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Abstract Silver ions, because of its recognised antimicrobial activity are reported in several regions for the very long time while ergosterol, apart from its role as a secondary metabolite, structural component of the fungal cell membranes, also turns out to be activating defence response in plants. Silver ions biosynthesized by terpene ergosterol producing Trichoderma harzianum could be used against other plant pathogenic fungi. In this work, possible interaction of the silver ions with ergosterol enzyme has been investigated using a computational approach. Protein model construction via prior knowledge of sequences and molecular ligand docking experiments as well as structural and sequence comparisons were executed to identify potential active-site in ergosterol enzyme. Moldock score of −48.5747 with the reranking score of −40.0228 has been reported by Molegro Virtual Docker(MVD) at ergosterol enzyme's active site positions for silver ion. Apart from the core of the active site, four other positions have been occupied by silver ion. The interacting site surrounded by Cys339, Arg343, Lue365, Leu336 and Trp371 formed hydrophobic bonds with silver. The anti-microbial activity against phytopathogens is believed to increase synergistically when combined with ergosterol enzyme. Thus the computational analysis of silver ion in conjugation with ergosterol enzyme provided additional strategies to improve the ability of the Trichoderma strains in biocontrol of pathogenic fungi. In the present study, silver ion based formulations which are produced by strong bio-control fungi as shown were estimated in response to different plant pathogen in further studies. Highlights • Ergosterol mediated biosynthesis of silver nanoformulation in T. harzianum is known. • Silver as well as T. harzianum, both are anti-pathogenic in nature. • Anti-microbial activity against phytopathogens increases synergistically. • Possible interactions of silver are explore via docking and MD Simulation. [ABSTRACT FROM AUTHOR]

Abstract Silver nanoparticles, one of the most popular nanomaterials, are used extensively in medicine and industries. The present study biosynthesized spherical Ag/AgCl nanoparticles with a size range of 10–50 nm in less than 5 min. The synthesis was performed in a single step, in a low-cost and eco-friendly manner, from the aqueous extract of Malva Sylvestris leaves. The aqueous extract had a large number of phenolic compounds and carbohydrates as reducing and capping agents. The nanoparticles also showed significant antibacterial and anti-biofilm activities against some multi drug resistant bacteria. They additionally showed antifungal activities on several Candida species. The highest concentration of Ag/AgCl-NPs (62.5 μg/ml) was required in order to inhibit P. aeruginosa B 52, C. glabrata and C. parapsilosis growth. The lowest concentration of Ag/AgCl-NPs (7.8125 μg/ml) inhibited the growth of C. orthopsilosis, P. aeruginosa ATCC 27853 and B. subtilis ATCC 6633. A total of 125 μg/ml of Ag/AgCl-NPs was used to prevent P. aeruginosa B 52 biofilm growth. The concentration of 62.5 μg/ml Ag/AgCl-NPs also eradicated both P. aeruginosa 48 and P. aeruginosa B 52 biofilms. The results showed that Hg2+ and Pb2+ contaminants in water could be colorimetrically detected by these nanoparticles. Graphical abstract Image 1 [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • Ag/BN nanohybrids produced via AgNO 3 decomposition under UV irradiation in polyethylene glycol. • Ag/BN nanohybrids and Ag polymer-based metallogels formed simultaneously during the synthesis. • Catalysts obtained in PEG showed higher concentration and uniform distribution of Ag nanoparticles. • Ag/BN nanohybrids demonstrated a pronounced catalytic activity toward CO oxidation. Abstract Nanohybrid materials made of h -BN nanoparticles (BNNPs) with Ag nanoparticles (AgNPs), covering their surfaces, were employed as catalysts in CO oxidation reaction. Ag/BN nanohybrids (NHs) were produced via AgNO 3 decomposition under UV irradiation in polyethylene glycol (PEG) and its solutions at room temperature. Influence of the synthetic media composition on the synthesis process and resultant NHs structures were investigated. Two different structural types (Ag/BN and polymer-based structure) formed during the synthesis were studied. It was demonstrated that Ag/BN NHs synthesized in a PEG media had possessed the highest Ag concentration and uniform distribution of AgNPs. Catalytic activity tests revealed that the lowest temperature of full CO conversion (194 °C) had been attained to the sample with the highest Ag content. CO oxidation mechanism on the surface of AgNPs was finally proposed based on DFT calculations. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • High-temperature annealing in air conferred CeO 2 nanorods abundant lattice oxygen. • O 3 activation enriched the active oxygen (O x −) on CeO 2 at cost of vacancy depletion. • CO oxidation relied crucially on the participation of pre-existing oxygen vacancies. • O x − (especially O 2 −) on CeO 2 affected the oxidation of soot and NO directly. • Aged CeO 2 nanorods impregnated with Ag exhibited superior oxidation activities. Abstract Though the catalytic oxidation of CO, NO and soot over CeO 2 could be understood within a similar Mars-van Krevelen-type mechanism, these reactions were likely to be driven by different active phases. In this work, several CeO 2 and Ag/CeO 2 nanorods with different contents of surface oxygen vacancies (V O-s) and active oxygen species (O x −) were designed as model catalysts. Their catalytic performance indicated that, CO oxidation was determined by pre-existing ceria V O-s , while O x − participated in NO and soot oxidation directly. Besides, by loading silver onto the high-temperature aged CeO 2 nanorods, Ag/CeO 2 catalysts with high availability of ceria lattice oxygen were obtained, whose low-temperature oxidation activity was proven comparable to that of the platinum catalysts. In this sense, the model designing in this work not only provided methods to find out proper reactivity descriptors, but also conferred low-cost catalysts with high practical potential. [ABSTRACT FROM AUTHOR]

Herein, we reported the photo-catalytic degradation/anti-bacterial property of Ag-doped ZnO nanoparticles (SDZO Nps) prepared by a facile gel-combustion technique and its self-cleaning/self-refreshing/self-disinfectant behaviour while on impregnating as pigment into the alkyd resin based coating. The influence of doping Ag (1% & 2%) with ZnO has been evaluated in terms of crystal structure, morphology, optical properties, etc. using X-ray diffraction analysis, Field Emission Scanning Electron Microscope, UV–Vis analysis, and Photoluminescence spectra. The photo-catalytic degradation of crystal violet solution by SDZO Nps is spectroscopically followed employing UV–Vis spectroscopy. From the obtained results, the rate of degradation of 1% SDZO Nps is found higher than that of other samples under sunlight illumination; degrading 1 mg of crystal violet in 30 min. Thus, implementing the synergic effect of nano ZnO and the doped Ag provides a suitable pathway for the development of high efficient photo-catalyst. Further, alkyd resin based self-cleaning coating is formulated using 1% SDZO Nps as pigment along with other additives; the contents are milled to form a homogeneous mixture by high energy ball milling technique. Crystal violet solution coated over dried alkyd coating gets decolorized on exposure to sunlight indicating the mineralization of pollutants and proves the fact that the as obtained coating possess self-cleaning nature. Besides the self-cleaning property, the coating exhibits self-refreshing property which is essential for the long lasting self-cleaning activity. Further, the disinfectant properties of 1% SDZO Nps and 1% SDZO Nps impregnated coating have been evaluated against gram negative Escherichia coli bacterial strain. The acquired experimental outcomes suggest the potential use of self-cleaning coating to keep the environment clean and hygienic economically. [ABSTRACT FROM AUTHOR]

Antimicrobial films based on distinct polymer matrices, poly (vinyl alcohol) (PVA) or poly (N-isopropylacrylamide) (PNIPAAm), and silver nanoparticles (AgNPs) immobilized onto cellulose nanowhiskers (CWs) were successfully prepared by either casting or electrospinning. CWs were first functionalized with carboxylate groups (labeled as CWSAc) and later they were immersed in a silver nitrate solution (AgNO 3 ). After Ag + ions anchored in the COO − groups are chemically reduced to produce AgNPs. The CWSAc/AgNPs biological activity was evaluated against Staphylococcus aureus ( S. aureus ), Bacillus Subtilis ( B. subtilis ), Escherichia coli ( E. coli ), and Candida albicans ( C. albicans ). The materials were more effective against C. albicans that showed a MIC of 15.6 µg/mL. In the process of AgNPs synthesis, the activity of the stabilizing agent (gelatin) and concentration of precursor and reducing agents were evaluated. The synthesized polymeric films displayed good antimicrobial activity against S. aureus , E. coli, and Pseudomonas aeruginosa ( P. aeruginosa ) bacteria. The PVA films with CWSAc/AgNPs showed diameter of the inhibition halo of up to 11 mm. The results obtained displayed that the films obtained have a potential application to be used in different fields such as packaging, membrane filtration, wound dressing, clothing and in different biomedical applications. [ABSTRACT FROM AUTHOR]

A facile and environmentally friendly approach was proposed to decorate Ag nanoparticles on melamine-formaldehyde (MF) colloidal particles (MF/Ag composite microspheres). In this approach, monodisperse MF colloidal particles were prepared via a two-step organic sol-gel process and served as the active templates for the decoration of Ag nanoparticles. Then, the [Ag(NH 3 ) 2 ] + ions as the Ag precursors can be adsorbed onto the surfaces of the MF colloidal particles and were in situ reduced into metallic Ag nanoparticles, forming MF/Ag composite microspheres. During this synthesis, neither presurface activation nor extra reductants were necessary. These MF/Ag composite microspheres can be used as the surface-enhanced Raman scattering (SERS) active substrates for the trace detection of organic compounds, e.g., 4-aminobenzenethiol (4-ABT) and penicillin G sodium. Furthermore, these MF/Ag composite microspheres also showed excellent antibacterial activities against both Escherichia coli ( E. coli , gram-negative bacteria) and Staphylococcus aureus ( S. aureus, gram-positive bacteria). [ABSTRACT FROM AUTHOR]

Abstract The wide use of Ag nanoparticles (Ag NPs) as antimicrobial agents has resulted in a massive release of Ag NPs into environment, such as water and soil. As bryophytes live ubiquitously in water and soil, their tolerance and response to Ag NPs could be employed as an indicator for the harm of Ag NPs to the environment. Herein, we report the study on the physiological and biochemical responses of bryophytes to Ag NPs with different surface coatings at the gametophyte stages: protonema and leafy gametophyte, by using Physcomitrella patens as a model system. We found that Ag NPs, including AgNPs-B (Ag NPs without surface coating), AgNPs-PVP (Ag NPs coated with poly (N -vinyl-2-pyrrolidone)) and AgNPs-Cit (Ag NPs coated with citrate), were toxic to P. patens in terms of growth and development of the gametophyte. The toxicity was closely related to the concentration and surface coating of Ag NPs, and the growth stage of P. patens. The protonema was more sensitive to Ag NPs than the leafy gametophyte. Ag NPs inhibited the growth of the protonema following the trend of AgNPs-B > AgNPs-Cit > AgNPs-PVP. Ag NPs changed the thylakoid and chlorophyll contents, but did not affect the contents of essential elements in the protonema. At the leafy gametophyte stage, Ag NPs inhibited the growth of P. patens following a different order: AgNPs-Cit > AgNPs-B ≈ AgNPs-PVP. Ag NPs decreased the chlorophyll b content and disturbed the balance of some important essential elements in the leafy gametophytes. Both the dissolved fraction of Ag NPs and Ag NPs per se contributed to the toxicity. This study for the first time reveals the effects of Ag NPs on bryophytes at different growth stages, which calls for more attention to the nanoecotoxicology of Ag NPs. Highlights • Ag NPs inhibited the growth of P. patens. • The protonema was more sensitive to Ag NPs than the leafy germetophyte. • Ag NPs inhibited the growth of the protonema: AgNPs-B > AgNPs-Cit > AgNPs-PVP. • Ag NPs inhibited the growth of the leafy germetophyte: AgNPs-Cit > AgNPs-B≈AgNPs-PVP. • Both dissolution and particulate of Ag NPs contributed to the toxicity. [ABSTRACT FROM AUTHOR]

Catalyst immobilization is of much significance not only for maintaining the high activity of the ultrafine catalyst, but also for the separation of catalyst during the practical application. Herein, a novel support material, three-dimensional hierarchically porous silica (HPS) with interconnected micro-meso-macro pores and high specific surface area was successfully fabricated though a freeze-drying technique in the presence of poly(vinyl alcohol) (PVA) and subsequent calcination process. A series of characterizations revealed that the specific surface area of HPS can be well adjusted by changing the addition of PVA. The specific surface area of HPS was as high as 360 m 2  g −1 , which was 211-fold higher than HPS-0 (silica prepared without using PVA). To demonstrate the potential application of such novel support material, highly dispersed silver nanoparticles (AgNPs) were immobilized on the surfaces of HPS and HPS-0 through in-situ reduction. By contrast, the catalytic activity of AgNPs anchored on HPS (531 s −1  g −1 ) was about 42-fold higher than that of AgNPs anchored on HPS-0 (12.67 s −1  g −1 ). The significantly enhanced catalytic activity of AgNPs/HPS was believed to be related to their high specific surface area and interconnected macroporous scaffolds, which could provide numerous reactive sites and mass transfer routes for the reactants. [ABSTRACT FROM AUTHOR]

Silver iodide nanowires have been grown within tubular J-aggregates of the cyanine dye 3,3′-bis(2-sulfopropyl)-5,5′,6,6′-tetrachloro-1,1′-dioctylbenzimida-carbo-cyanine (C8S3) from aqueous AgNO 3 solutions. Crystal structure analysis by selected area electron diffraction (SAED), high resolution transmission electron microscopy (HRTEM) and energy-dispersive X-ray spectroscopy (EDXS) of single nanowires revealed that they are of silver iodide (AgI), while previously they were presumed to be of metallic silver. Iodine has not been added intentionally, but it is a remnant from the chemical synthesis of the dye and present in a dye:iodine ratio of almost 2:1, as revealed by inductively coupled plasma mass spectrometry (ICP-MS). The AgI wires grow as single crystals with lengths of several 10–100 nm and width of 6.5 ± 0.5 nm. The width and the orientation of the crystal relative to the aggregate axis are defined by the tubular structure of the templating dye aggregate. Caused by the nucleation at the tube wall the main growth is not along the usually preferred [0 0 0 1] direction but along the extension of the basal plane, which is furthermore tilted by an angle of 6° ± 2° against the main axis of the aggregate. This self-assembled system represents an organic-inorganic hybrid system with a well-defined semiconductor nanowire, AgI, that is strictly oriented with respect to the aggregated phase of conjugated molecules. [ABSTRACT FROM AUTHOR]

Silver nanoparticles (AgNPs) have been reported to inhibit specification and differentiation of erythroid cells, chromatophores, and myofibrils during zebrafish embryogenesis. However, the knowledge of biological effects of AgNPs on eye development, especially on lens development is scarce. In this study, embryos were exposed to or injected with 0.4 mg/L AgNPs, and the results indicate that no obvious morphological changes in eye formation were observed in the stressed embryos compared to the controls. However, clefts and vacuoles were observed in lens of embryos from AgNPs stressed group. Additionally, the down-regulated expressions of different lens crystallin isoform genes and the normal expression of retinal genes were observed in AgNPs stressed embryos, suggesting AgNPs might inhibit the development of lens rather than the development of retina in zebrafish embryos. Moreover, no obvious cell apoptosis was observed, but normal nuclear DNA and RNA export was observed in lens cells. Together, the data in this study reveal that AgNPs damage the development of lens rather than retina resulting in eye abnormalities via some unknown mechanisms rather than via triggering cells apoptosis or blocking nuclear DNA or RNA export. [ABSTRACT FROM AUTHOR]

With increasing presence of silver nanoparticles (AgNPs) into the environment, the chronic and low-dose effects of AgNPs are of vital concern. This study evaluated chronic physiological effects of AgNPs on Daphnia similis , which were exposed to two ambient encountered concentrations (0.02 and 1 ppb) of AgNPs for 21 days. It was observed that the low-dose AgNPs stimulated a significant increase in average length/dry mass, but inhibited reproduction compared to control specimens. Non-targeted metabolomics based on liquid chromatography-quadrupole-time of flight-mass spectrometry (LC-QTOFMS-MS) and gas chromatograph-quadrupole time of flight mass spectrometry (GC-QTOF-MS) were utilized to elucidate the underlying molecular mechanisms of these responses. Forty one metabolites were identified, including 18 significantly-changed metabolites, suggesting up regulation in protein digestion and absorption (amino acids, such as isoleucine, tryptophan, lysine, leucine, valine, aspartic acid, threonine, tyrosine) and down regulation of lipid related metabolism (fatty acids, such as arachidonic acid, stearidonic acid, linoelaidic acid and eicosapentaenoic acid) were key events in these responses. The increase in these amino acid contents explains the accelerated growth of D. similis from the metabolic pathway of aminoacyl-tRNA biosynthesis. Down regulation of fatty acid contents corresponds to the observed drop in the reproduction rate considering the fatty acid biological enzymatic reaction pathways. Significant changes in metabolites provided a renewed mechanistic understanding of low concentration chronic toxicity of AgNP toxicity on D. similis . [ABSTRACT FROM AUTHOR]

Abstract Food plants Hungarian wax pepper (HWP) and Green Bell pepper (GBP), belonging to Capsicum annuum were utilized for biogenic fabrication of zero valent, nano-silver (AgNPs) through a photo-mediation procedure. In the bacterial strains evaluated, HWP/GBP AgNPs demonstrated effective bacteriostatic and bactericidal effect against Staphylococcus aureus. Time kill results portrayed that HWP/GBP nano-silver exhibited comparable bactericidal potency on S. aureus. Anti-biofilm potential of HWP/GBP AgNPs displayed significant effects at sub MIC levels, by triggering 50% biofilm reduction of the food spoilage microbe S. aureus , inferring that the anti-biofilm outcome is not dependent on antibacterial result, and this was confirmed by SEM and fluorescence studies. Histopathological analyses of S. aureus infected zebrafish liver did not display any abnormality changes such as extensive cell death and degeneration, upon treatment with HWP/GBP AgNPs and the zero-valent silver nanoparticles were comparatively less toxic and more operative in restraining the bioburden in S. aureus infected zebrafish model by a >1.7 log fold. Ability of light reduced HWP/GBP AgNPs to alleviate the in vitro and in vivo planktonic mode of growth and curb the biofilm formation of S. aureus is also demonstrated. Graphical abstract Image 1 Highlights • Hungarian wax pepper (HWP) and Green Bell pepper (GBP) capped silver nanoparticles were synthesized and characterized. • Studies from time kill revealed AgNPs displayed comparable bactericidal effect against Staphylococcus aureus. • Fluorescent imaging and SEM imaging demonstrated that the AgNPs were effective at sub MIC concentrations in causing 50% biofilm inhibition against Staphylococcus aureus. • HWP/GBP AgNPs were also relatively less toxic as per enzymatic assay and effective in curtailing bioburden of Staphylococcus aureus in infected zebrafish by > 1.7 log fold. • Histopathological analyses of zebrafish liver indicates no extensive cell death and degeneration when treated with HWP/GBP AgNPs. [ABSTRACT FROM AUTHOR]

Abstract Green synthesis of silver nanoparticles (AgNPs) is environmentally satisfactory because of their low cost and safe to nature. In the present study, extract of an agricultural waste, coconut (Cocos nucifera) shell is used to synthesize AgNPs and their antibacterial effect was investigated against selected human pathogens Staphylococcus aureus, Listeria monocytogenes, Escherichia coli, Salmonella typhimurium. The AgNPs synthesized using coconut shell extract (CSE-AgNPs) were characterized using UV–Visible spectroscopy (absorption peak at 432 nm), Transmission Electron Microscopy (spherical shaped particles size of 14.2–22.96 nm), Fourier-Transform Infrared Spectroscopy indicating the CSE capping around the AgNPs (Peaks 1384, 1609 and 3418 corresponds to organic molecules) and X-Ray Diffraction (Peak at 32.078 and 2-Theta). CSE-AgNPs exhibited zone of inhibition against S. aureus (15 mm), E. coli (13 mm), S. typhimurium (13 mm) and L. monocytogenes (10 mm) and minimum inhibitory concentration (MIC) of 26, 53, 106 and 212 μg/ml, respectively. Growth curve assay showed the effectiveness of CSE-AgNPs to inhibit the selected pathogens when compared to amphicillin control and extract. Scanning electron microscopy results indicated that the cell wall degradation might be the possible mechanism of antibacterial action of CSE-AgNPs. Different concentrations of AgNPs (0.078–2.5 mg/ml) showed no toxicity against human PBMC cell line. Hence, such highly effective CSE-AgNPs could be explored as antibacterial agent. Highlights • First time we have reported the use of agricultural waste (coconut shell) for the green synthesis of silver nanoparticles. • Nanocharacteristics of AgNPs were confirmed by using UV-VIS spectroscopy, TEM, FTIR and XRD. • Antibacterial activity and cell wall degradation mechanism of CSE-AgNPs were shown against selected human pathogens. [ABSTRACT FROM AUTHOR]

Abstract The present study is focused on the synthesis of silver nano particles (Ag NPs) using an aqueous extract of the whole plant of Sida cordifolia as a potential bio-reducing agent and assessment of their antibacterial activity. UV–Vis spectroscopy of composed silver colloidal solution displayed surface Plasmon resonance peak at 420 nm. XRD and TEM analysis revealed the morphology as ultra-small, monodispersed spherical nanoparticles with face-centered cubic structure and mean particle size of 3–6 nm. This ultra-small nano size might owe to the slow reaction time and phytochemicals existing in the S. cordifolia extract. The Ag NPs are trailed for antibacterial activity against 5 fish (Aeromonas hydrophila , Pseudomonas fluorescence , Flavobacterium branchiophilum, Edwardsiella tarda and Yersinia rukeri) and 4 human (Escherichia coli , Klebsiella pneumonia , Bacillus subtilis and Staphyloccocus aureus) bacterial pathogens. In all the cases, Ag NPs from Sida cordifolia plant extract manifested noteworthy antibacterial effects on par with positive control i.e.; Gentamicin. Highlights • First report on the biosynthesis of Ag NPs using Sida Cordifolia plant extract. • Ultra Small, Monodispersed Ag NPs using green Synthesis. • Act as a good antibacterial agent against various human and fish bacterial pathogens. • Ag NPs were characterized with UV–Vis, XRD, SEM and TEM. [ABSTRACT FROM AUTHOR]

There is considerable interest in understanding the catalytical, antibacterial, and photo-thermal properties of Ag nanoparticles. Herein, a simple, scalable and effective method is explored to generate Ag nanoclusters (∼3.57 nm) directly on reduced graphene oxide (rGO) (denoted as AgNC/GSH-rGO) using glutathione (GSH) as a green and mild co-reduction agent. Due to the good electrical conductivity of rGO, the extremely small particle size of Ag nanoclusters and the synergistic effect between Ag nanoclusters and rGO, high catalytic activity for reduction of 4-nitrophenol is achieved for AgNC/GSH-rGO at a very low Ag nanoclusters loading of 8.67 wt% on rGO. The conversion could reach 96.69% in 16 min and the apparent rate constant based on rGO is derived to be 0.55 min −1 when the concentration of AgNC/GSH-rGO is 0.04 mg mL −1 . Moreover, the AgNC/GSH-rGO nanohybrids are also proven to be an efficient antibacterial and photothermal ablation agent for avoiding wound infection and cancer therapy applications. [ABSTRACT FROM AUTHOR]

With the aim of exploring and modulating the interfacial charge kinetics, a ternary g-C 3 N 4 /Ag/BiVO 4 was constructed with excellent photocatalytic performance and preferable stability toward H 2 evolution in absence of cocatalyst. Both density functional theory (DFT) and experimental results implied that the type II g-C 3 N 4 /BiVO 4 composite can be switched to Z-scheme via Ag nanoparticles as the electron shuttle. The optimal photocatalytic H 2 yield rate achieved for g-C 3 N 4 /Ag/BiVO 4 was 57.4 µmol·g −1 ·h −1 , being far surpassed the H 2 harvest rate of g-C 3 N 4 /BiVO 4 , Ag/g-C 3 N 4 and g-C 3 N 4 , which is 2.9, 14.8 and 1.7 µmol·g −1 ·h −1 , respectively. The apparent quantum efficiency of g-C 3 N 4 /Ag/BiVO 4 photocatalyst was also determined to be 1.23%. Besides, the photocatalytic performance of g-C 3 N 4 /Ag/BiVO 4 well preserved over 5 runs in 50 h. The improved H 2 production performance is considered as the consequence of promoted segregation of photoexcited charge carriers and SPR effects of Ag nanoparticles. In combination with photocurrent measurement, examination of active species and DFT calculation, it is found that Ag nanoparticles as an electron mediator can highly promote the Z-scheme carrier migration that electrons come from conduction band of BiVO 4 will quickly assemble with the photo-induced holes from valence band of g-C 3 N 4 , leaving electrons in the conduction band of g-C 3 N 4 and holes in valence band of BiVO 4 that could greatly enhance the charge separation efficiency. [ABSTRACT FROM AUTHOR]

The prime aim of this research is to discover new, eco-friendly approaches to reducing agents for manufacturing silver nanoparticles (AgNPs) from fresh fruiting bodies of the edible mushroom Hypsizygus ulmarius (Hu). The confirmation of Hu-mediated AgNPs has been characterized by UV visible spectroscopy, XRD, FTIR, SEM with EDX, HRTEM, AFM, PSA, Zeta poetical and GCMS analysis. The absorption peak of Hu-AgNPs at 430 nm has been confirmed by UV–visible spectroscopy analysis. The findings of the particle size study show that AgNPs have a size distribution with an average of 20 nm. The Zeta potential of NPs reveals a significant build-up of negative charges on their surface. The additional hydrate layers that occurred at the surface of AgNPs are shown in the HR-TEM morphology images. The antibacterial activity results showed that Hu-AgNPs were highly effective against both bacterial pathogens, with gram-positive (+) and gram-negative (−) pathogens having a moderate inhibition effect on K. pneumoniae (5.3 ± 0.3 mm), E. coli (5.3 ± 0.1), and S. aureus (5.2 ± 0.3 mm). Hu-AgNPs (IC 50 of 50.78 μg/mL) were found to have dose-dependent cytotoxic action against human lung cancer cell lines (A549). Inhibited cell viability by up to 64.31% after 24 h of treatment. To the best of our knowledge, this is the hand information on the myco-synthesis of AgNPs from the H. ulmarius mushroom extract and the results suggest that it can an excellent source for developing a multipurpose and eco-friendly nano product in future. • We successfully synthesized AgNPs from Hypsizygus ulmarius mushroom extract. • We noticed the best particles size of Hu-AgNPs formed at 20 nm. • Hu-AgNPs expressed moderate antibacterial effects. • Hu-AgNPs have a strong anticancer effect against A549 cells. • The bioactive molecules were identified by GC-MS analysis of H. ulmarius. [ABSTRACT FROM AUTHOR]

The current study investigates the potential utilization of poultry intestines for the synthesis of stable silver nanoparticles (AgNPs) and their impact on fish physiology. The AgNPs were synthesized and characterized using various analytical techniques. The toxicity of AgNPs on Anabas testudineus was evaluated, determining a 96-h LC 50 value of 25.46 mg l−1. Subsequently, fish were exposed to concentrations corresponding to 1/10th, 1/25th, 1/50th, and 1/100th of the estimated LC 50 for a duration of 60 days in a sub-acute study. A comprehensive range of biomarkers, including haematological, serum, oxidative stress, and metabolizing markers, were analyzed to assess the physiological responses of the fish. Additionally, histopathological examinations were conducted, and the accumulation of silver in biomarker organs was measured. The results indicate that silver tends to bioaccumulate in all biomarker organs in a dose- and time-dependent manner, except for the muscle tissue, where accumulation initially increased and subsequently decreased, demonstrating the fish's inherent ability for natural attenuation. Analysis of physiological data and integrated biomarker responses reveal that concentrations of 1/10th, 1/25th, and 1/50th of the LC 50 can induce stress in the fish, while exposure to 1/100th of the LC 50 shows minimal to no stress response. Overall, this study provides valuable insights into the toxicity and physiological responses of fish exposed to poultry waste biosynthesized AgNPs, offering potential applications in aquaculture while harnessing their unique features. [Display omitted] • Successfully synthesized stable, capped, and non-agglomerated AgNPs using poultry waste dispensing with toxic chemicals. • Median lethal concentration of AgNPs on Anabas testudenius is estimated as 25.46 mg l−1. • Increased concentrations and prolonged exposure to AgNPs led to higher toxicity in fish. • AgNPs get bioaccumulated in various biomarker organs, except for muscle, indicating a natural detoxification mechanism. • AgNPs at a concentration of 0.25 mg l−1 show minimal to no adverse effects on fish physiology. [ABSTRACT FROM AUTHOR]

Biosynthesis of silver nanoparticles (AgNPs) by plant extracts and its antibacterial utilization has attracted great attention due to the spontaneous reducing and capping capacities of phytochemicals. However, the preferential role and mechanisms of the functional phytochemicals from different plants on AgNPs synthesis, and its catalytic and antibacterial performance remain largely unknown. This study used three widespread arbor species, including Eriobotrya japonica (EJ), Cupressus funebris (CF) and Populus (PL), as the precursors and their leaf extracts as reducing and stabilizing agents for the biosynthesis of AgNPs. A total of 18 phytochemicals in leaf extracts were identified by ultra-high liquid-phase mass spectrometer. For EJ extracts, most kinds of flavonoids participated in the generation of AgNPs by a reduced content of 5∼10%, while for CF extracts, about 15∼40% of the polyphenols were consumed to reduce Ag+ to Ag0. Notably, the more stable and homogeneous spherical AgNPs with smaller size (≈38 nm) and high catalytic capacity on Methylene blue were obtained from EJ extracts rather than CF extracts, and no AgNPs were synthesized from PL extracts, indicating that flavonoids are superior than polyphenols to act as reducer and stabilizer in AgNPs biosynthesis. The antibacterial activities against Gram-positive (Staphylococcus aureus and Bacillus mycoides) and Gram-negative bacteria (Pseudomonas putida and Escherichia coli) were higher in EJ-AgNPs than that in CF-AgNPs, which confirmed the synergistic antibacterial effects of flavonoids combined with AgNPs in EJ-AgNPs. This study provides a significant reference on the biosynthesis of AgNPs with efficient antibacterial utilization underlying effect of abundant flavonoids in plant extracts. [Display omitted] • Flavonoids are superior stabilizers to polyphenols for green synthesis of AgNPs. • Eriobotrya japonica leaf extract can act as reducer and stabilizer in AgNPs synthesis. • Flavonoids within synthesized AgNPs show synergistic effect on antibacterial activity. • Dominant phytochemicals in synthesis and stabilization of AgNPs vary with plants. [ABSTRACT FROM AUTHOR]

In this study, we synthesized silver nanoparticle-loaded cashew nut shell activated carbon (Ag/CNSAC). The synthesized samples were characterized by XRD, XPS, SEM with EDS, FT-IR, and BET analysis. The XRD, XPS, and EDS data provided convincing proof that Ag loaded on CNSAC is formed. The energy dispersive spectrum analysis and X-ray diffraction pattern both supported the face-centered cubic and amorphous structures of Ag/CNSAC. The SEM micrographs showed the inner surface development of Ag NPs and many tiny pores in CNSAC. The photodegradation of methylene blue (MB) dye by the Ag/CNSAC photocatalyst was investigated. This effective degradation of MB dye by Ag/CNSAC is attributed to the cooperative action of Ag as a photocatalyst and CNSAC as a catalytic support and adsorbent. In tests with gram-positive and negative bacteria including Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus) , the as-synthesized Ag/CNSAC showed outstanding antibacterial efficiency. Additionally, this study demonstrates a workable procedure for creating an affordable and efficient Ag/CNSAC for the photocatalytic eradication of organic contaminants. • Silver loaded cashew nut shell activated carbon (Ag/CNSAC) was synthesized from waste cashew nut shell. • The specific surface area of Ag/CNSAC was determined as 271.5 m2/g by BET analysis. • The photodegradation efficiency of Ag/CNSAC is improved (98.3%) compared to the CNSAC sample. • The produced Ag/CNSAC showed antibacterial activity against both of E. coli and S. aureus bacteria. [ABSTRACT FROM AUTHOR]

This study demonstrates the green, rapid and simple synthesis of silver nanoparticles (AgNPs) by employing bio-flavonoid (quercetin), which acts as a stabilizing and reducing agent. The nanoparticles were prepared by a simple one pot method. AgNPs were characterized by using various characterization techniques like High-resolution transmission electron microscopy (HRTEM), Ultraviolet-visible spectroscopy (UV–visible), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR) and Field emission scanning electron microscopy (FESEM) with energy dispersive spectrometry (EDS). Later on, these nanoparticles were further used to construct the electrochemical sensing electrode and also for the precise and sensitive determination of chloramphenicol (CAP) antibiotic using cyclic voltammetry (CV) and linear sweep voltammetry (LSV). The fabricated sensor exhibits outstanding electrochemical performance, with a linear response for CAP concentrations between 0 μM to 80 μM and a limit of detection (LOD) of 265.6 nM. Further, the present sensor displayed impressive selectivity, reproducibility and high sensitivity. The designed sensor was deployed for the detection of CAP in real samples (water, milk and honey) to demonstrate its ability to perform real-time analysis with a satisfactory recovery rate. The results of real sample analysis using LSV were compared with the standard method (HPLC) and found comparable. Hence, the developed electrochemical sensor displayed great potential for detecting CAP in real samples with desirable recovery rates. • One-pot synthesis of silver nanoparticles. • Green, simple and impressive chloramphenicol detection upto nM level. • The AgNPs modified electrode exhibits sensitive and selective detection of CAP. • Chloramphenicol was successfully detected in real samples with sensitivity. [ABSTRACT FROM AUTHOR]

The present study evaluates the biocompatibility of silver and zinc oxide nanoparticles with various effective microorganisms (EM), like beneficial microbial formulations. The respective nanoparticle was synthesised by chemical reduction of metal precursor with reducer via simple route green technology principles. The synthesised nanoparticles were characterised by UV visible spectroscopy, scanning electron microscopy (SEM), and X-ray diffraction (XRD) studies, revealing highly stable, nanoscale particles with marked crystallinity. EM-like beneficial cultures composed of viable cells of Lactobacillus lactis , Streptomyces sp, Candida lipolytica , and Aspergillus oryzae were formulated with rice bran, sugarcane syrup, and groundnut cake. The respective formulation was inoculated into the nanoparticles amalgamated pots raised with green gram seedlings. Biocompatibility was determined by measuring plant growth parameters of a green gram at pre-determined periods associated with enzymatic antioxidants like catalase (CAT), superoxide dismutase (SOD), and glutathione S transferase (GST) levels. Most significantly, the expression level of these enzymatic antioxidants level was also investigated by quantitative real-time polymerase chain reaction (qRT-PCR). The impact of the soil conditioning effect on soil nutrients like nitrogen, phosphorous, potassium, organic carbon, soil enzymes glucosidases, and β-xylosidases activity was also studied. Among the formulation, rice bran-groundnut cake-sugar syrup formulation recorded the best biocompatibility. This formulation showed high growth promotion, soil conditioning effect and no impact on the oxidative stress enzymes genes that revealed the best compatibility of nanoparticles. This study concluded that biocompatible, eco-friendly formulations of microbial inoculants could be used for the desirable agro active properties that show extreme tolerance or biocompatibility to the nanoparticles. This present study also suggests the utilisation of the above said beneficial microbial formulation and metal-based nanoparticles with desirable agro active properties in a synergistic manner due to their high tolerance or compatibility towards the metal or metal oxide nanoparticles. • Mixed microbial beneficial cultures were formulated with biocompatible agro-based ingredients. • Toxic effect of silver and zinc oxide nanoparticles on the respective formulation was evaluated. • Ricebran - sugar syrup - groundnut cake formulation exhibited the best compatibility with the nanoparticles. • The formulation did not affect plant growth promotion associated with the soil conditioning effect. • No sign of oxidative stress markers or expression induction, revealing notable compatibility. [ABSTRACT FROM AUTHOR]

The alarming impact of antibiotic resistance sparked the quest for complementary treatments to overcome the confrontation over resistant pathogens. Metallic nanoparticles, especially silver nanoparticles (Ag NPs) have gained a much attention because of their remarkable biological characteristics. Moreover, their medicinal properties can be enhanced by preparing the composites with other materials. This article delves a comprehensive review of biosynthesis route for Ag NPs and their nanocomposites (NCs) with in-depth mechanism, methods and favorable experimental parameters. Comprehensive biological features Ag NPs such as antibacterial, antiviral, antifungal have been examined, with a focus on their potential uses in biomedicine and diagnostics has also been discussed. Additionally, we have also explored the hitches and potential outcomes of biosynthesis of Ag NPs in biomedical filed. [Display omitted] • Delves a comprehensive review of biosynthesis route for Ag NPs and their nanocomposites (NCs) with in-depth mechanism. • Various biological applications such as antibacterial, antiviral, antifungal, anticancer has been discussed. • Explored potential challenges and outcomes of biosynthesis of Ag NPs in biomedical filed. [ABSTRACT FROM AUTHOR]

The bio-based nanoparticles synthesis and assessment of their potential biomedical applications related research is rapidly emerging. The ability of an aqueous ethanolic bark extract of Mangifera indica to synthesize silver nanoparticles (AgNPs) as well as its antibacterial, anti-inflammatory, and anticancer activities were investigated in this study. Interestingly, the bark extract effectively synthesized the AgNPs, including an absorbance peak at 412 nm and sizes ranging from 56 to 89 nm. The Fourier Transform Infrared spectroscopy (FTIR) analysis confirmed that the presence of most essential functional groups belongs to the most bioactive compounds. Synthesized AgNPs showed fine antibacterial activity against the Urinary Tract Infection (UTI) causing bacterial pathogens such as Escherichia coli, Enterococcus faecalis, Klebsiella pneumoniae, Proteus mirabilis, and Staphylococcus saprophyticus at 50 μg mL−1 concentrations. The minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of AgNPs against these pathogens were found as 12.5 ± 0.8 & 13 ± 0.6, 13.6 ± 0.5 & 14 ± 0.7, 11.5 ± 0.3 & 11.5 ± 0.4, 13 ± 0.8 & 13 ± 0.7, and 11.8 ± 0.4 & 12 ± 0.8 μg mL−1 respectively. Interestingly, this AgNPs also possesses outstanding anti-inflammatory and anticancer activities as studied against the egg albumin denaturation (85%) inhibition and MCF 7 (Michigan Cancer Foundation-7: breast cancer cells) cell line (cytotoxicity: 80.1%) at 50 μg mL−1 concentration. Similarly at 50 μg mL−1 concentration showed 75% of DPPH radical scavenging potential. These activities were dose dependent, and the findings suggest that the M. indica bark aqueous ethanolic extract synthesized AgNPs can be used as antibacterial, anti-inflammatory, and anticancer agents after in-vivo testing. • Mangifera indica bark aqueous ethanolic extract effectively synthesize the AgNPs. • Synthesized AgNPs were spherical in shape with size ranged from 56 to 89 nm. • AgNPs had considerable antibacterial activity against UTI causing bacterial pathogens. • Bark extract synthesized AgNPs also possesses fine anti-inflammatory activity. • AgNPs have remarkable anticancer activity (cytotoxicity) against MCF 7 cell line. [ABSTRACT FROM AUTHOR]

Nanomaterials have been produced with the use of bio-nanotechnology, which is a low-cost approach. Currently, research is being conducted to determine whether actinomycetes isolated from Egyptian soil can biosynthesize Ag nanoparticles (Ag NPs) and characterized by using the following techniques: Transmission electron microscopy (TEM), Dynamic light scattering (DLS), Fourier transforms infrared (FT-IR), Energy-dispersive X-ray spectroscopy (EDX), UV–Vis spectroscopy and X-ray diffraction (XRD). The most promising actinomycetes isolate were identified, morphologically, biochemically, and molecularly. Streptomyces avermitilis Azhar A.4 was found to be able to reduce silver metal nanoparticles from silver nitrate in nine isolates collected from Egyptian soil. Toxicity of biosynthesized against 2nd and 4th larval instar of Agrotis ipsilon (Hufn.) (Lepidoptera: Noctuidae) was estimated. In addition, activity of certain vital antioxidant and detoxifying enzymes as well as midgut histology of treated larvae were also investigated. The results showed appositive correlations between larval mortality percentage (y) and bio-AgNPs concentrations (x) with excellent (R2). The 4th larval instar was more susceptible than 2nd larval instar with LC 50 (with 95% confirmed limits) =8.61 (2.76–13.89) and 26.44(13.25–35.58) ppml−1, respectively of 5 days from treatment. The initial stages of biosynthesized AgNps exposure showed significant increases in carboxylesterase (CarE) and peroxidases (PODs) activity followed by significant suppression after 5 days pos-exposure. While protease activity was significantly decreased by increasing time post-exposure. Midgut histology showed abnormality and progressive damage by increasing time post exposure leading to complete destruction of midgut cells after 5 days from exposure. These results make biosynthesized AgNPs an appropriate alternative to chemical insecticide in A. ipsilon management. [Display omitted] • Isolation and identification of actinomycetes strain from soil samples and examination their potential as biosynthesis. • Study the toxicity impact of Ag nanoparticles on the black cutworm A. ipsilon larvae. • Determination of physiological changes in some antioxidant and detoxification enzymes of black cutworm A. ipsilon. • Finally, investigation of the changes in midgut histology of the black cutworm after its exposure to Ag nanoparticles. [ABSTRACT FROM AUTHOR]

Rice husk ash (RHA) is a widely discarded agricultural by-product, leading to environmental and health concerns due to its low density. In this study, we employed a hydrothermal reaction coupled with univariate and multi-parameter response surface method optimization to extract silicon, the key component, and prepare mesoporous silica (mSiO 2) from RHA. Furthermore, silver nanoparticles (Ag-NPs) were synthesized in situ in the pores of mSiO 2 to prepare mSiO 2 @Ag nanocomposites. The morphology, structure and composition of the prepared mSiO 2 @Ag were characterized using TEM, FT-IR, UV–Vis and XRD. To evaluate their antibacterial properties, Staphylococcus aureus and Escherichia coli were employed as model strains. The results revealed that the average particle size of the prepared mSiO 2 and mSiO 2 @Ag nanocomposites were 98 nm (PDI = 0.023) and 278 nm (PDI = 0.062), respectively. The FT-IR and XRD analysis confirmed the presence of SiO 2 , Ag, and Ag 2 O characteristic peaks. The specific surface area and pore diameter of the mSiO 2 were measured as 305 m2/g and 4 nm, respectively, whereas those of the mSiO 2 @Ag were significantly reduced. Remarkably, the mSiO 2 @Ag exhibited notable antibacterial activity, with MIC of 150 μg/mL and 200 μg/mL against S. aureus and E. coli , respectively. This research provides a novel avenue for the high-value utilization of RHA. [Display omitted] • Silicon from rice husk ash was extracted to prepare mesoporous silica (mSiO 2). • Ag@mSiO 2 nanocomposites were successfully prepared with in situ synthesis of silver nanoparticles in the pores of mSiO 2. • The prepared Ag@mSiO 2 nanocomposites have significant antibacterial activity. • The study provides methods for solving rice husk ash pollution and improving its reuse value. [ABSTRACT FROM AUTHOR]

Silver nanoparticles (Ag NPs) have well-known antibacterial properties and are widely applied in various medical products and general commodities. Although many studies have addressed the toxicity of Ag NPs to mammalian cells, the direct relationship between the number of Ag NPs in living cells and the corresponding cell toxicity has not yet been explicitly demonstrated. In this work, a simple and reusable microfluidic device composed of a quartz cover slip and a glass plate with etched micro-channel and micro-wells was employed for separating and trapping single living cells. The device was silanized to render the surface hydrophobic. For simplicity, HeLa cells as the model cancer cells were used in the study, which were pipette-loaded into an array of micro wells based on dead-end filling. Surface enhanced Raman spectroscopy (SERS) was then employed to examine the living cancer cells and assessed number and distribution of Ag NPs in the cells. Combined with the cell viability assay, we therefore correlated the number of Ag NPs in the cell with the toxicity to the cell directly. [ABSTRACT FROM AUTHOR]

Coal fly ash-derived zeolites have attracted considerable interest in the last decade due to their use in several environmental applications such as the removal of dyes and heavy metals from aqueous solutions. In this work, coal fly ash-derived zeolites and silver nanoparticles-impregnated zeolites (nanocomposites) were synthesized and characterized by TEM/EDX, SEM/EDX, XRD, XRF, porosimetry (BET), particle size analysis (PSA) and zeta potential measurements. The synthesized materials were used for the removal of Hg 2+ from aqueous solutions. The results demonstrated that nanocomposites can remove 99% of Hg 2+ , up to 10% and 90% higher than the removal achieved by the zeolite and the parent fly ash, respectively. Leaching studies further demonstrated the superiority of the nanocomposite over the parent materials. The Hg 2+ removal mechanism is complex, involving adsorption, surface precipitation and amalgamation. [ABSTRACT FROM AUTHOR]

The knowledge on the mode of action, biocompatibility and ecological tolerance of silver nanoparticles (AgNPs) is gradually accumulating over the years with contradictory findings. Most of the studies indicated the toxic impact of AgNPs on plant growth and development, where induction of oxidative stress was considered to be one of the causal factors. The present study demonstrates the phytostimulatory effect of bio-synthesized silver nanoparticles (AgNPs) during seed germination and seedling growth of rice ( Oryza sativa L., cv. Swarna) under in vitro condition. All the tested concentrations of AgNPs (10, 20, 40 ppm) promote both the shoot and root growth which was evident from the increased length and biomass of the seedlings. Exposure to AgNPs also significantly increased the chlorophyll a and carotenoid contents. The content and the pattern of distribution of phenolic metabolites among the different treatments are indicative of non-toxic impact of AgNP mimicking mild or no stress to the seedlings. Growth stimulation of rice seedlings by AgNPs was further supported by a low level of reactive oxygen species (ROS) concomitant with decreased amount of lipid peroxidation and H 2 O 2 content, compared to control. In order to unravel the stimulatory impact of AgNPs on rice seedling growth, the present study also describes the AgNPs induced changes in antioxidative enzyme activity and related gene expression levels. Elevated levels of catalase (CAT), ascorbate peroxidase (APX) and glutathione reductase (GR) activities were recorded in all the AgNPs treated seedlings with improved growth. The activity of superoxide dismutase (SOD) was not significantly altered at low concentration of AgNPs. It appears that enzymes of ascorbate cycle, APX and GR are more active in ensuring protection against oxidative damage than SOD. There was significant up-regulation of CAT and APX gene expressions in seedlings exposed to AgNPs, whereas the expression level of CuZnSOD gene was decreased gradually with an increase in the concentration of AgNPs. The antioxidant enzyme activities and gene expression patterns coupled with the levels of H 2 O 2 and lipid peroxidation indicates that the efficiency of redox reactions was increased in the presence of AgNPs and that accelerates the seedling growth. [ABSTRACT FROM AUTHOR]

Abstract Bacterial adhesion is a threshold event in the formation of biofilms which leads to serious bacterial diseases. This shows that the underlining the problem is interesting and need to solve the problem of biofilm-related complications. To support this, in the present study, we first time initiated to understand the role of methicillin-resistant Staphylococcus aureus (MRSA) biofilm using previously developed benzodioxane midst piperazine decorated chitosan silver nanoparticles (BP*C@AgNPs). The BP*C@AgNPs studied for antimicrobial, anti-biofilm, biofilm adherence inhibition, the role of ions in biofilm, and an antibiotic cocktail in the treatment of biofilm was assessed. The results showed that, the significant biocidal role of BP*C@AgNPs in controlling the MRSA biofilm and interaction of biofilm protein to calcium ions were significantly decreased. This confirms that calcium ion involved in the biofilm formation and for the treatment of BP*C@AgNPs, cocktail of enzyme and antibiotic have the promising therapeutic value was observed. In future the locking of biofilm protein and its expression in presence of calcium ion was interesting, and greater application related to biofilm infection was warrantable. Graphical abstract Image 1 Highlights • Synthesized BP*C@AgNPs acting as an antibiofilm candidate. • The biofilm of MRSA is Ca2+ and extracellular polysaccharide dependent. • Ruled out the cocktail of treatment beneficiary for the drug resistant pathogens. • Regulation of biofilm dependent protein in the Ca2+ presence, appreciate the future application in antibiofilm therapy. [ABSTRACT FROM AUTHOR]

Durable Ag-Fe 3 O 4 /Fe superhydrophobic surface (SHS) with dendritic structures on the galvanic sheet was obtained by chemical etching, deposition and following annealing process. The promising SHS showed fine superhydrophobicity having the water contact angle of 165° and dynamic sliding angle of 2°. Experimental results showed that the obtained SHS sample has excellent properties of anti-corrosion, catalysis, anti-icing, rolling-off and self-cleaning. The conditions of etching, chemical immersion, and annealing to obtain SHS were investigated. Chemical stability and durability of SHS were investigated via storage in air for ten months. The SHS as a catalyst showed long-term stability, catalytic activity, and reusability, as compared to the substrate of the un-annealed surface. It is an effortless and cheap method to fabricate SHS on the galvanic sheet for industrial applications. The SHS has a potential utilization in a diverse range of bio-medicines, chemistry, microfluidics fields, and electronics. [ABSTRACT FROM AUTHOR]

Herein, a catalytic mesh with unique wettability, high oil-water separation efficiency and excellent catalytic performance towards aromatic dyes was fabricated. Polypyrrole (PPy) was firstly pre-coated on pristine stainless-steel mesh (SSM) surface via cyclic voltammetry approach. Subsequently, a simple electrodeposition process was performed to prepare and anchor Ag nanoparticles (AgNPs) onto the PPy-coated SSM surface. The PPy-coated mesh with anchored AgNPs was denoted as PPy/AgNPs-coated SSM. The obtained PPy/AgNPs-coated SSM exhibited dual superlyophobic properties and were able to achieve on-demand separation to deal with various of light oil (ρ oil  < ρ water ) and heavy oil (ρ oil  > ρ water )-water mixtures. Importantly, benefitting from AgNPs on mesh surface, the obtained PPy/AgNPs-coated SSM exhibits exceptional catalytic activity. As proof-of-concept three typical aromatic dye molecules (methylene blue, rhodamine B and Congo red) can be effectivity degraded. Additionally, the degradation of aromatic dyes and oil-water separation were achieved simultaneously when the PPy/AgNPs-coated SSM was converted to water-removing mode. Therefore, the present work is of great significance to the development of novel oil-water filtration membranes and can open a new avenue towards the practicability of metal nanoparticle catalysts in wastewater treatment. [ABSTRACT FROM AUTHOR]

Abstract Silver nanoparticles (Ag-NPs) are increasingly being applied in many consumer products due to their unique properties. Widespread use of Ag-NPs leads to an increasing human exposure to Ag-NPs in many different pathways. This review summarized the toxicity mechanisms of Ag-NPs based on various environmentally relevant test species, such as bacteria, cells, plants, aquatic animals and mammals, in both in vitro and in vivo experiments. Nanoparticles were usually exposed to combination chemicals but to single chemicals in the environment and thereby exert combined toxicities to the organisms. Therefore, the joint effects of nanomaterials and their co-existing characteristics were also discussed. The current knowledge gaps and safe product designs of Ag-NPs have been discussed in detail. The limited and existing data implied that understanding the toxicity mechanisms is crucial to the future research development of nanomaterials. Highlights • Presented the possible human health hazards related to Ag-NPs exposure. • Identified the current research deficiencies in this area. • Summarized the underlying toxicity mechanisms. • Summarized the compound toxicity of NPs. [ABSTRACT FROM AUTHOR]

Abstract Silver is used in different applications that result in contact with skin and mucosal surfaces (e.g., jewelry, wound dressings, or eye drops). Intact skin poses an effective barrier against the absorption of silver. Mucosal surfaces are observed to be less effective barriers and compromised skin is often a poor barrier. Silver can deposit as particles in the human body causing a blue-gray discoloration known as argyria. Urine and feces are reported pathways of excretion. Acute human mortality has been observed following an abortion procedure involving the intrauterine administration of 7 g silver nitrate (64 mg silver/kg body weight). Localized argyria has been reported with exposure to silver ions, metallic surfaces, and nanocrystalline silver. Generalized argyria was observed with ionic and nanocrystalline silver in humans at cumulative doses in the range of 70–1500 mg silver/kg body weight. Silver is observed to have a low potential for skin irritation. Eye irritation and some cases of allergic contact dermatitis have been reported. Silver may cause genotoxicity, but additional data are required to assess its carcinogenic potential. Other reported toxicities include hepatic, renal, neurological, and hematological effects. Highlights • Silver is an ingredient in certain dermal and mucosal medical applications. • Silver can deposit in the body as particles causing a discoloration called argyria. • Silver seems to have a low potential for skin irritation. Eye irritation and allergic contact dermatitis have been reported. • Silver may cause genotoxicity, but additional data on its carcinogenic potential are required. [ABSTRACT FROM AUTHOR]

Abstract Metallic nanomaterials are utilized in an increasing number of applications in medicine and industry. Their general toxicity was tested in numerous reports both in vitro and in vivo but limited data exist on how nanomaterials affect the activity of cellular signaling pathways activated by growth factors and cytokines. The aim of the present work was to test the hypothesis predicting that silver, gold and superparamagnetic iron oxide nanoparticles may interfere with cellular signaling activated by tumor necrosis factor (TNF) and change the final cellular outcome of TNF action. Such interference may result in disruption of homeostasis and contribute to the development of malignancies such as cancer or autoimmune diseases. Experiments were performed on HepG2 and A549 cell lines. We did not observe any interaction between nanoparticles and TNF at the level of clonogenic growth, apoptosis/necrosis induction or cell cycle. At all these endpoints, the effects of TNF and nanoparticles were additive. In contrast, gene expression analysis revealed synergistic effects. A group of genes was significantly affected only by simultaneous treatment with TNF and nanoparticles and not by any of the factors alone. Observed synergistic effect on IL10 and IL8 expression seems to be of particular importance since these cytokines are often expressed by tumor cells to inhibit tumor-targeted immune response. The observed synergistic effects of TNF and nanoparticles on cytokines expression may have significant consequences for tissue homeostasis and tumor promotion and therefore should be taken into account during development of new nanoparticle-based anticancer therapies. Highlights • Nanoparticles can significantly modify response to TNF at transcriptional level. • AgNPs have synergistic effect on IL8 secretion by HepG2 cells after TNF treatment. • No interaction between NPs and TNF at the level of clonogenic growth. • No interaction between NPs and TNF at the level of apoptosis induction or cell cycle. [ABSTRACT FROM AUTHOR]

Abstract In the present article, the facile green synthesis of silver nanoparticles (AgNPs) using aqueous leaf extract of Enicostemma axillare (Lam.) has reported. This is a simple, cost-effective, stable for a long time and reproducible aqueous synthesis method to obtain a self-assembly Ag nanoparticles. The size and shape of Ag nanoparticles were characterized by XRD, TEM, and SEM-EDS. The formation and stability of the reduced silver nanoparticles in the colloidal solution were monitored by UV–Vis spectrophotometer analysis. Zeta potential was confirmed by DLS study. The mean particle diameter of silver nanoparticles was calculated from the TEM, SEM and the size of the particles was measured between 15 and 20 nm. TEM analysis revealed the spherical shape of the particles. Crystalline nature of the nanoparticles in the face-centred cubic structure are confirmed by the peaks in the XRD pattern corresponding to (111), (200), (220) and (311) planes. This study showed the biogenic, environmentally friendly and cost-effective synthesis and characterization of the silver nanoparticles. Graphical abstract Graphical abstract for synthesis of AgNPs and their characterization. Image Highlights • Green synthesis of AgNPs is using Enicostemma axillare. • Characterization of AgNPs was done by TEM, SEM and XRD. • The synthesized AgNP solution was stable for more than two months. • The method was eco-friendly, benign and cost-effective. [ABSTRACT FROM AUTHOR]

In this study, we have prepared silver nanoparticles deposited cellulose microfibers (Ag-CMFs) with excellent catalytic property. The cellulose microfibers with a mean diameter of approximately 270 nm are regenerated by deacetylation of cellulose acetate microfibers. Silver nanoparticles are deposited onto the surface of the cellulose microfibers by a simple wet reduction of silver precursor using glucose as reducing agent. The morphology, thermal stability and catalytic activities of the samples have been investigated by scanning electron microscopy (SEM), transmission electron microscopy (TEM), energy dispersive spectroscopy (EDS), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TG), and UV–vis spectrophotometer. The average size of Ag nanoparticles deposited on the fibers is approximately 10 ± 5 nm, and the deposition of the Ag nanoparticles does not change the morphology of the cellulose microfibers. The obtained Ag-CMFs exhibit excellent catalytic activity and reusable character for the reduction of p -nitrophenol by sodium borohydride. Therefore, the Ag-CMFs prepared by the facile method is expected to be an effective and promising catalytic material. [ABSTRACT FROM AUTHOR]

More discrete and active Ag nanoparticles (Ag NPs) were fabricated by decorating them on the surface of magnetic nanoparticles encapsulated in carbonized polydopamine nanospheres (M/C-PDA/Ag) via in-situ solid-state decomposition process. The morphology, structure, surface compositions and textural properties of the M/C-PDA and M/C-PDA/Ag catalyst were characterized. The results revealed a dispersion of Ag NPs with average particle size of less than 50 nm on C-PDA nanospheres uniformly embedded with Fe 3 C NPs of only 3–5 nm in size. With the synergistic effect of Ag NPs, nitrogen doping, and hierarchical mesopores, M/C-PDA/Ag displayed a superior catalytic capability for catalytic reduction of toxic Cr(VI) to less-toxic Cr(III) by formic acid as a reductant. Moreover, M/C-PDA/Ag maintained good physicochemical structure and stable activity even after several cycles of reactions. According to the results, the simple synthetic strategy, good stability, highly catalytic activity, and easy magnetic separation property of M/C-PDA/Ag hybrid make it serve as a promising environmentally friendly catalyst for the elimination of Cr(VI). [ABSTRACT FROM AUTHOR]

The present study explores alternate pericyclic chemistries for tethering amine-terminal biomolecules onto silver nanoparticles. Employing the versatile tool of the retro-Diels-Alder (rDA) reaction, three thermally-labile cycloadducts are constructed that cleave at variable temperature ranges. While the reaction between furan and maleimide has widely been reported, the current study also evaluates the reverse reaction kinetics between thiophene-maleimide, and pyrrole-maleimide cycloadducts. Density Functional Theorem (DFT) calculations used to model and plan the experiments, predict energy barriers for the thiophene-maleimide reverse reaction to be greatest, and the pyrrole-maleimide barriers the lowest. Based on the computational analyses, it is projected that the cycloreversion rate would occur slowest with the thiophene, followed by furan, and finally pyrrole would yield the promptest release. These thermally-responsive linkers, characterized by Electrospray Ionization Mass Spectrometry, 1 H and 13 C NMR, are thiol-linked to silver nanoparticles and conjugate single stranded siRNA mimics with 5′ fluorescein tag. Second harmonic generation spectroscopy (SHG) and fluorescence spectroscopy are used to measure release and rate of release. The SHG decay constants and fluorescence release profiles obtained for the three rDA reactions confirm the trends obtained from the DFT computations. [ABSTRACT FROM AUTHOR]

Magnesium (Mg) alloys have shown great potential in biomedical materials due to their biocompatibility and biodegradability. However, rapid corrosion rate, which is an inevitable obstacle, hinders their clinical applications. Besides, it is necessary to endow Mg alloys with antibacterial properties, which are crucial for temporary implants. In this study, silver nanoparticles (AgNPs) and polymethyltrimethoxysilane (PMTMS) were introduced into AZ31 Mg alloys via layer-by-layer (LbL) assembly and siloxane self-condensation reaction. The characteristics of the composite films were investigated by SEM, UV–vis, FT-IR, and XRD measurements. Corrosion resistance of the samples was measured by electrochemical and hydrogen evolution tests. Antibacterial activities of the films against Staphylococcus aureus were evaluated by plate-counting method. The results demonstrated that the composite film with smooth and uniform morphologies could enhance the corrosion resistance of Mg alloys owing to the physical barrier and the self-healing functionality of polysiloxane. Moreover, the composite coating possessed antibacterial properties and could prolong the release of assembled silver ions. [ABSTRACT FROM AUTHOR]

Micromass culture systems have been developed as three-dimensional organotypic in vitro alternatives to test developmental toxicity. We have optimized a murine-based embryonic midbrain micromass system in two genetic strains to evaluate neurodevelopmental effects of gold-cored silver nanoparticles (AgNPs) of differing sizes and coatings—20 nm AgCitrate, 110 nm AgCitrate, and 110 nm AgPVP. AgNPs are increasingly used in consumer, commercial, and medical products for their antimicrobial properties and observations of Ag in adult and fetal brain following in vivo exposures to AgNPs have led to concerns about the potential for AgNPs to elicit adverse effects on neurodevelopment and neurological function. Cytotoxicity was assessed at three time points of development by both nominal dose and by dosimetric dose. Ag dosimetry was assessed in cultures and the gold core component of the AgNPs was used as a tracer for determination of uptake of intact AgNPs and silver dissolution from particles in the culture system. Results by both nominal and dosimetric dose show cell death increased significantly in a dose-dependent manner at later time points (days 15 and 22 in vitro ) that coincide with differentiation stages of development in both strains. When assessed by dosimetric dose, cultures were more sensitive to smaller particles, despite less uptake of Ag in smaller particles in both strains. [ABSTRACT FROM AUTHOR]

Guiding and capturing photons at the nanoscale by means of metal nanoparticles and interfacial engineering for preventing back-electron transfer are well documented techniques for performance enhancement in excitonic solar cells. Drifting from the conventional route, we propose a simple one-step process to integrate both metal nanoparticles and surface passivation layer in the porous photoanode matrix of a dye-sensitized solar cell. Silver nanoparticles and Nb 2 O 5 surface passivation layer are simultaneously deposited on the surface of a highly porous nanocrystalline TiO 2 photoanode, facilitating an absorption enhancement in the 465 nm and 570 nm wavelength region and a reduction in back-electron transfer in the fabricated dye-sensitized solar cells together. The TiO 2 photoanodes were prepared by spray pyrolysis deposition method from a colloidal solution of TiO 2 nanoparticles. An impressive 43% enhancement in device performance was accomplished in photoanodes having an Ag-incorporated Nb 2 O 5 passivation layer as against a cell without Ag nanoparticles. By introducing this idea, we were able to record two benefits - the metal nanoparticles function as the absorption enhancement agent, and the Nb 2 O 5 layer as surface passivation for TiO 2 nanoparticles and as an energy barrier layer for preventing back-electron transfer - in a single step. [ABSTRACT FROM AUTHOR]

The green and one-step synthesis of silver nanoparticles (AgNPs) has been proposed as simple and ecofriendly. In the present study, a flower extract of Madhuca longifolia was used for the reduction of silver nitrate into AgNPs, with phytochemicals from the flower extract as a reducing and stabilizing agents. The synthesized AgNPs were spherical and oval shaped and about 30–50 nm sizes. The appearance of a brown color in the reaction mixture is a primary indication of AgNPs formation, and it was confirmed by observing UV-visible spectroscopy peak at 436 nm. The Energy Dispersive X-ray spectra and X-ray diffraction analysis results together confirm that the synthesized nanoparticles contain silver and silver chloride nanoparticles. The Zeta potential analysis indicates presence of negative charges on synthesized AgNPs. The FT-IR study represents involvement of functional groups in AgNPs synthesis. Synthesized AgNPs shows potential antibacterial activity against Gram-positive and Gram-negative pathogens. M. longifolia flower is a good source for AgNPs synthesis and synthesized AgNPs are applicable as antibacterial agent in therapeutics. [ABSTRACT FROM AUTHOR]

In an effort to verify a previous striking report that ethanol could be oxidized selectively to ethylene oxide, ethanol oxidation on Ag, Cu, or Au nanoparticles supported on Li 2 O/γ-Al 2 O 3 or γ-Al 2 O 3 was examined between 100 and 400 °C. Ag and Cu catalysts were found to be highly selective to acetaldehyde (>95% on Ag below 325 °C and on Cu below 250 °C). On Au, selectivities to acetaldehyde were lower, with higher selectivity to ethyl acetate and acetic acid. No ethylene oxide was observed under any conditions. Our results, including selectivity variations among these metals, are consistent with previous studies of ethanol oxidation over coinage metals supported on γ-Al 2 O 3 , with no changes in primary product identity and minor changes in selectivity upon addition of Li 2 O. Unfortunately, these results are in direct contradiction to previous work reporting the desirable direct conversion of ethanol to ethylene oxide on Ag, Cu, and Au on Li 2 O/γ-Al 2 O 3 . [ABSTRACT FROM AUTHOR]

To address the pollution problem of organic dyes, monodispersed anionic silver nanoparticles (AgNPs) with an average size of 6 nm were prepared in water media via chemical reduction method from oleic acid and n -butyl amine. The aqueous solution of the resultant AgNPs was utilized as a photocatalyst to investigate the adsorption and photodegradation behaviors of organic dyes under different light irradiation. The morphology and surface characteristics of the synthesized AgNPs were probed using TEM, XRD, FTIR and zeta potential analysis. The adsorption and degradation process of organic dyes on the AgNPs were characterized in details by UV–Vis spectrophotometer. The results showed that the AgNPs exhibited a characteristic charge- and size-selective adsorption of dyes owing to the profoundly negative charged surface, which enables the AgNPs to possess high selective degradation of Methylene Blue. More still, due to the surface plasmon resonance (SPR) effect of AgNPs, the obtained AgNPs presented a higher photocatalytic activity to Methylene Blue under UV light, visible light, and solar light compared with commercial photocatalysts. The 5 cyclic reactions revealed its high stability and reusability. In a nutshell, the proposed mechanism systematically combined the selective adsorption and the SPR effect to explain the detailed photocatalytic process of the obtained AgNPs. [ABSTRACT FROM AUTHOR]

It is the first time to do investigation the reliability and validity of thirty kinetic and isotherm models for describing the behaviors of adsorption of silver nanoparticles (AgNPs) onto different adsorbents. The purpose of this study is therefore to assess the most reliable models for the adsorption of AgNPs onto feasibility of an adsorbent. The fifteen kinetic models and fifteen isotherm models were used to test secondary data of AgNPs adsorption collected from the various data sources. The rankings of arithmetic mean were estimated based on the six statistical analysis methods of using a dedicated software of the MATLAB Optimization Toolbox with a least square curve fitting function. The use of fractal-like mixed 1, 2-order model for describing the adsorption kinetics and that of Fritz-Schlunder and Baudu models for describing the adsorption isotherms can be recommended as the most reliable models for AgNPs adsorption onto the natural and synthetic adsorbent materials. The application of thirty models have been identified for the adsorption of AgNPs to clarify the usefulness of both groups of the kinetic and isotherm equations in the rank order of the levels of accuracy, and this significantly contributes to understandability and usability of the proper models and makes to knowledge beyond the existing literatures. [ABSTRACT FROM AUTHOR]

The distribution and use of nanoparticles have rapidly increased over recent years, but the available knowledge regarding their mode of action, ecological tolerance and biodegradability remains insufficient. Wheat ( Triticum aestivum L.) is the most important crop worldwide. In the current study, the effects of silver nanoparticles (AgNPs) obtained from two different sources, namely, green and chemical syntheses, on chromosomal aberrations and cell division were investigated. Wheat root tips were treated with four different AgNP concentrations (10, 20, 40 and 50 ppm) for three different exposure durations (8, 16 and 24 h), and the different concentrations of the nanoparticles were added to the tested grains until the root lengths reached 1.5–2 cm. For each concentration, the mitotic indexes (%) were obtained from an analysis of ~ 2000 cells. The treated root-tip cells exhibited various types of chromosomal aberrations, such as incorrect orientation at metaphase, chromosomal breakage, metaphasic plate distortion, spindle dysfunction, stickiness, aberrant movement at metaphase, fragmentation, scattering, unequal separation, scattering, chromosomal gaps, multipolar anaphase, erosion, and distributed and lagging chromosomes. These results demonstrate that the root tip cells of wheat can readily internalize the AgNPs and that the internalized AgNPs can interfere with the cells’ normal function. [ABSTRACT FROM AUTHOR]

Phenolic acids are the major bioactive compounds responsible for the reducing properties of rice husk. This study quantified the phenolic acid profile, total phenolic content (TPC), reducing power, and ferric-reducing antioxidant power (FRAP) of rice husk extracts ameliorated with acid–alkali pretreatment extraction (AAPE) process. The AAPE rice husk extract exhibited higher phenolic content (TPC: 3428 mg gallic acid equivalent (GAE)/100 g husk) and possessed stronger reducing properties (FRAP of 1433 mM FeSO 4 /g husk) than the rice husk extract with hot water extraction (TPC: 33 mg GAE/100 g husk, FRAP: 12 mM FeSO 4 /g husk). A green synthesis process for preparing silver nanoparticles (AgNPs diameter approximately 19 nm) with stable dispersion was obtained, and a conceptual model using caffeic acids as protective agents in synthesized AgNPs was conducted. The recycling of rice husk not only reduces the pollution from the use of chemical reducing agents and dispersants but also enhances the value-addition of the husk. [ABSTRACT FROM AUTHOR]

Abstract Purified plant nutraceuticals afzelin and quercetrin from an edible plant- Crotolaria tetragona was employed for the fabrication of silver nanoparticles (AgNPs) by a sunlight mediated process. From among a panel of strains tested, AgNPs displayed potent bacteriostatic and bactericidal effect against P. aeruginosa and S. Typhi. Time kill studies revealed green synthesized AgNPs displayed comparable bactericidal effect with chemically synthesized AgNPs against S. Typhi. Antibiofilm potential of AgNPs showed that they were highly effective at sub MIC concentrations in causing 50% biofilm inhibition against food borne pathogen S. Typhi implying that antibiofilm effect is independent of antibacterial effect, which was evidenced by fluorescent imaging and SEM imaging. Mechanistic studies revealed that reduced cell surface hydrophobicity, decreased surface adherence, loss of membrane potential contributed to antibiofilm potential of afzelin/quercetrin AgNPs. Green synthesized afzelin/quercetrin AgNPs were also relatively less toxic and more effective in curtailing bioburden of S. Typhi in infected zebrafish by > 3 log fold. Ability of sunlight reduced afzelin/quercetrin NPs to mitigate planktonic mode of growth in vitro and in vivo and curtail biofilm formation of S. Typhi in vitro demonstrates its potential to curtail food borne pathogen in planktonic and biofilm mode of growth. Graphical abstract Image 1 Highlights • Nutraceuticals afzelin and quercetrin capped silver nanoparticles (AgNPs) were synthesized and characterized through UV, and TEM analysis. • Time kill studies revealed AgNPs displayed comparable bactericidal effect against S. Typhi. • AgNPs were highly effective at sub MIC concentrations in causing 50% biofilm inhibition against S. Typhi implying that antibiofilm effect is independent of antibacterial effect, as evidenced by fluorescent imaging and SEM imaging. • Mechanistic studies revealed that reduced cell surface hydrophobicity, decreased surface adherence, loss of membrane potential contributed to antibiofilm potential of afzelin/quercetrin AgNPs. • Afzelin/quercetrin AgNPs were also relatively less toxic and more effective in curtailing bioburden of S. Typhi in infected zebrafish by > 3 log fold. [ABSTRACT FROM AUTHOR]