Plantmediated synthesis of silver nanoparticles u

Authors: Kaushik Roy C K Sarkar C K Ghosh

Publish Date: 2014/12/27

Volume: 5, Issue: 8, Pages: 945-951

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Abstract

Synthesis of nanomaterials may involve various routes including physical chemical and biological approaches Here the biological green route was chosen to prepare silver nanoparticles from silver salts to avoid the requirement of costly instruments and involvement of hazardous chemicals as well To make the process clean and green leaf extract of parsley Petroselinum crispum was used to synthesize Ag nanoparticles at room temperature The formation of Agnanoparticles was monitored by UV–Vis spectroscopy The presence of silver in the sample and its crystalline nature were verified by Xray diffraction XRD analysis The size distribution profile and particle size in the suspension were manipulated from dynamic light scattering DLS pattern The shape size and morphology of the biogenic nanoparticles were studied using high resolution transmission electron microscope TEM Fourier transform infrared spectroscopy was used to detect the biomolecules responsible for reduction of silver ions These biogenic Agnanoparticles showed appreciable antibacterial efficacy against three bacteria—Klebsiella pneumoniae Escherichia coli and Staphylococcus aureusResearch on advanced nanomaterials of noble metals like silver has gained a lot of interest among scientists during the past decades due to their unique properties that originate from high number of surface atoms and their versatile utilities and innovative applications in various engineering fields like catalysis Santos et al 2012 optical Das et al 2010 and antimicrobial activity SooHwan et al 2011 Venkatesham et al 2014 ElNour et al 2010 etc Synthesis method of nanoparticles plays an important role in its technological advancement as it is the primary step to tune their physical electronic and optical properties of the synthesized nanoparticles by varying size shape and surface chemistry Wiley et al 2007 Sharma et al 2009 Naik et al 2002 Conventional procedures such as chemical reduction Szczepanowicz et al 2010 microwaveaided method Zhu et al 2013 and photocatalytic reaction Scaiano et al 2009 involve a variety of toxic chemicals like surfactants polymers starch citrates hydrides lipids etc for synthesis of stable and agglomerationfree Ag nanomaterials but the byproducts of these procedures were found to be hazardous to animals and environment Welton 1999 Vinod et al 2011 Chen et al 2005 Bakshi et al 2008 Bakshi 2009 Esumi et al 2000 Recently biological methods using biological microorganism plant extract and enzymes have proved itself an easy costeffective and ecofriendly alternative synthesis route of metallic nanoparticle compared to conventional procedures Li et al 2007 Mittal et al 2013 Tamulya et al 2013 Among different biological routes developed so far synthesis methods using either plant extract or fruit extract have several advantages over others as it does not require any cell culture and the process can easily be scaled up for large scale synthesis Numerous reports have already been established to synthesize metal nanoparticles using plant extract of Aloe vera Chandran et al 2006 Phyllanthus emblica Saini et al 2013 Azadirachta indica Saini et al 2013 Lalitha et al 2013 Rhinacanthus nasutus Pasupuleti et al 2013 Memecylon edule Elavazhagan and Arunachalam 2011 Magnolia kobus Lee et al 2013 Cymbopogan citratus Masurkar et al 2011 Morinda tinctoria Vanaja et al 2014 Malus domestica Roy et al 2014 etcHere we have reported another approach for biological green synthesis of silver nanoparticles using parsley Petroselinum crispum leaf extract Parsley Petroselinum crispum is a type of Mediterranean herb whose leaves are rich source of Vitamin C ascorbic acid The high content of ascorbic acid in parsley leaves can play vital role as it acts as a strong reducing agent in this reaction It reduced the silver cations present in the silver nitrate solution during interaction RodríguezLeón et al 2013 and caused the formation of Ag nanoparticles at room temperature Later antibacterial efficacy of these biosynthesized Agnanoparticles was tested against three bacteria—Klebsiella pneumoniae Escherichia coli and Staphylococcus aureusTo prepare the leaf extract of parsley Petroselinum crispum fresh parsley leaves weight 50 g were cleaned cut into small pieces and boiled in 100 ml deionized water for 15 min After cooling the mixture was filtered to obtain clear and pure leaf extract of parsley Petroselinum crispum 034 g silver nitrate was dissolved in 100 ml deionized water for preparing 20 mM stock solution of AgNO3 For reducing Ag+ ions present in silver nitrate solution equal amount of parsley Petroselinum crispum leaf extract was added drop wise so that the final concentration of the solution remained 10 mM The color of the mixture changed after 24 h and the silver ion reduction was monitored by UV–Vis spectroscopy of the solution To obtain pure nanoparticles from the mixture the solution was centrifuged at 10000 rpm for 30 min The precipitate was redispersed in 10 ml deionized water and centrifuged at 5000 rpm again for 15 min for removing unexpected biomass residue Decanting the soup the pellet of Ag nanoparticles was collected carefully and dried inside a desiccator overnight to obtain the dry powder of Ag nanoparticles The dried powder of silver nanoparticles was used for further analysisThe formation of Ag nanoparticles was investigated by scanning the original mixture under Perkin Elmer UV–Vis spectroscope Lambda35 in the wavelength range between 300 and 700 nm after 24 h of incubation period Xray diffractometer UltimaIII Rigaku Japan λ = 154 Å was used to identify proper phase and crystallinity of the synthesized Ag nanoparticles Dynamic light scattering technique was employed to analyze the size distribution profile of the nanoparticles present in the solution Transmission electron microscopy TEM 200 kV JEOL2010 was used to know the shape size and internal morphology of the synthesized nanoparticles A couple of drops of Agnanoparticle suspension concentration 50 μg/ml was placed on carbon coated copper grid and dried inside a vacuum dryer The copper grid was then scanned by TEM to examine the nanoparticles To prepare the sample for DLS analysis the dried powder of Ag nanoparticles was suspended in deionized water maintaining a certain concentration around 50 μg/ml Malvern DLS equipment was used to perform the dynamic light scattering analysis of these biosynthesized Ag nanoparticles Fourier transform infrared spectroscopy FTIR IRPrestige 21 Shimadzu was engaged to detect organic compounds present in the leaf extract and responsible for reducing silver ions to form Ag nanoparticlesThe antibacterial activity of the biologically synthesized Ag nanoparticles was studied against three bacteria using conventional disc diffusion procedure All cultures were maintained carefully on nutrient agar medium in favorable ambience Parsley Petroselinum crispum leaf extract was taken as a control for comparative study The leaf extract of parsley Petroselinum crispum and suspension of Ag nanoparticles were applied individually in two different wells created on each disc seeded with bacteria The bacteria were then allowed to grow overnight inside an incubator at 37 °C in darkness The antibacterial activity of the sample was assessed by observing and measuring the inhibition zone formed around the cups after 24 h

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