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     

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     

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     

Green synthesis of silver nanoparticle by cauliflower extract: characterisation and antibacterial activity against storage

Green synthesis of silver nanoparticles (AgNPs) was accomplished using different volumes of cauliflower extract and 0.001 M silver nitrate solution at 80°C for 15 min. A brownish‐red solution of AgNPs formed was tested by ultraviolet–visible absorption spectroscopy, Fourier‐transform infrared (FTIR), scanning electron microscopy (SEM), and X‐ray diffraction (XRD). Surface plasmon resonance of AgNPs appeared at 416 nm. Also, the kinetic of AgNPs formation was studied and follows a sigmoidal pattern. Storing time was studied for the freshly prepared AgNPs after 60 days. FTIR analysis shows the adsorption of active components on AgNPs surface, and these components are responsible for reduction besides working as a stabiliser like a capping agent, also FTIR analysis of AgNPs after storage showed no change in peaks location. The SEM exhibited a globular shape of AgNPs, and the particle size ranged from 25 to 100 nm, while the XRD particle size calculation was 25 nm with cubic phase lattice. The antibacterial activity was tested against Gram‐positive and ‐negative bacteria showed an inhibition zone of 16–27 mm and the antibacterial activity tested for the same bacteria after storage for about 10 months showed an inhibition zone of 6–10 mm.Inspec keywords: microorganisms, reduction (chemical), nanofabrication, surface plasmon resonance, silver, transmission electron microscopy, nanoparticles, particle size, visible spectra, ultraviolet spectra, adsorption, antibacterial activity, scanning electron microscopy, X‐ray diffraction, Fourier transform infrared spectra, nanomedicineOther keywords: antibacterial activity, green synthesis, silver nanoparticle, brownish‐red solution, surface plasmon resonance, FTIR analysis, active components, silver nitrate solution, ultraviolet‐visible absorption spectroscopy, AgNP surface, cauliflower extract, Fourier‐transform infrared spectroscopy, scanning electron microscopy, SEM, X‐ray diffraction, XRD, sigmoidal pattern, storing time, adsorption, stabiliser, capping agent, globular shape, particle size, cubic phase lattice, Gram‐positive bacteria, Gram‐negative bacteria, inhibition zone, reduction, time 60.0 d, temperature 80.0 degC, time 15.0 min, wavelength 416.0 nm, Ag     

Synthesis and characterisation of silver nanoparticles using leaf extract of Artemisia afra and their in vitro antimicrobial and antioxidant activities

In this study, the conversion of silver ions into ∼30.74 nm sized silver nanoparticles (AgNPs) was achieved in 30 min at a reaction temperature of 80–90°C in aqueous leaf extract of Artemisia afra. The synthesised AgNPs showed surface plasmon resonance in the range of 423–438 nm. Spherical and face‐centred cubic nanoparticles were confirmed by transmission electron microscope (TEM) and X‐ray diffraction (XRD) analysis, respectively. Fourier transform infra‐red (FTIR) results indicated that the obtained nanoparticles were stabilised and capped through the carbonyl and carboxylate ion groups possibly from flavonoids, terpenoids, phenolics and esters content of the extracts. In addition, the AgNPs were assessed for their biological potentials against some microbes and, also, their free radical scavenging ability was established. The AgNPs exhibited interesting antimicrobial and antioxidant properties better than the aqueous extract of A. afra. Inspec keywords: silver, transmission electron microscopy, ultraviolet spectra, visible spectra, surface plasmon resonance, antibacterial activity, X‐ray diffraction, microorganisms, nanoparticles, nanofabrication, Fourier transform infrared spectraOther keywords: silver nanoparticles, reaction temperature, surface plasmon resonance, face‐centred cubic nanoparticles, antioxidant properties, silver ion conversion, aqueous leaf extract, carboxylate ion group, antimicrobial properties, Artemisia afra, spherical nanoparticles, TEM, XRD, FTIR spectra, Ag, temperature 80 degC to 90 degC, time 30.0 min, free radical scavenging, esters, phenolics, terpenoids, flavonoids, carbonyl ion group     

Green synthesis of silver nanoparticles using Mentha pulegium and investigation of their antibacterial,antifungal and anticancer activity

A simple and eco‐friendly method for efficient synthesis of stable colloidal silver nanoparticles (AgNPs) using Mentha pulegium extracts is described. A series of reactions was conducted using different types and concentrations of plant extract as well as metal ions to optimize the reaction conditions. AgNPs were characterized by using UV–vis spectroscopy, transmission electron microscopy, atomic force microscopy, dynamic light scattering, zetasizer, energy‐dispersive X‐ray spectroscopy (EDAX) and Fourier transform infrared spectroscopy (FTIR). At the optimized conditions, plate shaped AgNPs with zeta potential value of ‐15.7 and plasmon absorption maximum at 450 nm were obtained using high concentration of aqueous extract. Efficient adsorption of organic compounds on the nanoparticles was confirmed by FTIR and EDAX. The biogenic AgNPs displayed promising antibacterial activity on Escherichia coli, Staphylococcus aureus, and Streptococcus pyogenes. The highest antibacterial activity of 25 µg mL‐1 was obtained for all the strains using aqueous extract synthesized AgNPs. The aqueous extract synthesised AgNPs also showed considerable antifungal activity against fluconazole resistant Candida albicans. The cytotoxicity assay revealed considerable anticancer activity of AgNPs on HeLa and MCF‐7 cancer cells. Overall results indicated high potential of M. pulegium extract to synthesis high quality AgNPs for biomedical applications.Inspec keywords: silver, nanoparticles, nanofabrication, botany, antibacterial activity, biomedical materials, nanomedicine, ultraviolet spectra, visible spectra, transmission electron microscopy, atomic force microscopy, X‐ray chemical analysis, Fourier transform infrared spectra, electrokinetic effects, microorganisms, cellular biophysics, cancerOther keywords: antibacterial activity, antifungal activity, anticancer activity, stable colloidal silver nanoparticle, Mentha pulegium, plant extract, UV‐visible spectroscopy, transmission electron microscopy, atomic force microscopy, DLS, zetasizer, energy‐dispersive X‐ray spectroscopy, Fourier transform infrared spectroscopy, methanolic extract, aqueous extract, plate‐shaped silver nanoparticle, zeta potential, plasmon absorption maximum, organic compounds adsorption, biogenic silver nanoparticle, Escherichia coli, Staphylococcus aureus, Streptococcus pyogenes, fluconazole‐resistant Candida albicans, MTT assay, HeLa cancer cell, MCF‐7 cancer cell, 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     

Fabrication and characterisation of silver nanoparticles using bract extract of Musa paradisiaca for its synergistic combating effect on phytopathogens,free radical scavenging activity,and catalytic efficiency

This work explores the rapid synthesis of silver nanoparticles (AgNPs) from Musa paradisiaca (M. paradisiaca) bract extract. The bio‐reduction of Ag⁺ ion was recorded using ultraviolet–visible spectroscopy by a surface plasmon resonance extinction peak with an absorbance at 420 nm. The phytoconstituents responsible for the reduction of AgNPs was probed using Fourier transform infrared spectroscopy. The X‐ray diffraction pattern confirmed the formation of crystalline AgNPs that were analogous to selected area electron diffraction patterns. Morphological studies showed that the obtained AgNPs were monodispersed with an average size of 15 nm. The biologically synthesised AgNPs showed higher obstruction against tested phytopathogens. The synthesised AgNPs exhibited higher inhibitory zone against fungal pathogen Alternaria alternata and bacterial pathogen Pseudomonas syringae. Free radical scavenging potential of AgNPs was investigated using 1,1‐diphenyl‐2‐picryl hydroxyl and 2,2‐azinobis (3‐ethylbenzothiazoline)‐6‐sulphonic acid assays which revealed that the synthesised AgNPs act as a potent radical scavenger. The catalytic efficiency of the synthesised AgNPs was investigated for azo dyes, methyl orange (MO), methylene blue (MB) and reduction of o‐nitrophenol to o‐aminophenol. The results portrayed that AgNPs act as an effective nanocatalyst to degrade MO to hydrazine derivatives, MB to leucomethylene blue, and o‐nitro phenol to o‐amino phenolInspec keywords: catalysis, dyes, electron diffraction, nanofabrication, silver, catalysts, surface plasmon resonance, reduction (chemical), free radicals, nanoparticles, transmission electron microscopy, nanobiotechnology, X‐ray diffraction, microorganisms, organic compounds, Fourier transform spectra, nanomedicine, visible spectra, antibacterial activity, infrared spectra, ultraviolet spectraOther keywords: silver nanoparticles, musa paradisiaca, synergistic combating effect, free radical scavenging activity, catalytic efficiency, M. paradisiaca, bio‐reduction, ultraviolet–visible spectroscopy, surface plasmon resonance extinction peak, Fourier transform infrared spectroscopy, X‐ray diffraction pattern, selected area electron diffraction patterns, radical scavenging potential, potent radical scavenger, size 420.0 nm, size 15.0 nm, Ag⁺      

Rapid synthesis of silver nanoparticles by Pseudomonas stutzeri isolated from textile soil under optimised conditions and evaluation of their antimicrobial and cytotoxicity properties

Present study utilised textile soil isolated bacterium Pseudomonas stutzeri to synthesise extracellular silver nanoparticles (AgNPs) under optimised conditions. The synthesised AgNPs were characterised using ultraviolet‐visible spectroscopy, Fourier transform infrared spectroscopy (FTIR) and transmission electron microscopy (TEM). Optimisation showed AgNPs synthesis within 8 h using 2mM Ag nitrate at pH9, temperature 80°C and maximum absorbance toward 400 nm. TEM analysis revealed spherical shape AgNPs and reduction in size upto 8 nm was observed under optimised conditions. FTIR spectra confirmed presence of proteins bound to AgNPs act as reducing agent. AgNPs showed strong antibacterial activity against multi‐drug resistant (MDR) Escherichia coli and Klebsiella pneumoniae as demonstrated by disc diffusion and colony forming unit assays. Zone of inhibition increased with increasing concentration of AgNPs with maximum of 19 mm against E. coli and 17 mm against K. pneumoniae at concentration of 2 μg/disc. Furthermore, AgNPs did not show any cytotoxic effects on human epithelial cells as demonstrated by 3‐(4,5‐dimethylthiazol‐2‐yl)‐2,5‐diphenyl tetrazolium bromide assay even at 2 μg/ml concentration of AgNPs. The results of the present study suggest that AgNPs can be synthesised rapidly under optimised conditions and show strong antimicrobial property against MDR pathogens without having toxicity effect on human epithelial cells.Inspec keywords: ultraviolet spectra, proteins, transmission electron microscopy, infrared spectra, Fourier transform spectra, visible spectra, microorganisms, toxicology, cellular biophysics, biomedical materials, antibacterial activity, nanomedicine, nanofabrication, nanoparticles, silverOther keywords: 3‐(4,5‐dimethylthiazol‐2‐yl)‐2,5‐diphenyl tetrazolium bromide assay, human epithelial cells, cytotoxic effects, K. pneumoniae, colony forming unit counting assays, disc diffusion, Klebsiella pneumoniae, Escherichia coli, multidrug resistant, stabilising agent, reducing agent, proteins, parametric optimisation, TEM, transmission electron microscopy, FTIR spectra, Fourier transform infrared spectroscopy, ultraviolet‐visible spectroscopy, bacterium, cytotoxicity properties, antimicrobial properties, textile soil, Pseudomonas stutzeri, silver nanoparticle synthesis     

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 and characterisation of neem leaf extract, 2, 3‐dehydrosalanol and quercetin dihydrate mediated silver nano particles for therapeutic applications

The utility of green silver nanoparticles (AgNPs) in veterinary medicine is steadily increasing as they have many therapeutic applications against pathogens and arthropods of livestock. In this study, green AgNPs using neem (N‐AgNPs), 2,3‐dehydrosalanol (2,3‐DHS‐AgNPs) and quercetin dihydrate (QDH‐AgNPs) were synthesised and characterised. Synthesised compounds were characterised by UV‐Vis spectroscopy and the peak absorbance was recorded at 370 nm for neem extract. For N‐AgNPs, 2,3‐DHS‐AgNPs and QDH‐AgNPs, the maximum absorbance peaks were at 430, 230 and 220 nm, respectively. The FTIR analysis confirmed the synthesis of green AgNPs. The XRD pattern of N‐AgNPs showed the peaks corresponding to whole spectra of 2 θ values ranging from 10–80. The relatively higher intensity of (111, 222) planes in face centred cubic crystalline structure supports the formation of synthesised AgNPs. In DLS analysis, the hydrodynamic diameter of neem leaf extract was found to be 259.8 nm, followed by 5.3, 6.7 and 261.8 nm for 2,3‐DHS‐AgNPs, N‐AgNPs and QDH‐AgNPs, respectively. Based on the transmission electron microscopy and scanning electron microscopy image analyses, confirmed the formation of N‐AgNPs, 2,3‐DHS‐AgNPs and QDH‐AgNPs. These eco‐friendly phyto‐AgNPs may be of use as an effective alternative to chemical control methods against the arthropods of livestock.Inspec keywords: nanoparticles, silver, nanomedicine, biomedical materials, nanofabrication, Fourier transform infrared spectra, ultraviolet spectra, visible spectra, X‐ray diffraction, light scattering, transmission electron microscopy, scanning electron microscopy, aggregation, veterinary medicineOther keywords: 2,3‐dehydrosalanol mediated silver nanoparticles, quercetin dihydrate mediated silver nanoparticles, therapeutic applications, green silver nanoparticles, veterinary medicine, Azadirachta indica, UV‐visible spectroscopy, Fourier transformed infrared analysis, X‐ray diffraction, (111) planes, (222) planes, face centred cubic crystalline structure, dynamic light scattering, hydrodynamic diameter, aqueous neem leaf extract, transmission electron microscopy, hexagonal shape, pencil head shape, cuboid shape, scanning electron microscopy, aggregation, arthropod infesting livestock, Ag, in‐vivo antiectoparasitic activity, in‐vitro antiectoparasitic activity     

Phyto‐assisted synthesis of bio‐functionalised silver nanoparticles and their potential anti‐oxidant,anti‐microbial and wound healing activities

Bio‐ synthesis of silver nanoparticles (AgNPs) was made by using the aqueous leaf extract of Ardisia solanacea. Rapid formation of AgNPs was observed from silver nitrate upon treatment with the aqueous extract of A. solanacea leaf. The formation and stability of the AgNPs in the colloidal solution were monitored by UV–visible spectrophotometer. The mean particle diameter of AgNPs was calculated from the DLS with an average size ∼4 nm and ∼65 nm. ATR‐FTIR spectroscopy confirmed the presence of alcohols, aldehydes, flavonoids, phenols and nitro compounds in the leaf which act as the stabilizing agent. Antimicrobial activity of the synthesized AgNPs was performed using agar well diffusion and broth dilution method against the Gram‐positive and Gram‐negative bacteria. Further, robust anti‐oxidative potential was evaluated by DPPH assay. The highest antimicrobial activity of synthesized AgNPs was found against Pseudomonas aeruginosa (28.2 ± 0.52 mm) whereas moderate activity was found against Bacillus subtilis (16.1 ± 0.76), Candida kruseii (13.0 ± 1.0), and Trichophyton mentagrophytes (12.6 ± 1.52). Moreover, the potential wound healing activity was observed against the BJ‐5Ta normal fibroblast cell line. Current research revealed that A. solanacea was found to be a suitable source for the green synthesis of silver nanoparticles.Inspec keywords: antibacterial activity, nanoparticles, silver, nanomedicine, wounds, microorganisms, X‐ray diffraction, ultraviolet spectra, visible spectra, Fourier transform infrared spectra, transmission electron microscopyOther keywords: phyto‐assisted synthesis, biofunctionalised silver nanoparticles, antioxidant antimicrobial wound healing activities, silver nanoparticle biosynthesis, aqueous leaf extract, Ardisia solanacea, silver nitrate, UV–visible spectroscopy, dynamic light scattering, Fourier transform infra‐red spectroscopy, X‐ray diffraction, electron microscopy, attenuated total reflection Fourier transform infra‐red spectroscopy, dilution method, Gram‐positive bacteria, Gram‐negative bacteria, radical scavenging method, Pseudomonas aeruginosa, Trichophyton mentagrophytes, Bacillus subtilis, Candida kruseii, BJ‐5Ta normal fibroblast cell line, SEM, alcohols, aldehydes, flavonoids, phenols, nitro compounds, Ag     

Phytochemical constituents of fucoidan (Padina tetrastromatica) and its assisted AgNPs for enhanced antibacterial activity

Biological synthesis of nanomaterials is a growing innovative approach and it was broadly utilised in the field of nanotechnology and nanomedicine. This study illustrates that biosynthesis of silver nanoparticles (AgNPs) using fucoidan extracted from seaweed Padina tetrastromatica. The functional groups of extracted fucoidan were characterised by Fourier transform infrared spectroscopy (FTIR) and used to NPs synthesis. Synthesised AgNPs were characterised by ultraviolet–visible spectra, scanning electron microscope, energy dispersive X‐ray, transmission electron microscope, selected area electron diffraction and FTIR. In this study, their main focus is enhancement antibacterial activity of AgNPs coated antibiotics against antibiotic resistant bacteria. Among the microorganisms, Serratia nematodiphila was resistant to novobiocin and penicillin, but it was sensitive to AgNPs impregnated antibiotic discs. The zone of inhibition was 12 and 15 mm. The synergistic effect of combined antibiotics and AgNPs resulted in increased fold area which was greater than the sum of their separate effects. It reveals that AgNPs are highly sought in the medicinal field due to their broad spectrum of antibacterial activity and relatively cheaper. This enhanced synergistic effect potentially superior to control the growth of bacteria and it is the budding process for the development of new remedial agents for severe diseases.Inspec keywords: silver, nanoparticles, nanomedicine, antibacterial activity, drug delivery systems, Fourier transform infrared spectra, ultraviolet spectra, visible spectra, scanning electron microscopy, X‐ray chemical analysis, transmission electron microscopy, electron diffraction, microorganisms, diseases, nanofabrication, drugs, cellular biophysicsOther keywords: phytochemical constituents, enhanced antibacterial activity, nanotechnology, nanomedicine, drug delivery, silver nanoparticles, biosynthesis, fucoidan extraction, marine brown seaweed Padina tetrastromatica, functional groups, Fourier transform infrared spectroscopy, FTIR spectroscopy, ultraviolet‐visible spectra, scanning electron microscopy, energy dispersive X‐ray analysis, transmission electron microscopy, selected area electron diffraction, AgNP coated antibiotics, antibiotic resistant bacteria, Serratia nematodiphila, novobiocin, penicillin, AgNP impregnated antibiotic discs, medicinal field, broad spectrum, enhanced synergistic effect, diseases, Ag     

Role of catalytic protein and stabilising agents in the transformation of Ag ions to nanoparticles by Pseudomonas aeruginosa

Biological routes of synthesising metal nanoparticles (NPs) using microbes have been gaining much attention due to their low toxicity and eco‐friendly nature. Pseudomonas aeruginosa JP2 isolated from metal contaminated soil was evaluated towards extracellular synthesis of silver NPs (AgNPs). Cell‐free extract (24 h) of the bacterial isolate was reacted with AgNO₃ for 24 h in order to fabricate AgNPs. Preliminary observations were recorded in terms of colour change of the reaction mixture from yellow to greyish black. UV‐visible spectroscopy of the reaction mixture has shown a progressive increase in optical densities that correspond to peaks near 430 nm, depicting reduction of ionic silver (Ag⁺) to atomic silver (Ag⁰) thereby synthesising NPs. X‐ray diffraction spectra exhibited the 2θ values to be 38.4577° confirming the crystalline and spherical nature of NPs [9.6 − 26.7 (Ave. = 17.2 nm)]. Transmission electron microscopy finally confirmed the size of the particles varying from 5 to 60 nm. Moreover, rhamnolipids and proteins were identified as stabilising molecules for the AgNPs through Fourier transform‐infrared spectroscopy. Characterisation of bacterial crude and purified protein fractions confirmed the involvement of nitrate reductase (molecular weight 66 kDa and specific activity = 3.8 U/mg) in the Synthesis of AgNPs.Inspec keywords: microorganisms, silver, nanoparticles, enzymes, molecular biophysics, ultraviolet spectra, visible spectra, X‐ray diffraction, transmission electron microscopy, Fourier transform infrared spectra, catalysis, biochemistry, nanobiotechnologyOther keywords: catalytic protein, stabilising agents, Pseudomonas aeruginosa, metal nanoparticles, UV–visible spectroscopy, optical densities, ionic silver, atomic silver, X‐ray diffraction spectra, transmission electron microscopy, nitrate reductase, rhamnolipids, Fourier transform‐infrared spectroscopy, Ag     

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     

Biomimetic synthesis and anticancer activity of Eurycoma longifolia branch extract‐mediated silver nanoparticles

In the present study, silver nanoparticles (AgNPs) were synthesised by adding 1 mM Ag nitrate solution to different concentrations (1%, 2.5%, 5%) of branch extracts of Eurycoma longifolia, a well known medicinal plant in South–East Asian countries. Characterisation of AgNPs was carried out using techniques such as ultraviolet–visible spectrophotometry, X‐ray diffractrometry, Fourier transform infrared–attenuated total reflection spectroscopy (FTIR–ATR), scanning electron microscopy. XRD analysis revealed face centre cubic structure of AgNPs and FTIR–ATR showed that primary and secondary amide groups in combination with the protein molecules present in the branch extract were responsible for the reduction and stabilisation of AgNPs. Furthermore, antioxidant [2,2‐diphenyl‐1‐picrylhydrazyl and 2,2′‐Azino‐bis(3‐ethylbenzthiazoline‐6‐sulphonic acid)], antimicrobial and anticancer activities of AgNPs were investigated. The highest bactericidal activity of these biogenic AgNPs was found against Escherichia coli with zone inhibition of 11 mm. AgNPs exhibited significant anticancer activity against human glioma cells (DBTRG and U87) and human breast adenocarcinoma cells (MCF‐7 and MDA‐MB‐231) with IC₅₀ values of 33, 42, 60 and 38 µg/ml.Inspec keywords: biomimetics, cancer, antibacterial activity, nanoparticles, silver, microorganisms, cellular biophysics, biomedical materials, nanomedicine, nanofabrication, X‐ray diffraction, Fourier transform infrared spectra, attenuated total reflection, ultraviolet spectra, visible spectra, proteins, molecular biophysics, biochemistryOther keywords: Biomimetic synthesis, anticancer activity, Eurycoma longifolia branch extract‐mediated silver nanoparticles, nitrate solution, medicinal plant, ultraviolet‐visible spectrophotometry, X‐ray diffractometry, Fourier transform infrared‐attenuated total reflection spectroscopy, FTIR‐ATR spectroscopy, scanning electron microscopy, XRD, face centre cubic structure, primary amide groups, secondary amide groups, protein molecules, antioxidant, 2,2‐diphenyl‐1‐picrylhydrazyl, 2,2′‐azino‐bis(3‐ethylbenzthiazoline‐6‐sulphonic acid), antimicrobial activity, bactericidal activity, biogenic silver nanoparticles, Escherichia coli, zone inhibition, DBTRG human glioma cells, U87 human glioma cells, MCF‐7 human breast adenocarcinoma cells, MDA‐MB‐231 human breast adenocarcinoma cells, Ag     

Porcine skin gelatin–silver nanocomposites: synthesis,characterisation, cell cytotoxicity,and antibacterial properties

Silver nanoparticles (AgNPs) were synthesised with hydrothermal autoclaving technique by using AgNO₃ salt (silver precursor) at different concentrations (0.01, 0.1, 0.55, 1.1, 5.5, and 11 mM) and porcine skin (1% (w/v)) gelatin polymeric matrix (reducing and stabiliser agent). The reaction was performed in an autoclave at 103 kPa and 121°C and the hydrothermal autoclaving exposure time and AgNO₃ molar concentration were varied at a constant porcine skin gelatin concentration. The as‐prepared AgNPs were characterised by UV–visible spectroscopy, transmission electron microscopy, and Fourier transform infrared spectroscopy. The antibacterial properties of AgNPs were tested against gram‐positive and gram‐negative bacteria. Furthermore, 3‐(4,5‐dimethylthiazol‐2‐yl) 2,5‐diphenyltetrazolium bromide and 2,2‐diphenyl‐1‐picrylhydrazyl assays were used to test whether the synthesised AgNPs can be potentially applied in cancer therapy or used as an antioxidant. This approach is a promising simple route for synthesising AgNPs with a smaller average particle 10 nm diameter. Furthermore, AgNPs exhibited a good cytotoxicity activity, reducing the viability of the liver cancer cell line HepG2 with a moderate IC₅₀; they also showed a low‐to‐fair antioxidant activity. In addition, AgNPs had a remarkable preferential antibacterial activity against gram‐positive bacteria than gram‐negative bacteria. Therefore, these fabricated AgNPs can be used as an antibacterial agent in curative and preventive health care.Inspec keywords: gelatin, silver, nanoparticles, nanocomposites, nanobiotechnology, biomedical materials, antibacterial activity, microorganisms, Fourier transform infrared spectra, ultraviolet spectra, visible spectra, transmission electron microscopy, cancer, cellular biophysicsOther keywords: porcine skin gelatin–silver nanocomposites, cell cytotoxicity, antibacterial properties, silver nanoparticles, hydrothermal autoclaving technique, gelatin polymeric matrix, UV–visible spectroscopy, transmission electron microscopy, Fourier transform infrared spectroscopy, gram‐positive bacteria, gram‐negative bacteria, 3‐(4,5‐dimethylthiazol‐2‐yl) 2,5‐diphenyltetrazolium bromide assays, 2,2‐diphenyl‐1‐picrylhydrazyl assays, cancer therapy, antioxidant, liver cancer cell line HepG2, 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     

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     

Bio‐inspired synthesis of silver nanoparticles from leaf extracts of Cleistanthus collinus (Roxb.): its potential antibacterial and anticancer activities

In this investigation, the biological synthesis method was adopted to synthesise silver nanoparticles (AgNPs) by using the leaf extracts of Cleistanthus collinus (C. collinus). This plant has traditionally been used to remove the harmful pest from the agriculture field. Leaf extract of C. collinus was used as bioreductant on the precursor solvent of AgNO₃. The synthesised AgNPs were characterised by spectroscopic method such as UV–vis spectroscopy, attenuated total reflection Fourier transform infrared spectroscopy, dynamic light scattering and microscopic method by field‐emission scanning electron microscopy analysis. The AgNPs were studied for both antibacterial and antifungal activities and found to exhibit potential antibacterial activity against Bacillus subtilis, Staphylococcus aureus and Pseudomonas aeruginosa. The anticancer activity of AgNPs was screened against A‐431 osteosarcoma cell line by [3‐(4, 5‐dimetheylthiazol‐2)‐2, 5 diphenyl tetrazolium bromide] assay and the IC₅₀ value was found to be 91.05 ± 1.53 μg/ml. This trend of eco‐friendly stable synthesis of AgNPs could prove a better substitute for the chemical methods and offer greater opportunity to use these nanosilvers in agricultural and biomedical sectors.Inspec keywords: bio‐inspired materials, silver, nanoparticles, nanomedicine, antibacterial activity, cancer, biomedical materials, microorganisms, nanofabrication, attenuated total reflection, Fourier transform infrared spectra, ultraviolet spectra, visible spectra, light scattering, scanning electron microscopy, field emission electron microscopy, cellular biophysicsOther keywords: bio‐inspired synthesis, silver nanoparticles, Cleistanthus collinus, antibacterial activity, anticancer activity, leaf extracts, biological synthesis method, bioreductant, precursor solvent, UV‐visible spectroscopy, attenuated total reflection Fourier transform infrared spectroscopy, dynamic light scattering, field‐emission scanning electron microscopy, Bacillus subtilis, Staphylococcus aureus, Pseudomonas aeruginosa, A‐431 osteosarcoma cell line, 3‐(4, 5‐dimetheylthiazol‐2)‐2,5 diphenyl tetrazolium bromide assay, eco‐friendly stable synthesis, Ag