Green synthesis of highly concentrated aqueous colloidal solutions of large starch-stabilised silver nanoplatelets (original) (raw)
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Advanced Materials Letters, 2016
Silver nano particles (AgNPs) was synthesized using extract of Senecio glaucus extraxt. The effect of extract source on the shape of the Ag nanoparticles and antibacterial activity are investigated. The nature of AgNPs synthesized was analyzed by UV-vis spectroscopy and transmission electron microscopy (TEM). Silver nanoparticles were found to have an average size of 15-20 nm and mostly spherical. The antibacterial potential of modified extract containing synthesized AgNPs was compared with that of pure extract by cup plate method. Antibacterial activity of modified plant extract was reported and evaluated against drug resistant of bacterial isolates. Modified shoot extract gives higher response than that of modified root extract which facilitate them as a good alternative therapeutic approach in future. Phytochemical analysis revealed that Senecio glaucus extract act as reducing and stabilizing agent for synthesized silver nanoparticles (AgNPs).
Fabrication of antibacterial cotton fibres loaded with silver nanoparticles via “Green Approach”
Colloids and Surfaces A-physicochemical and Engineering Aspects, 2010
In the present investigation the antimicrobial efficiency of cotton fibres loaded with silver nanoparticles (AgNPs) was studied which are developed by “green process” using natural extracts, of Eucalyptus citriodora and Ficus bengalensis. The formation of AgNPs on the cotton fibres was observed by UV–vis spectrophotometer. The size of silver nanoparticles was found to have ∼20nm. The structure and morphology of
A novel green synthesis of silver nanoparticles using soluble starch and its antibacterial activity
International journal of clinical and experimental medicine, 2015
A green method of Silver nanoparticles (AgNPs) preparation has been established. This method depends on reduction of silver nitrate with soluble starch. The formation of AgNPs was observed by the color change from colorless to dark brown through the starch addition into silver nitrate solution. It was observed that use of starch makes convenient method for the synthesis of silver nanoparticles and can reduce silver ions into the produced silver nanoparticles within one hour of reaction time without using any harsh conditions. The prepared silver nanoparticles were characterized by using UV-visible spectroscopy and evaluated for its antimicrobial activity. The synthesized green AgNPs showed a potential antibacterial activity that was stronger against Gram positive pathogenic bacteria (Staphylococus aureus and Streptococus pyogenes) than against Gram negative pathogenic bacteria (Salmonella typhi, Shigellasonnei and Pseudomonas aeruginosa). Inhibition zones diameter of antibacterial a...
International Journal of Nanomaterials, Nanotechnology and Nanomedicine, 2019
Silver nanoparticles have an extremely large specifi c surface area, which increases when in contact with bacteria, viruses, and fungi. This signifi cantly increases their bactericidal activity by decreasing the sizes of silver nanoparticles and by increasing their surface area to volume ratio [15]. According to the literature, the mechanisms of the antimicrobial activity of Ag + and Ag NPs are very similar to each other. Both Ag + and Ag NPs can participate in intermolecular interactions with the cell membrane of bacteria. Furthermore, Ag particles smaller than 10nm have been reported to penetrate into the interior of microorganism cells, where they bind to the thiol groups of enzymes and nucleic acids [16,17].
Antibacterial Textile's Surface via Bio-molecule Encapsulated Silver Nanoparticles
Introduction: The new sources of antibiotics or antibacterial substance are green synthesized encapsulated (Bio-molecules/Ag) nanoparticles (NPs) .In this research I have investigated Artocarpus heterophyllus leaf extracts of bio-molecules encapsulated AgNPs against bacterial contamination on wool fiber surfaces. AgNPs synthesized by using AgNO3 solution, lab grade reagents and Artocarpus heterophyllus leaf extracted bio-molecules etc. Objectives: My main aim of this study is to achieve a smart way for the synthesis of bio-molecules capped magnetic Ag NPs by utilizing Artocarpus heterophyllus leaf extract and evaluatuation their antibacterial properties and feasibility against both Gram-positive and Gram-negative bacteria after assemble synthesized AgNPs on the surfaces of textiles substance.
Green synthetic approach for starch capped silver nanoparticles and their antibacterial activity
Pure and Applied Chemistry, 2016
In this work silver nanoparticles (AgNPs) have been prepared from silver nitrate (AgNO3) precursor using a green synthesis method at room temperature. Starch with its abundance of hydroxyl groups and its biocompatibility was used as a capping and reducing agent. The formation of AgNPs was confirmed by absorption spectroscopy with the surface plasmon resonance peak at 400 nm. The sharp reflection at (111), (200), (220) and (311) was observed by powder X-ray diffraction (XRD), which indicated the presence of cubic phase AgNPs. Transmission electron microscopy (TEM) revealed that the average size of AgNPs were between 0.5 and 4 nm with a spherical shape under optimum conditions. The nanoparticles showed a decrease in size with an increase in precursor concentration as well as the increase in capping agent concentration. The nanoparticles also showed to be bactericidal towards the tested Gram-negative (Escherichia coli) and Gram-positive (Staphylococcus aureus) bacteria.
Synthesis and characterization of silver nanoparticles for antibacterial activity
This article presents a study about the synthesis of colloidal silver (Ag)/biopolymer where Ag submicron particles were prepared in situ on bacterial cellulose (BC) produced by Gluconacetobacter xylinus. Different reducing agents were compared (hydrazine, hydroxylamine or ascorbic acid) together with the influence of gelatin or polyvinylpyrrolidone (PVP) employed as colloid protectors. Particle size distribution and morphology were investigated by scanning electron microscope (SEM). SEM images show silver nanoparticles (40-100 nm) size range attached on (BC) microfibrils. XRD analyses confirmed the Ag cubic phase deposited on to BC fibrils. The ash contents determined by thermogravimetric analyses have indicated high level of silver loading on the obtained composites.
Synthesis, antibacterial, cytotoxicity and sensing properties of starch-capped silver nanoparticles
Journal of Molecular Liquids, 2016
In this study, we report the antibacterial, cytotoxicity and sensing properties of dextrose reduced starch-capped silver nanoparticles (Ag-NPs) synthesized via a completely green method. The synthesis involved the use of water, starch, and dextrose as the solvent, the stabilizing and the reducing agents respectively. Silver nitrate was used as the silver precursor without the use of any accelerator. The as-synthesised Ag-NPs were characterized with UV-vis absorption spectroscopy, Fourier transform infra-red spectroscopy (FTIR), Raman spectroscopy, X-Ray diffraction analysis (XRD) and high resolution transmission electron microscopy (HR-TEM). All the assynthesised Ag-NPs showed good antibacterial activities against Escherichia coli and two strains of Pseudomonas aeruginosa, which are antibiotic sensitive and resistant bacteria. The study also indicated that the time of reaction did not have any significant effect on the antibacterial activity of the Ag-NPs synthesized despite the different particle sizes of the as-synthesised Ag-NPs. The cytotoxicity evaluation on human THP-1 monocyte cell line indicated that the as-synthesised Ag-NPs are less toxic than AgNO 3 at lower concentrations (2 μg/ml). Furthermore, the as-synthesised Ag-NPs were found to be very useful for colorimetric detection of hydrogen peroxide (H 2 O 2 ) at lower concentration up to 10 −10 M with a linear regression coefficient value of 0.8822 .
Scientific Reports
The use of cellulosic polymers as efficient reducing, coating agents, and stabilizers in the formulation of silver nanoparticles (AgNPs) with antioxidant and antibacterial activity was investigated. AgNPs were synthesized using different cellulosic polymers, polyethylene glycol, and without polymers using tri-sodium citrate, for comparison. The yield, morphology, size, charge, in vitro release of silver ion, and physical stability of the resulting AgNPs were evaluated. Their antioxidant activity was measured as a scavenging percentage compared with ascorbic acid, while their antibacterial activity was evaluated against different strains of bacteria. The amount of AgNPs inside bacterial cells was quantified using an ICP-OES spectrometer, and morphological examination of the bacteria was performed after AgNPs internalization. Cellulosic polymers generated physically stable AgNPs without any aggregation, which remained physically stable for 3 months at 25.0 ± 0.5 and 4.0 ± 0.5 °C. AgNP...
Carbohydrate Polymers, 2009
The aim of this study was to examine the antimicrobial efficiency and color changes of cotton fabrics loaded with colloidal silver nanoparticles which were synthesized without using any stabilizer. The influence of colloidal concentration and consequently, the amount of silver deposited onto the fabric surface, on antimicrobial activity against Gram-negative bacterium Escherichia coli, Gram-positive bacterium Staphylococcus aureus and fungus Candida albicans as well as laundering durability of obtained effects were studied. Although cotton fabrics loaded with silver nanoparticles from 10 ppm colloid exhibited good antimicrobial efficiency, their poor laundering durability indicated that higher concentrated colloids (50 ppm) must be applied for obtaining long-term durability. Additionally, the influence of dyeing with C.I. Direct Red 81 on antimicrobial activity of cotton fabrics loaded with silver nanoparticles as well as the influence of their presence on the color change of dyed fabrics were evaluated. Unlike color change, the antimicrobial efficiency was not affected by the order of dyeing and loading of silver nanoparticles.