vitro and in vivo support in bone tissue engineering for nonloading bearing applications.

Resistome and mobilome in surface runoff from manured soil as affected by setback distance.

Land application of livestock manure introduces antibiotic resistance genes (ARGs) and mobile genetic elements (MGEs) into the soil environment. The objectives of this study were to examine the changes of resistome and mobilome in runoff and soil as a function of setback distance, i.e., the distance between manured soil and surface water, and to quantify the contributions of manure and background soil to the ARGs and MGEs in surface runoff. The resistome and mobilome in runoff and soil from a field-scale plot study were characterized using a high throughput quantitative polymerase chain reaction (HT-qPCR) array. It was estimated that a setback distance of ~40 m is required to reduce the total abundance of ARGs and MGEs in runoff from amended plots to that in control runoff. The resistome and mobilome of the soil in the setback region was not affected by manure-borne ARGs and MGEs. SourceTracker analyses revealed that background soil gradually became the predominant source of the ARGs and MGEs in runoff as setback distance increased. The results demonstrate how manure-borne ARGs and MGEs dissipated in agricultural runoff with increasing setback distance and had limited impacts on the resistome and mobilome of soil within the setback region.

Mesoporous Mn-doped hydroxyapatite nanorods obtained via pyridinium chloride enabled microwave-assisted synthesis by utilizing Donax variabilis seashells for implant applications.

Manganese-doped mesoporous hydroxyapatite (MnHAp) nanorods, a bio-apatite were synthesized via pyridinium chloride mediated microwave approach using bio-waste Donax variabilis seashells to treat orthopedic infections. This is the first report on using pyridinium chloride mediated mesoporous MnHAp nanorods synthesis. Pure and Mn doped HAp samples were examined using Raman spectroscopy, X-ray powder diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR) studies to confirm the prepared HAp nanorods. Furthermore, the fabrication of manganese-doped HAp was successful with the formation of a hexagonal crystal lattice without disturbing the HAp phase. It is because, at the time of synthesis, PO43- ions form an electrostatic interaction with the Mn ions. Furthermore, Mn-doped HAp samples showed a reduction in their sizes of 15, 10-15, 5-10 nm width, and 80-100, 10-15, 20-30 nm length with varied pore diameters and surface area. The pure HAp, MnHAp-1, MnHAp-2, and MnHAp-3 nanorods disclose the surface area of 39.4, 18.0, 49.2, and 80.4 m2 g-1, with a pore volume of 0.0102, 0.0047, 0.0143, and 0.0447 cm3 g-1, the corresponding pore diameter was estimated to be 6, 7, 6, and 4 nm, respectively. Moreover, antibacterial activity reveals effective bactericidal action against infections causing pathogens whereas cytotoxicity examination (MTT assay), and zebrafish results reveal their non-toxic behavior. Therefore, it is evident from the study, that rapid fabrication of mesoporous and diverse structured MnHAp nanorods could be convenient with pyridinium chloride enabled microwave-assisted method as a bactericidal biomaterial for implant applications.

Mesoporous ferromagnetic manganese ferrite nanoparticles for enhanced visible light mineralization of azoic dye into nontoxic by-products.

In this study, a one pot facile synthesis of ferromagnetic manganese ferrite nanoparticles (MnFe2O4) was carried out using chemical co-precipitation method for mineralization of azo dye (Congo red (CR)) in aqueous solution under visible light irradiation. The synthesized MnFe2O4 nanoparticles were highly crystalline and showed face-centred cubic (FCC) structure with average particle size of 58 ± 4 nm. The BET analysis of the MnFe2O4 nanoparticles revealed the mesoporous distribution of material with high surface area can provide large electro active sites and short diffusion paths for the transport of ions which plays a vital role in the photocatalytic degradation of CR. The point of zero charge (pHPZC) was observed to be 6.7 indicating favourable condition for material-anionic dye interaction. The XPS studies revealed that the large amounts of oxygen vacancies were produced due to the defects in the lattice oxygen. The MnFe2O4 nanoparticles mineralised 98.3 ± 0.2% of 50 mg/L CR within 30 min when tested in photocatalytic reactor under 565 nm. The particles were recoverable under the influence of an external magnet after the photocatalytic reaction and were reusable. The recovered nanoparticles showed 96% of CR degradation efficiency even after five cycles of reuse. The by-product analysis with GC-MS indicated mineralization of CR into simple alcohols and acids. The aqueous solution containing mineralised CR was nontoxic to Trigonella foenumgraecum and Vigna mungo seeds and favoured increased germination, plumule and radicle length when compared to untreated CR.

Electrospun PCL nanofibers blended with Wattakaka volubilis active phytochemicals for bone and cartilage tissue engineering.

In the present study, the polycaprolactone (PCL) nanofibers were investigated as a carrier to deliver phytochemicals for bone and cartilage tissue engineering. The PCL nanofibers was blended with phytochemicals hexadecanoic acid, octadecanoic acid and N,N-diisopropyl (2,2,3,3,3-pentafluoropropyl) amine isolated from a medicinal plant, Wattakaka volubilis. The scaffolds were characterized using scanning electron microscope (SEM) and Fourier transform infrared (FTIR) spectroscopy. The average diameter of control and phytochemical loaded nanofiber was 208 ±â€¯9.6 nm and 316 ±â€¯7.0 nm respectively. Biodegradation rate of nanofibers, impact of nanofiber on meniscus and osteoblast cell growth was analyzed using 3-(4,5-dimethyl thiazolyl-2)-2,5-diphenyl tetrazolium bromide (MTT) assay, DNA content and extra cellular matrix secretion. Hoechst stain and SEM images were used to visualize and monitor the cell growth on PCL scaffold. The phytochemicals incorporated PCL nanofibers enhanced the growth and proliferation of primary human meniscus and osteoblast like cells and hence may be suitable scaffold for bone and cartilage tissue engineering applications.

Ascorbic Acid-Assisted Microwave Synthesis of Mesoporous Ag-Doped Hydroxyapatite Nanorods from Biowaste Seashells for Implant Applications.

Post-surgery implant infection is one of the most challenging issues in orthopedics and it is mainly caused by infective micro-organisms. A potential approach to overcome this issue is developing biomaterials with efficient antibacterial activity. The main intention of this present research is devoted to ascorbic acid-assisted microwave synthesis of mesoporous (silver) Ag-doped hydroxyapatite (HAp) nanorods using biowaste seashells with antibacterial properties. XRD, FTIR, and Raman spectroscopy results revealed that the synthesized nanoparticles are hexagonal crystalline HAp. Further, the silver-doped HAp was also successfully produced without affecting the HAp crystalline phase by forming electrostatic interaction with PO43- ions during the synthesis. The morphological features confirm that the pure HAp is elongated mesoporous nanorods with 20 nm width and 300-500 nm length. However, silver doped HAp nanoparticles such as AgHA-1, AgHA-2, and AgHA-3 are found to be similar mesoporous rods but with different aspect ratios in sizes of 15, 10-15, and 5-10 nm width and 80-100, 10-15, and 20-30 nm length. The BET specific surface areas were obtained as 29 ± 3, 84 ± 2, 87 ± 2, and 128 ± 3 m2 g-1, and pore diameters were 4.68, 4.18, 9.30, and 3.77 nm, respectively, for pure HA, AgHA-1, AgHA-2, and AgHA-3. Therefore, HAp nanoparticles with different dimensions and mesoporous structures could be rapidly prepared using a microwave-assisted method and ascorbic acid as a supporting material. In addition, the synthesized HAp nanoparticles are analyzed for its antibacterial and cytotoxicity studies. The antibacterial and cytotoxicity study clearly reveals that the Ag-doped HAp nanorods are efficiently antibacterial and nontoxic in nature. Hence, it is clear that the ascorbic acid-enabled microwave-assisted method will be one of the best methods for the rapid production of HAp nanoparticles with different dimensions and mesoporous structures for its application as an implant material.

In vitro evaluation of phytochemical loaded electrospun gelatin nanofibers for application in bone and cartilage tissue engineering.

Wattakaka volubilis, a medicinal plant, is known to exhibit various potential health benefits and has traditionally been used in Ayurveda for various medicinal applications. In the present study, phytochemicals hexadecanoic acid, octadecanoic acid and N,N-Diisopropyl(2,2,3,3,3-pentafluoropropyl)amine isolated from W. volubilis leaf extract were co-electrospun with gelatin nanofibers for meniscus and osteoblast cell attachment and proliferation. The electrospun nanofibers were characterized using suitable techniques such as a scanning electron microscope and Fourier transform infrared spectroscopy. The mechanical property of electrospun gelatin nanofibers and phytochemicals incorporated gelatin nanofibers were tensile tested. Both the control and phytochemical loaded nanofiber exhibited a similar stress-strain trend. The average diameter of the control and phytocompound loaded gelatin nanofiber was found to be 300 ± 5.5 nm and 483 ± 12 nm, respectively. The rate of biodegradation of the control and phytochemical loaded nanofiber was analyzed in a simulated body fluid. The cell attachment and proliferation were monitored using a fluorescence microscope after appropriate staining. The cell viability, DNA content, extracellular secretion confirmed that the phytocompound loaded gelatin nanofibers were non-toxic and enhanced the meniscus and osteoblast cell growth and proliferation. This phytocompound loaded gelatin matrix may be used as a potential scaffold for cartilage and bone tissue engineering applications.

Phase Competition Induced Bio-Electrochemical Resistance and Bio-Compatibility Effect in Nanocrystalline Zrx-Cu100-x Thin Films.

Nano-crystalline Zrx-Cu100-x (x = 20-100 at.%) thin films with thickness ranging from 50 to 185 nm were deposited by magnetron co-sputtering with individual Zr and Cu targets. The as-sputtered thin films were characterized by Field Emission Scanning Electron Microscope (FE-SEM), Atomic Force Microscopy (AFM) and Glancing Incidence X-ray Diffraction (GIXRD) for structural and morphological properties. The crystallite size was found to decrease from 57 nm to 37 nm upon increasing the Zr content from 20 to 30 at.% with slight increase in the lattice strain from 0.17 to 0.33%. Further, increase in Zr content to 40 at.% leads to increase in the crystallite size to 57 nm due to stabilization of C10Zr7 phase along with the presence of nanocrystalline Cu-Zr phase. A bimodal distribution of grain size was observed from FE-SEM micrograph was attributed to the highest surface roughness in Zr30Cu70 thin films comprised of Cu10Zr7, Cu9Zr2, Cu-Zr intermetallic phases. In-vitro electrochemical behaviors of nano-crystalline Zrx-Cu100-x thin films in simulated body fluid (SBF) were investigated using potentiodynamic polarization studies. Electrochemical impedance spectroscopy (EIS) data fitting by equivalent electrical circuit fit model suggests that inner bulk layer contributes to high bio-corrosion resistance in Zrx-Cu100-x thin films with increase in Zr content. The results of cyto-compatibility assay suggested that Zr-Cu thin film did not introduce cytotoxicity to osteoblast cells, indicating its suitability as a bio-coating for minimally invasive medical devices.

Development and evaluation of finasteride loaded ethosomes for targeting to the pilosebaceous unit.

Androgenetic alopecia, a major cause for baldness, is caused by the deposition of dihydrotestosterone (DHT) at the androgen receptors present in the pilosebaceous unit (PSU). Finasteride (FIN) is a potent 5α-reductase inhibitor capable of preventing the conversion of testosterone to DHT. But, its oral administration in males causes infertility. An attempt was made to prepare ethosomes of FIN with a size range 100-300 nm to enhance its delivery to the PSU. Finasteride loaded ethosomes (FES) were prepared using an ultra-probe sonicator and characterized for its size, morphology, surface charge and entrapment efficiency. The ability of FES to permeate across rat skin and frontal scalp skin of human cadaver was also evaluated. The spherical shaped ethosomes of different batches were in the size range of 107.8 ± 2.50 to 220.4 ± 6.92 nm and showed good permeation across rat skin and frontal scalp skin of human cadaver when compared to the unencapsulated FIN. The results portrayed the ability of FES to permeate across the stratum corneum to reach the PSU of the hair follicle. Although additional use of permeation enhancer increases the permeation of FIN across the skin, its addition may not be a favourable option for the deposition of ethosomes in the PSU.

Stimulation of human osteoblast cells (MG63) proliferation using decanoic acid and isopropyl amine fractions of Wattakaka volubilis leaves.

OBJECTIVES: This study was carried out to investigate the impact of various isolated phytochemical components present in the Wattakaka volubilis leaves for the growth and proliferation of human osteoblast like cells (MG63). KEY FINDINGS: Ethyl acetate was found to be the best solvent for potential extraction of phytocompounds. Further, the MTT assay was carried out to deduce the viability of 44 isolated phytochemicals. Ten phytochemical fractions found to increase the cell growth were subjected to statistical tool namely Plackett-Burman and Central composite design to screen the optimum phytochemical fraction and its dosage. The active phytochemical constituents were analysed and identified as hexadeconoic acid, octadeconoic acid, N,N-diisopropyl(2,2,3,3,3-pentafluoropropyl)amine using GC-MS and HPLC techniques. The impact of optimized concentration was assessed on osteoblast cells. The maximum % cell viability, % DNA and collagen content were found to be 164.44, 159.32 and 3.81, respectively. CONCLUSIONS: The results confirmed that the optimized fraction containing decanoic acid and isopropyl amine at particular concentration stimulated the proliferation of human osteoblast (MG63) cells. Hence, the optimized concentration of this compound from W. volubilis may used for treatment of bone related injuries externally.

Impact of silk fibroin-based scaffold structures on human osteoblast MG63 cell attachment and proliferation.

The present study was carried out to investigate the impact of various types of silk fibroin (SF) scaffolds on human osteoblast-like cell (MG63) attachment and proliferation. SF was isolated from Bombyx mori silk worm cocoons after degumming. Protein concentration in the degummed SF solution was estimated using Bradford method. Aqueous SF solution was used to fabricate three different types of scaffolds, viz, electrospun nanofiber mat, sponge, and porous film. The structures of the prepared scaffolds were characterized using optical microscopy and field emission scanning electron microscopy. The changes in the secondary structure of the proteins and the thermal behavior of the scaffolds were determined by Fourier transform infrared spectroscopy and thermo-gravimetric analysis, respectively. The biodegradation rate of scaffolds was determined by incubating the scaffolds in simulated body fluid for 4 weeks. MG63 cells were seeded on the scaffolds and their attachment and proliferation onto the scaffolds were studied. The MTT assay was carried out to deduce the toxicity of the developed scaffolds. All the scaffolds were found to be biocompatible. The amount of collagen produced by the osteoblast-like cells growing on different scaffolds was estimated.

Phytochemicals as inhibitors of bacterial cell division protein FtsZ: coumarins are promising candidates.

Naturally occurring phytochemicals with reported antibacterial activity were screened for their ability to inhibit the bacterial cell division protein Escherichia coli FtsZ. Among the representative compounds, coumarins inhibit the GTPase and polymerization activities of this protein effectively. Further screening with ten coumarin analogs we identified two promising candidates, scopoletin and daphnetin. The former is found to inhibit the GTPase activity of the protein in a noncompetitive manner. Docking of these coumarins with the modeled protein indicate that they bind to T7 loop, which is different from the GTP-binding site (active site), thereby supporting the experimental data. Lowest binding energy is obtained with scopoletin. 3D QSAR indicates the need for groups such as hydroxyl, diethyl, or dimethyl amino in the 7th carbon for enhanced activity. None of the coumarins exhibited cytotoxicity against NIH/3T3 and human embryonic kidney cell lines. The length of Bacillus subtilis increases in the presence of these compounds probably due to the lack of septum formation. Results of this study indicate the role of coumarins in halting the first step of bacterial cell division process.