Synthesis of silver nanoparticles by Bacillus subtilis T‐1 growing on agro‐industrial wastes and producing biosurfactant

In this study, culture supernatnats of Bacillus subtilis T‐1 growing on brewery effluents and molasses was used for silver nanoparticles (Ag‐NPs) synthesis. The biosurfactant production of B. subtilis T‐1 was confirmed by the detection of genes in the genome and by the identification of the product in the supernatants. The genes for synthesis of surfactin (sfp, srfAA) and iturin (ituC) were noted by PCR reactions. Also, in examined culture supernatants the presence of C₁₃, C₁₄ and C₁₅ surfactin homologues with the sodiated molecules [M + Na]⁺ at m /z 1030, 1044 and 1058 was confirmed using LC/MS/MS analysis. The formation of NPs in the culture supernatants was confirmed by UV–vis spectroscopy. The dynamic light scattering measurements and transmission electron microscopy images showed the nanometric sizes of the biosynthesised Ag‐NPs which ranged from several nm to several tens of nm depending on the used culture supernatant. Biological properties of Ag‐NPs were evaluated by binding of Ag‐NPs with DNA isolated from the Escherichia coli ATCC 25922 and B. subtilis ATCC 6633. Biogenic Ag‐NPs were actively bound to DNA in increased concentration which could be the one important mode of antibacterial action of the Ag‐NPs.Inspec keywords: silver, nanoparticles, nanofabrication, materials preparation, microorganisms, antibacterial activity, industrial waste, agrochemicals, surfactants, breweries, genomics, genetics, chromatography, mass spectroscopic chemical analysis, ultraviolet spectroscopy, visible spectroscopy, spectrochemical analysis, light scattering, transmission electron microscopy, DNA, bonds (chemical), biochemistry, molecular biophysics, nanobiotechnology, biological techniques, particle size, enzymesOther keywords: silver nanoparticle synthesis, Bacillus subtilis T‐1 growth, agro‐industrial waste, biosurfactant production, brewery effluent, molasses, Ag‐NP synthesis, B. subtilis T‐1, gene detection, genome, supernatant product identification, surfactin synthesis, sfp, srfAA, iturin synthesis, ituC, PCR reaction, C₁₃ surfactin homologue, C₁₄ surfactin homologue, C₁₅ surfactin homologue, sodiated molecules, LC‐MS‐MS analysis, UV‐vis spectroscopy, dynamic light scattering measurement, transmission electron microscopy image, Ag‐NP nanometric size range, Ag‐NP biosynthesis, used culture supernatant dependence, biological properties, DNA isolation, Escherichia coli ATCC 25922, B. subtilis ATCC 6633, biogenic Ag‐NP‐DNA binding, Ag‐NP antibacterial action, Ag     

Antimicrobial potential and in vitro cytotoxicity study of polyvinyl pyrollidone‐stabilised silver nanoparticles synthesised from Lysinibacillus boronitolerans

The main emphasis herein is on the eco‐friendly synthesis and assessment of the antimicrobial potential of silver nanoparticles (AgNPs) and a cytotoxicity study. Silver nanoparticles were synthesised by an extracellular method using bacterial supernatant. Biosynthesised silver nanoparticles were characterised by UV‐vis spectroscopy, transmission electron microscopy (TEM), Fourier transform infrared spectroscopy, dynamic light scattering, and zeta potential analysis. The synthesised silver nanoparticles exhibited a characteristic peak at 420 nm. TEM analysis depicted the spherical shape and approximately 20 nm size of nanoparticles. Silver nanoparticles carry a charge of −33.75 mV, which confirms their stability. Biogenic polyvinyl pyrrolidone‐coated AgNPs exhibited significant antimicrobial effects against all opportunistic pathogens (Gram‐positive and Gram‐negative bacteria, and fungi). Silver nanoparticles equally affect the growth of both Gram‐positive and Gram‐negative bacteria, with a maximum inhibition zone observed at 22 mm and a minimum at 13 mm against Pseudomonas aeruginosa and Fusarium graminearum, respectively. The minimum inhibitory concentration (MIC) of AgNPs against P. aeruginosa and Staphylococcus aureus was recorded at between 15 and 20 μg/ml. Synthesised nanoparticles exhibited a significant synergistic effect in combination with conventional antibiotics. Cytotoxicity estimates using C2C12 skeletal muscle cell line via 3‐(4,5‐dimethylthiazol‐2‐yl)‐2,5‐diphenyltetrazolium bromide (MTT) test and lactate dehydrogenase assay were directly related to the concentration of AgNPs and length of exposure. On the basis of the MTT test, the IC50 of AgNPs for the C2C12 cell line was approximately 5.45 μg/ml concentration after 4 h exposure.     

Evaluation of antimicrobial activity of synthesised silver nanoparticles using Thymus kotschyanus aqueous extract

Development of a green chemistry process for the synthesis of silver nanoparticles (AgNPs) has become a focus of interest. Characteristics of AgNPs were determined using techniques, such as ultraviolet–visible spectroscopy (UV–vis), Fourier transform infrared (FTIR) analysis, scanning electron microscopy (SEM), energy‐dispersive X‐ray spectroscopy and X‐ray diffraction (XRD). The synthesised AgNPs using Thymus kotschyanus had the most growth inhibition against gram‐positive bacteria such as Staphylococcus aureus and Bacillus subtilise, while the growth inhibition of AgNPs at 1000–500 µg/ml occurred against Klebsiella pneumonia and at 1000–250 µg/ml of AgNPs was observed against E. coli. The UV–vis absorption spectra confirmed the formation of the AgNPs with the characteristic peak at 415 nm and SEM micrograph acknowledged spherical particles in a nanosize range. FTIR measured the possible biomolecules that are responsible for stabilisation of AgNPs. XRD analysis exhibited the crystalline nature of AgNPs and showed face‐centred cubic structure. The synthesised AgNPs revealed significant antibacterial activity against gram‐positive bacteria.Inspec keywords: visible spectra, microorganisms, ultraviolet spectra, biomedical materials, nanofabrication, nanoparticles, X‐ray diffraction, scanning electron microscopy, molecular biophysics, X‐ray chemical analysis, nanomedicine, silver, antibacterial activity, Fourier transform infrared spectraOther keywords: green chemistry process, ultraviolet–visible spectroscopy, gram‐positive bacteria, silver nanoparticles, Thymus kotschyanus aqueous extract, UV–vis spectroscopy, Fourier transform infrared spectroscopy, FTIR analysis, scanning electron microscopy, energy‐dispersive X‐ray spectroscopy, SEM micrograph, X‐ray diffraction, XRD, Staphylococcus aureus, Bacillus subtilise, Klebsiella pneumonia, E. coli, UV–vis absorption spectra, face‐centred cubic structure, antibacterial activity, antimicrobial activity, wavelength 415.0 nm, Ag     

Preparation of silver iodide nanoparticles using laser ablation in liquid for antibacterial applications

In this study, the authors reported the first synthesis process of silver iodide (AgI) nanoparticles (NPs) by pulsed laser ablation of the AgI target in deionised distilled water. The optical and structural properties of AgI NPs were investigated by using UV–vis absorption, X‐ray diffraction, scanning electron microscope (SEM), energy dispersive X‐ray, Fourier transform infrared spectroscopy, and transmission electron microscope (TEM). The optical data showed the presence of plasmon peak at 434 nm and the optical bandgap was found to be 2.6 eV at room temperature. SEM results confirm the agglomeration and aggregation of synthesised AgI NPs. TEM investigation showed that AgI NPs have a spherical shape and the average particle size was around 20 nm. The particle size distribution was the Gaussian type. The results showed that the synthesised AgI NPs have antibacterial activities against both bacterial strains and the activities were more potent against gram‐negative bacteria.Inspec keywords: antibacterial activity, nanoparticles, X‐ray chemical analysis, particle size, transmission electron microscopy, X‐ray diffraction, nanofabrication, scanning electron microscopy, visible spectra, ultraviolet spectra, silver compounds, pulsed laser deposition, Fourier transform infrared spectra, optical constants, energy gap, aggregationOther keywords: synthesis process, pulsed laser ablation, AgI target, deionised distilled water, optical properties, structural properties, UV–vis absorption, X‐ray diffraction, transmission electron microscope, optical data, optical bandgap, antibacterial activities, silver iodide nanoparticles, energy dispersive X‐ray analysis, SEM, wavelength 434.0 nm, temperature 293 K to 298 K, AgI     

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     

Biomimetic production,characterisation, in vitro cytotoxic and anticancer assessment of aqueous extract‐mediated AgNPs of Teucrium stocksianum Boiss

Owing to the numerous biological applications, cost effectiveness and low cytotoxicity of the biomimetic nanoparticles (NPs), the authors optimised the production of silver NPs (AgNPs) using aqueous extract of Teucrium stocksianum Boiss. The NPs were characterised by ultraviolet‐visible (UV‐vis) spectroscopy, X‐ray diffraction (XRD), scanning electron microscopy (SEM), dynamic light scattering (DLS) and Fourier transform‐infrared spectroscopy (FTIR). The UV‐vis spectroscopy revealed a surface plasmon resonance (410‐440 nm) at an incubation temperature of 90°C when 1 mM Ag nitrate combined to 5 mg/ml extract concentration in the ratio of 1:10. DLS results show an average zeta size of ∼44.61 nm and zeta potential of −15.3 mV. SEM and XRD confirmed the high crystallinity and cubical symmetry with an average size below 100 nm. FTIR measurement shows the presence of various functional groups, responsible for the capping and reduction of Ag metal. The 3‐(4,5‐dimethylthiazol‐2‐yl)‐2,5‐diphenyltetrazolium bromide cell viability assay shows that AgNPs are less cytotoxic to J774 and L929 cells as compared with enhanced anticancer activity with low IC50 concentrations (68.24 µg/ml) against Michigan Cancer Foundation‐7 (MCF‐7) cells. The ethidium bromide/acridine orange assay shows that the AgNPs kill the cell by apoptosis. Overall, the results show that AgNPs possesses potent anticancer activities.Inspec keywords: cellular biophysics, cancer, nanobiotechnology, nanomedicine, ultraviolet spectra, X‐ray diffraction, scanning electron microscopes, light scattering, patient treatmentOther keywords: anticancer assessment, in vitro cytotoxic assessment, aqueous extract‐mediated AgNPs, Teucrium stocksianum Boiss, nanoparticles, biological applications, biosynthesis, silver NPs, X‐ray diffraction, scanning electron microscopy, dynamic light scattering, Fourier transform‐infrared spectroscopy, UV‐vis spectroscopy, surface plasmon resonance, extract concentration, zeta potential, high crystallinity, FTIR measurement, amide molecules, viability assay, enhanced anticancer activity, potent anticancer activities     

Biosynthesised silver nanoparticles using aqueous leaf extract of Tagetes patula L. and evaluation of their antifungal activity against phytopathogenic fungi

In the recent decades, nanotechnology is gaining tremendous impetus due to its capability of modulating metals into their nanosize, which drastically changes the chemical, physical, biological and optical properties of metals. In this study, silver nanoparticles (AgNPs) synthesis using aqueous leaf extracts of Tagetes patula L. which act as reducing agent as well as capping agent is reported. Synthesis of AgNPs was observed at different parameters like temperature, concentration of silver nitrate, leaf extract concentration and time of reduction. The AgNPs were characterized using UV‐vis spectroscopy, scanning electron microscope with energy dispersive spectroscopy, transmission electron microscopy with selected area electron diffraction, X‐ray diffraction, Fourier transform infrared and dynamic light scattering analysis. These analyses revealed the size of nanoparticles ranging from 15 to 30 nm as well revealed their spherical shape and cubic and hexagonal lattice structure. The lower zeta potential (−14.2mV) and the FTIR spectra indicate that the synthesized AgNPs are remarkably stable for a long period due to the capped biomolecules on the surface of nanoparticles. Furthermore, these AgNPs were found to be highly toxic against phytopathogenic fungi Colletotrichum chlorophyti by both in vitro and in vivo and might be a safer alternative to chemical fungicides.Inspec keywords: silver, nanoparticles, nanofabrication, nanobiotechnology, ultraviolet spectra, visible spectra, scanning electron microscopy, X‐ray chemical analysis, electron diffraction, X‐ray diffraction, Fourier transform infrared spectra, crystal structure, electrokinetic effects, antibacterial activityOther keywords: biosynthesised silver nanoparticles, aqueous leaf extract, Tagetes patula L, antifungal activity, phytopathogenic fungi, nanotechnology, UV–vis spectroscopy, scanning electron microscope, energy dispersive spectroscopy, transmission electron microscopy, selected area electron diffraction, X‐ray diffraction, Fourier transform infrared spectra, dynamic light scattering analysis, hexagonal lattice structure, zeta potential, phytopathogenic fungi Colletotrichum chlorophyti, cubic lattice structure, size 15 nm to 30 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     

Biocompatibility enhancement of graphene oxide‐silver nanocomposite by functionalisation with polyvinylpyrrolidone

Several materials such as silver are used to enhance graphene oxide (GO) sheets antimicrobial activity. However, these toxic materials decrease its biocompatibility and hinder its usage in many biological applications. Therefore, there is an urgent need to develop nanocomposites that can preserve both the antimicrobial activity and biocompatibility simultaneously. This work highlights the importance of functionalisation of GO sheets using Polyvinylpyrrolidone (PVP) and decorating them with silver nanoparticles (AgNPs) in order to enhance their antimicrobial activity and biocompatibility at the same time. The structural and morphological characterisations were performed by UV‐Visible, Fourier transform infrared (FTIR), and Raman spectroscopic techniques, X‐ray diffraction (XRD), and high‐resolution transmission electron microscopy (HR‐TEM). The antimicrobial activities of the prepared samples against Staphylococcus aureus, Pseudomonas aeruginosa, and Candida albicans were studied. The cytotoxicity of prepared materials was tested against BJ1 normal skin fibroblasts. The results indicated that the decoration with AgNPs showed a significant increase in the antimicrobial activity of GO and FGO sheets, and functionalisation of GO sheets and GO‐Ag nanocomposite with PVP improved the cell viability about 40 and 35%, respectively.Inspec keywords: biomedical materials, nanocomposites, visible spectra, ultraviolet spectra, X‐ray diffraction, cellular biophysics, nanoparticles, Raman spectra, filled polymers, transmission electron microscopy, silver, microorganisms, antibacterial activity, nanomedicine, nanofabrication, graphene compounds, toxicology, Fourier transform infrared spectraOther keywords: graphene oxide‐silver nanocomposite, polyvinylpyrrolidone, toxic materials, biocompatibility, antimicrobial activity, morphological characterisations, structural characterisations, UV‐visible spectra, Fourier transform infrared spectra, Raman spectra, X‐ray diffraction, high‐resolution transmission electron microscopy, Staphylococcus aureus, Pseudomonas aeruginosa, Candida albicans, cytotoxicity, BJ1 normal skin fibroblasts, cell viability, CO‐Ag     

Bacteriogenic synthesis of selenium nanoparticles by Escherichia coli ATCC 35218 and its structural characterisation

A biosynthetic method for the production of selenium nanoparticles under ambient temperature and pressure from sodium selenite was developed using Gram‐negative bacterial strain Escherichia coli ATCC 35218. Bacteriogenic nanoparticles were methodologically characterized employing UV‐vis, XRD, Raman spectroscopy, SEM, TEM, DLS and FTIR techniques. Generation of nanoparticles was visualized from the appearance of red colour in the selenite supplemented culture medium and broad absorption bands in the UV‐vis. Biofabricated nanoparticles were spherical, polydisperse, ranged from 100‐183 nm and the average particle size was about 155 nm. Based on selected‐area electron diffraction, XRD patterns; and Raman spectroscopy the nanospheres were found to be amorphous. IR spectrum revealed the involvement of bacterial proteins in the reduction of selenite and stabilization of nanoparticles. Used bacterial strain demonstrated efficient selenite reduction capability which was evident from 89.2% of selenium removal within 72 h at a concentration of 1 mM. Observation noted in the current study highlight the importance of bacterial reduction in selenium nanoparticle generation which can be scaled up for commercial production. Also, the bacteriogenic, amorphous nanoparticles can also be used as nutritional supplements for humans since selenium nanoparticles of 5‐200 nm are bioavailable and known to induce seleno enzymes involved in antioxidant defence.Inspec keywords: Fourier transform infrared spectra, transmission electron microscopy, scanning electron microscopy, electron diffraction, ultraviolet spectra, microorganisms, X‐ray diffraction, nanofabrication, Raman spectra, visible spectra, nanoparticles, particle size, seleniumOther keywords: bacteriogenic synthesis, selenium nanoparticles, Escherichia coli ATCC 35218, structural characterisation, biosynthetic method, gram negative bacterial strain, UV–visible spectroscopy, X‐ray diffraction, Raman spectroscopy, scanning electron microscopy, transmission electron microscopy, dynamic light scattering, Fourier transform infrared spectroscopy, particle size, selected area electron diffraction, bacteriological reduction, seleno enzymes, size 100 nm to 183 nm, Se     

Green synthesis of silver nanoparticles and their applications as colorimetric probe for determination of Fe3+ and Hg2+ ions

Silver nanoparticles (AgNPs) were prepared by a green method using Cordia myxa leaf extract. They were characterised by UV–vis spectroscopy, Fourier transform infrared spectroscopy and their X‐ray diffraction pattern. Their sizes were determined by scanning electron micrographs, transmission electron micrographs imaging and dynamic light scattering analysis. The shapes of nanoparticles were spherical or truncated triangular and their average size was determined to be 51.6 nm. Their solution was stable at least for one month. The prepared AgNPs were used as a selective chemical sensor for determination of iron(III) (only when Cl⁻ ions were present in the medium) and mercury(II) ions with detection limits of 0.084 and 0.037 nM, respectively. It was shown that the mechanism of these detections is through oxidation of Ag atoms by Fe³⁺ and Hg²⁺ ions.Inspec keywords: visible spectra, nanoparticles, transmission electron microscopy, nanofabrication, ultraviolet spectra, chemical sensors, scanning electron microscopy, silver, X‐ray diffraction, Fourier transform infrared spectra, oxidationOther keywords: Ag, Cordia myxa leaf extract, iron(III) ions, mercury(II) ions, oxidation, scanning electron micrographs, Fourier transform infrared spectroscopy, silver nanoparticles, chemical sensor, dynamic light scattering analysis, transmission electron micrographs, X‐ray diffraction pattern, UV–vis spectroscopy, colorimetric probe, green synthesis     

Green synthesis of silver nanoparticles using Rubia tinctorum extract and evaluation the anti‐cancer properties in vitro

Cancer is one of the leading causes of human death. Nanotechnology could offer new and optimised anticancer agents in order to fight cancer. It was shown that metal nanoparticles, in particular silver nanoparticles (AgNPs) were effective in cancer therapy. In this study, AgNPs were synthesised using Rubia tinctorum L. extract (Ru‐AgNPs). Then, cytotoxicity effects of the Ru‐AgNPs against MDA‐MB‐231 carcinoma cell line and human dermal fibroblast as normal cell line were performed. Furthermore, anti‐apoptotic effects of Ru‐AgNPs on these cancer and normal cell lines were compared using acridine orange/propidium iodide staining, flow cytometry analysis and real‐time qPCR in apoptosis gene markers. Results of UV‐vis spectroscopy showed that Ru‐AgNPs have a peak at 430 nm, which indicated synthesis of AgNPs. Ru‐AgNPs had spherical shape and average size of 12 nm. Ru‐AgNPs have cytotoxicity on MDA‐MB‐231 cells and decrease cancerous cell viability (IC50 = 4 µg/ml/48 h). Ru‐AgNPs could induce apoptosis in MDA‐MB‐231 cells through upregulation of Bax and downregulation of Bcl‐2 gene expression. The results opened up new avenues to develop Rubia based metal complexes as an anticancer agent.Inspec keywords: cellular biophysics, genetics, cancer, toxicology, nanoparticles, nanofabrication, nanomedicine, silver, biomedical materials, ultraviolet spectra, visible spectraOther keywords: Ru‐AgNPs, MDA‐MB‐231 carcinoma cell line, normal cell line, cancerous cell viability, in vitro anticancer properties, green synthesis, silver nanoparticles, Rubia tinctorum L. extract, cytotoxicity effects, human dermal fibroblast HFF, antiapoptotic effects, acridine orange‐propidium iodide staining, flow cytometry analysis, real‐time qPCR, apoptosis gene markers, UV‐visible spectroscopy, spherical shape, Bcl‐2 gene expression, Ag     

Cytotoxicity of spherical gold nanoparticles synthesised using aqueous extracts of aerial roots of Rhaphidophora aurea (Linden ex Andre) intertwined over Lawsonia inermis and Areca catechu on MCF‐7 cell line

A facile synthesis of gold nanoparticles (GNPs) using the aqueous extracts of the aerial roots of Rhaphidophora aurea (Linden ex Andre) intertwined over Lawsonia inermis and Areca catechu was carried out under different conditions, namely room temperature, higher temperature, sonication, solar irradiation and pH variation. The surface plasmon resonance (SPR) band at 536 and 575 nm obtained in UV–visible spectrum revealed the formation of AuNP''s. The sharp SPR band of the synthesised nanogold indicates the formation of spherical‐shaped and uniform‐sized nanoparticles. The TEM analysis revealed spherical nanogold particles of size 35 and 10 nm for MM and MP extracts. The secondary metabolites present in the aqueous extract are suggested to be responsible for the reduction of metal ions to metal nanoparticles as evidenced from results of FTIR analysis. Rapid synthesis of GNPs by sunlight is the production of microscopic grains of gold due to the dissociation of gold chloride. This may induce the reaction between secondary metabolites and gold chloride solutions and results in GNPs. The cytotoxic activity of the synthesised nanogold studied against human breast cancer cells (MCF‐7) by 3‐[4,5‐dimethylthiazol‐2‐yl]2,5‐diphenyltetrazolium bromide assay showed significant activity at higher concentration.Inspec keywords: toxicology, gold, nanoparticles, nanomedicine, nanofabrication, cellular biophysics, particle size, surface plasmon resonance, ultraviolet spectra, visible spectra, transmission electron microscopy, dissociation, cancer, biological organs, Fourier transform infrared spectraOther keywords: cytotoxicity, spherical gold nanoparticles, aerial roots, Rhaphidophora aurea, Linden ex Andre, Lawsonia inermis, Areca catechu, MCF‐7 cell line, sonication, solar irradiation, pH variation, surface plasmon resonance, UV–visible spectrum, spherical‐shaped nanoparticles, uniform‐sized nanoparticles, TEM analysis, spherical nanogold particles, secondary metabolites, metal ions, FTIR analysis, microscopic grains, dissociation, gold chloride solutions, cytotoxic activity, human breast cancer cells, 3‐[4,5‐dimethylthiazol‐2‐ yl]2,5‐diphenyltetrazolium bromide assay, wavelength 536 nm, wavelength 575 nm, Au     

Green synthesis,characterisation and biological evaluation of plant‐based silver nanoparticles using Quercus semecarpifolia Smith aqueous leaf extract

The development of reliable and green methods for the fabrication of metallic nanoparticles (NPs) has many advantages in the field of nanotechnology. In this direction, the present work describes an eco‐friendly and cost‐effective protocol for the production of silver NPs (AgNPs) using an aqueous extract of Quercus semecarpifolia leaves. Different techniques were carried out for the characterisation of the synthesised AgNPs. The ultraviolet–visible spectroscopic analysis showed the highest absorbance peak at 430 nm. The particle size and structure were confirmed by scanning electron microscopy as well as transmission electron microscopy (TEM) analysis. From TEM imaging, it was revealed that the formed particles were spherical with an average size of 20–50 nm. The crystalline nature of the NPs was determined by X‐ray powder diffraction patterns. Thermogravimetry and differential thermal analysis were also evaluated by a temperature increment from 100 to 1000°C. Bio‐inspired synthesis of AgNPs was performed for their pharmacological evaluation in relation to the activities of the crude methanolic, n ‐hexane, chloroform, ethyl acetate, and aqueous extracts. Good cytotoxic activity was exhibited by the green‐synthesised AgNPs (77%). Furthermore, the AgNPs were found to exhibit significant antioxidant activity at 300 μg/ml (82%). The AgNPs also exhibited good phytotoxic potential (75%).Inspec keywords: scanning electron microscopy, toxicology, visible spectra, particle size, nanofabrication, nanomedicine, transmission electron microscopy, silver, ultraviolet spectra, differential thermal analysis, nanoparticles, X‐ray diffraction, botany, biochemistry, cellular biophysicsOther keywords: green synthesis, biological evaluation, plant‐based silver nanoparticles, reliable methods, metallic nanoparticles, eco‐friendly cost‐effective protocol, silver NPs, ultraviolet–visible spectroscopic analysis, highest absorbance peak, particle size, structure, transmission electron microscopy analysis, TEM imaging, crystalline nature, X‐ray powder diffraction patterns, differential thermal analysis, pharmacological evaluation, aqueous extracts, good cytotoxic activity, significant antioxidant activity, AgNPs exhibited good phytotoxic potential, bio‐inspired synthesis, Quercus semecarpifolia Smith aqueous leaf extract, scanning electron microscopy, thermogravimetry, crude methanolic, n‐hexane, chloroform, ethyl acetate, phytotoxic potential, haemagglutination activity, size 20.0 nm to 50.0 nm, wavelength 430.0 nm, temperature 100 degC to 1000 degC, Ag     

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 Silver Nanoparticles by Streptomyces griseorubens isolated from Soil and Their Antioxidant Activity

Microbial mediated biological synthesis of metallic nanoparticles was carried out ecofriendly in the present study. Silver nanoparticles (AgNPs) were extracellularly biosynthesised from Streptomyces griseorubens AU2 and extensively characterised by ultraviolet–visible (UV–vis) and Fourier transform infrared spectroscopy, high‐resolution transmission electron microscopy, scanning electron microscopy and X‐ray diffraction analysis. Elemental analysis of nanoparticles was also carried out using energy dispersive X‐ray spectroscopy. The biosynthesised AgNPs showed the characteristic absorption spectra in UV–vis at 422 nm which confirmed the presence of metallic AgNPs. According to the further characterisation analysis, the biosynthesised AgNPs were found to be spherical and crystalline particles with 5–20 nm average size. Antioxidant properties of the biosynthesised AgNPs were determined by 2,2‐diphenyl‐1‐picrylhydrazyl free radical scavenging assay and was found to increase in a dose‐dependent matter. The identification of the strain was determined by molecular characterisation method using 16s rDNA sequencing. The present study is the first report on the microbial biosynthesis of AgNPs using S. griseorubens isolated from soil and provides that the active biological components found in the cell‐free culture supernatant of S. griseorubens AU2 enable the synthesis of AgNPs.Inspec keywords: silver, microorganisms, nanoparticles, nanofabrication, DNA, molecular biophysics, ultraviolet spectra, visible spectra, scanning electron microscopy, Fourier transform infrared spectra, transmission electron microscopy, X‐ray diffraction, X‐ray chemical analysis, absorption coefficients, cellular biophysicsOther keywords: silver nanoparticles, Streptomyces griseorubens AU2, soil, antioxidant activity, microbial mediated biological synthesis, ultraviolet‐visible spectroscopy, Fourier transform infrared spectroscopy, UV‐vis spectroscopy, high‐resolution transmission electron microscopy, scanning electron microscopy, X‐ray diffraction, elemental analysis, energy dispersive X‐ray spectroscopy, absorption spectra, spherical particles, crystalline particles, 2,2‐diphenyl‐1‐picrylhydrazyl free radical scavenging assay, strain identification, molecular characterisation method, rDNA sequencing, active biological components, cell‐free culture supernatant, wavelength 422 nm, size 5 nm to 20 nm, Ag     

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      

Multifaceted activities of plant gum synthesised platinum nanoparticles: catalytic,peroxidase, PCR enhancing and antioxidant activities

A single pot, green method for platinum nanoparticles (Pt NP) production was devised with gum ghatti (Anogeissus latifolia). Analytical tools: ultraviolet–visible (UV‐vis), dynamic light scattering, zeta potential, transmission electron microscope, X‐ray diffraction (XRD), and Fourier transform infrared spectroscopy were employed. Wide continuous UV‐vis absorption and black solution colouration proved Pt NP formation. Face‐centred cubic crystalline structure of NP was evidenced from XRD. NPs formed were nearly spherical with a mean particle size of 3 nm. NP demonstrated a myriad of properties including catalytic, peroxidase, polymerase chain reaction (PCR) enhancing and antioxidant activities. Catalytic action of NP was probed via NaBH₄ reduction of arsenazo‐III dye. NP displayed considerable peroxidase activity via catalysis of 3, 3′, 5, 5′‐tetramethylbenzidine oxidation by H₂ O₂. NP showed exceptional stability towards varying pH (3–11), temperature (25–100°C), salt concentration (0–100 mM) and storage time duration (0–12 months). In comparison with horse radish peroxidase, its applicability as an artificial peroxidase is advantageous. NP caused a two‐fold enhancement in PCR yield at 0.4 nM. Also showed significant 1′, 1′ diphenyl picryl‐hydrazyle scavenging (80.1%) at 15 µg/mL. Author envisages that the biogenic Pt NP can be used in a range of biological and environmental applications.Inspec keywords: nanofabrication, ultraviolet spectra, catalysis, molecular biophysics, enzymes, dyes, platinum, electrokinetic effects, transmission electron microscopy, particle size, X‐ray diffraction, visible spectra, pH, nanomedicine, nanoparticles, biochemistry, light scattering, scanning electron microscopy, Fourier transform infrared spectra, reduction (chemical), oxidationOther keywords: antioxidant activities, catalytic action, salt concentration, artificial peroxidase, two‐fold enhancement, PCR yield, multifaceted activities, plant gum synthesised platinum nanoparticles, gum ghatti, anogeissus latifolia, analytical characterisation tools, dynamic light scattering, zeta potential, X‐ray diffraction, XRD, black solution colouration, Pt NP formation, face‐centred cubic crystalline structure, peroxidase activity, ultraviolet‐visible spectroscopy, transmission electron microscopy, Fourier transform infrared spectroscopy, particle size, catalytic activity, PCR enhancing activity, single pot green method, wide continuous UV‐visible absorption, polymerase chain reaction enhancing activity, arsenazo‐III, azo dye decolourisation, 3, 3′, 5, 5′‐tetramethylbenzidine oxidation, pH, environmental conditions, 1′,1′ diphenyl picryl‐hydrazyle scavenging, time 0.0 month to 12.0 month, temperature 25.0 degC to 100.0 degC, Pt     

Diospyros assimilis root extract assisted biosynthesised silver nanoparticles and their evaluation of antimicrobial activity

The current research study focuses on biosynthesis of silver nanoparticles (Ag NPs) for the first time from silver acetate employing methanolic root extract of Diospyros assimilis. The UV–Vis absorption spectrum of biologically synthesised nanoparticles displayed a surface plasmon peak at 428 nm indicating the formation of Ag NPs. The influence of metal ion concentration, reaction time and amount of root extract in forming Ag NPs by microscopic and spectral analysis was thoroughly investigated. Structural analysis from transmission electron microscopy confirmed the nature of metallic silver as face‐centered cubic (FCC) crystalline with an average diameter of 17 nm, which correlates with an average crystallite size (19 nm) calculated from X‐ray diffraction analysis. Further, the work was extended for the preliminary examination of antimicrobial activity of biologically synthesised Ag NPs that displayed promising activity against all the tested pathogenic strains.Inspec keywords: antibacterial activity, nanoparticles, silver, particle size, nanofabrication, nanomedicine, biomedical materials, ultraviolet spectra, visible spectra, optical microscopy, surface plasmon resonance, transmission electron microscopy, crystallites, X‐ray diffraction, microorganismsOther keywords: Diospyros assimilis root extract assisted biosynthesised silver nanoparticles, antimicrobial activity, silver acetate, methanolic root extract, UV‐visible absorption spectrum, biologically synthesised nanoparticles, surface plasmon peak, Ag NPs formation, metal ion concentration, reaction time, microscopic analysis, spectral analysis, structural analysis, transmission electron microscopy, metallic silver, FCC crystalline phase, average crystallite size, X‐ray diffraction analysis, pathogenic strains, Ag     

Green‐route mediated synthesis of silver nanoparticles (AgNPs) from Syzygium cumini (L.) Skeels polyphenolic‐rich leaf extracts and investigation of their antimicrobial activity

Medicinal plants are widely utilised by the African population since they have no harmful side effects and low cost compared with different treatments. The field of nanotechnology is the most active part of research in modern material''s science. Though there are several chemicals as well as physical methods, however, green synthesis of nanomaterials is the most emerging method of synthesis. Conventionally, chemical reduction is the most often applied approach for the preparation of metallic nanoparticle''s however, in most of the synthesis protocols it cannot avoid the utilisation of toxic chemicals. Hence, the authors report an environmentally friendly, cost effective and green approach for synthesis of 1 mM AgNO₃ solution using the polyphenolic‐rich leaf extracts of Syzygium cumini (S. cumini) (L.) Skeels as a reducing and capping agent. The synthesised AgNPs are characterised by UV‐Vis spectroscopy and Fourier transform infrared (FTIR) spectroscopy. FTIR analysis revealed that the AgNPs were stable due to eugenols, terpenes, and other different aromatic compounds present in the extract. The green biosynthesised S. cumini AgNPs significantly inhibited the growth of human pathogenic both gram‐positive Staphylococcus aureus (1.40 mm) and gram‐negative bacteria Escherichia coli (2.75 mm) and Salmonella typhimurium (1.45 mm) showing promising antimicrobial activity.Inspec keywords: silver, nanoparticles, nanofabrication, nanomedicine, antibacterial activity, biomedical materials, visible spectra, ultraviolet spectra, Fourier transform infrared spectra, microorganismsOther keywords: green‐route mediated synthesis, silver nanoparticles, Syzygium cumini, Skeels polyphenolic‐rich leaf extracts, antimicrobial activity, medicinal plants, African population, nanotechnology, physical methods, nanomaterials, metallic nanoparticles, AgNO₃ solution, polyphenolic‐rich leaf extracts, capping agent, UV‐visible spectroscopy, Fourier transform infrared spectroscopy, FTIR, eugenols, terpenes, aromatic compounds, green biosynthesis, human pathogenic growth, gram‐positive Staphylococcus aureus, gram‐negative bacteria Escherichia coli, Salmonella typhimurium, antimicrobial activity, size 2.75 mm, size 1.45 mm, size 1.40 mm, Ag