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     

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     

Broad‐spectrum inhibitory effect of green synthesised silver nanoparticles from Withania somnifera (L.) on microbial growth,biofilm and respiration: a putative mechanistic approach

Multi‐drug resistance in pathogenic bacteria has created immense clinical problem globally. To address these, there is need to develop new therapeutic strategies to combat bacterial infections. Silver nanoparticles (AgNPs) might prove to be next generation nano‐antibiotics. However, improved efficacy and broad‐spectrum activity is still needed to be evaluated and understood. The authors have synthesised AgNPs from Withania somnifera (WS) by green process and characterised. The effect of WS‐AgNPs on growth kinetics, biofilm inhibition as well as eradication of preformed biofilms on both gram‐positive and gram‐negative pathogenic bacteria was evaluated. The authors have demonstrated the inhibitory effect on bacterial respiration and disruption of membrane permeability and integrity. It was found that WS‐AgNPs inhibited growth of pathogenic bacteria even at 16 µg/ml. At sub‐minimum inhibitory concentration concentration, there was approximately 50% inhibition in biofilm formation which was further validated by light and electron microscopy. WS‐AgNPs also eradicated the performed biofilms by varying levels at elevated concentration. The bacterial respiration was also significantly inhibited. Interaction of WS‐AgNPs with test pathogen caused the disruption of cell membrane leading to leakage of cellular content. The production of intracellular reactive oxygen species reveals that WS‐AgNPs exerted oxidative stress inside bacterial cell causing microbial growth inhibition and disrupting cellular functions.Inspec keywords: silver, nanoparticles, nanofabrication, nanomedicine, antibacterial activity, biomedical materials, cellular biophysics, microorganisms, biomembranes, electron microscopy, oxidation, biochemistry, permeabilityOther keywords: broad‐spectrum inhibitory effect, green synthesised silver nanoparticles, Withania somnifera (L.), microbial growth, putative mechanistic approach, multidrug resistance, therapeutic strategies, bacterial infections, next generation nanoantibiotics, broad‐spectrum activity, WS‐AgNPs, growth kinetics, biofilm inhibition, gram‐positive pathogenic bacteria, gram‐negative pathogenic bacteria, bacterial respiration, membrane permeability, membrane integrity, subminimum inhibitory concentration concentration, biofilm formation, light pathogenic bacteria, electron microscopy, cell membrane, cellular content leakage, intracellular reactive oxygen species, oxidative stress, microbial growth inhibition, 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     

Enhanced antimicrobial activity of silver nanoparticles‐Lonicera Japonica Thunb combo

Silver metals have long been known to possess antimicrobial properties. Recently, even the nanoparticle version of silver (AgNPs) has also been established as antimicrobials. In this study AgNPs were combined with extracts of the medicinal plant Chinese honeysuckle, Lonicera japonica Thunb. The antimicrobial activity of the AgNPs‐herb was tested against pathogenic Escherichia coli CMCC44113. Using different AgNPs or herb (honeysuckle water extract or HWE) ratios in the presence of a fixed concentration of E. coli CMCC44113, potencies were found to be proportional with concentrations. The antimicrobial activities of AgNPs‐HWE combo were significant enhanced, when compared with solely AgNPs or HWE. Thus, atomic force microscopic and propidium monoazide‐PCR were used to probe the damages caused by AgNPs‐HWE combo on the cell morphology and cell membrane integrity of E. coli. The mechanism of AgNPs‐HWE combo against E. coli may attribute to AgNPs leads to cell wall lysis and damages cell membrane integrity, and thus increases the penetration of HWE into the bacterium, which results in more serious damage to bacterial cells. These findings indicated that AgNPs‐herb was more potent than the AgNPs alone and holds promise for the development of nanoparticle enhanced herbal pharmaceuticals.Inspec keywords: microorganisms, cellular biophysics, silver, nanoparticles, nanomedicine, antibacterial activity, vegetation, biomembranes, biomedical materialsOther keywords: enhanced antimicrobial activity, silver nanoparticle‐Lonicera japonica Thunb combo, silver metals, antimicrobial properties, medicinal plant Chinese honeysuckle, AgNP‐herb, pathogenic Escherichia coli CMCC44113, E. coli CMCC44113 concentration, antimicrobial activity, AgNP‐HWE combo, atomic force microscopy, propidium monoazide‐PCR, cell morphology, E. coli, cell wall lysis, cell membrane integrity, HWE penetration, bacterial cells, nanoparticle enhanced herbal pharmaceuticals, Ag     

Seed germination and biochemical profile of Citrus reticulata (Kinnow) exposed to green synthesised silver nanoparticles

The biosynthesis of silver nanoparticles (AgNPs) is substantial for its applications in different fields. The Moringa oleifera leaves were used as reducing and stabilising agent for the biosynthesis of AgNPs. The synthesised AgNPs were characterised through UV–visible spectroscopy, zeta analyser, scanning electron microscopy (SEM) and energy dispersive Xray (EDX). In this study, effects of the synthesised AgNPs were also evaluated on nucellus tissues germination frequency and biochemical parameters of plant tissues. Nucellus tissues of Citrus reticulata were inoculated on MS medium supplemented with 10, 20, 30 and 40 µg/ml suspension of the synthesised AgNPs. Green synthesised AgNPs enhanced the in vitro germination because of low toxicity and nonfriendly issues. Significant results were obtained for germination parameters i.e. root and shoot length and seedling vigour index in response to 30 µg/ml suspension of green synthesised AgNPs. The 30 µ/ml suspension of AgNPs also enhanced antioxidant activity (41%) and SOD activity (0.36 nM/min/mg FW) while total phenolic content (4.7 µg/mg FW) and total flavonoid content (1.1 µg/mg FW) was significantly high when MS medium was fortified with 40 µg/ml suspension of the synthesised AgNPs. The content of total protein was significant (558 µg/BSA Eq/mg FW) in control plantlets as compared to the other treatments.Inspec keywords: antibacterial activity, ultraviolet spectra, X‐ray chemical analysis, proteins, microorganisms, biochemistry, nanofabrication, silver, nanotechnology, visible spectra, surface plasmon resonance, nanoparticles, suspensions, nanomedicine, scanning electron microscopy, electrokinetic effectsOther keywords: green synthesised silver nanoparticles, superoxide dismutase activity, biochemical profile, UV–visible spectroscopy, Citrus reticulata, green synthesised suspension, EDX detector, zeta potential, scanning electron microscopy, SEM, energy dispersive X‐ray, EDX, total phenolic content, total flavonoid content, size 423.0 nm to 425.0 nm, size 8.0 nm to 28.0 nm     

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     

Green synthesis of nanosilver‐decorated graphene oxide sheets

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

Green synthesis 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     

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     

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

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

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

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

Green synthesis and characterisation of silver nanoparticles and their effects on antimicrobial efficacy and biochemical profiling in Citrus reticulata

The synthesis of nanoparticles by utilising plant extract has revolutionised the field of nanotechnology. In the present study, AgNPs were synthesised by utilising the leaves of Moringa oleifera as reducing and stabilising agent. UV‐visible spectroscopy showed characteristic surface plasmon band in the range of 413–420 nm. Scanning electron microscopy (SEM) elucidated rectangular segments fused together. X‐ray diffraction (XRD) analysis confirmed the crystalline nature of AgNPs and presence of metallic silver ions was confirmed by energy dispersive X‐ray (EDX). The different concentrations (10, 20, 30 and 40 ppm) of AgNPs were exogenously applied on Citrus reticulata to record the disease incidence at different day intervals. The disease intensity was progressively increased in all the applied treatments with the passage of time. The 30 ppm concentration of AgNPs was found to be most suitable concentration for creating the resistance against brown spot disease. Moreover, the effects of AgNPs were also assessed for biochemical profiling in C. reticulata. The enhanced production of endogenous enzymes and non‐enzymatic components was observed in response to 30 ppm concentration of AgNPs. The present work highlighted that green synthesised AgNPs can be as used as biological control of citrus diseases and the enhanced production of secondary metabolites antioxidants.Inspec keywords: nanoparticles, silver, nanofabrication, nanomedicine, biomedical materials, biochemistry, enzymes, molecular biophysics, plant diseases, ultraviolet spectra, visible spectra, scanning electron microscopy, surface plasmon resonance, X‐ray diffraction, X‐ray chemical analysisOther keywords: green synthesis, silver nanoparticles, antimicrobial efficacy, biochemical profiling, Citrus reticulata, plant extract, nanotechnology, medical sciences, environment friendly AgNPs, biomedical fields, leaves, Moringa oleifera, reducing agent, stabilising agent, ultraviolet‐visible spectroscopy, characteristic surface plasmon band, scanning electron microscopy, rectangular shape, X‐ray diffraction analysis, crystalline nature, energy dispersive X‐ray spectroscopy, disease incidence, disease intensity, applied treatments, Alternaria brown spot disease, total phenolic content, dry weight, total flavonoid content, T4 treatment, superoxide dismutase activity, fresh weight, maximum peroxidase production, DPPH radical scavenging assay, biological control, citrus disease, secondary metabolites antioxidants     

Silver nanoparticles and silver salt (AgNO3) elicits morphogenic and biochemical variations in callus cultures of sugarcane

The research work was arranged to check the role of AgNPs and silver ions on callus cells of sugarcane (Saccharum spp. cv CP‐77,400). AgNPs were synthesized chemically and characterized by UV‐Vis spectra, XRD and SEM. AgNPs and silver ions were applied in various concentrations (0, 20, 40, 60 ppm) to sugarcane calli and the induced stress was characterized by studying various morphological and biochemical parameters. AgNPs and silver ions treatments produced high levels of malondialdehyde, proline, proteins, TP and TF contents. Similarly, CAT, SOD and POX activity was also significant in both treatments. The lower concentration of AgNPs and silver ions (20 ppm) provided maximum intracellular GSH level. This work mainly showed effects of AgNPs and silver ions on sugarcane calli in terms of morphological aberrations and cell membrane damage due to severe oxidative stress and production of enhanced levels of enzymatic and non‐enzymatic antioxidants as self‐defence to tolerate oxidative stress by scavenging reactive oxygen species. These preliminary findings will provide the way to study ecotoxicity mechanism of the metal ions and NPs in medicine industry and in vitro toxicity research. Furthermore, silver ions alone and their chemically synthesised AgNPs can be used for various biomedical applications in future.Inspec keywords: nanoparticles, biomedical materials, X‐ray diffraction, scanning electron microscopy, silver, molecular biophysics, toxicology, enzymes, visible spectra, nanofabrication, ultraviolet spectra, microorganisms, nanotechnology, plant diseases, crops, agricultural safetyOther keywords: silver nanoparticles, silver salt, scanning electron microscopy, total flavonoid contents, callus cultures, sugarcane cultivation, Saccharum spp, UV‐visible spectroscopy, X‐ray diffraction analysis, malondialdehyde, proline, proteins, total phenolic content, catalase, superoxide dismutase, peroxidases activities, scavenging reactive oxygen species, biomedical applications, microbial disease resistance, AgNO₃ , Ag     

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

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

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

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

Preparation and characterisation of ciprofloxacin‐loaded silver nanoparticles for drug delivery

Silver nanoparticles (AgNPs) have shown potential applications in drug delivery. In this study, the AgNPs was prepared from silver nitrate in the presence of alginate as a capping agent. The ciprofloxacin (Cipro) was loaded on the surface of AgNPs to produce Cipro‐AgNPs nanocomposite. The characteristics of the Cipro‐AgNPs nanocomposite were studied by X‐ray diffraction (XRD), UV–Vis, transmission electron microscopy (TEM), thermogravimetric analysis (TGA), scanning electron microscopy (SEM), Fourier‐transform infra‐red analysis (FT‐IR) and zeta potential analyses. The XRD of AgNPs and Cipro‐AgNPs nanocomposite data showed that both have a crystalline structure in nature. The FT‐IR data indicate that the AgNPs have been wrapped by the alginate and loaded with the Cipro drug. The TEM image showed that the Cipro‐AgNPs nanocomposites have an average size of 96 nm with a spherical shape. The SEM image for AgNPs and Cipro‐AgNPs nanocomposites confirmed the needle‐lumpy shape. The zeta potential for Cipro‐AgNPs nanocomposites exhibited a positive charge with a value of 6.5 mV. The TGA for Cipro‐AgNPs nanocomposites showed loss of 79.7% in total mass compared to 57.6% for AgNPs which is due to the Cipro loaded in the AgNPs. The release of Cipro from Cipro‐AgNPs nanocomposites showed slow release properties which reached 98% release within 750 min, and followed the Hixson–Crowell kinetic model. In addition, the toxicity of AgNPs and Cipro‐AgNPs nanocomposites was evaluated using normal (3T3) cell line. The present work suggests that Cipro‐AgNPs are suitable for drug delivery.     

Actinobacterial‐mediated synthesis of silver nanoparticles and their activity against pathogenic bacteria

In this study, silver nanoparticles (AgNPs) were biosynthesised by using acidophilic actinobacterial SH11 strain isolated from pine forest soil. Isolate SH11 was identified based on 16S rRNA gene sequence to Streptomyces kasugaensis M338‐M1^T and S. celluloflavus NRRL B‐2493^T (99.8% similarity, both). Biosynthesised AgNPs were analysed by UV–visible spectroscopy, which revealed specific peak at λ  = 420 nm. Transmission electron microscopy analyses showed polydispersed, spherical nanoparticles with a mean size of 13.2 nm, while Fourier transform infrared spectroscopy confirmed the presence of proteins as the capping agents over the surface of AgNPs. The zeta potential was found to be −16.6 mV, which indicated stability of AgNPs. The antibacterial activity of AgNPs from SH11 strain against gram‐positive (Staphylococcus aureus and Bacillus subtilis) and gram‐negative (Escherichia coli) bacteria was estimated using disc diffusion, minimum inhibitory concentration and live/dead analyses. The AgNPs showed the maximum antimicrobial activity against E. coli, followed by B. subtilis and S. aureus. Further, the synergistic effect of AgNPs in combination with commercial antibiotics (kanamycin, ampicillin, tetracycline) was also evaluated against bacterial isolates. The antimicrobial efficacy of antibiotics was found to be enhanced in the presence of AgNPs.Inspec keywords: antibacterial activity, silver, nanoparticles, electrokinetic effects, Fourier transform infrared spectra, microorganisms, nanofabricationOther keywords: actinobacterial mediated synthesis, silver nanoparticles, pathogenic bacteria, biosynthesis, acidophilic actinobacterial SH11 strain, pine forest soil, 16S rRNA gene sequence, Streptomyces kasugaensis M338‐M1T, S. celluloflavus NRRL B‐2493T, UV–visible spectroscopy, transmission electron microscopy, Fourier transform infrared spectroscopy, zeta potential, gram positive bacteria, Staphylococcus aureus, Bacillus subtilis, gram negative bacteria, Escherichia coli, disc diffusion, wavelength 420 nm, Ag     

Bio‐fabrication of silver nanoparticles by Pseudomonas aeruginosa : optimisation and antibacterial activity against selected waterborne human pathogens

Multiple drug resistance and treatment of contaminated water has become a serious issue in past years. Silver nanoparticles (AgNPs), being bactericidal, non‐toxic, cheap and environment friendly behaviour, have drawn attention to overcome these problems. This study has been designed to synthesise AgNPs from Pseudomonas aeruginosa. AgNPs formation was confirmed by colour change and UV–vis spectroscopy. Furthermore, Fourier transform infrared spectroscopy peaks demonstrated the presence of capped proteins as reducing and stabilising agent. Transmission electron microscopy micrograph revealed spherical shape AgNPs with the size ranging between 10 and 20 nm. Antibacterial activity of AgNPs was evaluated against the most prevalent waterborne pathogens enterohaemorrhagic Escherichia coli and Salmonellae typhimurium. Moreover, the antibacterial activity of AgNPs was tested for the treatment of contaminated water which showed attenuation in bacterial load within 8 h as demonstrated by growth kinetics data. Furthermore, AgNPs did not exhibit haemolytic effects on human red blood cells (RBCs) even at 100 mg L⁻¹ concentration of AgNPs. The results herein suggest that AgNPs synthesised by P. aeruginosa under optimised conditions exhibit microbicidal property against waterborne pathogens and having no toxic effect on human RBCs. These AgNPs could be employed for treatment of contaminated water after process optimisation.Inspec keywords: silver, nanoparticles, nanobiotechnology, nanofabrication, microorganisms, antibacterial activity, water treatment, ultraviolet spectra, visible spectra, Fourier transform infrared spectra, transmission electron microscopy, blood, cellular biophysicsOther keywords: biofabrication, silver nanoparticles, Pseudomonas aeruginosa, optimisation, antibacterial activity, waterborne human pathogens, multiple drug resistance, contaminated water treatment, colour change, UV‐vis spectroscopy, Fourier transform infrared spectroscopy, capped proteins, reducing agent, stabilising agent, transmission electron microscopy micrograph, enterohaemorrhagic Escherichia coli, Salmonellae typhimurium, growth kinetics, human red blood cells, microbicidal property, process optimisation, 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