Comparison of physical and electrochemical properties of ZnO prepared via different surfactant-assisted precipitation routes

In Silico Studies on Zinc Oxide Based Nanostructured Oil Carriers with Seed Extracts of Nigella sativa and Pimpinella anisum as Potential Inhibitors of 3CL Protease of SARS-CoV-2

Coming into the second year of the pandemic, the acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and its variants continue to be a serious health hazard globally. A surge in the omicron wave, despite the discovery of the vaccines, has shifted the attention of research towards the discovery and use of bioactive compounds, being potential inhibitors of the viral structural proteins. The present study aimed at the green synthesis of zinc oxide (ZnO) nanoparticles with seed extracts of Nigella sativa and Pimpinella anisum—loaded nanostructured oil carriers (NLC)—using a mixture of olive and black seed essential oils. The synthesized ZnO NLC were extensively characterized. In addition, the constituent compounds in ZnO NLC were investigated as a potential inhibitor for the SARS-CoV-2 main protease (3CLpro or Mpro) where 27 bioactive constituents, along with ZnO in the nanostructure, were subjected to molecular docking studies. The resultant high-score compounds were further validated by molecular dynamics simulation. The study optimized the compounds dithymoquinone, δ-hederin, oleuropein, and zinc oxide with high docking energy scores (ranging from −7.9 to −9.9 kcal/mol). The RMSD and RMSF data that ensued also mirrored these results for the stability of proteins and ligands. RMSD and RMSF data showed no conformational change in the protein during the MD simulation. Histograms of every simulation trajectory explained the ligand properties and ligand–protein contacts. Nevertheless, further experimental investigations and validation of the selected candidates are imperative to take forward the applicability of the nanostructure as a potent inhibitor of COVID-19 (Coronavirus Disease 2019) for clinical trials.

Solar radiation-induced synthesis of bacterial cellulose/silver nanoparticles (BC/AgNPs) composite using BC as reducing and capping agent

In the present work, a simple, novel, and ecofriendly method for synthesis of silver nanoparticles (AgNPs) and BC/AgNP composite using bacterial cellulose (BC) nanofibers soaked in AgNO₃ solution under induction action of solar radiation. The photochemical reduction of silver Ag + ions into silver nanoparticles (Ag^o) was confirmed using UV visible spectra; the surface plasmon resonance of synthesized AgNPs was localized around 425 nm. The mean diameter of AgNPs obtained by DLS analysis was 52.0 nm with a zeta potential value of - 9.98 mV. TEM images showed a spherical shape of AgNPs. The formation of BC/AgNP composite was confirmed by FESEM, EDX, FTIR, and XRD analysis. FESEM images for BC showed the 3D structures of BC nanofibers and the deposited AgNPs in the BC crystalline nanofibers. XRD measurements revealed the high crystallinity of BC and BC/AgNP composite with crystal sizes of 5.13 and 5.6 nm, respectively. BC/AgNP composite and AgNPs exhibited strong antibacterial activity against both Gram-positive and Gram-negative bacteria. The present work introduces a facile green approach for BC/AgNP composite synthesis and its utility as potential food packaging and wound dressings, as well as sunlight indicator application.

Bio-inspired ZnO NPs synthesized from Citrus sinensis peels extract for Congo red removal from textile wastewater via photocatalysis: Optimization, mechanisms, techno-economic analysis

Textile industry is one of the most environmental unfriendly industrial processes due to the massive generation of colored wastewater contaminated with dyes and other chemical auxiliaries. These contaminants are known to have undesirable consequences to ecosystem. The present study investigated the best operating parameters for the removal of congo red (CR, as the model for dye wastewater) by orange peels extract biosynthesized zinc oxide nanoparticles (ZnO NPs) via photocatalysis in an aqueous solution. The response surface methodology (RSM) with ZnO NPs loadings (0.05-0.20 g), pH (3.00-11.00), and initial CR concentration (5-20 ppm) were used for the optimization process. The applicability of ZnO NPs in the dye wastewater treatment was evaluated based on the techno-economic analysis (TEA). ZnO NPs exhibited hexagonal wurtzite structure with = C-H, C-O, -C-O-C, CC, O-H as the main functional groups. The maximum degradation of CR was more than 96% with 0.171 g of ZnO NPs, at pH 6.43 and 5 ppm of CR and 90% of the R² coefficient. The specific cost of ZnO NPs production is USD 20.25 per kg. These findings indicated that the biosynthesized ZnO NPs with orange peels extract provides alternative method for treating dye wastewater.

Biosynthesis, characterization, and antibacterial activity of ZnO nanoaggregates using aqueous extract from Anacardium occidentale leaf: comparative study of different precursors

Background

Various parts of Anacardium occidentale plant possess curative qualities like antidiabetic, anti-inflammatory, antibacterial, antifungal, and antioxidant. Aqueous extract of this plant leaf was used in biosynthesizing zinc oxide (ZnO) nanoaggregates using two precursors of zinc salt (zinc acetate dihydrate [Zn(CH3COO)2∙2H2O] and zinc chloride [ZnCl2]). The synthesized ZnO samples were used in a comparative study to investigate the antibacterial activity against selected Gram-positive and Gram-negative microbes [Staphylococcus aureus, Exiguobacterium aquaticum (Gram +ve) and Escherichia coli, Klebsiella pneumoniae, Acinetobacter baumannii (Gram −ve)]. The synthesized ZnO nanoaggregates from the two precursors were characterized using Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and energy-dispersive x-ray spectroscopy (EDX) techniques.

Results

Micrographs of SEM and TEM confirmed nanoparticles agglomerated into aggregates. While spherical nanoaggregates were identified in samples prepared from Zn(CH3COO)2∙2H2O, flake-like structures were identified in samples synthesized from ZnCl2. Particle size determined by TEM was 107.03 ± 1.54 nm and 206.58 ± 1.86 nm for zinc acetate dihydrate and zinc chloride precursors respectively. ZnO nanoaggregate synthesized using zinc acetate as precursor gave higher antibacterial activity than its counterpart, zinc chloride with K. pneumonia recording the highest inhibition zone of 2.08 ± 0.03 mm (67.53%) whereas S. aureus recorded the least inhibition zone of 1.06 ± 0.14 mm (34.75%) for ZnO nanoaggregate from zinc chloride precursor. Also, antibacterial activity increases with increasing concentration of the extract in general. However, A. baumannii, E. aquaticum, and K. pneumoniae did not follow the continuity trend with regards to the 250 ppm and 500 ppm concentrations.

Conclusion

Biosynthesis of ZnO nanoaggregates using aqueous extract of A. occidentale leaf from zinc acetate dihydrate and zinc chloride as precursors was successful with the formation of nanospheres and nanoflakes. The study suggested that A. occidentale sp. could be an alternative source for the production of ZnO nanoparticles and are efficient antibacterial compounds against both Gram +ve and Gram −ve microbes with its promising effect against infectious bacteria.

Bioinspired Green Synthesis of Chitosan and Zinc Oxide Nanoparticles with Strong Antibacterial Activity against Rice Pathogen Xanthomonas oryzae pv. oryzae

Bacterial leaf blight caused by Xanthomonas oryzae pv. oryzae (Xoo) is one of the most devastating diseases, resulting in significant yield losses in rice. The extensive use of chemical antibacterial agents has led to an increase the environmental toxicity. Nanotechnology products are being developed as a promising alternative to control plant disease with low environmental impact. In the present study, we investigated the antibacterial activity of biosynthesized chitosan nanoparticles (CSNPs) and zinc oxide nanoparticles (ZnONPs) against rice pathogen Xoo. The formation of CSNPs and ZnONPs in the reaction mixture was confirmed by using UV-vis spectroscopy at 300-550 nm. Moreover, CSNPs and ZnONPs with strong antibacterial activity against Xoo were further characterized by scanning and transmission electron microscopy, Fourier-transform infrared spectroscopy, and X-ray diffraction. Compared with the corresponding chitosan and ZnO alone, CSNPs and ZnONPs showed greater inhibition in the growth of Xoo, which may be mainly attributed to the reduction in biofilm formation and swimming, cell membrane damage, reactive oxygen species production, and apoptosis of bacterial cells. Overall, this study revealed that the two biosynthesized nanoparticles, particularly CSNPs, are a promising alternative to control rice bacterial disease.

Chitosan capped ZnO nanoparticles with cell specific apoptosis induction through P53 activation and G2/M arrest in breast cancer cells - In vitro approaches

Now a days the well-organized strategy to induce apoptosis in cancer chemotherapy is to produce anti-cancer agent without any side effects is in needy. Hence the present investigation was aimed to explore the anticancer potentials of Amorphophallus paeoniifolius reduced zinc nanoparticles capped with chitosan against MCF 7 cell line (breast cancer cells)and studied for its optical and surface charge properties. The size, shape, dispersion and uniform distribution of biosynthesized zincoxide nanoparticle was examined using Field emission scanning electron microscope (FESEM) and Transmission electron microscope (TEM) respectively. The spherical and cubic nanocrystals were found to be lethal against MCF 7 cells on MTT assay at dose dependant manner (20-80 μg/ml) whose IC₅₀ value 42 μg/ml. Bright field light microscopic study showed the apoptotic morphology of treated and control MCF-7 cells. Fluorescence staining A/O:EB and DAPI methods further cleared the chromosome condensation, nuclear fragmentation and confirms the apoptosis induced by Ch-Ap-ZnONPS within IC₅₀ concentrations. Significant cell cycle arrest at particular stage of G2/M was achieved with the nanocomplex treatment at dose dependant manner. Finally, it was observed that the apoptotic gens and protein expressions of MCF-7 cell line were up and down regulation with the treatment of Ch-Ap-ZnONPS when compared to normal cells.

Carpogenic ZnO nanoparticles: amplified nanophotocatalytic and antimicrobial action

This investigation has for the first time utilised environmental resource Prunus cerasifera seed extract phytochemicals for the green synthesis of carpogenic ZnO nanoparticles (NPs). Spherical morphology and size range of 56.57-107.70 nm at variable calcination temperatures without the use of any external reducing agent was obtained. The synthesised NPs exhibited hexagonal wurtzite geometry with an average crystal size 5.62 nm and a band gap of 3.4 eV. Carpogenic NPs were investigated for optical, compositional, morphological, and phytochemical make up via ultraviolet spectroscopy (UV-Vis), Fourier transform infrared analysis, X-ray powder diffraction, scanning electron microscopy, and gas chromatography and mass spectrometry. Carpogenic NPs degraded methyl red up to 83% with pseudo-first-order degradation kinetics (R2 = 0.88) in 18 min signifying their remediation role in environment in conformity with all principles of green chemistry. Photocatalytic assays were performed in direct solar irradiance. Nine pathogens of biomedical and agricultural significance having multi-drug resistance were inhibited in vitro via the Kirby-Bauer disc diffusion assay. The enhanced photocatalytic and antimicrobial inhibition not only makes carpogenic ZnO NPs a future photo-degradative candidate for environmental remediation but also a nanofertiliser, nanofungicide, and nanobactericide synthesised via bioinspired, biomimetic, green, and unprecedented route.

Enhanced photoelectrochemical performance of novel p-type MoBiCuSe4 thin films deposited by a simple surfactant-mediated solution route

Nanostructured MoBiCuSe₄ thin films with different morphologies deposited using different surfactants, such as PEG, SDS and TOPO, through a surfactant-mediated modified chemical route for PEC application.

Nanoscaled Electrocatalytic Optically Modulated ZnO Nanoparticles through Green Process ofPunica granatumL. and Their Antibacterial Activities

Most recently, green synthesis of metal oxide nanoparticles has become an interesting subject of the nanoscience and nanotechnology. The use of plant systems has been deemed a green route and a dependable method for nanoparticle biosynthesis, owing to its environmental friendly nature. The present work demonstrates the bioreductive green synthesis of nanosized zinc oxide (ZnO) using peel extracts of pomegranate. Highly crystalline ZnO nanoparticles (ZnO NPs) which are 5 nm in particle size were characterised by HRTEM and XRD. FT-IR spectra confirmed the presence of the biomolecules and formation of plant protein-coated ZnO NPs and also the pure ZnO NPs. Electrochemical investigation revealed the redox properties and the conductivity of the as-prepared ZnO nanoparticles. The optical band gap of ZnO NPs was calculated to be 3.48 eV which indicates that ZnO NPs can be used in metal oxide semiconductor-based devices. Further, the nanomaterials were also found to be good inhibitors of bacterial strains at both low and high concentrations of 5–10 mg mL−1.