Surface characterisation and reaction kinetics of silver nanoparticles mediated by the leaf and flower extracts of French marigold (Tagetes patula)

In this study, French marigold''s leaf and flower were used for the synthesis of silver nanoparticles (SNPs) in order to explore their potentials towards bioreduction of Ag⁺ to Agᵒ. The as‐synthesised SNPs were characterised using UV–Vis spectroscopy, Fourier transform infrared (FTIR) spectroscopy, powder X‐ray diffraction, transmission electron microscopy, and zeta‐potential analysis. The results obtained showed that the particles are polydispersed with sizes in the range 15.8–42.8 nm. The bioreduction was believed to be due to the amides, aldehyde functional groups, and essential oils present in the extracts as confirmed by the FTIR analysis. The growth mechanism involved in the reaction was studied which revealed oriented attachment (OA) onwards Ostwald ripening in the case of the flower‐mediated synthesis and typical OA in the leaf‐mediated synthesis. The studied kinetics of the particle formation showed that the reaction is possibly a pseudo‐first‐order reaction with some diffusion‐controlled mechanism which is driven by high surface area to volume ratio in both the leaf‐ and flower‐mediated synthesis.Inspec keywords: ultraviolet spectra, nanoparticles, visible spectra, particle size, reaction kinetics, transmission electron microscopy, electrokinetic effects, X‐ray diffraction, scanning electron microscopy, nanomedicine, silver, nanofabrication, biomedical materials, Fourier transform infrared spectraOther keywords: powder X‐ray diffraction, transmission electron microscopy, zeta‐potential analysis, bioreduction, aldehyde functional groups, FTIR analysis, flower‐mediated synthesis, leaf‐mediated synthesis, pseudofirst‐order reaction, surface characterisation, silver nanoparticles, flower extracts, French marigold, UV‐visible spectroscopy, Fourier transform infrared spectroscopy, Tagetes patula, attachment onwards Ostwald ripening, Ag     

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     

Green synthesis of silver nanoparticles using flower extract of Malva sylvestris and investigation of their antibacterial activity

High‐quality colloidal silver nanoparticles (AgNP) were synthesised via a green approach by using hydroalcoholic extracts of Malva sylvestris. Silver nitrate was used as a substrate ion while the plant extract successfully played the role of reducing and stabilising agents. The synthesised nanoparticles were carefully characterised by using transmission electron microscopy, atomic‐force microscopy, energy dispersive X‐ray spectroscopy, Fourier transform infrared spectroscopy and UV–vis spectroscopy. The maximum absorption wavelengths of the colloidal solutions synthesised using 70 and 96% ethanol and 100% methanol, as extraction solvents, were 430, 485 and 504 nm, respectively. Interestingly, the size distribution of nanoparticles depended on the used solvent. The best particle size distribution belonged to the nanoparticles synthesised by 70% ethanol extract, which was 20–40 nm. The antibacterial activity of the synthesised nanoparticles was studied on Escherichia coli, Staphylococcus aureus and Streptococcus pyogenes using disk diffusion, minimum inhibitory concentrations and minimum bactericidal concentrations assays. The best antibacterial activity obtained for the AgNPs produced by using 96% ethanolic extract.Inspec keywords: silver, nanoparticles, nanofabrication, antibacterial activity, colloids, particle size, transmission electron microscopy, atomic force microscopy, X‐ray chemical analysis, Fourier transform spectra, infrared spectra, ultraviolet spectra, visible spectra, microorganisms, nanomedicine, biomedical materialsOther keywords: Green synthesis, flower extract, Malva sylvestris, antibacterial activity, high‐quality colloidal silver nanoparticles, hydroalcoholic extracts, plant extract, reducing agents, stabilising agents, transmission electron microscopy, atomic‐force microscopy, energy dispersive X‐ray spectroscopy, Fourier transform infrared spectroscopy, UV– vis spectroscopy, colloidal solutions, particle size distribution, Escherichia coli, Staphylococcus aureus, Streptococcus pyogenes, disk diffusion, minimum inhibitory concentrations, minimum bactericidal concentrations assays, ethanolic extract, size 430 nm, size 485 nm, size 504 nm, size 20 nm to 40 nm, Ag     

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     

Biosynthesis of Ag3 PO4 nanoparticles in the absence of phosphate source using a phosphorus mineralising bacterium

Silver phosphate nanoparticles were biologically synthesised, for the first time, using a dilute silver nitrate solution as the silver ion supplier, and without any source of phosphate ion. The applied bacterium was Sporosarcina pasteurii formerly known as Bacillus pasteurii which is capable of solubilising phosphate from soils. It was speculated that the microbe accumulated phosphate from the organic source during the growth period, and then released it to deionised water. According to the transmission electron microscopy images and X‐ray diffraction results, the produced nanoparticles were around 20 nm in size and identified as silver phosphate nanocrystals. The outcomes were also approved by energy‐dispersive X‐ray analysis, thermogravimetric and differential scanning calorimetry analyses, ultraviolet–visible spectroscopy, and Fourier transform infrared spectroscopy analysis. Finally, the antibacterial effect of the obtained nanoparticles was verified by testing them against Bacillus cereus, Staphylococcus aureus, Escherichia coli, and Salmonella typhimurium. The activity of silver phosphate nanoparticles against gram‐negative strains was better than the gram positives. It should be mentioned that the concentrations of 500 and 1000 mg/l were found to be strongly inhibitory for all of the strains.Inspec keywords: nanoparticles, silver compounds, nanofabrication, microorganisms, antibacterial activity, transmission electron microscopy, X‐ray diffraction, X‐ray chemical analysis, differential scanning calorimetry, ultraviolet spectra, visible spectra, Fourier transform infrared spectraOther keywords: biosynthesis, phosphate source, phosphorus mineralising bacterium, silver phosphate nanoparticles, Sporosarcina pasteurii, Bacillus pasteurii, deionised water, transmission electron microscopy images, X‐ray diffraction, energy‐dispersive X‐ray analysis, thermogravimetric analyses, differential scanning calorimetry analyses, ultraviolet–visible spectroscopy, Fourier transform infrared spectroscopy, antibacterial effect, Bacillus cereus, Staphylococcus aureus, Escherichia coli, Salmonella typhimurium, Ag₃ PO₄      

Sunlight induced biosynthesis of silver nanoparticle from the bark extract of Amentotaxus assamica D.K. Ferguson and its antibacterial activity against Escherichia coli and Staphylococcus aureus

Green synthesis of nanoparticles has gained importance due to its eco‐friendly, low toxicity and cost effective nature. This study deals with the biosynthesis of silver nanoparticles (AgNPs) from the bark extract of Amentotaxus assamica. The AgNPs have been synthesised by reducing the silver ions into stable AgNPs using the bark extract of Amentotaxus assamica under the influence of sunlight irradiation. The characterisation of the biosynthesised AgNPs was carried out by UV–vis spectroscopy, X‐ray diffraction analysis (XRD), Fourier transform infrared spectroscopy, scanning electron microscopy (SEM) and energy dispersive X‐ray analysis. The UV–vis spectrum showed a broad peak at 472 nm. Also, the XRD confirmed the crystalline structure of the AgNPs. Moreover, the SEM analysis revealed that the biosynthesised AgNPs were spherical in shape. Also, dynamic light scattering techniques were used to evaluate the size distribution profile of the biosynthesised AgNPs. Furthermore, the biosynthesised AgNPs showed a prominent inhibitory effect against both Escherichia coli (MTCC 111) and Staphylococcus aureus (MTCC 97). Thus the biosynthesis of AgNPs from the bark extract of Amentotaxus assamica is found to eco‐friendly way of producing AgNPs compared to chemical method.Inspec keywords: X‐ray chemical analysis, microorganisms, transmission electron microscopy, nanoparticles, toxicology, scanning electron microscopy, ultraviolet spectra, particle size, Fourier transform spectra, X‐ray diffraction, antibacterial activity, visible spectra, infrared spectra, nanomedicine, silverOther keywords: stable AgNP, biosynthesised AgNP, SEM analysis, sunlight irradiation, silver ions, silver nanoparticle, amentotaxus assamica, biosynthesis, escherichia coli     

Green biosynthesis,characterisation and antimicrobial activities of silver nanoparticles using fruit extract of Solanum viarum

Green synthesis of nanoparticles is considered an efficient method when compared with chemical and physical methods because of its bulk production, eco‐friendliness and low cost norms. The present study reports, for the first time, green synthesis of silver nanoparticles (AgNPs) at room temperature using Solanum viarum fruit extract. The visual appearance of brownish colour with an absorption band at 450 nm, as detected by ultraviolet‐visible spectrophotometer analysis, confirmed the formation of AgNPs. X‐ray diffraction confirmed the AgNPs to be crystalline with a face‐centred lattice. The transmission electron microscopy‐energy dispersive X‐ray spectroscopy image showed the AgNPs are poly‐dispersed and are mostly spherical and oval in shape with particle size ranging from 2 to 40 nm. Furthermore, Fourier transform‐infrared spectra of the synthesised AgNPs confirmed the presence of phytoconstituents as a capping agent. The antimicrobial activity study showed that the AgNPs exhibited high microbial activity against Bacillus subtilis, Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus susp. aureus, Aspergillus niger, and Candida albicans. The highest antimicrobial activity of AgNPs synthesised by S. viarum fruit extract was observed in P. aeruginosa, S. aureus susp. aureus and C. albicans with zone of inhibition, 26.67 mm.Inspec keywords: nanomedicine, antibacterial activity, X‐ray chemical analysis, nanoparticles, transmission electron microscopy, particle size, infrared spectra, microorganisms, X‐ray diffraction, Fourier transform spectra, ultraviolet spectra, scanning electron microscopy, visible spectra, nanofabricationOther keywords: green biosynthesis, antimicrobial activities, silver nanoparticles, green synthesis, physical methods, study reports, solanum viarum fruit, ultraviolet‐visible spectrophotometer analysis, high microbial activity, highest antimicrobial activity, s. viarum fruit, transmission electron microscopy, energy dispersive X‐ray spectroscopy image     

Sustainable green synthesis of silver nanoparticles by using Rangoon creeper leaves extract and their spectral analysis and anti‐bacterial studies

The plant‐based biological molecules possess exceptionally controlled assembling properties to make them suitable in the synthesis of metal nanoparticles. In the present study, an efficient simple one‐pot method was employed for the synthesis of silver nanoparticles (SNPs) from the Rangoon creeper (RC) aqueous leaf extract. Biomolecules present in the leaf extract play a significant role as reducing agent as well as capping agent in the formation of RC‐SNPs. The formation of RC‐SNPs was confirmed by using several analytical techniques such as Fourier‐transform infrared spectroscopy and ultraviolet–visible spectrophotometer studies. The presence of a sharp surface plasmon resonance peak at 449 nm showed the formation of RC‐SNPs. X‐ray diffraction analysis showed the crystalline nature of the RC‐SNPs with a face‐centred cubic structure. Elemental analysis of RC‐SNPs was done by using energy‐dispersive X‐ray spectroscopy and X‐ray photoelectron spectroscopy. The morphology of RC‐SNPs was examined by transmission electron microscopy (TEM) in the nano range 12 nm, and thermogravimetric‐differential thermal analysis demonstrated the mechanical strength of RC‐SNPs at various temperatures. The authors’ newly synthesised RC‐SNPs exhibited significant anti‐bacterial activity against Staphylococcus aureus and Escherichia coli. Inspec keywords: silver, nanoparticles, X‐ray photoelectron spectra, antibacterial activity, ultraviolet spectra, microorganisms, X‐ray chemical analysis, differential thermal analysis, X‐ray diffraction, transmission electron microscopy, visible spectra, nanofabrication, surface plasmon resonance, Fourier transform infrared spectra, mechanical strengthOther keywords: silver nanoparticles, ultraviolet–visible spectrophotometry, antibacterial activity, sustainable green synthesis, plant‐based biological molecules, assembling properties, reducing agent, capping agent, Fourier‐transform infrared spectroscopy, surface plasmon resonance, Rangoon creeper aqueous leaf extract, X‐ray diffraction, face‐centred cubic structure, elemental analysis, energy‐dispersive X‐ray spectroscopy, X‐ray photoelectron spectroscopy, transmission electron microscopy, TEM, thermogravimetric‐differential thermal analysis, mechanical strength, Staphylococcus aureus, Escherichia coli, Ag     

Influence of ball milling on the particle size and antimicrobial properties of Tridax procumbens leaf nanoparticles

The herbal nanoparticles were prepared from shade dried Tridax procumbens plant leaves employing ball milling technique using different process parameters, like ball ratio/size and milling time. The obtained nanoparticles were comprehensively characterised using X‐ray diffraction, Fourier transform infrared spectroscopy, UV–visible spectroscopy, dynamic light scattering, scanning electron microscopy and antimicrobial analysis techniques. The crystallinity of the nanoparticles was retained without altering even though the particle size changes due to milling periods. The antibacterial activities of the prepared herbal nanoparticles against Staphylococcus aureus and Escherichia coli were explored to understand the influence of particle size on antimicrobial activities and their functional properties. The increase in ball ratio and milling time periods leads to a decrease in nanoparticle size from 114 to 45 nm which in turn increases the antimicrobial activities. The above study confirms that antimicrobial activity relies on nanoparticle size. The observed knowledge on influence of particle size on antimicrobial activities will help to optimise the production of potential herbal nanoparticles for different biomedical applications.Inspec keywords: nanoparticles, antibacterial activity, biomedical materials, nanomedicine, X‐ray diffraction, Fourier transform infrared spectra, scanning electron microscopy, ultraviolet spectra, visible spectra, microorganisms, particle sizeOther keywords: antimicrobial properties, Tridax procumbens leaf nanoparticles, herbal nanoparticles, ball milling technique, X‐ray diffraction, Fourier transform infrared spectroscopy, UV‐visible spectroscopy, dynamic light scattering, scanning electron microscopy, antimicrobial analysis techniques, Staphylococcus aureus, Escherichia coli, nanoparticle size     

Efficacy of mycosynthesised AgNPs from Earliella scabrosa as an in vitro antibacterial and wound healing agent

The silver nanoparticles (AgNPs) with their unique chemical and physical properties are proving as a new therapeutical agent. In the present study, the AgNPs synthesised from an aqueous extract of a macrofungus, Earliella scabrosa, were characterised by field emission scanning electron microscopy (FESEM), energy dispersive X‐ray analysis (EDX), high‐resolution transmission electron microscopy, X‐ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR) and further evaluate for its in vitro antibacterial and wound healing efficacy. The mycosynthesised AgNPs exhibited the surface plasmon resonance peak at 410 nm with good stability over a period of a month. The FESEM and EDX analyses revealed the spherical‐shaped AgNPs of an average size of 20 nm and the presence of elemental Ag, respectively. The XRD pattern showed the crystalline nature of AgNPs. The FTIR spectra confirmed the conversion of Ag⁺ ions to AgNPs due to reduction by biomolecules of macrofungus extract. The mycosynthesised AgNPs showed effective antibacterial activity against two Gram‐positive bacteria, namely Bacillus subtilis and Staphylococcus aureus, and two Gram‐negative bacteria Escherichia coli and Pseudomonas aeruginosa. The pathogens were highly sensitive to AgNPs, whereas less sensitive to AgNO₃. The mycosynthesised AgNPs showed significant wound healing potential with 68.58% of wound closure.Inspec keywords: surface plasmon resonance, wounds, X‐ray diffraction, nanoparticles, molecular biophysics, nanomedicine, antibacterial activity, biomedical materials, reduction (chemical), silver, microorganisms, X‐ray chemical analysis, nanofabrication, transmission electron microscopy, particle size, field emission scanning electron microscopy, Fourier transform infrared spectraOther keywords: high‐resolution transmission electron microscopy, healing efficacy, mycosynthesised AgNPs, spherical‐shaped AgNPs, wound healing agent, in vitro antibacterial efficacy, Earliella scabrosa, silver nanoparticles, physical properties, chemical properties, therapeutical agent, aqueous extract, macrofungus, field emission scanning electron microscopy, FESEM, energy dispersive X‐ray analysis, EDX, X‐ray diffraction, XRD, Fourier transform infrared spectroscopy, FTIR spectroscopy, surface plasmon resonance peak, crystalline nature, biomolecules, Gram‐positive bacteria, Bacillus subtilis, Staphylococcus aureus, Gram‐negative bacteria, Escherichia coli, Pseudomonas aeruginosa, pathogens, wound closure, Ag     

Synthesis of gold and silver nanoparticles using Mukia maderaspatna plant extract and its anticancer activity

The present investigation reveals the in vitro cytotoxic effect of the biosynthesised metal nanoparticles on the MCF 7 breast cancer cell lines. The gold and silver nanoparticles were synthesised through an environmentally admissible route using the Mukia Maderaspatna plant extract. Initially, the biomolecules present in the plant extract were analysed using phytochemical analysis. Further, these biomolecules reduce the metal ion solution resulting from the formation of metal nanoparticles. The reaction parameters were optimised to control the size of nanoparticles which were confirmed by UV visible spectroscopy. Various instrumental techniques such as Fourier transform‐infrared spectroscopy, high resolution transmission electron microscopy, energy dispersive X‐ray and scanning electron microscopy were employed to characterise the synthesised gold and silver nanoparticles. The synthesised gold and silver nanoparticles were found to be 20–50 nm and were of different shapes including spherical, triangle and hexagonal. MTT and dual staining assays were carried out with different concentrations (1, 10, 25, 50 and 100 µg/ml) of gold and silver nanoparticles. The results show that the nanoparticles exhibited significant cytotoxic effects with IC 50 value of 44.8 µg/g for gold nanoparticles and 51.3 µg/g for silver nanoparticles. The observations in this study show that this can be developed as a promising nanomaterial in pharmaceutical and healthcare sector.Inspec keywords: gold, silver, nanoparticles, nanofabrication, nanomedicine, biomedical materials, cancer, cellular biophysics, ultraviolet spectra, visible spectra, Fourier transform infrared spectra, transmission electron microscopy, X‐ray chemical analysis, scanning electron microscopyOther keywords: gold nanoparticle synthesis, silver nanoparticle synthesis, Mukia maderaspatna plant extract, anticancer activity, MCF 7 breast cancer cell line, biomolecule, phytochemical analysis, size 20 nm to 50 nm, healt hcare sector, pharmaceutical sector, nanomaterial, dual staining assay, MTT assay, scanning electron microscopy, energy dispersive X‐ray spectrocopy, high resolution transmission electron microscopy, Fourier transform‐infrared spectroscopy, instrumental technique, ultraviolet‐visible spectroscopy, metal nanoparticle formation, metal ion solution     

Unveiling the cytotoxicity of phytosynthesised silver nanoparticles using Tinospora cordifolia leaves against human lung adenocarcinoma A549 cell line

Biosynthesis of silver nanoparticles (AgNPs) using plant extract is a cheap, easily accessible and natural process in which the phyto‐constituents of the plants act as capping, stabilising and reducing agent. The present study explored the biosynthesis of AgNPs using aqueous leaf extract of Tinospora cordifolia and characterised via various techniques such as Fourier transform infrared, scanning electron microscopy, transmission electron microscopy (TEM), energy dispersive X‐ray analysis and X‐ray diffraction. Here, TEM confirmed the spherical morphology with 25–50 nm size of synthesised AgNPs. Further, anticancer efficiency of AgNPs synthesised using T. cordifolia leaves were evaluated against human lung adenocarcinoma cell line A549 by MTT, trypan blue assay, apoptotic morphological changes using Annexin V‐FITC and Propidium iodide (PI), nuclear morphological changes by DAPI (4, 6‐diamidino‐2‐phenylindole dihydrochloride) staining, reactive oxygen species generation and mitochondrial membrane potential determination. Results confirmed the AgNPs synthesised using T. cordifolia leaves are found to be highly toxic against human lung adenocarcinoma cell line A549.Inspec keywords: toxicology, cellular biophysics, cancer, silver, biomembranes, drugs, nanofabrication, nanoparticles, transmission electron microscopy, drug delivery systems, nanomedicine, lung, biomedical materials, antibacterial activity, X‐ray diffraction, Fourier transform infrared spectra, scanning‐transmission electron microscopyOther keywords: cytotoxicity, phytosynthesised silver nanoparticles, A549 cell line, biosynthesis, aqueous leaf, transmission electron microscopy, TEM, X‐ray analysis, X‐ray diffraction, spherical morphology, human lung adenocarcinoma cell line, nuclear morphological changes, 4, 6‐diamidino‐2‐phenylindole dihydrochloride, Tinospora cordifolia leaves, scanning electron microscopy, Fourier transform infrared, energy dispersive X‐ray analysis, Ag, size 25.0 nm to 50.0 nm, anticancer efficiency, trypan blue assay, propidium iodide, Annexin V‐FITC, DAPI staining, reactive oxygen species generation, mitochondrial membrane potential determination     

Role of Ribes khorassanicum in the biosynthesis of AgNPs and their antibacterial properties

Silver nanoparticles (AgNPs) have been biosynthesised through the extracts of Ribes khorassanicum fruits, which served as the reducing agents and capping agents. Biosynthesised AgNPs have been found to be ultraviolet–visible (UV–vis) absorption spectra since they have displayed one surface plasmon resonance peak at 438 nm, attesting the formation of spherical NPs. These particles have been characterised by UV–vis, field‐emission scanning electron microscopy, energy‐dispersive X‐ray spectroscopy, X‐ray diffraction, Fourier transform infrared spectroscopy, and transmission electron microscopy analysis. The formation of AgNPs at 1.0 mM concentration of AgNO₃ has resulted in NPs that contained mean diameters in a range of 20–40 nm. The green‐synthesised AgNPs have demonstrated high antibacterial effect against pathogenic bacteria (i.e. Staphylococcus aureus, Escherichia coli, and Pseudomonas aeruginosa). Biosynthesising metal NPs through plant extracts can serve as the facile and eco‐friendly alternative for chemical and/or physical methods that are utilised for large‐scale nanometal fabrication in various medical and industrial applications.Inspec keywords: X‐ray diffraction, X‐ray chemical analysis, nanofabrication, surface plasmon resonance, nanoparticles, antibacterial activity, microorganisms, scanning electron microscopy, silver, nanomedicine, visible spectra, ultraviolet spectra, transmission electron microscopy, Fourier transform infrared spectra, field emission scanning electron microscopy, biomedical materialsOther keywords: antibacterial properties, silver nanoparticles, reducing agents, capping agents, surface plasmon resonance peak, spherical NPs, field‐emission scanning electron microscopy, energy‐dispersive X‐ray spectroscopy, X‐ray diffraction, transmission electron microscopy analysis, plant extracts, ultraviolet‐visible absorption spectra, Fourier transform infrared spectroscopy, antibacterial effect, Ribes khorassanicum fruits, Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa, surface plasmon resonance, AgNO₃ , Ag     

Comparative antibacterial activity of silver nanoparticles synthesised by biological and chemical routes with pluronic F68 as a stabilising agent

The authors report the comparative antibacterial activity of silver nanoparticles synthesised by biological (using Fusarium oxysporum) and chemical routes in the presence and absence of pluronic F68 as a stabilising agent. The production of silver nanoparticles was evidenced by UV–visible spectra, with absorbance at about 420 nm in the case of both biological and chemical synthesis. X‐ray diffraction pattern confirmed the presence of face‐centred cubic structure (FCC plane). The nanoparticles characterised by transmission and scanning electron microscopy showed spherical silver nanoparticles with size range of 5–40 and 10–70 nm in the case of biologically and chemically synthesised nanoparticles, respectively. Addition of pluronic F68 showed the stabilisation of silver nanoparticles. Antibacterial efficacy of silver nanoparticles demonstrated different inhibitory activity against Escherichia coli, Pseudomonas aeruginosa and Staphylococcus aureus. Overall, biologically synthesised silver nanoparticles showed higher activity as compared with chemically synthesised nanoparticles. Silver nanoparticles synthesised in the presence of pluronic F68 by the chemical route exhibited synergism in antibacterial activity as compared with those synthesised without pluronic F68. On the contrary, biogenic silver nanoparticles without pluronic F68 showed higher antibacterial potential.Inspec keywords: antibacterial activity, nanofabrication, silver, X‐ray diffraction, biomedical materials, nanomedicine, transmission electron microscopy, scanning electron microscopy, ultraviolet spectra, visible spectra, materials preparation, nanoparticlesOther keywords: pluronic F68, stabilising agent, comparative antibacterial activity, Fusarium oxysporum, UV‐visible spectra, biological synthesis, chemical synthesis, X‐ray diffraction pattern, face‐centred cubic structure, FCC plane, transmission electron microscopy, scanning electron microscopy, spherical silver nanoparticles, antibacterial efficacy, Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus, synergism, biogenic silver nanoparticles, wavelength 420 nm, size 10 nm to 70 nm, size 5 nm to 40 nm, Ag     

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     

Green synthesis,characterisation and biological studies of AgNPs prepared using Shivlingi (Bryonia laciniosa) seed extract

Green synthesis of silver nanoparticles (AgNPs) using Shivlingi (Bryonia laciniosa) seed extract was carried out. Characterisation of synthesised nanoparticles was accomplished through the optical absorption and photoluminescence spectrum, X‐ray diffraction (XRD), transmission electron microscopy (TEM), scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR) and Raman spectroscopy. The XRD analysis further confirmed the size of nanoparticles ∼15 nm. TEM images revealed homogeneous spherical ∼10 nm Bryonia extract capped AgNPs. The biological studies indicated that both Bryonia seed extract and the nanoparticles lack anti‐microbial activity; however, the nanoparticles had better cytotoxicity and total antioxidant activity. The Lethal concentration (LC)₅₀ value of water extract and the nanoparticles were found to be 1091 and 592 μg/ml, respectively. The lower LC₅₀ of nanoparticles indicates that it is more cytotoxic than the crude extract. The results indicate that the Bryonia seed is safe to be used as a medicine and the formation of their nanoparticle has further enriched the chemical reactivity, energy absorption and biological mobility.Inspec keywords: silver, nanoparticles, nanomedicine, particle size, microorganisms, cellular biophysics, nanofabrication, photoluminescence, X‐ray diffraction, transmission electron microscopy, scanning electron microscopy, Fourier transform infrared spectra, Raman spectra, antibacterial activity, biochemistryOther keywords: green synthesis, biological studies, Shivlingi seed extraction, Bryonia laciniosa, silver nanoparticles, optical absorption, photoluminescence spectrum, X‐ray diffraction, transmission electron microscopy, scanning electron microscopy, SEM, Fourier transform infrared spectroscopy, Raman spectroscopy, XRD analysis, nanoparticle size, TEM images, homogeneous spherical images, antioxidant activity, water extraction, chemical reactivity, energy absorption, biological mobility, Ag     

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     

Biogenic synthesis,optimisation and antibacterial efficacy of extracellular silver nanoparticles using novel fungal isolate Aspergillus fumigatus MA

To eliminate the elaborate processes employed in other non‐biological‐based protocols and low cost production of silver nanoparticles (AgNPs), this study reports biogenic synthesis of AgNPs using silver salt precursor with aqueous extract of Aspergillus fumigates MA. Influence of silver precursor concentrations, concentration ratio of fungal extract and silver nitrate, contact time, reaction temperature and pH are evaluated to find their effects on AgNPs synthesis. Ultraviolet–visible spectra gave surface plasmon resonance at 420 nm for AgNPs. Fourier transform infrared spectroscopy and X‐ray diffraction techniques further confirmed the synthesis and crystalline nature of AgNPs, respectively. Transmission electron microscopy observed spherical shapes of synthesised AgNPs within the range of 3–20 nm. The AgNPs showed potent antimicrobial efficacy against various bacterial strains. Thus, the results of the current study indicate that optimisation process plays a pivotal role in the AgNPs synthesis and biogenic synthesised AgNPs might be used against bacterial pathogens; however, it necessitates clinical studies to find out their potential as antibacterial agents.Inspec keywords: nanoparticles, microorganisms, cellular biophysics, silver, antibacterial activity, pH, surface plasmon resonance, ultraviolet spectra, visible spectra, X‐ray diffraction, Fourier transform infrared spectra, optimisation, nanomedicine, nanofabricationOther keywords: biogenic synthesis, optimisation, antibacterial efficacy, extracellular silver nanoparticles, fungal isolate Aspergillus fumigatus MA, nonbiological‐based protocols, silver salt precursor, fungal extract, silver nitrate, pH, ultraviolet‐visible spectra, surface plasmon resonance, Fourier transform infrared spectroscopy, X‐ray diffraction, crystalline nature, transmission electron microscopy, spherical shapes, potent antimicrobial efficacy, bacterial strains, optimisation process, bacterial pathogens, antibacterial agents, wavelength 420 nm, size 3 nm to 20 nm, Ag     

Antineoplastic and antioxidant potential of phycofabricated silver nanoparticles using microalgae Chlorella minutissima

This study for the first time reports on fresh water microalgae Chlorella minutissima aqueous extract (CmAe) which was utilized for the biogenic synthesis of silver nanoparticles and tested their antineoplastic potential against Liver Hepatocellular Carcinoma (HepG2) cell line. The characteristic colour change of the reaction mixture from greenish yellow to yellowish brown confirmed the synthesis of Chlorella minutissima silver nanoparticles (CmAgNPs). Microscopic analysis revealed CmAgNPs to be spherical‐shaped with particle size ranging from 10 to 30 nm. The carbohydrates and proteins distinctive peaks were observed in Fourier transform infrared spectroscopy (FTIR) spectra which suggested these biomolecules acted as reducing and capping agents. Further, the crystalline nature of CmAgNPs was confirmed by X‐ray diffraction (XRD) analysis. CmAgNPs showed maximum free radical scavenging proving it to be more potent antioxidant agent as compared to CmAe. The mortality rate of HepG2 cells treated with CmAgNPs was found to be 91.8 % at 120 μg/ml with IC₅₀ value 12.42 ± 1.096 μg/ml after 48 h whereas no effect was observed on normal Human Embryonic Kidney (HEK 293) cells. Fluorescent images of the treated HepG2 cells revealed the formation of apoptotic bodies, condensed nuclei and cell shrinkage indicating their effectiveness against the cancer cells.Inspec keywords: silver, nanoparticles, nanomedicine, microorganisms, cellular biophysics, nanofabrication, scanning electron microscopy, transmission electron microscopy, atomic force microscopy, proteins, Fourier transform infrared spectra, molecular biophysics, X‐ray chemical analysis, X‐ray diffraction, kidney, cancer, biomedical materialsOther keywords: antineoplastic potential, antioxidant potential, phycofabricated silver nanoparticle, Chlorella minutissima, freshwater microalgae, aqueous extract, liver hepatocellular carcinoma cell line, CmAgNP synthesis, field emission scanning electron microscopy, high‐resolution transmission electron microscopy, atomic force microscopy, dynamic light scattering, carbohydrate, protein, Fourier transform infrared spectroscopy, biomolecule, energy‐dispersive X‐ray spectroscopy, elemental silver signal, CmAgNP crystalline, X‐ray diffraction analysis, antioxidant agent, HepG2 cell mortality rate, human embryonic kidney, HEK 293 cell, fluorescent image, apoptotic body formation, condensed nuclei, cell shrinkage, cancer cell, antineoplastic agent, Ag     

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