Silver decorated 2D nanosheets of GO and MoS2serve as nanocatalyst for water treatment and antimicrobial applications as ascertained with molecular docking evaluation

Synergistic effect of silver nanoparticle-embedded calcite-rich biochar derived from Tamarindus indica bark on 4-nitrophenol reduction

Calcite-biochar composites are attractive materials with outstanding adsorption capabilities for removing various recalcitrant contaminants in wastewater treatment, however, the complexity of their synthesis limits their practical applications. In this work, we have prepared calcite-rich biochar (Ca-BC) from a single precursor (Tamarindus indica bark), which simplifies the synthetic route for preparing calcite-biochar composite. The as-synthesized composite is utilized to make a heterogeneous catalytic system containing the supported silver nanoparticles (Ag@Ca-BC) formed by the reduction of Ag+ ions on the surface of the composite. The formation of Ag@Ca-BC is confirmed by various characterization techniques such as PXRD, FT-IR, UV-Vis, cyclic voltammetry, impedance measurement, SEM, and TEM analyses. Especially, the TEM analysis confirms the presence of Ag nanoparticles with size ranging between 20 and 50 nm on the surface of Ca-BC composite. The nano-catalyst Ag@Ca-BC efficiently promotes the conversion of 4-nitrophenol to 4-aminophenol using NaBH4 as the reductant in water within 24 minutes at room temperature, suggesting that Ag@Ca-BC can be an efficient catalyst to remove nitroaromatics from the industrial effluents. The straightforward synthesis of Ca-BC from a single precursor along with its utility as a catalytic support presents a compelling proposition for application in the field of materials synthesis, catalysis, and green chemistry.

Mechanistic view of MoS2 confined chitosan-polyaniline hybrid composite for the photo-oxidation of cationic dyes

In this article, we describe the formulation of polyaniline-chitosan/MoS2 (PANI-CS @MoS2) blended composite and evaluated its efficiency to degrade the dye molecules Rhodamine B (RhB) and Malachite Green (MG) under visible light. In the photocatalytic mechanism, the CS acts as an electron carrier and binding agent during the oxidation reaction to decrease the recombination of electrons and holes generated by the irradiation of light. FTIR, XPS, XRD, TG, Zeta Potential, UV, SEM, AFM and TEM were used to characterize the PANI-CS@MoS2 composite after it had been synthesized. For the degradation analysis, 30 mg/L concentrations of 50 mL MG and RhB dye solutions were used. The recommended dosage of the composite was 100 mg. For MG and RhB dyes, the colour removal rates were 96.2 % and 91.5 %, respectively, under exposure to visible light and at the pH ranges of 8-11. After being exposed to visible light for 60 min, the whole decay process was accomplished. The photocatalyst offers great extensibility up to five iterations. The Langmuir-Hinshelwood kinetic model governs the rate of dye molecules degradation. The result of the study revealed that the PANI-CS@MoS2 composite matrix perhaps be a trustworthy and practical substrate for the efficient refinement of dye-deteriorated water⁠⁠⁠⁠⁠⁠⁠.

Advancements of Nanotechnology and Nanomaterials in Environmental and Human Protection for Combatting the COVID-19 During and Post-pandemic Era: A Comprehensive Scientific Review

In December 2019, an outbreak of unknown pneumonia emerged in Wuhan City, Hubei Province, China. It was later identified as the SARS-CoV-2 virus and has since infected over 9 million people in more than 213 countries worldwide. Massive papers on the topic of SARS-CoV-2 that have already been published are necessary to be analyzed and discussed. This paper used the combination of systematic literature network analysis and content analysis to develop a comprehensive discussion related to the use of nanotechnology and materials in environmental and human protection. Its is shown that various efforts have been made to control the transmission of this pandemic. Nanotechnology plays a crucial role in modern vaccine design, as nanomaterials are essential tools for antigen delivery, adjuvants, and mimics of viral structures. In addition, nanomaterials and nanotechnology also reported a crucial role in environmental protection for defence and treating the pandemic. To eradicate pandemics now and in the future, successful treatments must enable rapid discovery, scalable manufacturing, and global distribution. In this review, we discuss the current approaches to COVID-19 development and highlight the critical role of nanotechnology and nanomaterials in combating the virus in the human body and the environment.

Graphene oxide/polyvinylpyrrolidone-doped MoO3 nanocomposites used for dye degradation and their antibacterial activity: a molecular docking analysis

In this study, MoO₃ nanostructures were prepared, doped with various concentrations of graphene oxide (2 and 4% GO) and a fixed amount of polyvinylpyrrolidone (PVP) using the co-precipitation method. The motive of this study was to examine the catalytic and antimicrobial efficacy with evidential molecular docking analyses of GO/PVP-doped MoO₃. GO and PVP were utilized as doping agents to reduce the exciton recombination rate of MoO₃ by providing more active sites that increase the antibacterial activity of MoO₃. The prepared binary dopant (GO and PVP)-dependent MoO₃ was used as an effective antibacterial agent against Escherichia coli (E. coli). Notably, 4% GO/PVP-doped MoO₃ showed good bactericidal potential against E. coli at higher concentrations in comparison to ciprofloxacin. Furthermore, in silico docking revealed the possible inhibitory impact of the synthesized nanocomposites on folate and fatty acid synthesis enzymes, dihydrofolate reductase and enoyl-[acyl carrier protein] reductase, respectively.

Bactericidal Action and Industrial Dye Degradation of Graphene Oxide and Polyacrylic Acid-Doped SnO2 Quantum Dots: In Silico Molecular Docking Study

The present work demonstrates the systematic incorporation of different concentrations of graphene oxide (GO) into a fixed amount of polyacrylic acid (PAA)-doped SnO₂ quantum dots (QDs) through a co-precipitation approach. The research aimed to evaluate the catalytic and antibacterial actions of GO/PAA-SnO₂ QDs. Moreover, optical properties, surface morphologies, crystal structures, elemental compositions, and d-spacings of prepared QDs were examined. X-ray diffraction patterns revealed the tetragonal configuration of SnO₂, and the crystallinity of QDs was suppressed upon dopants verified by the SAED patterns. Electronic spectra identified the blue shift by incorporating GO and PAA led to a reduction in band gap energy. Fourier transform infrared spectra showed the existence of rotational and vibrational modes associated with the functional groups during the synthesis process. A drastic increase in the catalytic efficacy of QDs was observed in the neutral medium by including dopants, indicating that GO/PAA-SnO₂ is a promising catalyst. GO/PAA-SnO₂ showed strong bactericidal efficacy against Escherichia coli (E. coli) at higher GO concentrations. Molecular docking studies predicted the given nanocomposites, i.e., SnO₂, PAA-SnO₂, and GO/PAA-SnO₂, as potential inhibitors of beta-lactamase_E. coli and DNA gyrase_E. coli.

Photocatalytic and antibacterial activity of graphene oxide/cellulose-doped TiO2 quantum dots: in silico molecular docking studies

Graphene oxide (GO) and cellulose nanocrystal (CNC)-doped TiO₂ quantum dots (QDs) were effectively synthesized by employing the co-precipitation method for the degradation of dyes and antimicrobial applications. A series of characterizations, i.e., XRD, FTIR, UV-visible spectroscopy, EDS, FE-SEM, and HR-TEM, was used to characterize the prepared samples. A reduction in PL intensity was observed, while the band gap energy (E _g) decreased from 3.22 to 2.96 eV upon the incorporation of GO/CNC in TiO₂. In the Raman spectra, the D and G bands were detected, indicating the presence of graphene oxide in the composites. Upon doping, the crystallinity of TiO₂ increased. HR-TEM was employed to estimate the interlayer d-spacing of the nanocomposites, which matched well with the XRD data. The photocatalytic potential of the prepared samples was tested against methylene blue, methylene violet, and ciprofloxacin (MB:MV:CF) when exposed to visible light for a certain period. The antibacterial activity of GO/CNC/TiO₂ QDs against Staphylococcus aureus (S. aureus) and Escherichia coli (E. coli) bacteria in vitro was tested to determine their potential for medicinal applications. The molecular docking investigations of CNC-TiO₂ and GO/CNC-doped TiO₂ against DNA gyrase and FabI from E. coli and S. aureus were found to be consistent with the results of the in vitro bactericidal activity test. We believe that the prepared nanocomposites will be highly efficient for wastewater treatment and antimicrobial activities.

In-silico predicting as a tool to develop plant-based biomedicines and nanoparticles: Lycium shawii metabolites

INTRODUCTION AND PURPOSE

In silico approach helps develop biomedicines and is useful for exploring the pharmacology of potential therapeutics using computer-simulated models. In vitro assays were used to determine the anti-microbial and cytotoxic efficacies of silver nanoparticles (AgNPs) synthesized with the shrub Lycium shawii.

METHODS

In silico predicting was performed to assess the L. shawii metabolites identified using QTOF-LCMS for their pharmacological properties. L. shawii mediated AgNPs were synthesized and characterized (FTIR, TEM, SEM, DLS and EDX). The anti-bacterial efficacies of L. shawii extract, AgNPs, and penicillin-conjugated AgNPs (pen-AgNPs) were determined. The cytotoxicity of the AgNPs was measured against colorectal cancer cell line (HCT116), normal breast epithelium (MCF 10 A), and breast cancer cell line (MDA MB 231).

RESULTS AND DISCUSSION

Five molecules (costunolide, catechin, emodin, lyciumaside, and aloe emodin 11-O-rhamnoside) were detected in the L. shawii extract. AgNPs (69 nm) were spherical with crystallographic structure. All three agents prepared showed inhibitory activity against the tested bacteria, the most efficacious being pen-AgNPs. High cytotoxicity of AgNPs (IC₅₀ 62 μg/ml) was observed against HCT116, IC₅₀ was 78 μg/ml for MCF 10 A, and 250 μg/ml for MDA MB 231, of which cells showed apoptotic features under TEM examination. The in silico approach indicated that the carbonic anhydrase IX enzyme was the target molecule mediating anti-cancer and anti-bacterial activities and that emodin was the metabolite in action.

CONCLUSIONS

Combining in vitro studies and in silico molecular target prediction helps find novel therapeutic agents. Among L. shawii metabolites, emodin is suggested for further studies as an agent for drug development against pathogenic bacteria and cancer.