Extracellular Synthesis Of Silver Nanoparticles Research Articles

Extracellular Synthesis of Silver Nanoparticles by Endophytic Bordetella SP. Isolated from Piper Nigrum and Its Antibacterial Activity Analysis

Extracellular Synthesis of Silver Nanoparticles by Endophytic Bordetella SP. Isolated from Piper Nigrum and Its Antibacterial Activity Analysis

Antimicrobial activity and biosynthesis of nanoparticles by endophytic bacterium inhabiting Coffee arabica L.

The interface between endophytes and nanomaterials is a relatively new and unexplored area the present study evaluates screening of bacterial endophytes from surfaced sterilized leaf and stem segments of agro economical plant Coffee arabica L. towards synthesis of silver nanoparticles and antimicrobial metabolites. Among thirty two endophytes isolated nine isolates exhibited antimicrobial activity among which one bacterium was capable of extracellular synthesis of silver nanoparticles upon evaluation of supernatant with 1 mM of silver nitrate, biosynthesis of silver nanoparticles were assessed by UV-Visible Spectroscopy and the bacterium was capable of secreting antimicrobial secondary metabolites upon crude ethyl acetate extract evaluated for antimicrobial activity against panel of both gram positive and gram negative as well as phytopathogenic fungi. Partial characterization was carried out via bioautographic technique with Rf value 0.3 and 0.6 exhibiting antimicrobial activity against MRSA strain. Further studies in this area will be promising enough for molecular characterization of endophytic bacterium and chemical profiling of antimicrobial metabolites at the same time physiochemical characterization of nanoparticles will be valuable to reveal the size and shape.

Biosynthesis of silver nanoparticles using Saccharum officinarum and its antimicrobial activity

The present Letter deals with the rapid green synthesis of silver nanoparticles using fresh leaves of Saccharum officinarum (sugarcane). Silver nanoparticles were formed by treatment of aqueous solution of AgNO3 (1 mM) with fresh leaves extract of S. officinarum. Rapid synthesis was achieved within a few minutes with increased pH and microwave irradiation. UV-vis specrophotometric analysis was carried out to assess the formation of silver nanoparticles. Microwave irradiation mediated synthesised silver nanoparticles were further characterised by using nanoparticle tracking analyser, transmission electron microscope (TEM) and energy dispersive X-ray spectra. Silver nanoparticles with controlled size and shape were observed under TEM micrograph. Silver nanoparticles showed antibacterial activity against multiple drug resistant hospital isolates of Escherichia coli, Staphylococcus aureus, Proteus mirabilis and hospital isolates of Salmonella typhi, Klebsiella pneumoniae, and Enterococcus feacalis. The antifungal activity was checked against Candida albicans (hospital isolate) and Aspergillus niger (NCIM 616). The synergistic effect of silver nanoparticles along with antibiotics against multiple drug resistant hospital isolates was found to be effective. The extracellular synthesis of silver nanoparticles using leaves of S. officinarum appears to be rapid, cost effective and eco-friendly.

Antimicrobial Activity of Silver Nanoparticles Synthesized by Streptomyces Species JF714876

Microorganisms like fungi, actinomycetes and bacteria are considered nanofactories and are helpful in the production of nanoparticles useful in the welfare of human beings. In the present study, we investigated the production of silver nanoparticles from Streptomyces species JF714876. Extracellular synthesis of silver nanoparticles by Streptomyces species was carried out using two different media. Silver nanoparticles were examined using UV-visible, IR and atomic force microscopy. The size of silver nanoparticles was in the range of 80-100 nm. Antimicrobial activity of silver nanoparticle against bacteria such as E. coli, S. aureus, and dermatophytes like T. rubrum and T. tonsurans was determined. Thus, this study suggests that the Streptomyces sp. JF741876 can produce silver ions that can be used as an antimicrobial substance.

Functionalization of single-walled carbon nanotubes with silver nanoparticles using Tecoma stans leaf extract

Bioreduction mechanism of Tecoma stans leaf extract for the extracellular synthesis of silver nanoparticles was investigated using ultraviolet-visible spectroscopy (UV–vis). Nanostructure of the bio synthesized silver particles was confirmed by transmission electron microscopic (TEM) analysis. Crystalline cubic phase of the synthesized silver nanoparticles was confirmed by X-ray diffraction (XRD) technique. Observed rapid reduction behavior of Tecoma stans leaf extract was effectively explored for the functionalization of single-walled carbon nanotubes (SWCNT) with silver nanoparticles. Scanning electron microscopic (SEM) and TEM characterization confirmed the functionalization of single walled carbon nanotubes with the silver nanoparticles and the size of silver nanoparticles were found to be in the range of ∼5–10nm.

Rapid Biosynthesis of Silver Nanoparticles Using Cymbopogan Citratus (Lemongrass) and its Antimicrobial Activity

Abstract The present study deals with the rapid green synthesis of silver nanoparticles using fresh leaves of Cymbopogan Citratus (Lemongrass). Silver nanoparticles were formed within 8∼10 minutes by microwave irradiation using aqueous solution of AgNO3 (1 mM) with fresh leaves extract of Cymbopogan Citratus. The synthesized silver nanoparticles were characterized by using UV-visible spectrophotometer analysis, nanoparticle tracking analyzer, transmission electron microscope and energy dispersive X-ray spectra. The antibacterial activity of these nanoparticles was studied against multiple drug resistant hospital isolates of E.coli, S.aureus, P.mirabilis and hospital isolates of S. typhi, K.pnuemoniae. Also, the antifungal activity of these nanoparticles was studied against C.albicans (hospital isolate) and A.niger (NCIM 616). The synergistic effect of silver nanoparticles along with antibiotics was also studied against multiple drug resistant hospital isolates and found to be effective. The extracellular synthesis of Silver nanoparticles using leaves of Cymbopogan Citratus appears to be rapid and eco-friendly.

Silver Nanoparticles: Novel Antimicrobial Agent Synthesized from an Endophytic Fungus Pestalotia sp. Isolated from Leaves of Syzygium cumini (L)

We report the extracellular synthesis of silver nanoparticles using an endophytic fungus Pestalotia sp. isolated from leaves of Syzygium cumini (L) and their antibacterial activity against human pathogenic bacteria viz. Staphylococcus aureus (ATCC-25923) and Salmonella typhi (ATCC-51812) alone and in combination with commercially available antibiotics. Detection of synthesized silver nanoparticles was carried out using UV-Visible spectrophotometer analysis, which showed a peak at 415 nm indicating the formation of nanoparticles. Further characterization includes the Fourier Transform Infra-Red spectroscopic analysis for the detection of proteins as capping agents on nanoparticles. Nanoparticle Tracking Analysis Syatem (LM-20) analysis and TEM analysis confirmed the formation of spherical and polydispersed nanoparticles in the range of 10-40 nm having average size of 12.40 nm. Biologically synthesized silver nanoparticles showed significant antibacterial activity but their efficacy was increased in combination of antibiotics like gentamycin and sulphamethizole. Silver nanoparticles in combination with gentamycin showed maximum activity (30 mm) against S. aureus followed by sulphamethizole (25 mm). Similar results were reported in case of S. typhi where silver nanoparticles in combination with gentamycin (28 mm) showed more activity than combination of silver nanoparticles and sulphamethizole (24 mm). Biosynthetic approach using an endophytic fungus is a novel way towards the development of safe, economically viable and green method for the synthesis of silver nanoparticles and thus synthesized silver nanoparticles can be used in antibacterial formulations.

Extracellular synthesis of silver nanoparticles using the leaf extract of Coleus amboinicus Lour.

In the present investigation, Coleus amboinicus Lour. leaf extract-mediated green chemistry approach for the synthesis of silver nanoparticles was described. The nanoparticles were characterized by ultraviolet–visible (UV–Vis) spectroscopy, X-ray diffraction (XRD), energy dispersive X-ray analysis (EDAX), Fourier transform infrared spectroscopy (FTIR) and transmission electron microscopy (TEM). The influence of leaf extract on the control of size and shape of silver nanoparticles is reported. Upon an increase in the concentration of leaf extract, there was a shift in the shape of nanoparticles from anisotrophic nanostructures like triangle, decahedral and hexagonal to isotrophic spherical nanoparticles. Crystalline nature of fcc structured nanoparticles was confirmed by XRD spectrum with peaks corresponding to (1 1 1), (2 0 0), (2 2 0) and (3 1 1) planes and bright circular spots in the selected-area electron diffraction (SAED). Such environment friendly and sustainable methods are non-toxic, cheap and alternative to hazardous chemical procedures.

Photo-Irradiated Biosynthesis of Silver Nanoparticles Using Edible MushroomPleurotus floridaand Their Antibacterial Activity Studies

This is a report on photo-irradiated extracellular synthesis of silver nanoparticles using the aqueous extract of edible oyster mushroom (Pleurotus florida) as a reducing agent. The appearance, size, and shape of the silver nanoparticles are understood by UV-visible spectroscopy, field emission scanning electron microscopy, transmission electron microscopy, and atomic force microscopy. The X-ray diffraction studies, energy dispersive X-ray analysis indicate that particles are crystalline in nature. Fourier transform infrared spectroscopy analysis revealed that the nanoparticles are covered with biomoieties on their surface. As can be seen from our studies, the biofunctionalized silver nanoparticles thus produced have shown admirable antimicrobial effects, and the synthetic procedure involved is eco-friendly and simple, and hence high range production of the same can be considered for using them in many pharmaceutical applications.

Fungal mediated biosynthesis of silver nanoparticles, characterization and antimicrobial activity

Microbial assisted biosynthesis of nanoparticles is a rapidly progressing area of nanobiotechnology. In this paper Aspergillus niger assisted extracellular synthesis of silver nanoparticles is reported. The silver nanoparticles were characterized by UV–vis spectrophotometry, TEM, EDX and FTIR. TEM studies showed the size of the silver nanoparticles to be in the range of 3–30 nm. The probable mechanism for the extracellular synthesis of silver nanoparticles by Aspergillus niger was investigated. The nanoparticles showed antimicrobial activity against fungal and bacterial strains.

Extracellular synthesis of silver nanoparticles using dried leaves of pongamia pinnata (L) pierre

Abstract Extract of oven dried leaves of Pongamia pinnata (L) Pierre was used for the synthesis of silver nanoparticles. Stable and crystalline silver nanoparticles were formed by the treatment of aqueous solution of AgNO3 (1mM) with dried leaf extract of Pongamia pinnata (L) Pierre. UV-visible spectroscopy studies were carried out to quantify the formation of silver nanoparticles. Transmission electron microscopy, X-ray diffraction and Fourier transform infrared spectroscopy were used to characterize the silver nanoparticles. TEM image divulges that silver nanoparticles are quite polydispersed, the size ranging from 20 nm to 50 nm with an average of 38 nm. Water soluble heterocyclic compounds such as flavones were mainly responsible for the reduction and stabilization of the nanoparticles. Silver nanoparticles were effective against Escherichia coli (ATCC 8739), Staphylococcus aureus (ATCC 6538p), Pseudomonas aeruginosa (ATCC 9027) and Klebsiella pneumoniae (clinical isolate). The move towards extracellular synthesis using dried biomass appears to be cost effective, eco-friendly to the conventional methods of nanoparticles synthesis.

Extracellular synthesis of silver nanoparticles by a marine alga, Sargassum wightii Grevilli and their antibacterial effects.

Extracellular synthesis of silver nanoparticles by a brown seaweed, Sargassum wightii is reported in this study. The silver nanoparticles synthesized by this method were characterized by means of UV-Vis spectroscopy, FT-IR, XRD and HR-TEM. Antibacterial studies were carried out using the bacteriae isolated from the infected silkworm. The recorded antibacterial effect of silver nanoparticles was found more potent when compared to the chemically synthesized silver nanoparticles and it is expected to be biocompatible.

Intra/Extracellular Biosynthesis of Silver Nanoparticles by an Autochthonous Strain of <I>Proteus mirabilis</I> Isolated fromPhotographic Waste

There is an enormous interest in developing green synthesis procedures for production of nanoparticles by using biomimetic approaches. In our research focus has been given to the development of an efficient and eco-friendly viable process for the synthesis of nanoscale silver particles using Proteus mirabilis PTCC 1710, a bacterial strain that was isolated during a screening program from photographic waste. A significant result of this study is our observation that silver nanoparticles could be induced to synthesis intra and extracellulary. The silver nanoparticles were characterized by means of UV-Vis spectroscopy, transmission electron microscopy (TEM), energy-dispersive spectroscopy (EDS) and atomic absorption spectrometer (AAS). The nanoparticles exhibited maximum absorbance at 400-410 nm in UV-Vis spectroscopy. TEM images showed formation of stable silver nanoparticles of spherical shape with most of the particles in the size range of 10-20 nm. It was found that incubation of bacterial cells in Muller-Hinton broth medium resulted in higher extracellular synthesis of silver nanoparticles, whereas intracellular synthesis of silver nanoparticles effectively increased in tryptic soy broth. The method of extraction of intracellular silver nanoparticles was inexpensive, simple and effective in large scale with no need to complex instruments. The bacteria work as a bionanofactory which continued to grow after synthesis of silver nanoparticles. The silver reduction by this strain is occurred through energy-dependent processes that lead to the high output of this reaction. Hence this new approach of using a non-pathogenic bacterial strain for the successful synthesis of nanosized silvers could be easily scaled up which establishes its commercial viability.

Fabrication of silver nanoparticles byPhoma glomerataand its combined effect againstEscherichia coli,Pseudomonas aeruginosaandStaphylococcus aureus

We report extracellular synthesis of silver nanoparticles (Ag-NPs) from Phoma glomerata and its efficacy against Escherichia coli, Staphylococcus aureus and Pseudomonas aeruginosa. The bacteria exhibiting resistance to various antibiotics showed remarkable sensitivity, when used in combination of antibiotics and Ag-NPs. Biosynthesis of Ag-NPs was carried out by challenging the fungal cell filtrate with 1 mmol l(-1) silver nitrate. The Ag-NPs were characterized with the help of UV-Visible spectrophotometer and Fourier transform infrared spectroscopy. Scanning electron microscopy was carried out to detect the size of Ag-NPs. Evaluation of the combined effect(s) was studied by disc diffusion method against E. coli, Staph. aureus and Ps. aeruginosa. The biosynthesis route seems to be eco-friendly and easy to scale up the process. Thus, these Ag-NPs may prove as a better candidate for drugs and can potentially eliminate the problem of chemical agents because of their biogenic nature. The bacterial resistance against antibiotics has been increasing with alarming rate. To overcome this problem, there is a pressing need to develop bactericidal agents. Ag-NPs may prove to be an answer to drug-resistant bacteria.

Fusarium solani: a novel biological agent for the extracellular synthesis of silver nanoparticles

We report extracellular biosynthesis of silver nanoparticles by Fusarium solani (USM-3799), a phytopathogen causing disease in onion, when challenged with 1 mM silver nitrate (AgNO3). The formation of nanoparticles was characterized by visual observation followed by UV-Vis spectropho- tometric analysis, which showed a peak at about 420 nm, which is very specific for silver nanoparti- cles. Further analysis carried out by Fourier Transform Infrared Spectroscopy (FTIR), provides evidence for the presence of proteins as capping agent, which helps in increasing the stability of the synthesized silver nanoparticles. Transmission Elec- tron Microscopy (TEM) investigations confirmed that silver nanoparticles were formed. The synthesized silver nanoparticles were found to be polydispersed, spherical in the range of 5-35 nm with average diameter of 16.23 nm. Extracellular synthesis of nanoparticles could be highly advantageous from the point of view of synthesis in large quantities and easy downstream processing.

Extracellular biosynthesis of silver nanoparticles using the fungus Fusarium semitectum

Development of environmental friendly procedures for the synthesis of metal nanoparticles through biological processes is evolving into an important branch of nanobiotechnology. In this paper, we report on the use of fungus “ Fusarium semitectum” for the extracellular synthesis of silver nanoparticles from silver nitrate solution (i.e. through the reduction of Ag + to Ag 0). Highly stable and crystalline silver nanoparticles are produced in solution by treating the filtrate of the fungus F. semitectum with the aqueous silver nitrate solution. The formations of nanoparticles are understood from the UV–vis and X-ray diffraction studies. Transmission electron microscopy of the silver particles indicated that they ranged in size from 10 to 60 nm and are mostly spherical in shape. Interestingly the colloidal suspensions of silver nanoparticles are stable for many weeks. Possible medicinal applications of these silver nanoparticles are envisaged.

Biomimetics of silver nanoparticles by white rot fungus, Phaenerochaete chrysosporium

Extracellular synthesis of silver nanoparticles by a white rot fungus, Phaenerochaete chrysosporium is reported in this paper . Incubation of P. chrysosporium mycelium with silver nitrate solution produced silver nanoparticles in 24 h. These silver nanoparticles were characterized by means of UV–vis spectroscopy, X-ray diffraction analysis, scanning electron microscopy, transmission electron microscopy, and photoluminescence spectroscopy. The synthesized silver nanoparticles absorbed maximum at 470 nm in the visible region. XRD spectrum of the silver nanoparticles confirmed the formation of metallic silver. The SEM characterization of the fungus reacted on the Ag + indicated that the protein might be responsible for the stabilization of silver nanoparticles. This result was further supported by the TEM examination. Though shape variation was noticed, majority of the nanoparticles were found to be of pyramidal shape as seen under TEM. Photoluminescence spectrum showed a broad emission peak of silver nanoparticles at 423 nm when excited at 350 nm. Apart from eco-friendliness, fungus as bio-manufacturing unit will give us an added advantage in ease of handling when compared to other classes of microorganisms.

Extracellular synthesis of silver nanoparticles by a silver-tolerant yeast strainMKY3

Silver nanoparticles in the size range of 2–5 nm were synthesized extracellularlyby a silver-tolerant yeast strain MKY3, when challenged with 1 mM soluble silverin the log phase of growth. The nanoparticles were separated from dilutesuspension by devising a new method based on differential thawing ofthe sample. Optical absorption, transmission electron microscopy, x-raydiffraction and x-ray photoelectron spectroscopy investigations confirmedthat metallic (elemental) silver nanoparticles were formed. Extracellularsynthesis of nanoparticles could be highly advantageous from the point ofview of synthesis in large quantities and easy downstream processing.