ABSTRACT
The effluent contains many harmful microbes which should be eliminated before it is discharged into a water body. Silver nanoparticles (AgNPs) being high-quality significance and have a great impact on this research field as it inhibits microbial proliferation and infection. Therefore, it may use for Bioremediation purposes, our laboratory is fascinated by the production of polymer matrix entrapment silver nanoparticles for in situ bio-remediation purposes. The AgNPs was prepared from sawdust by decoction method. The yellowish solution turns into dark brown colour indicating the formation of AgNPs. A sharp SPR (Surface Plasmon Resonance) band formation in UV-vis spectroscopy scan establishes the formation and stability of silver nanoparticles in an aqueous solution. SEM microphotograph indicated roughly spheroidal structure with (63±3) nm average diameters of newly synthesized AgNp. Polyvinyl alcohol (PVA) is eco-friendly and non-toxic to the environment was chosen for the preparation of polymeric matrix. The non-toxic concentration (1 ?g/mL) of AgNp was dispersed into PVA solution followed by cross-linked with maleic acid. PVA- maleic acid is cross-linked by the formation of an ester bond, whereas silver nanoparticles physically entrap into the cross-linked matrix. The silver nanoparticles were released from the matrix nearly after 10 min of swelling of the composite film. In a microbial assay using E. coli agar medium, PVA-AgNp composite film shows the significant killing of microorganisms. Microbial elimination is measured indirectly by pH measurement and dissolved oxygen concentration measurement of the effluent in situ against RO- water, taken as control. The dissolved oxygen concentration from RO water and effluent water was measured on Day “0” followed by treatment and incubation at the BOD chamber. The treatment with PVA-AgNp composite film reduced the BOD Level and increase dissolved oxygen level simultaneously increasing the quality of water.
ABSTRACT
Aim: The present study was aimed to synthesis and characterization of silver nanoparticles (AgNPs) using Zanthoxylum ovalifolium leaf essential oil extracts and to screen the anti-oxidant and antimicrobial potential of the same. Place and Duration of Study: The studies were carried out at Department of Botany, AVK College for Women, Hassan and Department of Biochemistry, Aurora’s Degree & PG College, Hyderabad from July 2017 to June 2018 Methodology: The essential oil from leaves of Zanthoxylum ovalifolium was obtained by hydrodistillation and analyzed by GC and GC-MS. Synthesis of silver nanoparticles of essential oil extract was carried out and characterized by using UV-VIS spectroscopy and transmission electron microscopy (TEM). The total phenolic and flavonoid contents were estimated in all the extracts. Furthermore, all the extracts were evaluated for anti-microbial activity against two gram-positive and two gram-negative bacteria and four pathogenic fungi using agar disc diffusion technique. Subsequently the minimum inhibitory concentration (MIC) was also determined. Results: The major compounds identified were Limonene, isofenchol, Geijerene, isothujanol, Borneol, dihydrocarveol, isobornyl acetate, pregeijerene, b-elemene, trans-caryophyllene and Germacrene D. The TEM analysis of nanoparticles synthesized showed a size of 8 to 14 nm with a lmax of 450nm. All the extracts were evaluated for in vitro anti-oxidant activity where the AgNP of essential oil extract showed maximum activity of 89.61% and 84.92% respectively for both DPPH free radical scavenging and Hydrogen peroxide free radical scavenging assays at a concentration of 100µg/ml. Among all the bacteria tested, B. subtilis was most susceptible at 100µg/ml with zone of inhibition of 22.5mm. While among all the fungi tested, A. niger inhibited more effectively by the AgNP of essential oil extract at 100µg/ml with a zone of inhibition of 16.2mm. Conclusion: The results obtained were remarkable suggesting that AgNP of essential oil extract possess excellent anti-oxidant and anti-microbial activity and can be an alternative bio-friendly source for various pharmaceutical industries.
ABSTRACT
Silver nanoparticles ( AgNP) , the metallic silver par-ticles with the diameter of 1 ~100 nm are now widely used in many fields. Many researches show that the smaller size of Ag-NP, the stronger toxicity it shows. Generally speaking, AgNP with 20 nm shows strongest toxicity. After entering the body, they are distributed in different organs in the body, and the dis-tribution in the kidney shows a certain gender difference. They also produce some toxic effects after entering body organs. AgNP often exhibit dose effect on the toxicity in vitro cells,while in vivo experiments, their toxic effects change with the different objects and ways of acting. In addition, AgNP can produce toxic effects on reproduction, and may cause parental reproductive activity to deteriorate, and pass the toxic effects to offspring through the placenta to exert a negative influence on the growth and develop-ment of the offspring. The toxicity mechanisms of AgNP are oxi-dative stress injury caused by producing free radicals;metabolic disorders caused by reducing of drug metabolic enzyme activity;and also related gene expression defects and certain molecules, such as transcription factor NF-E2-related factor 2(Nrf2) prote-ase caused by abnormal expression. In short, AgNP can be toxic to organisms, and we must evaluate their biological safety when we use it, to minimize or even avoid the danger it brings about.