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We synthesized silver nanoparticles using thirty Chinese plant extracts via a green synthetic strategy. UV–visible spectra showed that the silver nanoparticles have an absorbance at 450 nm. Among the thirty extracts, seven extracts (Cratoxylum formosum , Phoebe lanceolata , Scurrula parasitica , Ceratostigma minus , Mucuna birdwoodiana , Myrsine africana and Lindera strychnifolia) exhibited the successful synthesis of silver nanoparticles. These seven extracts showed higher 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activity and reducing power than the other extracts. The silver nanoparticles synthesized using these seven extracts were mostly spherical with high colloidal stability. The cytotoxicity of these seven silver nanoparticle samples on human lung cancer cells (A549) was clearly higher than that of the extracts alone. Furthermore, the cytotoxicity was affected by the presence or absence of fetal bovine serum. Moreover, the cytotoxicity of the silver nanoparticles synthesized with Cratoxylum formosum and Mucuna birdwoodiana extracts resulted in apoptotic cell death in A549 cells. The wound healing activity observed by the cell scratch method on mouse fibroblast cells (NIH3T3) suggested that the Lindera strychnifolia extract produced silver nanoparticles with decent activity. These results provide ample and systematic information for researchers on the green synthesis of silver nanoparticles using plant extracts. Unlabelled Image • Thirty plant extracts are used for green synthesis of silver nanoparticles. • Synthetic process is totally green and eco-friendly. • Plant extracts play a role as a reducing and a stabilizing agent. • Silver nanoparticles exert biological activities. [ABSTRACT FROM AUTHOR]

Abstract The present research work describes a novel method for green synthesis of silver nanoparticles using purple heart plant leaves extract, which is recognized as frequently found in households as an ornamental plant. The aqueous methanolic extract of purple heart plant leaves was prepared and employed in the synthesis of stable silver nanoparticles via biological reduction method. The purple heart plant leaves extract-mediated synthesized silver nanoparticles were systematically optimized using Box-Behnken design considering the effect of various independent variables (factors) like concentration of AgNO 3 , temperature and volume of purple heart plant leaves extract solution on the responses like particle size and polydispersity index of synthesized silver nanoparticles were optimized. Mathematical modelling was performed using quadratic polynomial model and response surface analysis was done to understand the factor-response relationship. The synthesized silver nanoparticles at optimum condition were found to be of spherical in shape under TEM with particle size of 98 nm and polydispersity index of 0.15. Optimized silver nanoparticles were further characterized through UV-VIS spectrophotometry, FTIR spectroscopy and TEM imaging studies. Also, the silver nanoparticles were evaluated for antibacterial activity on E. coli and S. aureus. In a nutshell, the studies construed successful synthesis of silver nanoparticles along with thorough understanding of the associated factors influencing their quality characteristics and significantly improved antibacterial activity as beneficial effect. Graphical abstract Unlabelled Image Highlights • Silver nanoparticles were synthesized using purple heart plant leaves extract. • These synthesized silver nanoparticles were optimized by Box-Behnken design. • Particle size and polydispersity index were investigated as response variables. • Optimized silver nanoparticles showed 98 nm particle size and 0.15 polydispersity index. • Optimized silver nanoparticles showed antibacterial activity against E. coli and S. aureus. [ABSTRACT FROM AUTHOR]

Abstract This project is focuses on novel, cost effective and simple plant mediated synthesis of silver nanoparticles (Ag-NPs) using leaf extract of Albizia procera. The optical, structural and physical properties of green synthesized Ag-NPs have been investigated by UV–Visible spectroscopy, X-ray Diffraction (XRD) and Atomic Force Microscopy (AFM), respectively. Prepared Ag-NPs are spherical in shape and crystalline in nature with an average size of 6.18 nm. Ag-NPs have showed promising potential in removal of organic pollutant methylene blue (MB) dye. Careful investigation on the removal of dye as a function of contact time, UV light and exposure time, dose of nanoparticles, temperature and pH have also been carried out. Moreover, Ag-NPs exhibit outstanding antibacterial activities against gram negative Escherichia coli (E. coli) and gram positive Staphylococcus aureus (S. aureus) bacterial pathogens. Graphical abstract Unlabelled Image Highlights • Cost effective facile synthesis of Silver Nanoparticles (Ag-NPs) using Albizia procera leaf extract is report first ever. • Ag-NPs are promising candidate for removal of organic pollutant Methylene Blue (MB) dye from textile industry wastewater. • Synthesized Ag-NPs can be effectively used as an antibacterial agent for different pathogens. [ABSTRACT FROM AUTHOR]

Abstract The green synthesis of biomaterials is of significant interest as it enables the safe and sustainable preparation of noble metallic nanoparticles for medical applications. Microalgae polysaccharides have received attention due to their outstanding properties such as biocompatibility, biodegradability and low cost. In addition, due to their variety of remarkable biological and physicochemical properties, polysaccharide-based nanoparticles have advantageous features yet to be explored. The primary objective of the current research was to investigate exopolysaccharides isolated from green microalgae Botryococcus braunii (EPBb) and Chlorella pyrenoidosa (EPCp), as both reducing and stabilizing agents, for the green synthesis of silver nanoparticles (AgNPs). Their antibacterial activity towards Gram-positive bacteria (Staphylococcus aureus), Gram-negative bacteria (Escherichia coli), and antibiotic-resistant bacteria (methicillin-resistant Staphylococcus aureus) was studied, as well as their cytotoxicity to human dermal fibroblasts. The presently synthesized AgNPs were spherical in shape and exhibited characteristic surface plasmon resonance at 430 nm. The main population had a particle size which ranged between 5 and 15 nm as analyzed by transmission electron micrographs. Zeta potentials averaged −51.81 ± 3.01 mV using EPBb and −12.16 ± 2.41 mV using EPCp. More importantly, AgNPs possessed strong antibacterial activity in a dose-dependent manner, even against drug-resistant bacteria. The enhanced antibacterial activity of these particles is explained due to extensive reactive oxygen species generation and bacterial cell membrane damage. In contrast, such AgNPs were not cytotoxic at the same therapeutic range to fibroblasts (0.5–10.0 μg/mL). In summary, these results showed that polysaccharide-capped AgNPs have a strong potential for numerous medical applications, such as antibacterial agents in pharmaceutical and biomedical areas. Graphical abstract (A) UV/Vis spectra and TEM micrographs of polysaccharide-capped silver nanoparticles, (B) growth curve and effect on the cell morphology of E. coli treated with the silver nanoparticles. Unlabelled Image Highlights • A new and useful application for exopolysaccharides from microalgae Botryococcus braunii and Chlorella pyrenoidosa. • Green and sustainable approach for the synthesis of silver nanoparticles based on the biorefinery from microalgae is highlighted. • Nanoparticles exhibited antibacterial activity towards Gram-positive, Gram-negative, and antibiotic-resistant bacteria. • The killing mechanisms involved in the observed antibacterial activity were investigated. • The polysaccharide capped‑silver nanoparticles were not cytotoxic to fibroblasts at the same therapeutic range. [ABSTRACT FROM AUTHOR]

Abstract Herbs having various natural substances can be utilized for the biosynthesis of Silver nanoparticles (AgNPs) and act as a stable, reliable and biocompatible alternative instead of the current physical and chemical approaches. It has been reported that Matricaria chamomilla possesses unique properties, especially anti-cancerous effects. The objective of the current work was to assess the chemical characteristics and anticancer effects of biosynthesized AgNPs applying aqueous extracts of M. chamomilla against A549 lung cancer cells. UV–visible spectrum showed the maximum absorption of the biosynthesized AgNPs at 430 nm. The crystalline structure of biosynthesized AgNPs in optimal conditions was confirmed by XRD. Moreover, the presence of Ag as the ingredient element was exhibited via EDX analysis. FT-IR results also verified the AgNPs synthesis using a plant extract. The spherical shapes of the AgNPs with an average diameter size around 45.12 nm and a zeta potential value of −34 mV were characterized using DLS, and confirmed through FE-SEM and TEM. In vitro cytotoxicity assay using MTT revealed that the biosynthesized AgNPs exhibited a dose- and time- dependent cytotoxic effect against A549 lung cancer cells. Moreover, the apoptotic effects of the AgNPs were demonstrated using DAPI staining, real-time PCR and flow cytometry. According to these findings, using M. chamomilla in combination with AgNPs via green-synthesis approach may be an efficient strategy for effective treatment of lung cancer. Highlights • Matricaria chamomilla extract was used as capping agent to synthesize AgNPs without production of any harmful chemicals. • The biosynthesized AgNPs with uniformity and good stability exhibited remarkable anti-cancer effects against A549 cells. • Using M. chamomilla in combination with AgNPs may be an efficient strategy for effective treatment of lung cancer. [ABSTRACT FROM AUTHOR]

The use of nontoxic biological compounds in the synthesis of nanomaterials is an ecofriendly and cost-effective approach in nanotechnology. The present work was carried out to develop silver nanoparticles (Ag-NPs) by a green method using white tea ( Wt ) extract as reducing agent for reduction of silver nitrate as silver precursor into the lamellar space of inorganic polymer montmorillonite (Mt) as an effective protective reagent and support as well. The bioformed Wt /Ag@Mt nanocomposite (NCs) was compared with pure biosynthesized Wt /Ag-NPs under free stabilizer condition and effect of Mt stabilizer on antioxidant, cytotoxicity and structural properties were also investigated. The prepared Wt /Ag-NPs and Wt /Ag@Mt-NCs were characterized by UV–vis spectroscopy, FTIR, XRD, TEM, SEM and EDX. The interlamellar space limits were without many changes, therefore Ag-NPs formed on the exterior surface of Mt. The XRD study showed that the particles are crystalline structure in nature, with a facecentered cubic (fcc) structure. The TEM result shows the bioformed Ag-NPs are spherical in shapes with mean particle size of 19.77 ± 3.82 for Wt /Ag-NPs and 15.87 ± 2.38 nm for Wt /Ag@Mt-NCs. In vitro cytotoxicity studies on MOLT-4 cells, a dose dependent toxicity with non-toxic effect of concentration below 40 μg/mL was shown. The outcome shows that IC 50 of our green synthesized Wt /Ag@Mt-NCs was 0.0039 in comparison to 2.13329 for Doxorubicin and 0.013 μM for Cisplatin which is much better than IC 50 of these anticancer drugs and more active than them for MOLT-4 cell line. Antioxidant activity indicated that they can be applied as potential radical scavenger and also showed that DPPH activity increased in a dose dependent manner. The bio-synthesized nanoparticles can potentially useful in pharmaceutical and biomedical applications. [ABSTRACT FROM AUTHOR]

Silver nanoparticle has been widely applied to a variety of fields for its outstanding antimicrobial activity. However, the stability of silver nanoparticle limits its application under certain conditions. Thus, improving the stability of silver nanoparticle via biosynthesis is a promising shortcut to expand its application. Sericin from silkworm cocoon has good hydrophilicity, reaction activity, biocompatibility and biodegradability. In this study, we developed a novel, simple, one-step biosynthesis method to prepare sericin-silver nanoparticle composite in situ in solution. Sericin served as the reductant of silver ion, the dispersant and stabilizer of the prepared sericin-silver nanoparticle composite. Natural light was the only power source used to catalyze the synthesis of silver nanoparticle in situ in solution. The novel sericin-silver nanoparticle composite was characterized by ultraviolet-visible and fluorescence spectroscopy, X-ray diffraction, transmission electron microscopy and fourier transform infrared spectroscopy. The results showed silver nanoparticle could be synthesized through the reduction of AgNO 3 by the phenolic hydroxyl group of tyrosine residues of sericin under the catalysis of natural light. The synthesized silver nanoparticle had good crystalline, size distribution and long-term stability at room temperature. Light irradiation was essential for the preparation of sericin-silver nanoparticle composite. The antibacterial activity assay showed 25 mg/L and 100 mg/L were the minimum concentrations of sericin-silver nanoparticle composite required to inhibit the growth of Staphylococcus aureus and kill this bacterium, respectively. The cytotoxicity assay showed cell viability and cell growth were almost not affected by sericin-silver nanoparticle composite under the concentration of 25 mg/L. Our study suggested the preparation of sericin-silver nanoparticle composite was environmentally friendly and energy conservation, and the prepared sericin-silver nanoparticle composite had long-term stability, effective antibacterial activity and good biocompatibility. This novel sericin-silver nanoparticle composite has shown great potentials for biomedical application such as antibacterial agent and wound care. [ABSTRACT FROM AUTHOR]

A highly sensitive, selective, and rapid interference green synthesis based determination of potential milk adulterant melamine has been reported here. Melamine is a nitrogenous compound added to milk for mimicking proteins, consumption of which leads to kidney stones and renal failures. Melamine interacts with ascorbic acid (AA) through strong hydrogen-bonding interactions, thus resulting in an interference/interruption in the formation of silver (Ag) nanoparticles which was confirmed by UV–Vis spectroscopy and Transmission Electron Microscopy (TEM). The corresponding benchmark validations for melamine spiked milk samples were performed using High Performance Liquid Chromatography (HPLC). This interference in the formation of Ag nanoparticles resulted in color change that varies with concentration of melamine, thereby enabling in-situ rapid sensing of melamine from milk to a lower limit of 0.1 ppm with a linear correlation coefficient of 0.9908. [ABSTRACT FROM AUTHOR]

In recent years, green synthesis of metallic nanoparticles is a growing area of research because of their potential applications in nanomedicine. In the present study we synthesized silver nanoparticles (silver NPs) from AgNO 3 using aqueous extract of Lonicera hypoglauca flower as reducing and capping agents. The synthesized silver NPs were characterized using UV–Vis spectroscopy, FTIR, SEM-ED, TEM and SAED. Silver NPs were found to be significantly toxic to MCF-7 cells via the induction of apoptosis whereas sparing normal immune system (RAW 264.7) cells. [ABSTRACT FROM AUTHOR]

In the current investigation we report the biosynthesis potentials of bark extracts of Ficus benghalensis and Azadirachta indica for production of silver nanoparticle without use of any external reducing or capping agent. The appearance of dark brown color indicated the complete nanoparticle synthesis which was further validated by absorbance peak by UV–vis spectroscopy. The morphology of the synthesized particles was characterized by Field emission- scanning electron microscopy (Fe-SEM) and atomic force microscopy (AFM). The X-ray diffraction (XRD) patterns clearly illustrated the crystalline phase of the synthesized nanoparticles. ATR-Fourier Transform Infrared (ATR-FTIR) spectroscopy was performed to identify the role of various functional groups in the nanoparticle synthesis. The synthesized nanoparticles showed promising antimicrobial activity against Gram negative ( Escherichia coli , Pseudomonas aeruginosa and Vibrio cholerae ) and Gram positive ( Bacillus subtilis ) bacteria. The synthesized nano Ag also showed antiproliferative activity against MG-63 osteosarcoma cell line in a dose dependent manner. Thus, these synthesized Ag nanoparticles can be used as a broad spectrum therapeutic agent against osteosarcoma and microorganisms. [ABSTRACT FROM AUTHOR]

In this work, we have investigated on Lantana camara mediated silver nanoparticles (AgNPs) with different leaf extract (LE) quantity for the evaluation of efficient bactericidal activity. The AgNPs were prepared by simple, capable, eco-friendly and biosynthesis method using L. camara LE. This method allowed the synthesis of crystalline nanoparticles, which was confirmed by X-ray diffraction (XRD) and selected area electron diffraction (SAED) patterns. The X-ray photoelectron spectroscopy (XPS) analysis confirmed the formation of metallic silver and elucidates the surface state composition of AgNPs. UV–vis spectra of AgNPs and visual perception of brownish yellow color from colorless reaction mixture confirmed the AgNP formation. Involvement of functional groups of L. camara leaf extract in the reduction and capping process of nanoparticles was well displayed in Fourier transform infrared spectroscopy (FTIR). Decrement of particle size with an increment of leaf extract volume was evident in AFM, TEM images and also through a blue shift in the UV–vis spectra. The rate of formation and size of AgNPs were dependent on LE quantity. Meanwhile, these AgNPs exhibited effective antibacterial activity with the decrement of particle size against all tested bacterial cultures. [ABSTRACT FROM AUTHOR]

Over the last years, there has been an increasing trend towards the use of environmentally friendly processes to synthesize nanomaterials. In the case of nanomedicine, the use of bionanofactories with associated biological properties, such as seaweed, has emerged as a promising field of work due to the possibility they open for both the preservation of those properties in the nanomaterials synthesized and/or the reduction of their toxicity. In the present study, gold (Au@SP) and silver (Ag@SP) nanoparticles were synthesized using an aqueous extract of Saccorhiza polyschides (SP). Several techniques showed that the nanoparticles formed were spherical and stable, with mean diameters of 14 ± 2 nm for Au@SP and 15 ± 3 nm for Ag@SP. The composition of the biomolecules in the extract and the nanoparticles were also analyzed. The analyses performed indicate that the extract acts as a protective medium, with the particles embedded in it preventing aggregation and coalescence. Au@SP and Ag@SP showed superior immunostimulant and antiproliferative activity on immune and tumor cells, respectively, to that of the SP extract. Moreover, the nanoparticles were able to modulate the release of reactive oxygen species depending on the concentration. Hence, both nanoparticles have a significant therapeutic potential for the treatment of cancer or in immunostimulant therapy. • Optimization of the method of synthesis of silver and gold NPs by Saccorhiza polyschides • Study of carbohydrate composition by HPLC of the extract prior and after the synthesis • Analysis of in vitro antioxidant activity of SP extract, Au@SP and Ag@SP • Au@SP had an improved immunostimulant efficacy and Ag@SP anti-tumor in comparison with the extract. • NPs induced ROS release at high concentration but they showed an antioxidant activity at low doses. [ABSTRACT FROM AUTHOR]

Nanoparticles (NPs) have gained importance in technological advances owing to their user friendly enhanced and efficient physical, chemical, and biological characteristics compared to their bulk counterparts. Biological synthesis of NPs by using a microorganism, enzymes, or plant extracts offers a greener and eco-friendly approach besides many advantages over physical or chemical approaches. This study reports the biosynthesis of silver nanoparticles (AgNPs) using Nostoc muscorum NCCU 442 aqueous extract as the reducing and capping agent for AgNPs synthesis. The synthesized nanoparticles were characterized by UV‐VIS spectrum, SEM, EDS, TEM, AFM, DLS and XRD. Results showed distinguishing polycrystalline nature of synthesized AgNPs with surface plasmon significant band in the size range of 6‐45nm with average 30 size nm. FT-IR study revealed the role of secondary metabolites present in aqueous extract for the synthesis of AgNPs. Biological activities of purified AgNPs as antioxidant and antibacterial potential showed the highest antibacterial activity against Staphylococcus aureus MTCC 902. Unlabelled Image • AgNP biosynthesis optimization and characterizations were done by using Nostoc musco-rum NCCU 442 aqueous extract. • Size, shape and purity of AgNP were characterized by SEM, EDS, TEM, AFM and DLS. • XRD pattern exhibited polycrystalline nature of the AgNP. • FT-IR study revealed that the secondary metabolites of extract were responsible for the synthesis of AgNP. • Biosynthesized AgNP showed significant antioxidant and antibacterial potential. [ABSTRACT FROM AUTHOR]

Lichens dispose a wide spectrum of bioactive compounds known as secondary metabolites. Their biological effects like antioxidant and antibacterial activities are widely studied. Green synthesis of silver nanoparticles (AgNPs) is a method where the compounds/substances present in plants are used for reduction of AgNO 3 instead of toxic chemicals. However, this methodology is usually a two-step process (extract preparation step and the synthesis step) performed under the elevated temperatures nad in the case of lichens, the redicing compounds are insoluble in water. These disadvantages can be overcome by a solid-state mechanochemical synthesis applied in the present study. As microorganisms are becoming more resistant to commercial antibiotics, AgNPs prepared in an environmentally friendly way represent an interesting alternative. In the present study, we compared the processing of lichen material of Pseudevernia furfuracea and Lobaria pulmonaria for extraction as well as for synthesis of AgNPs, and tested the antibacterial and antioxidant activity of the extracts. Both selected lichen species could be successfully used as reducing agents to produce AgNPs. Six different bacterial strains were tested for antibacterial activity of AgNPs-containing products and it was highly effective on all strains. However, the antioxidant activity of lichen extracts showed the lowest effect even if AgNPs are present which positively correlated with the content of total phenols and flavonoids. Both phenols and flavonoids are natural antioxidants and react with silver nitrate. Due to this fact, we observed a decrease of total phenols, total flavonoids as well as antioxidant activity when processing of lichen extracts with silver nitrate was used. We demonstrated that the formation of AgNPs increased the antibacterial activity but on the other hand reduced the antioxidant activity. Thus, antibacterial and antioxidant effects have to be treated differentially. • Extracts of tested lichens are applicable as reduction agents for green synthesis and preparation of Ag NPs. • There are no significant differences in processing of lichens between grinding by liquid nitrogen or by milling • Mechanochemical approach is environmentally friendly and most effective in antibacterial activity • Bio-mechanochemical synthesis of AgNPs increase antibacterial activity however decrease antioxidant activity [ABSTRACT FROM AUTHOR]

In the present work, the fabrication of hybrid porous silicon/green synthetized Ag microparticles was shown and the potential use as carriers for Ag nanoparticles and drug delivery was explored. Hybrid microparticles were fabricated by incorporating green synthetized Ag nanoparticles into porous silicon matrix. The main physicochemical characteristics of the hybrid systems were studied by several techniques including UV–vis spectroscopy, TEM, SEM, XRD and XPS. The toxicology of these hybrid systems was investigated by cell viability, MTT, and comet assays. In addition, the possibility to aggregate different drug to use as drug delivery system was demonstrated by using florfenicol as drug model, due to its importance in salmon industry. The experimental results showed the potential to use these hybrid systems as carries for drug delivery in salmon industry. • Hybrid porous silicon/green synthetized Ag microparticles were synthetized for multicarrier delivery • In vitro fish toxicity studies showed a low toxicity and great cell viability for the hybrid microparticles • Porous hybrid microparticles allowed to load florfenicol (FF) drug and control the release • Release profiles showed that the delivery mechanism of FF was based on Gallagher-Corrigan models in distillated water and PBS [ABSTRACT FROM AUTHOR]

Silver nanoparticles (AgNPs) were synthesized via a green strategy using fifty-eight plant extracts that originated from Vietnam and Indonesia. Among the fifty-eight AgNP samples, we selected six AgNP samples synthesized by the extracts of Areca catechu , Hypotrachyna laevigata , Ardisia incarnata , Maesa calophylla , Maesa laxiflora and Adinandra poilanei. Remarkably, these six extracts exhibited higher 2,2-diphenyl-1-picrylhydrazyl radical scavenging activity and reducing power than the other extracts. Furthermore, the contents of total phenolic compounds and reducing sugars in the six selected extracts were also higher than those in the other extracts. The six selected AgNP samples showed strong surface plasmon resonance in the range of 416–438 nm. They were all spherical shaped with an average size from 12.5 ± 1.0 nm to 21.3 ± 4.9 nm as measured by field-emission transmission electron microscopy images. The hydrodynamic sizes were measured to be 49.5–122.6 nm with negative zeta potential values. Colloidal stability was excellent on the shelf for 28 days and in cell culture medium. The cytotoxicity assessment and generation of reactive oxygen species (ROS) in A549 and HeLa cells demonstrated that the AgNP samples prepared by Ardisia incarnata , Maesa calophylla , and Maesa laxiflora showed relatively high cytotoxicity and excess ROS generation among the six selected AgNP samples. Exposure of the AgNP samples to A549 and HeLa cells resulted in cell death, which was mostly due to necrosis but slightly due to late apoptosis. Cell cycle analysis demonstrated a significant increase in the cell population in the S phase. The green-synthesized AgNPs induced cell death, suggesting anticancer prospects that may offer new insight into the development of an anticancer nanomedicine. Unlabelled Image • Fifty-eight plant extracts are used for green synthesis of silver nanoparticles. • Synthetic process is totally sustainable and green. • Silver nanoparticles are cytotoxic and generate ROS in cancer cells. • Silver nanoparticles induce cell death via mostly necrosis. [ABSTRACT FROM AUTHOR]

Nanocomposite materials have been proposed to enhance the properties of different materials. In this study, palygorskite (Pal) clay is proposed as a support matrix for silver nanoparticles stabilised with cashew gum (Anacardium occidentale L.) (AgNPs-CG), producing the Pal/AgNPs-CG nanocomposite, whose bactericidal activity was studied. AgNPs-CG was synthesised using a green method in which CG acted as a reducing and stabilising agent for these nanostructures. AgNPs-CGs were subsequently characterised then adsorbed to the Pal surface, which was previously treated to remove impurities such as quartz. Pal and Pal/AgNPs-CG were characterised by X-ray diffraction, specific surface area, thermal analysis, Fourier transform infrared spectroscopy, scanning electron microscopy, energy dispersive spectroscopy, and transmission electron microscopy. The antibacterial activity assay by the direct contact method showed that the synergistic effect of the combination of AgNPs-CG and Pal increased the bactericidal effect of the nanomaterial compared with the AgNPs-CG activity, reaching a percentage inhibition of up to 70.2% against E. coli and 85.3% against S. aureus. Nanocomposite atoxicity was demonstrated by the Artemia Salina model. Thus, the Pal/AgNPs-CG nanocomposite emerges as a nanomaterial with potential antibacterial applications. Unlabelled Image • Palirgoskite (Pal) was used as support for immobilization of AgNPs. • AgNPs were synthesised via green synthesis method using cashew gum (CG) (from Anacardium occidentale L.). • Pal-AgNPs-CG nanocomposite showed excellent antibacterial effect against E. coli and S. aureus bacteria. • Preliminary toxicity tests have shown that nanocomposite is nontoxic. [ABSTRACT FROM AUTHOR]

Silver nanowires (AgNWs) with a high-aspect-ratio were successfully synthesized by a green method using Lavandula angustifolia plant extract. The morphology of the AgNWs was evaluated as a function of the concentration of precursor salt and nucleating agent. Furthermore, AgNWs were analyzed in a biological model using rat liver mitochondria by measuring their effect on membrane potential. The scanning electron microscopy (SEM), X-ray diffraction (XRD), and transmission electron microscopy (TEM) techniques structurally characterized the nanowires obtained. Also, ultraviolet-visible spectroscopy (UV–Vis) investigated the optical properties of AgNWs. Structural studies show AgNWs fcc with lengths up to 100 μm and diameters ranging from 60 to 130 nm growing in the [110] orientation. Both the CuSO 4 nucleating agent and the centrifugation process are essential for the growth of nanowires. Furthermore, inhibition of mitochondrial membrane potential (MMP) depends on the concentration of the nanowires (NWs), suggesting dissipation of the electron transport chain. In this way, AgNWs can be used as a potential tool to verify biological reactions, such as modulation of metabolic pathways, together with the evaluation of a possible influence of biotic or abiotic factors in organisms. Unlabelled Image • High-aspect-ratio silver nanowires were synthesized by a simple green method. • Electron microscopy shows silver nanowires with a length of 100 μm. • AgNWs' growth was influenced by CuSO 4 nucleating agent and a centrifugation process. • AgNWs caused dissipation of the electrons transport chain. • Silver nanowires can be used as modulators of metabolic pathways. [ABSTRACT FROM AUTHOR]

Graphene oxide (GO) materials loaded with silver nanoparticles (AgNPs) have drawn considerable attention due to their capacity to efficiently inactivate bacteria though a multifaceted mechanism of action, as well as for presenting a synergetic effect against bacteria when compared to the activity of AgNPs and GO alone. In this investigation, we present an inexpensive and environmentally-friendly method for synthesizing reduced GO sheets coated with silver nanoparticles (AgNPs/r-GO) using a coffee extract solution as a green reducing agent. The physical and chemical properties of the produced materials were extensively characterized by scanning electron microscopy (SEM), field-emission gun transmission electron microscopy (FEG-TEM), ultraviolet and visible absorption (UV–Vis), Raman spectroscopy, X-ray photoelectron spectroscopy (XPS), inductively coupled plasma-optical emission spectroscopy (ICP-OES) and ion release determination. The results demonstrated that AgNPs/r-GO composites were successfully produced, revealing the formation of micrometer-sized r-GO sheets decorated by AgNPs of approximately 70 nm diameter. Finally, bactericidal and photobactericidal effects of the AgNPs/r-GO composites were tested against Staphylococcus aureus , in which the results showed that the composites presented antimicrobial and photoantimicrobial activities. Moreover, our results demonstrated for the first time, to our knowledge, that an efficient process of bacterial inactivation can be achieved by using AgNPs/r-GO composites under blue light irradiation as a result of three different bacterial killing processes: (i) chemical effect promoted by Ag+ ion release from AgNPs; (ii) photocatalytic activity induced by AgNPs/r-GO composites, enhancing the bacterial photoinactivation due to the excited-Plasmons of the AgNPs when anchored on r-GO; and (iii) photodynamic effect produced by bacterial endogenous photosensitizers under blue-light irradiation. In summary, the present findings demonstrated that AgNPs/r-GO can be obtained by a non-toxic procedure with great potential for biomedical-related applications. Unlabelled Image • AgNPs and AgNPs/r-GO composites were prepared by an environmentally-friendly, efficient, and inexpensive method. • Coffee extract was used as a green reducing agent for obtaining AgNPs and AgNPs/r-GO composites. • Bactericidal and photobactericidal effects of AgNPs and AgNPs/r-GO were tested against staphylococcus aureus. • An effective killing of bacteria under blue-light illumination was achieved. • Blue-light irradiation enhanced the antimicrobial activity of AgNPs/r-GO when compared to the AgNPs and GO alone. [ABSTRACT FROM AUTHOR]

The purpose of current study was green synthesis of silver nanoparticles (AgNPs) from seeds and wild Silybum plants in comparison with their respective extracts followed by characterization and biological potency. The biologically synthesized AgNPs were subjected to characterization using techniques like XRD, FTIR, TEM, HPLC and SPE. Highly crystalline and stable NPs were obtained using Silybum wild plant (NP1) and seeds (NP3) with size range between 18.12 and 13.20 nm respectively. The synthesized NPs and their respective extracts revealed a vast range of biological applications showing antibacterial, antioxidant, anti-inflammatory, cytotoxic and anti-aging potencies. The highest antioxidant activity (478.23 ± 1.9 μM, 176.91 ± 1.3 μM, 83.5 ± 1.6% μgAAE/mg, 156.32 ± 0.6 μgAAE/mg) for ABTS, FRAP, FRSA, TRP respectively was shown by seed extract (NP4) followed by highest value of (117.35 ± 0.9 μgAAE/mg) for TAC by wild extract (NP2). The highest antifungal activity (13 mm ± 0.76) against Candida albicans was shown by NP3 while antibacterial activity of (6 mm against Klebsiella pneumonia) was shown by NP3 and NP4. The highest anti-inflammatory activity (38.56 ± 1.29 against COX1) was shown by NP2. Similarly, the high value of (48.89 ± 1.34 against Pentosidine-Like AGEs) was shown by NP4. Also, the high anti-diabetic activity (38.74 ± 1.09 against α-amylase) was shown by NP4. The extracts and the synthesized NPs have shown activity against hepato-cellular carcinoma (HepG2) human cells. The HPLC analysis revealed that the highest value of silymarin component (silybin B 2289 mg/g DW) was found for NP4. Silydianin is responsible for capping. Among the green synthesized AgNPs and the extracts used, the effect of NP4 was most promising for further use. Unlabelled Image • Facile and single step biogenic synthesis of highly stable spherical silver nanoparticles (AgNPs). • Phytochemicals i.e. flavonoids and phenols act as reducing and capping agent. • Both extracts and synthesized NPs exhibit potent antioxidant activity. • Antioxidant activity is directly linked with anticancer and anti-aging activities. • Both extracts and NPs can be used as antidiabetic and anti-inflammatory agent with few improvements. [ABSTRACT FROM AUTHOR]

Green synthesis of nanoparticles (NPs) involves the use of diverse extracts of biological origin as substrates to synthesize NPs and can overcome the hazards associated with chemical methods. Coconut inflorescence sap, which is unfermented phloem sap obtained by tapping of coconut inflorescence, is a rich source of sugars and secondary metabolites. In this study, coconut inflorescence sap was used to synthesize silver NPs (AgNPs). We have initially undertaken metabolomic profiling of coconut inflorescence sap from West Coast Tall cultivar to delineate its individual components. It was found to comprise of 64% secondary metabolites, 9% sugars, 12% lipids/fats and 9% peptides in positive mode, whereas in the negative mode, it was 33, 20, 9 and 11%, respectively. The concentration of silver nitrate, inflorescence sap and incubation temperature for the synthesis of AgNPs were optimized. Incubating the reaction mixture at 40 °C was found to enhance AgNP synthesis. The AgNPs synthesized were characterized using UV–visible (UV-Vis) spectrophotometry, X-Ray Diffraction (XRD), Fourier Transform Infrared spectroscopy (FTIR) and Transmission Electron Microscopy (TEM). The particles were crystalline in nature and the bulk of the particles were spherical with smooth (thin) shell and poly-dispersed with a diameter ranging from 10 nm to 30 nm. Antimicrobial property of AgNPs was tested in tissue culture of arecanut (Areca catechu L.) where bacterial contamination (Bacillus pumilus) was a frequent occurrence. A significant reduction in the contamination was observed when plantlets were treated with aqueous solutions of AgNPs. Notably, treatment with AgNPs did not affect the growth and development of the arecanut plantlets. Antimicrobial properties of AgNPs synthesized from inflorescence sap were also evaluated in human pathogenic bacteria viz., Escherichia coli ATCC 25922; Salmonella Typhimurium ATCC 14028 and Vibrio parahaemolyticus AQ4037. The antibacterial action was confirmed by determining the production of reactive oxygen species (ROS) and protein leakage studies. Cytotoxicity of AgNPs was quantified in HeLa cells. The viability (%) of HeLa cells declined significantly at 10 mg L−1 concentration of AgNP and complete mortality was observed at a concentration of 60 mg L−1. The study concludes that unfermented inflorescence sap, with above neutral pH, serves as an excellent reducing agent to synthesize AgNPs from Ag+. Unlabelled Image • Coconut inflorescence sap is a rich source of metabolites, sugars, lipids & peptides. • Coconut inflorescence sap was used to synthesize silver nanoparticles (AgNPs). • The AgNPs synthesized were characterized extensively. • Its antimicrobial and cytotoxic properties were also assessed. [ABSTRACT FROM AUTHOR]

Phytochemicals sources have been extensively used as reducing and capping agents for synthesis of nanoparticles (NPs). However, morphology-controlled synthesis and shape/size dependent applications of these NPs still need to be explored further, and there is a need to develop a way in which particular and optimized phytochemicals result in the desired NPs in lesser time and cost with higher reproducibility rate. The present study is focused on morphology-controlled synthesis and shape/size dependent application of silver NPs based on the fractionated phytochemicals of Elaeagnus umbellata extract (EU). Unlike other approaches, in this study the reaction parameters such as time, temperature, pH, stirring speed and concentration of the precursor solutions were not altered during the optimization process. The fractionated phytochemicals were used separately for the synthesis of AgNPs, and the synthesized NPs were characterized by UV–visible, FT-IR, atomic force microscopy (AFM) and scanning electron microscopy (SEM). Our findings suggested that the constituents of the extract fractions varied with the selection of the extraction solvent, and the shape/size, bactericidal properties and toxicity of the NPs have a strong correlation with the phytochemicals of the plant extract. The fractionated phytochemicals present in the water fractions (EUW) resulted in monodispersed spherical AgNPs in the size about 40 nm. The NPs have significant stability in physiological conditions (i.e. temperature, pH and salt), have good antibacterial activity, and were found to be non-toxic. Furthermore, AFM and SEM analysis exposed that the NPs killed the bacteria by disturbing the cellular morphology and releasing the cellular matrix. Our results justify the use of different fractions of plant extract to obtain detail implications on shape, size, antibacterial potential and toxicity of AgNPs. This is the first step in a controllable, easy and cheap approach for the synthesis of highly stable, uniform, non-toxic and bactericidal AgNPs using five fractions of EU. The findings suggested that the synthesized NPs, particularly from EUW, could be used in pharmaceutical and homeopathic industry for the development of antibacterial medications. Unlabelled Image • Bio-inspired synthesis of AgNPs by using five fractions of Elaeagnus umbellata extract. • The use of fractionated phytochemicals in the extract for controllable synthesis of AgNPs. • AgNPs exhibited promising antibacterial activity against gram-positive and gram-negative bacteria. • Phytochemicals in the extract provides a simple, efficient and cost-effective way for the synthesis of stable and non-toxic AgNPs. • Use of AFM and SEM for morphological characterization of S. aureus and E. coli. [ABSTRACT FROM AUTHOR]

Biosynthesis of metal nanoparticles is expected as a cost efficient and ecofriendly option in the research study. Therefore, the aqueous extracts made from leaf of Aesculus hippocastanum (horse chestnut) were used as the reducing factors to synthesize silver nanoparticles (AgNPs) and their antioxidant, antibacterial and the application of resveratrol combined AgNPs as efficient delivery vehicles have also been evaluated. The biosynthesized AgNPs were characterized by UV–Visible Spectroscopy, Fourier-Transform Infrared Spectroscopy (FTIR), X Ray Diffraction (XRD), Zeta potential, and Scanning Electron Microscopy (SEM). The AgNPs were found to be stable at −29.1 mV through zeta potential study. According to the UV-Vis measurements, AgNP formation was observed at a wavelength range of 420–470 nm. The Ag NPs were spherical with a size of 50 ± 5 nm. AgNPs exhibited strong antibacterial activity against all tested bacterial species but have no effect against fungal strains. AgNPs showed an important inhibitive activity counter the DPPH radical and thereby indicate a source for antioxidants. The free radical scavenging activity of AgNP was calculated as 54.72% at the highest concentration (100 ppm). The superoxide radical scavenging activity of AgNPs was found to be increased with increasing concentrations and the average inhibition was about 62.9% as compared to the activity of plant extract. In vitro investigations on the drug delivery from AgNPs exhibited pH dependency; the release was significant (45.6%) below acidic terms (pH 5.2) when in proportion to physiological terms (pH7.4). It was observed that the resveratrol-combined to AgNPs stays on the nanoparticle surface for a lengthy time in the plasma at physiological pH (7.4), so very reducing the flank influence on the normal tissues. It can be concluded that horse chestnut leaves has reduction potential as well as being a capping agent to produce well-defined nanoscale silver particles. Our biosynthesized Ag NPs can be used antibacterial, antioxidant agent and also for as effective delivery vehicles in the near future. • Green synthesis of AgNPs using Aesculum hippocastanum leaf extract. • The synthesized nanoparticles were analyzed by FT-IR, XRD, Zeta Potantial and SEM. • Obtained AgNPs showed significant antioxidant and antimicrobial activities. • In vitro observations on the drug release from AgNPs exhibited pH dependency. [ABSTRACT FROM AUTHOR]

This research has revealed the promising, green and one-pot approach for fabrication of antimicrobial nanohybrids based on organic nanofibers including cellulose (CNF), chitosan (CHNF), and lignocellulose (LCNF) nanofibers impregnated with silver nanoparticles (AgNPs). Lythrum salicaria extract was used as a reducing agent as well as a capping agent. Formation of the spherical AgNPs ranging between 45 and 65 nm was proved by UV–Vis spectroscopy, transmission electron microscopy (TEM), and dynamic light scattering (DLS). Biomaterials supported AgNPs were characterized and compared for their morphological, thermal, release, and antimicrobial properties. The considerable influence of the phenolic compounds of L.salicaria extract on the synthesis and uniform distribution of AgNPs on nanofibers was confirmed by field emission electron microscopy (FE-SEM). Energy dispersive X-ray spectroscopy (EDX) and ICP-OES analysis of nanohybrids, reflected a high loading capacity for LCNF and also CHNF in contrast to CNF. The release of AgNPs from LCNF substrate was lower than other nanofibers but the order of antimicrobial activity of nanohybrids against E.coli and S.aureus was as this: CHNF ˃ LCNF ˃ CNF. Generally, this research suggested that the efficiency of CHNF and LCNF as immobilizing support of AgNPs is higher than CNF and L.salicaria extract was proposed as a high potential reducing and capping agent. Unlabelled Image • Biosynthesized AgNPs ranging between 45 and 65 nm were obtained using Lythrum salicaria extract. • L. salicaria extract was proposed as a high potential reducing and capping agent. • CNF-AgNPs, CHNF-AgNPs, and LCNF-AgNPs, were characterized and compared by ICP-OES, FE-SEM, EDX, XRD, and TGA analyses. • Hybrid nanomaterials manifested antimicrobial activity against foodborne pathogenic bacteria. • CHNF and LCNF were proposed as suitable multifunctional nanofillers. [ABSTRACT FROM AUTHOR]

The present investigation highlights the strong antioxidant, anticancer and larvicidal potential of green synthesized silver nanoparticles (AgNPs) using aqueous leaf extract of Piper longum L. for their diverse therapeutic applications. The optimum conditions for the synthesis of AgNPs were recorded as 1 mM AgNO 3 , 60 ± 2 °C at pH 6 for 120 min. Synthesized AgNPs proved to be highly stable and monodispersed as characterized through various techniques. UV–Vis spectrum of biosynthesized AgNPs showed a maximum absorption peak at 420 nm. Field emission-Scanning electron microscopy (FE-SEM) and High resolution-Transmission electron microscopy (HR-TEM) micrographs showed the spherical shape of AgNPs with mean diameter size of 28.8 nm. Existence of crystallographic AgNPs was proved by X-ray diffraction (XRD) pattern analysis. Presence of phenolics, terpenoids and flavonoids compounds which act as bioreducing agents were confirmed by Fourier-transform infrared spectroscopy (FTIR) analysis. Furthermore, the AgNPs and leaf extracts prepared individually in different solvents such as methanol, ethyl acetate, chloroform, hexane and aqueous were assessed for their bio-efficacies. AgNPs showed the enhanced antioxidant (IC 50 67.56 μg) and radical-scavenging activities (IC 50 196.8 μg) as compared to the crude leaf extracts. Anticancer activity revealed the strong and dose-dependent cytotoxic effect of AgNPs against the HeLa cells showing maximum IC 50 value being 5.27 μg/mL after 24 h and was also found to be non-toxic to normal cells (HEK). The AgNPs induced the fragmentation of DNA in the cells, indicating the occurrence of apoptosis and necrosis. Subsequently, an efficient larvae mortality was also recorded against Anopheles stephensi having LC 50 and LC 90 values being 8.969 and 16.102 ppm, followed by Aedes aegypti (LC 50 ;14.791 and LC 90 ;28.526 ppm) and Culex quinquefasciatus (LC 50 ;18.662 and LC 90 ;40.903 ppm) after 72 h of exposure. Besides, they showed no toxicity against Mesocyclops thermocyclopoides (non-target organism). This is the first report showing strong anti-tumorous and larvicidal activity of AgNPs synthesized using P. longum leaf extract against cervical cancer cell line and mosquito vectors causing dengue, malaria and filariasis. Based on our findings, we suggest that AgNPs derived using P. longum leaf extract possessed excellent anti-cancerous and mosquito larvicidal potential and therefore, can be bioprospected further for the management of these hazardous health diseases. This study has given a new insight for the novel drug designing after conducting experiments on the in vivo models. Unlabelled Image • This study highlights the bio-fabrication of silver nanoparticles (AgNPs) using Piper longum leaf extract. • AgNPs were monodispersed and completely spherical in shape with an average diameter of 28 nm. • AgNPs showed enhanced antioxidant and radical-scavenging activities due to the high phenol and flavonoid content. • AgNPs manifested excellent anticancer and larvicidal potential against cervical cancer cell line and mosquito vectors. • Besides, they showed no toxicity towards normal cells (HEK) and non-targeted organism (M. thermocyclopoides). [ABSTRACT FROM AUTHOR]