Green synthesis,characterisation and bioactivity of plant‐mediated silver nanoparticles using Decalepis hamiltonii root extract

Consistent search of plants for green synthesis of silver nanoparticles (SNPs) is an important arena in Nanomedicine. This study focuses on synthesis of SNPs using bioreduction of silver nitrate (AgNO₃) by aqueous root extract of Decalepis hamiltonii. The biosynthesis of SNPs was monitored by UV–vis analysis at absorbance maxima 432 nm. The fluorescence emission spectra of SNPs illustrated the broad emission peak 450–483 nm at different excitation wavelengths. The surface characteristics were studied by scanning electron microscope and atomic force microscopy, showed spherical shape of SNPs and dynamic light scattering analysis confirmed the average particle size 32.5 nm and the presence of metallic silver was confirmed by energy dispersive X‐ray. Face centred cubic structure with crystal size 33.3 nm was revealed by powder X‐ray diffraction. Fourier transform infrared spectroscopy indicated the biomolecules involved in the reduction mainly polyols and phenols present in root extracts were found to be responsible for the synthesis of SNPs. The stability and charge on SNPs were revealed by zeta potential analysis. In addition, on therapeutic forum, the synthesised SNPs elicit antioxidant and antimicrobial activity against Bacillus cereus, Bacillus licheniformis, Escherichia coli, Pseudomonas aeruginosa and Staphylococcus aureus.Inspec keywords: silver, nanoparticles, nanomedicine, antibacterial activity, biomedical materials, nanofabrication, particle size, microorganisms, ultraviolet spectra, visible spectra, fluorescence, scanning electron microscopy, atomic force microscopy, light scattering, X‐ray diffraction, X‐ray chemical analysis, Fourier transform infrared spectra, molecular biophysics, electrokinetic effectsOther keywords: phenols, zeta potential analysis, therapeutic forum, antioxidant activity, antimicrobial activity, Bacillus cereus, Bacillus licheniformis, Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus, Ag, polyols, biomolecules, Fourier transform infrared spectroscopy, powder X‐ray diffraction, crystal size, face centred cubic structure, energy dispersive X‐ray analysis, metallic silver, particle size, dynamic light scattering analysis, spherical shape, atomic force microscopy, scanning electron microscopy, surface characteristics, excitation wavelengths, fluorescence emission spectra, UV‐visible analysis, biosynthesis, silver nitrate bioreduction, nanomedicine, Decalepis hamiltonii aqueous root extract, bioactivity, plant‐mediated silver nanoparticles, green synthesis     

Biosynthesis of the CuO nanoparticles using Euphorbia Chamaesyce leaf extract and investigation of their catalytic activity for the reduction of 4‐nitrophenol

Through this study an eco‐friendly, simple, efficient, cheap and biocompatible approach to the biosynthesis and stabilisation of CuO nanoparticles (NPs) using the Euphorbia Chamaesyce leaf extract is presented. The CuO NPs were monitored and characterised by field emission scanning electron microscopy, energy dispersive X‐ray spectroscopy, Fourier transformed infrared spectroscopy, transmission electron microscope and UV‐visible spectroscopy. The biosynthesised CuO NPs showed good catalytic activity for the reduction of 4‐nitrophenol (4‐NP) in water during 180 s and reused 4 times without considerable loss of activity.Inspec keywords: copper compounds, nanoparticles, nanofabrication, catalysis, reduction (chemical), field emission electron microscopy, X‐ray chemical analysis, Fourier transform infrared spectra, transmission electron microscopy, ultraviolet spectra, visible spectraOther keywords: biosynthesis, CuO nanoparticles, Euphorbia Chamaesyce leaf extract, catalytic activity, 4‐nitrophenol reduction, nanoparticle stabilisation, field emission scanning electron microscopy, energy dispersive X‐ray spectroscopy, Fourier transformed infrared spectroscopy, transmission electron microscope, UV‐visible spectroscopy, CuO     

Green synthesis of nanosilver‐decorated graphene oxide sheets

A green facile method has been successfully used for the synthesis of graphene oxide sheets decorated with silver nanoparticles (rGO/AgNPs), employing graphite oxide as a precursor of graphene oxide (GO), AgNO₃ as a precursor of Ag nanoparticles (AgNPs), and geranium (Pelargonium graveolens) extract as reducing agent. Synthesis was accomplished using the weight ratios 1:1 and 1:3 GO/Ag, respectively. The synthesised nanocomposites were characterised by scanning electron microscopy, transmission electron microscopy, atomic force microscopy, X‐ray diffraction, UV‐visible spectroscopy, Raman spectroscopy, energy dispersive X‐ray spectroscopy and thermogravimetric analysis. The results show a more uniform and homogeneous distribution of AgNPs on the surface of the GO sheets with the weight ratio 1:1 in comparison with the ratio 1:3. This eco‐friendly method provides a rGO/AgNPs nanocomposite with promising applications, such as surface enhanced Raman scattering, catalysis, biomedical material and antibacterial agent.Inspec keywords: silver, nanoparticles, graphene, nanocomposites, scanning electron microscopy, transmission electron microscopy, atomic force microscopy, X‐ray diffraction, ultraviolet spectra, visible spectra, X‐ray chemical analysis, surface enhanced Raman scattering, catalysis, nanofabricationOther keywords: antibacterial agent, biomedical material, catalysis, surface enhanced Raman scattering, rGO‐AgNP nanocomposite, eco‐friendly method, homogeneous distribution, thermogravimetric analysis, energy dispersive X‐ray spectroscopy, Raman spectroscopy, UV‐visible spectroscopy, X‐ray diffraction, atomic force microscopy, transmission electron microscopy, scanning electron microscopy, nanocomposites, reducing agent, geranium, graphene oxide sheets, graphite oxide, silver nanoparticles, green facile method     

Green synthesis of silver nanoparticles with the Arial part of Dorema ammoniacum D. extract by antimicrobial analysis

Silver nanoparticles (SNPs) were synthesised by using the Arial part extract of Dorema ammoniacum D. and characterised by employing UV–visible spectroscopy, Fourier transform infrared spectroscopy and X‐ray diffraction techniques. Transmission electron microscopy and field emission scanning electron microscopy were applied to investigate the morphological structure of the bio‐synthesised SNPs. The antimicrobial activity of SNPs was studied against Gram positive (Bacillus cereus and Staphylococcus aureus) and Gram‐negative (Escherichia coli and Salmonella typhimurium) bacteria by employing the disk diffusion agar process. An extremely antimicrobial effect was observed for SNPs. Utilising D. ammoniacum D. as a mediator for the synthesis of SNPs helped to save time and cost.Inspec keywords: silver, nanoparticles, nanofabrication, nanomedicine, biomedical materials, particle size, antibacterial activity, visible spectra, ultraviolet spectra, microorganisms, field emission scanning electron microscopy, transmission electron microscopy, X‐ray diffraction, surface diffusionOther keywords: green synthesis, silver nanoparticles, Dorema ammoniacum D. extract, antimicrobial analysis, Arial part extract, UV‐visible spectroscopy, Fourier transform infrared spectroscopy, X‐ray diffraction, transmission electron microscopy, field emission scanning electron microscopy, morphological structure, bio‐synthesised SNPs, antimicrobial activity, gram positive Bacillus cereus bacteria, gram positive Staphylococcus aureus bacteria, gram‐negative Escherichia coli bacteria, gram‐negative Salmonella typhimurium bacteria, disk diffusion agar process, antimicrobial effect, Ag     

Biogenic synthesis,characterisation and antifungal activity of gum kondagogu‐silver nano bio composite construct: assessment of its mode of action

The biogenic synthesis of silver nanoparticles was achieved by using gum kondagogu (Cochlospermum gossypium), a natural biopolymer (Gk‐AgNPs). Synthesised nanoparticles were characterised by using UV–visible spectroscopy, inductively coupled plasma‐atomic emission spectrometer, X‐ray diffraction, transmission electron microscope techniques. The silver nano particle size determined was found to be 3.6 ± 2.2 nm. The synthesised Gk‐AgNPs showed antifungal activity and exhibited minimum inhibitory concentration and minimal fungicidal concentration values ranging from 3.5 to 6.5 µg mL⁻¹ against Aspergillus parasiticus (NRRL‐2999) and Aspergillus flavus (NRRL‐6513). Scanning electron microscopy–energy dispersive spectroscopy analysis revealed morphological changes including deformation, shrunken and ruptured mycelium of the fungi. At the biochemical level, the mode of action revealed that there was an elevated level of reactive oxygen species, lipid peroxidation, superoxide dismutase, and catalase enzyme activity. Increased oxidative stress led to increased outer membrane damage, which was confirmed by the entry of N ‐phenyl naphthylamine to the phospholipid layer of outer membrane and higher levels of K⁺ release from the fungi treated with Gk‐AgNPs. This study explores the possible application of biogenic silver nanoparticles produced from gum kondagogu as potent antifungal agents. The potent antifungal activity of Gk‐AgNPs gives scope for its relevance in biomedical application and as a seed dressing material.Inspec keywords: antibacterial activity, nanocomposites, silver, nanofabrication, nanoparticles, biomedical materials, polymers, visible spectra, ultraviolet spectra, atomic emission spectroscopy, X‐ray diffraction, transmission electron microscopy, scanning electron microscopy, microorganisms, X‐ray chemical analysis, enzymes, lipid bilayers, biomembranes, biomechanics, nanomedicineOther keywords: antifungal activity, gum kondagogu‐silver nanobiocomposite, Cochlospermum gossypium, natural biopolymer, UV‐visible spectroscopy, inductively coupled plasma‐atomic emission spectrometer, X‐ray diffraction, transmission electron microscope, fungicidal concentration, Aspergillus parasiticus, Aspergillus flavus, scanning electron microscopy, SEM‐energy dispersive spectroscopy, fungi deformation, ruptured mycelium, reactive oxygen species, lipid peroxidation, superoxide dismutase, catalase enzyme activity, oxidative stress, membrane damage, N‐phenyl naphthylamine, phospholipid layer, potassium ion release, biogenic silver nanoparticle, antifungal agent, seed dressing material, Ag     

In vivo biosynthesis and spatial distribution of Ag nanoparticles in maize (Zea mays L.)

Nanoparticles (NPs), especially biosynthesised in living plants by absorbing soluble salts and reducing metal ions, are extensively used in various fields. This work aimed at investigating the in vivo biosynthesis of silver NPs (Ag‐NPs) in maize and the spatial distribution of the NPs and some important nutrient elements in the plant. The content of silver in plant was examined by inductively coupled plasma‐atomic emission spectrometer showing that Ag can be absorbed by plant as soluble salts. The NPs in different parts of maize plant were detected and analysed by transmission electron microscopy, demonstrating the synthesis of NPs and their transport from the root to the shoots. Two‐dimensional proton induced X‐ray emission of silver, chlorine and several nutrient elements elucidated the possible relationship between synthesis of NPs and several nutrient elements in plant tissues. To their knowledge, this is the first report of possibility of synthesis of Ag‐NPs in living plants maize (Zea mays L.). This study presents direct evidence for synthesis of NPs and distribution of related nutrient elements in maize, which has great significance for studying synthetic application of NPs in crop plants.Inspec keywords: atomic emission spectroscopy, nanoparticles, nanofabrication, crops, silver, transmission electron microscopy, X‐ray chemical analysis, sorption, chlorineOther keywords: maize plant, plant tissues, crop plants, spatial distribution, metal ion reduction, nutrient elements, inductively coupled plasma analysis, atomic emission spectrometry, Zea mays L., soluble salt absorbtion, transmission electron microscopy, proton induced X‐ray emission analysis, chlorine, silver nanoparticle biosynthesis process, Ag, Cl     

Synthesis,characterisation and potential applications of polyaniline/chitosan‐Ag‐nano‐biocomposite

Biodegradable polymers have greatly promoted the development of environmental, biomedical and allied sciences because of their biocompatibility and doping chemistry. The emergence of nanotechnology has envisaged greater options for the development of biodegradable materials. Polyaniline grafted chitosan (i.e. biodegradable PANI) copolymer was prepared by the chemical in situ polymerisation of aniline using ammonium per sulphate as initiator while Ag nanoparticle were synthesised by chemical reduction method and incorporated in to the polymer matrix. The as prepared materials were characterised by X‐ray diffraction, Fourier transform Infra‐red spectroscopy, transmission electron microscopy, energy dispersive X‐ray analysis. Moreover energy storage capacity, impedance properties were also studied. The main focus was on the photocatalytic degradation of organic dyes to remove the toxic and carcinogenic pollutants. This polymer nano‐biocomposite has multifold applications and can be used as excellent materials for enhanced photodegradation and removal of toxic contaminants from waste waters and natural water streams. In addition, the biocompatible materials with excellent mechanical properties and low toxicity can also be used for tissue engineering, drug delivery and electrical energy storage devices.Inspec keywords: silver, filled polymers, polymer blends, nanocomposites, nanoparticles, nanofabrication, biodegradable materials, polymerisation, reduction (chemical), Fourier transform infrared spectra, transmission electron microscopy, X‐ray chemical analysis, X‐ray diffractionOther keywords: polyaniline‐chitosan‐silver‐nanobiocomposite, biodegradable polymers, biocompatibility, doping chemistry, nanotechnology, biodegradable PANI, polyaniline grafted chitosan copolymer, biodegradable materials, chemical in situ polymerisation, nanoparticle, polymer matrix, chemical reduction method, Fourier transform Infrared spectroscopy, transmission electron microscopy, energy dispersive X‐ray analysis, X‐ray diffraction, energy storage capacity, impedance properties, carcinogenic pollutants, toxic pollutants, photodegradation, toxic contaminants, natural water streams, waste waters, drug delivery, tissue engineering, electrical energy storage devices, mechanical properties, Ag     

Biosynthesis of Ag nanoparticles and two‐dimensional element distribution in Arabidopsis

Metallic nanoparticles can be synthesised in living plants, which provide a friendly approach. In this work, the authors aimed to study the synthesis of silver nanoparticles (AgNPs) in Arabidopsis and the two‐dimensional (2D) distribution of Ag and other elements (Ca, P, S, Mg, and CI) in the Arabidopsis plant tissues. The concentrations of Ag in the plant tissues were determined by inductively coupled plasma‐atomic emission spectrometer, showing that the majority of Ag was retained in the roots. Transmission electron micrographs showed the morphology of AgNPs and the location in plant cells. The distributions of Cl and Ag were consistent in plant tissues by 2D proton‐induced X‐ray emission. In conclusion, this is the first report of the AgNP synthesis in Arabidopsis living plants and its 2D distribution of important elements, which provide a new clue for further research.Inspec keywords: silver, botany, atomic emission spectroscopy, antibacterial activity, nanoparticles, nanofabrication, transmission electron microscopy, chlorine, calcium, sulphur, phosphorusOther keywords: biosynthesis, two‐dimensional element distribution, metallic nanoparticles, silver nanoparticles, Arabidopsis plant tissues, inductively coupled plasma‐atomic emission spectrometry, transmission electron micrography, plant cells, 2D proton‐induced X‐ray emission, Arabidopsis living plants, Ag, Cl, Ca, P, S, Mg     

Alkaline treatment effect on the properties of in‐situ synthesised ZnO nanoparticles on cotton fabric

In this study, an in‐situ approach was used to synthesise zinc oxide nanoparticles on the surface of cotton fabric. The effect of alkaline pre‐ and after‐treatment and Zn²⁺ concentration was studied on the morphological, structural, thermal, photocatalytic, and antibacterial properties of loaded cotton fabrics. Scanning electron microscopy, energy dispersive X‐ray spectroscopy, X‐ray diffractometer, thermogravimetric analysis, and attenuated total reflection Fourier transform infrared spectrometer were used to characterise the properties of loaded cotton fabrics. Alkaline after‐treatment of cotton fabric presented more dispersed zinc oxide nanoparticles, and an increase in Zn²⁺ concentration led to form agglomerated nanoparticles on the surface of cotton fibres. The loaded cotton fabrics with zinc oxide nanoparticles presented an inhibition zone against Staphylococcus aureus and Escherichia coli. In addition, the stain of methylene blue on the surface of loaded samples was degraded after irradiated under visible light.Inspec keywords: nanofabrication, zinc compounds, II‐VI semiconductors, nanoparticles, nanomedicine, antibacterial activity, catalysis, photochemistry, cotton fabrics, scanning electron microscopy, X‐ray chemical analysis, X‐ray diffraction, thermal analysis, attenuated total reflection, Fourier transform infrared spectroscopy, microorganisms, materials preparationOther keywords: alkaline treatment effect, in‐situ synthesised ZnO nanoparticles, alkaline pretreatment, alkaline after‐treatment, Zn²⁺ concentration, morphological property, structural property, thermal property, photocatalytic property, antibacterial property, loaded cotton fabrics, scanning electron microscopy, energy dispersive X‐ray spectroscopy, X‐ray diffractometer, thermogravimetric analysis, attenuated total reflection Fourier transform infrared spectrometer, agglomerated nanoparticles, zinc oxide nanoparticles, inhibition zone, Staphylococcus aureus, Escherichia coli, methylene blue, visible light, ZnO     

Role of AgNPs in the enhancement of seed germination and its effect on plumule and radicle length of Pennisetum glaucum

The authors have investigated beneficial effects of 1 mM of silver nanoparticles (AgNPs) on agriculturally important plant Pennisetum glaucum (Bajara). The extracellular AgNPs were synthesised using Bacillus subtilis spizizenni and characterised using ultraviolet–visible absorption spectroscopy, Fourier transform infrared spectroscopy (FT‐IR) and transmission electron microscopy (TEM). Optical absorption spectrum showed characteristic peak of AgNPs at 423 nm. FT‐IR analysis of AgNPs showed peak at 3435 cm⁻¹, which indicates the presence of N–H group (primary, secondary amines and amides) on the surface of AgNPs. TEM studies indicate that synthesised AgNPs have average size of ∼2 nm. Energy dispersive X‐ray spectroscopy showed strong signal of Ag at 3 keV. Treatment of 1 mM AgNPs to the bajara seeds was found to be sufficient for excellent germination of seeds within 3 days. There was also significant increase in radicle and plumule length as compared with control bajara seeds according to statistical analysis by one‐way analysis of variance, followed by Tukey''s test. The percentage of AgNPs detected in root samples was 0.003% (by inductively coupled plasma atomic emission spectroscopy), which is negligible. There is still need to study the bioavailability and the type of interaction of AgNPs with plants, necessary for application in agriculture.Inspec keywords: transmission electron microscopy, ultraviolet spectra, scanning electron microscopy, nanofabrication, X‐ray diffraction, nanoparticles, visible spectra, silver, atomic emission spectroscopy, X‐ray chemical analysis, Fourier transform infrared spectra, statistical analysis, agricultureOther keywords: ultraviolet–visible absorption spectroscopy, transmission electron microscopy, Pennisetum glaucum, Bacillus subtilis spizizenni, energy dispersive X‐ray spectroscopy, Fourier transform infrared spectroscopy, optical absorption spectrum, plumule length, radicle length, silver nanoparticles, Tukey''s test, inductively coupled plasma atomic emission spectroscopy, statistical analysis, Bajara seeds, scanning electron microscopy, X‐ray diffraction, analysis of variance, electron volt energy 3.0 keV, time 3.0 d, Ag     

Differential antibacterial response exhibited by graphene nanosheets toward gram‐positive bacterium Staphylococcus aureus

Two different morphological forms of graphene nanosheets: improved reduced graphene oxide (IRGO) and modified reduced GO (rGO) (MRGO) have been synthesised by improved and modified methods, respectively. Physical characterisations of these graphene nanosheets were carried out using X‐ray diffraction, Fourier transform infrared spectroscopy, and Raman spectroscopy. Colloidal stability of these nanosheets toward a selected bacterium (e.g. Staphylococcus aureus) was ascertained by zeta potential. In the present study, the authors for the first time made an attempt to study and compare the potentialities of these two different forms of graphene nanosheets as efficient bactericidal agents. Field‐emission scanning electron microscopy and TEM with energy dispersive X‐ray spectroscopy (EDAX) studies of IRGO and MRGO have been carried out to explore their underlying mechanism of antibacterial responses through physical as well as chemical interactions with the selected bacterial species.Inspec keywords: scanning electron microscopy, X‐ray diffraction, graphene, Raman spectra, field emission electron microscopy, microorganisms, colloids, X‐ray chemical analysis, antibacterial activity, electrokinetic effects, nanofabrication, Fourier transform infrared spectra, nanobiotechnologyOther keywords: graphene nanosheets, differential antibacterial response, gram‐positive bacterium, reduced graphene oxide, Staphylococcus aureus, X‐ray diffraction, Fourier transform infrared spectroscopy, Raman spectroscopy, colloidal stability, field‐emission scanning electron microscopy, TEM, EDAX, C     

Biological synthesis and characterisation of silver nanoparticles using Pseudomonas geniculata H10 for pharmaceutical activity

In the present study, silver nanoparticles (SNPs) were synthesised for the first time using Pseudomonas geniculata H10 as reducing and stabilising agents. The synthesis of SNPs was the maximum when the culture supernatant was treated with 2.5 mM AgNO₃ at pH 7 and 40°C for 10 h. The SNPs were characterised by field emission scanning electron microscopy‐energy‐dispersive spectroscopy, transmission electron microscopy, dynamic light scattering, X‐ray diffraction and UV–vis spectroscopy. Fourier transform infrared spectroscopy indicated the presence of proteins, suggesting they may have been responsible for the reduction and acted as capping agents. The SNPs displayed 1,1‐diphenyl‐2‐picrylhydrazyl (IC₅₀  = 28.301 μg/ml) and 2,2′‐azinobis‐3‐ethylbenzothiazoline‐6‐sulphonate (IC₅₀  = 27.076 μg/ml) radical scavenging activities. The SNPs exhibited a broad antimicrobial spectrum against several human pathogenic Gram‐positive and Gram‐negative bacteria and Candida albicans. The antimicrobial action of SNPs was due to cell deformation resulting in cytoplasmic leakage and subsequent lysis. The authors’ results indicate P. geniculata H10 could be used to produce antimicrobial SNPs in a facile, non‐toxic, cost‐effective manner, and that these SNPs can be used as effective growth inhibitors in various microorganisms, making them applicable to various biomedical and environmental systems. As far as the authors are aware, this study is the first to describe the potential biomedical applications of SNPs synthesised using P. geniculata.Inspec keywords: X‐ray diffraction, proteins, scanning electron microscopy, enzymes, reduction (chemical), transmission electron microscopy, Fourier transform spectra, field emission electron microscopy, microorganisms, antibacterial activity, pharmaceutical technology, biotechnology, silver compoundsOther keywords: silver nanoparticles, Pseudomonas geniculata H10, field emission scanning electron microscopy‐energy‐dispersive spectroscopy, transmission electron microscopy, 1‐diphenyl‐2‐picrylhydrazyl, antimicrobial SNPs, Fourier transform infrared spectroscopy, Candida albicans, cytoplasmic leakage, microorganisms, biomedical applications, temperature 40.0 degC, time 10.0 hour, AgNO₃      

Catalytic reduction of 2,4‐dinitrophenylhydrazine by cuttlebone supported Pd NPs prepared using Conium maculatum leaf extract

A facile and green process to synthesise cuttlebone supported palladium nanoparticles (Pd NPs/cuttlebone) is reported using Conium maculatum leaf extract and in the absence of chemical solvents and hazardous materials. The antioxidant content of the C. maculatum leaf extract played a significant role in converting Pd²⁺ ions to Pd NPs. Various techniques were used for the characterisation of the Pd NPs/cuttlebone such as field‐emission scanning electron microscopy, X‐ray diffraction, energy dispersive X‐ray spectroscopy, Fourier transform infrared and ultraviolet–visible spectroscopy. This Pd NPs/cuttlebone showed excellent catalytic activity in the reduction of 2,4‐dinitrophenylhydrazine to 2,4‐diaminophenylhydrazine by sodium borohydride as the source of hydrogen at ambient condition. The catalyst could be separated and recycled up to five cycles with no loss of its activity.Inspec keywords: catalysis, catalysts, chemical engineering, palladium, nanoparticles, field emission electron microscopy, scanning electron microscopy, X‐ray diffraction, X‐ray chemical analysis, sodium compounds, ultraviolet spectroscopy, visible spectroscopyOther keywords: catalytic reduction, 2,4‐dinitrophenylhydrazine, cuttlebone, Conium maculatum leaf extract, green process, palladium nanoparticles, antioxidant content, field‐emission scanning electron microscopy, X‐ray diffraction, energy dispersive X‐ray spectroscopy, Fourier transform infrared, ultraviolet–visible spectroscopy, 2,4‐diaminophenylhydrazine, sodium borohydride     

Facile phyto‐mediated synthesis of silver nanoparticles using Chinese winter jujube (Ziziphus jujuba Mill. cv. Dongzao) extract and their antibacterial/catalytic properties

The aqueous extract of Chinese winter jujube (Ziziphus jujuba Mill. cv. Dongzao) was used as reducing and capping agents for the synthesis of silver nanoparticles (AgNPs) for the first time. The resulting AgNPs were characterised by UV/Visible (UV–Vis) spectroscopy, atomic force microscope, transmission electron microscopy, selected area electron diffraction, X‐ray diffraction, scanning electron microscopy, energy‐dispersive X‐ray and Fourier transform infrared spectroscopy (FTIR). The colloidal solution of AgNPs gave a maximum UV–Vis absorbance at 446 nm. The synthesised nanoparticles were almost in the spherical shapes with an average size of 11.5 ± 4. 8 nm. FTIR spectra were applied to identify the functional groups which were possibly responsible for the conversion of metal ions into nanoparticles. The results showed that the prepared AgNPs were coated with the biomolecules in the extract. The biosynthesised AgNPs showed a remarkable catalytic activity at room temperature, and they also showed good antibacterial properties against Escherichia coli and Staphylococcus aureus.Inspec keywords: silver, nanoparticles, nanofabrication, antibacterial activity, biomedical materials, nanobiotechnology, scanning electron microscopy, X‐ray diffraction, transmission electron microscopy, ultraviolet spectra, visible spectra, X‐ray chemical analysis, Fourier transform infrared spectra, catalysisOther keywords: wavelength 446 nm, temperature 293 K to 298 K, Ag, Escherichia coli, Staphylococcus aureus, biomolecules, catalytic activity, metal ions, colloidal solution, FTIR spectra, UV‐vis absorbance, TEM, SEM, XRD, Fourier transform infrared spectroscopy, energy‐dispersive X‐ray spectroscopy, scanning electron microscopy, X‐ray diffraction, selected area electron diffraction, transmission electron microscopy, atomic force microscopy, UV‐visible spectroscopy, catalytic properties, antibacterial properties, Chinese winter jujube extract, silver nanoparticles, facile phyto‐mediated synthesis     

Construction of active bio‐nanocomposite by inseminated metal nanoparticles onto activated carbon: probing to antimicrobial activity

The bio‐nanocomposite role in wastewater treatment is a primary concern of this research. The physical, chemical, mechanical stability and antimicrobial activity of these bio‐nanocomposites were investigated. The method is based on the biological reduction of aqueous copper sulphate pentahydrate, lead nitrate, silver nitrate, zinc sulphate heptahydrate salt using seed extract of Eucalyptus globulus as reducing agent at ambient temperature. The synthesised metal nanoparticles (MNPs) were analysed by UV‐visible spectroscopy and Fourier transform infrared spectroscopy analyses. An ex‐situ method involves constructing bio‐nanocomposite by blending MNPs with tea waste activated carbon. Cross‐linking in activated carbon takes place which was confirmed by changes in the mixture of components. The present yield of activated carbon was characterised by scanning electron microscopy and energy dispersive X‐ray measurements. A few micro or nano range, spherical shape of activated carbon was studied by SEM. The main elements found in the activated carbon by EDX are C, O, S, Ag, Cl and Cu. The efficacy of such active bio‐nanocomposite (ABN) tested against human pathogen includes both type of bacteria and fungus. The inhibitory effects of ABN are discernible from the results that reveal biologically inseminated MNPs can be used to clean up the contaminated environment.Inspec keywords: nanocomposites, activated carbon, wastewater treatment, copper compounds, nitrogen compounds, Fourier transform infrared spectra, scanning electron microscopyOther keywords: active bio‐nanocomposite, inseminated metal nanoparticles, activated carbon, antimicrobial activity, wastewater treatment, mechanical stability, biological reduction, aqueous copper sulphate pentahydrate, lead nitrate, silver nitrate, zinc sulphate heptahydrate salt, Eucalyptus globulus, synthesised metal nanoparticle, MNP, UV‐visible spectroscopy, Fourier transform infrared spectroscopy analysis, scanning electron microscopy, energy dispersive X‐ray measurement, SEM     

Biosynthesis of γ ‐Fe2 O3 @CuO core–shell nanoclusters using aqueous extract of Sesbania grandiflora Linn fresh leaves,its characterisation,and antimicrobial activity studies against Staphylococcus aureus strains

The present study reports an eco‐friendly and rapid method for the synthesis of core–shell nanoclusters using the modified reverse micelle method. It is a green synthetic method which uses Sesbania grandiflora Linn extract which acts as a reducing and capping agent. It is observed that this method is very fast and convenient and the nanoclusters are formed with 5–10 min of the reaction time without using harsh conditions. The core–shell nanoclusters so prepared were characterised using UV–Vis spectroscopy, scanning electron microscopy, transmission electron microscopy, X‐ray diffraction, and X‐ray photoelectron spectroscopy. Further, their effective antibacterial activity towards the gram‐positive bacteria Staphylococcus aureus was found to be due to their smaller particle size.Inspec keywords: iron compounds, copper compounds, nanoparticles, particle size, nanofabrication, nanomedicine, biomedical materials, core‐shell nanostructures, antibacterial activity, ultraviolet spectra, visible spectra, microorganisms, reduction (chemical), scanning electron microscopy, transmission electron microscopy, X‐ray diffraction, X‐ray photoelectron spectraOther keywords: biosynthesis, γ‐Fe₂ O₃ ‐CuO core‐shell nanoclusters, aqueous extract, Sesbania grandiflora Linn fresh leaves, antimicrobial activity, Staphylococcus aureus strains, eco‐friendly method, modified reverse micelle method, green synthetic method, reducing agent, capping agent, UV‐visible spectroscopy, scanning electron microscopy, transmission electron microscopy, X‐ray diffraction, X‐ray photoelectron spectroscopy, antibacterial activity, gram‐positive bacteria Staphylococcus aureus, particle size, time 5 min to 10 min, Fe₂ O₃ ‐CuO     

Biosynthesis of waste pistachio shell supported silver nanoparticles for the catalytic reduction processes

Silver nanoparticles (NPs) are immobilised on pistachio shell surface by Cichorium intybus L. leaves extract as an antioxidant media. The Fourier transform infrared spectra, X‐ray diffraction, field‐emission scanning electron microscopy equipped with energy‐dispersive X‐ray spectroscopy, and transmission electron microscope analyses confirmed the support of silver NPs on the pistachio shell (Ag NPs/pistachio shell). Ag NPs on the pistachio shell had a diameter basically in the 10–15 nm range. Reduction reactions of 4‐nitrophenol (4‐NP), and organic dyes at ambient condition were used in the investigation of the catalytic performance of the prepared catalyst. Through this research, the Ag NPs/pistachio shell shows a high activity and recyclability, and reusability without loss of its catalytic activity.Inspec keywords: transmission electron microscopy, nanoparticles, X‐ray diffraction, catalysis, nanofabrication, dyes, X‐ray chemical analysis, reduction (chemical), silver, catalysts, Fourier transform infrared spectra, field emission scanning electron microscopyOther keywords: waste pistachio shell, silver nanoparticles, catalytic reduction processes, pistachio shell surface, antioxidant media, infrared spectra, X‐ray diffraction, field‐emission scanning electron microscopy, energy‐dispersive X‐ray spectroscopy, transmission electron microscope analyses, reduction reactions, catalytic performance, catalytic activity, Cichorium intybus L. leaves extract, size 10.0 nm to 15.0 nm, Ag     

Biofabrication of silver nanoparticles using bacteria from mangrove swamp

The last decade has observed a rapid advancement in utilising biological system towards bioremediation of metal ions in the form of respective metal nanostructures or microstructures. The process may also be adopted for respective metal nanoparticle biofabrication. Among different biological methods, bacteria‐mediated method is gaining great attention for nanoparticle fabrication due to their eco‐friendly and cost‐effective process. In the present study, silver nanoparticle (AgNP) was synthesised via continuous biofabrication using Aeromonas veronii, isolated from swamp wetland of Sunderban, West Bengal, India. The biofabricated AgNP was further purified to remove non‐conjugated biomolecules using size exclusion chromatography, and the purified AgNPs were characterised using UV–visible spectroscopy, X‐ray diffraction, field emission scanning electron microscopy and transmission electron microscopy (TEM). Additionally, the presence of proteins as capping and stabilising agents was confirmed by the amide‐I and amide‐II peaks in the spectra obtained using attenuated total reflection Fourier transform infrared spectroscopy. The size of biofabricated AgNP was 10–20 nm, as observed using TEM. Additionally, biofabricated AgNP shows significant antibacterial potential against E. coli and S. aureus. Hence, biofabricated AgNP using Aeromonas veronii, which found resistant to a significant concentration of Ag ion, showed enhanced antimicrobial activity compared to commercially available AgNP.Inspec keywords: silver, nanoparticles, microorganisms, nanofabrication, purification, chromatography, ultraviolet spectra, visible spectra, X‐ray diffraction, field emission scanning electron microscopy, transmission electron microscopy, proteins, molecular biophysics, biochemistry, molecular configurations, attenuated total reflection, Fourier transform infrared spectra, particle size, antibacterial activity, biomedical materials, nanomedicineOther keywords: capping agents, stabilising agents, amide‐I peaks, amide‐II peaks, attenuated total reflection Fourier transform infrared spectroscopy, antibacterial potential, E. coli, S. aureus, Aeromonas veronii, antimicrobial activity, size 10 nm to 20 nm, Ag, proteins, TEM, transmission electron microscopy, field emission scanning electron microscopy, X‐ray diffraction, UV‐visible spectroscopy, size exclusion chromatography, nonconjugated biomolecules, purification, swamp wetland, Aeromonas veronii, cost‐effective process, eco‐friendly, bacteria‐mediated method, biological methods, metal nanoparticle biofabrication, microstructures, metal nanostructures, metal ions, bioremediation, biological system, mangrove swamp, bacteria, silver nanoparticles     

Peanut skin extract mediated synthesis of gold nanoparticles,silver nanoparticles and gold–silver bionanocomposites for electrochemical Sudan IV sensing

Sustainable methods are needed for rapid and efficient detection of environmental and food pollutants. The Sudan group of dyes has been used extensively as adulterants in food and also are found to be polluting the soil and water bodies. There have been several methods for detection of Sudan dyes, but most of them are not practical enough for common use. In this study, the electrochemical detection efficiency and stability of gold nanoparticle (AuNPs), silver NPs and Au–Ag bionanocomposites, synthesised by peanut skin extract, modified glassy carbon electrode has been investigated. The synthesised nanomaterial samples were characterised, for their quality and quantity, using ultra–visible spectroscopy, inductive coupled plasma mass spectrophotometer, Fourier transform infrared spectroscopy, energy‐dispersive X‐ray spectroscopy, high‐resolution transmission electron microscope and field emission scanning electron microscope. The nanomaterial hybrid electrodes showed great efficiency and stability in the detection of Sudan IV compared with the other previous electrodes. The peak current of the Sudan IV oxidation and reduction was found to be proportional to its concentration, in the range of 10–80 µM, with a detection limit of 4 µM. The hybrid electrodes showed 90% stability in detection for 20 cycles.Inspec keywords: gold, silver, nanoparticles, nanocomposites, biomedical materials, electrochemical sensors, dyes, nanofabrication, ultraviolet spectra, visible spectra, spectrophotometry, Fourier transform infrared spectra, X‐ray chemical analysis, transmission electron microscopy, scanning electron microscopy, field emission electron microscopyOther keywords: peanut skin extract mediated synthesis, gold nanoparticles, silver nanoparticles, gold–silver bionanocomposites, electrochemical Sudan IV sensing, electrochemical detection efficiency, modified glassy carbon electrode, ultra–visible spectroscopy, inductive coupled plasma mass spectrophotometer, Fourier transform infrared spectroscopy, energy‐dispersive X‐ray spectroscopy, high‐resolution transmission electron microscope, field emission scanning electron microscope, oxidation, reduction, detection limit, Au, Ag, Au‐Ag     

Antibacterial,anticancer and antioxidant potential of silver nanoparticles engineered using Trigonella foenum‐graecum seed extract

In this study, the authors report a simple and eco‐friendly method for the synthesis of silver nanoparticles (AgNPs) using Trigonella foenum‐graecum (TFG) seed extract. They explored several parameters dictating the biosynthesis of TFG‐AgNPs such as reaction time, temperature, concentration of AgNO₃, and TFG extract amount. Physicochemical characterisation of TFG‐AgNPs was done on dynamic light scattering (DLS), field emission electron microscopy, energy dispersive X‐ray spectroscopy, X‐ray diffraction and Fourier transform infrared spectroscopy. The size determination studies using DLS revealed of TFG‐AgNPs size between 95 and 110 nm. The antibacterial activity was studied against Escherichia coli, Proteus vulgaris, Pseudomonas aeruginosa and Staphylococcus aureus. The biosynthesised TFG‐AgNPs showed remarkable anticancer efficacy against skin cancer cell line, A431 and also exhibited significant antioxidant efficacy.Inspec keywords: antibacterial activity, cancer, biomedical materials, silver, nanofabrication, nanomedicine, nanoparticles, microorganisms, skin, cellular biophysics, biochemistry, light scattering, X‐ray chemical analysis, X‐ray diffraction, Fourier transform infrared spectra, particle sizeOther keywords: antibacterial potential, anticancer potential, antioxidant potential, silver nanoparticles, Trigonella foenum‐graecum seed extract, eco‐friendly method, biosynthesis, reaction time, AgNO₃ concentration, TFG extract amount, physicochemical characterisation, dynamic light scattering, field emission electron microscopy, energy dispersive X‐ray spectroscopy, X‐ray diffraction, Fourier transform infrared spectroscopy, size determination, TFG‐AgNPs size, Escherichia coli, Proteus vulgaris, Pseudomonas aeruginosa, Staphylococcus aureus, skin cancer cell line A431, Ag