Fungus Mediated Synthesis of Silver Nano-particles & …
T1 - Fungus-Mediated Synthesis of Silver Nanoparticles and Their Immobilization in the Mycelial Matrix
Fungal mediated biosynthesis of silver nanoparticles, ..
The present study deals with the extracellular biosynthesis of silver nanoparticles, using cell-free extract of phytopathogenic soil-borne fungus Macrophomina phaseolina (Tassi) Goid, the causal organism of charcoal rot disease of about 500 agronomical important crops all over the world . It describes not only a new method of green synthesis of silver nanoparticles but also their physical attributes, antibacterial activity against human and plant pathogenic multidrug-resistant bacteria, the inhibitory effect on the growth kinetics of microbes, the capping material around the silver nanoparticles, as well as their genotoxic effect.
The AgNPs synthesized by any or all of the above mentioned techniques, however, have attracted criticism as these involve multistep reactions requiring high energy consumption but with poor material conversions. Overall, the hazardous nature of the lingering reactants and the products very often make purification of the nanoparticles cumbersome, non-ecofriendly and expensive. Biological systems offer an attractive option which is relatively simple, rapid, cheap and more importantly, environment-friendly and thereby overcomes most of the aforementioned issues associated with chemical and physical synthesis of nanoparticles 10.
Biological synthesis of silver nanoparticles - IOPscience
The biosynthesised silver nanostructure by using Gelidiella acerosa extract was further demonstrated and confirmed by the characteristic peaks observed in the XRD image at 2θ = 28.09o, marked with (220). A number of Bragg reflections corresponding to the (220) sets of lattice planes are observed which may be indexed based on the face-centred crystal structure of silver. The XRD pattern thus clearly shows that the Ag-NPs are crystalline in nature ().
It is well known that Ag-NPs exhibit reddish-brown in water (). The formation of Ag-NPs by reduction of the aqueous Ag+ during exposure to the aqueous extract of Gelidiella acerosa showed reddish-brown colour, which suggested the formation of Ag- NPs in solution. The colour arises due to excitation of surface plasmon vibrations in the silver metal nanoparticles (). The reduction of silver was subjected to analysis by using the UV-Vis Spectrophotometer. Absorption spectra of Ag-NPs formed in the reaction media has absorbance peak at 408 nm, broadening of peak indicated that the particles are polydispersed (). The frequency and width of the surface plasmon absorption depends on the size and shape of the metal nanoparticles as well as on the dielectric constant of the metal itself and the surrounding medium (–).
Fungus Mediated Synthesis of Silver Nano-Particles & …
Silver nitrate (AgNO3) was of analytical grade (AR) and purchased from E. Marck (India). In the typical synthesis of silver nanoparticles, 10 ml of the aqueous extract of Gelidiella acerosa was added to 90 ml of 1 mM aqueous AgNO3 solution in 250 ml conical flask and kept at room temperature for 48 hr at 120 rpm. Suitable controls were maintained throughout the conduct of experiments.
In this article, we describe a simple one-step method for the synthesis of Ag-NPs by the reduction of aqueous Ag-ions using extracts of red sea weed, at direct sunlight condition. The amount of nanoparticles synthesized and qualitative differences between synthesized nanoparticles were also investigated by various analytical methods.
of Silver Nanoparticles Using the Fungus ..
Fungus mediated biosynthesis of WO3 nanoparticles …
Today the synthesis of silver nanoparticles is very common due to their numerous applications in various fields
A Review: Biological Synthesis Of Silver ..
A novel biological method for the synthesis of silver nanoparticles using the fungus Verticillium is reported
Biosynthesis of nanoparticles and silver nanoparticles
Download Free Full-Text of an article FUNGUS MEDIATED SYNTHESIS OF SILVER NANOPARTICLES: A NOVEL BIOLOGICAL APPROACH
PHYTO-MEDIATED SYNTHESIS OF SILVER NANOPARTICLES …
To prepare biomass for biosynthesis, A. terreus was grown in potato dextrose broth liquid medium (PDB). The flasks were inoculated with spores and incubated at 28 °C on a rotary shaker (120 rpm) for 96 h. The biomass was harvested by filtration through filter paper (Whatman filter paper No. 1), and then washed with distilled water to remove any components of the medium. 25 g biomass (wet weight) was placed in individual flasks containing 100 mL Milli-Q water. The flasks were incubated under the conditions described above for 24 h. The biomass was filtered, and the crude cell filtrate was collected for subsequent experiment.
PHYTO-MEDIATED SYNTHESIS OF SILVER NANOPARTICLES FROM ..
Representative TEM images of AgNPs film which was derived from dialyzed cell filtrate with the addition of NADH were shown in . The AgNPs were spherical or nearly spherical, which was same as the ones synthesized by crude cell filtrate. Nevertheless, the size of nanospheres was about 21.3 nm on average and in the range of 10–30 nm, a little larger than the ones synthesized by crude cell filtrate. This size difference might be caused by different concentrations of NADH in these two reaction mixtures, and the presence or absence of other small molecules (might as stabilizers). Therefore, the concentration of reducing agent and the presence of stabilizer were crucial to the size and shape control of nanoparticles in such a biosynthesis system.
Fungus-mediated synthesis of silver nanoparticles and ..
In organism, NADH is a widespread reduced coenzyme involved in redox reaction, and can be used as a reducing agent by many enzymes in vivo [,]. Thus, we interfered that a NADH-dependent reductase released by A. terreus might account for the synthesis of AgNPs. In the process, NADH acted as an electron carrier, and the silver ions obtained electrons from NADH via the NADH-dependent reductase, and then were reduced to Ag (). Similarly, there were other reports that NADH-dependent reductases were believed to be involved in the biosynthesis of AgNPs in F. oxysporum and P. fellutanum [,,]. These findings might be of great significance to the development of a continuous biological production of nanoparticles at a large scale through the addition of NADH or couple with the regenerating system of co-enzymes.
Bacteriagenic silver nanoparticles: synthesis, …
In the present study, the key factors in the supernatant of A. terreus governing the formation of AgNPs were investigated. The AgNO3 solution was added to the dialyzed cell filtrate under the same conditions for the synthesis of AgNPs. However, the color of reaction mixture did not change over 24 h. Meanwhile, the absence of SPR at 440 nm for the reaction mixture of dialyzed cell filtrate () indicated that the reaction was highly dependent on an active substance with a low molecular weight (). These results indicated that NADH might be a key factor for the synthesis of AgNPs by A. terreus. As a negative control, when NADH alone was added to the AgNO3 solution, no band was observed at 440 nm (), which confirmed that NADH alone was not sufficient for the reaction to occur, and other active substances with higher molecular weight might also play important roles in the reduction of silver ions.
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