Silver nanoparticles biologically synthesised using tea leaf extracts and their use for extension of fruit shelf life

The biosynthesis of nanoparticles (NPs) from plant extracts is important in nanotechnology because the employed methods are environmentally friendly and cost‐effective. In this study, silver NPs (AgNPs) were synthesised using Chinese tea (Oolong tea) extract. The effects of the relative content of the employed silver nitrate, the reaction temperature, the incubation time, and the tea‐to‐water ratio on the formation of the AgNPs were examined. The synthesised AgNPs were also analysed by UV–vis spectroscopy, dynamic light scattering, transmission electron microscopy, X‐ray diffraction, Fourier transform infrared spectroscopy, and thermo‐gravimetric analysis. The NPs were observed to be highly crystalline, approximately spherical, and 10–50 nm in diameter. They were also tested for their use in preserving the postharvest quality of cherry tomatoes, with good results obtained. The tea AgNP treatment was specifically found to reduce the weight loss of the tomatoes, as well as changes in their total soluble solids, vitamin C, and titratable acid contents. The findings of this study indicate that postharvest tea AgNP treatment affords a clean, safe, high‐quality, and environmentally friendly method for extending the shelf life of fruits.Inspec keywords: silver, nanoparticles, nanofabrication, ultraviolet spectra, visible spectra, light scattering, transmission electron microscopy, X‐ray diffraction, Fourier transform infrared spectra, thermal analysisOther keywords: silver nanoparticles, tea leaf extracts, fruit shelf life, Chinese tea extract, Oolong tea, silver nitrate, reaction temperature, incubation time, tea‐water ratio, UV‐vis spectroscopy, dynamic light scattering, transmission electron microscopy, X‐ray diffraction, Fourier transform infrared spectroscopy, thermo‐gravimetric analysis, cherry tomatoes, Ag     

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     

Silver nanoparticles biosynthesised using Centella asiatica leaf extract: apoptosis induction in MCF‐7 breast cancer cell line

The aim of this study was to green synthesised silver nanoparticles (AgNPs) using Centella asiatica leaf extract and investigate the cytotoxic and apoptosis‐inducing effects of these nanoparticles in MCF‐7 breast cancer cell line. The characteristics and morphology of the green synthesised AgNPs were evaluated using transmission electron microscopy, scanning electron microscopy, UV–visible spectroscopy, X‐ray diffraction, and Fourier‐transform infrared spectroscopy. The MTT assay was used to investigate the anti‐proliferative activity of biosynthesised nanoparticles in MCF‐7 cells. Apoptosis test was performed using flow cytometry and expression of caspase 3 and 9 genes. The spherical AgNPs with an average size of 19.17 nm were synthesised. The results showed that biosynthesised AgNPs exhibited cytotoxicity, anti‐cancer, apoptosis induction, and increased expression of genes encoding for caspases 3 and 9 in MCF‐7 cancer cells in a concentration‐ and time‐dependent manner. It seems that green synthesised AgNPs have potential uses for pharmaceutical industries.Inspec keywords: ultraviolet spectra, transmission electron microscopy, cellular biophysics, infrared spectra, visible spectra, nanofabrication, cancer, toxicology, nanomedicine, nanoparticles, biomedical materials, scanning electron microscopy, silver, Fourier transform spectra, X‐ray diffraction, genetics, enzymes, botany, biochemistryOther keywords: spherical AgNPs, biosynthesised AgNPs, anti‐cancer, apoptosis induction, green synthesised AgNPs, MCF‐7 breast cancer cell line, green synthesised silver nanoparticles, Ag, caspase gene expression, flow cytometry, anti‐proliferative activity, MTT assay, pharmaceutical industries, cytotoxicity, UV–visible spectroscopy, nanoparticle morphology, scanning electron microscopy, Centella asiatica leaf extract, biosynthesised nanoparticles, Fourier‐transform infrared spectroscopy, transmission electron microscopy     

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     

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     

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     

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 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     

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     

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     

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     

One‐pot green synthesis and structural characterisation of silver nanoparticles using aqueous leaves extract of Carissa carandas : antioxidant,anticancer and antibacterial activities

Facile green synthesis of silver nanoparticles (AgNPs) using an aqueous extract of Carissa carandas (C. carandas) leaves was studied. Fabrication of AgNPs was confirmed by the UV–visible spectroscopy which gives absorption maxima at 420 nm. C. carandas leaves are the rich source of the bioactive molecules, acts as a reducing and stabilising agent in AgNPs, confirmed by Fourier transforms infrared spectroscopy. The field emission scanning electron microscope revealed the spherical shape of biosynthesised AgNPs. A distinctive peak of silver at 3 keV was determined by energy dispersive X‐ray spectroscopy. X‐ray diffraction showed the facecentred cubic structure of biosynthesised AgNPs and thermal stability was confirmed by the thermogravimetric analysis. Total flavonoid and total phenolic contents were evaluated in biosynthesised AgNPs. Biosynthesised AgNPs showed free radical scavenging activities against 2, 2‐diphenyl‐1‐picrylhydrazyl test and ferric reducing antioxidant power assay. In vitro cytotoxicity against hepatic cell lines (HUH‐7) and renal cell lines (HEK‐293) were also assessed. Finally, biosynthesised AgNPs were scrutinised for their antibacterial activity against methicillin‐resistant Staphylococcus aureus, Shigella sonnei, Shigella boydii and Salmonella typhimurium. This study demonstrated the biofabrication of AgNPs by using C. carandas leaves extract and a potential in vitro biological application as antioxidant, anticancer and antibacterial agents.Inspec keywords: antibacterial activity, biomedical materials, cancer, tumours, nanomedicine, silver, nanoparticles, reduction (chemical), nanofabrication, ultraviolet spectra, visible spectra, field emission scanning electron microscopy, Fourier transform infrared spectra, X‐ray chemical analysis, X‐ray diffraction, thermal stability, thermal analysis, free radical reactions, toxicology, cellular biophysics, microorganismsOther keywords: total phenolic contents, free radical scavenging activities, 2,2‐diphenyl‐1‐picrylhydrazyl test, ferric reducing antioxidant power assay, in vitro cytotoxicity, hepatic cell lines HUH‐7, renal cell lines HEK‐293, antibacterial activity, methicillin‐resistant Staphylococcus aureus, Shigella sonnei, Shigella boydii, Salmonella typhimurium, biofabrication, in vitro biological application, Ag, total flavonoid contents, thermogravimetric analysis, thermal stability, face‐centred cubic structure, X‐ray diffraction, energy dispersive X‐ray spectroscopy, distinctive peak, spherical shape, field emission scanning electron microscope, Fourier transforms infrared spectroscopy, stabilising agent, reducing agent, bioactive molecules, absorption maxima, UV‐visible spectroscopy, plant extract colour, antibacterial activities, anticancer activities, antioxidant activities, Carissa carandas, aqueous leaves extract, silver nanoparticles, structural characterisation, one‐pot green synthesis     

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     

Green synthesis and evaluation of silver nanoparticles for antimicrobial and biochemical profiling in Kinnow (Citrus reticulata L.) to enhance fruit quality and productivity under biotic stress

Green synthesis of silver nanoparticles (AgNPs) by utilising plant extract is an emerging class of nanotechnology. It revolutionizes all the field of biological sciences by synthesizing chemical free AgNPs. In the present study, AgNPs were synthesised by utilising Moringa oleifera leaves as the main reducing and stabilising agent and characterised through UV–visible spectroscopy, zeta analyser, X‐ray diffraction spectroscopy (XRD), energy dispersive X‐ray (EDX), and scanning electron microscopy (SEM). The different concentrations of biosynthesised AgNPs (10, 20, 30, and 40 ppm) were exogenously applied on the already infected plants (canker) of Citrus reticulata at different day intervals. The AgNPs at a concentration of 30 ppm was found to be most suitable concentration for creating the resistance against canker disease in Citrus reticulata. The enzymatic activities were also explored and it was found that 30 ppm concentration of biosynthesised AgNPs significantly reduced the biotic stress. Fruit quality and productivity parameters were also assessed and it was found that fruit quality and productivity were significant in response to 30 ppm concentration of biosynthesised AgNPs. The present work highlights the potent role of biosynthesised AgNPs, which can be used as biological control of citrus diseases and ultimately improving the quality and productivity of Citrus.Inspec keywords: X‐ray diffraction, scanning electron microscopy, silver, X‐ray chemical analysis, biochemistry, ultraviolet spectra, atomic force microscopy, visible spectra, biotechnology, microorganisms, nanoparticles, antibacterial activity, enzymes, nanotechnology, electrokinetic effects, plant diseases, crops, product qualityOther keywords: green synthesis, silver nanoparticles, fruit quality, chemical‐free AgNP synthesis, antimicrobial activity, biochemical profiling, Citrus reticulata L, Kinnow productivity, nanotechnology, Moringa oleifera leaves, stabilising agent, UV–Visible spectroscopy, zeta analyser, energy‐dispersive X‐ray spectroscopy, X‐ray diffraction, scanning electron microscopy, atomic force microscopy, Xanthomonas axonopodis, canker disease, enzymatic activities, superoxide dismutase, peroxidase, catalase, biological control, 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     

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     

Analytical study of biosynthesised silver nanoparticles against multi‐drug resistant biofilm‐forming pathogens

The emergence of the huge number of multi‐drug resistant (MDR) bacteria requires an alternative to the drugs. Silver nanoparticles (AgNPs) are a strong candidate for this due to their bactericidal properties, which can be better concluded by understanding their morphology and chemistry. The study hypothesised that AgNPs synthesised using leaves of Syzygium cumini can be used to treat locally emerging MDRs forming biofilms on indwelling medical devices. Synthesised particles were characterised by methods like UV–visible spectroscopy, X‐ray powder diffraction, scanning electron microscopy, transmission electron microscopy, and Zetasizer. Fourier transform infrared spectroscopy, and high‐performance liquid chromatography were used to predict phytochemicals present in the leaves. The shape of particles is revealed to be relatively spherical, with average size to be around 10–100 nm. Phenolic compounds are attributed to the formation of nanoparticles, stability analysis shows particles to be stable, and zeta potential determined the surface charge to be −20.1 mV. Biosynthesised particles are found to possess efficient antibacterial activity MDR bacteria developing biofilms in medical devices; hence, it is concluded that S. cumini based NPs can be used to develop a layer on implant‐related medical devices. Toxicity evaluation against A594 cancer cells portrays AgNPs to be potential tumour reduction agents in a concentration‐dependent manner.Inspec keywords: silver, visible spectra, X‐ray diffraction, transmission electron microscopy, scanning electron microscopy, chromatography, electrokinetic effects, cancer, biomedical materials, reduction (chemical), cellular biophysics, nanofabrication, nanoparticles, antibacterial activity, particle size, drugs, toxicology, nanomedicine, ultraviolet spectra, microorganisms, tumours, Fourier transform infrared spectraOther keywords: Syzygium cumini, biofilms, indwelling medical devices, UV‐visible spectroscopy, X‐ray powder diffraction, transmission electron microscopy, Fourier transform infrared spectroscopy, high‐performance liquid chromatography, biosynthesised particles, implant‐related medical devices, biosynthesised silver nanoparticles, multidrug resistant biofilm‐forming pathogens, multidrug resistant bacteria, MDR, bactericidal properties, morphology, scanning electron microscopy, s. cumini based NP, A594 cancer cells, tumour reduction, Ag     

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     

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     

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⁺