scholarly journals Synthesis, Characterization and Size Evaluation of Biosynthesized Silver Nanoparticles by UV–Vis Spectroscopy

2021 ◽  
Vol 1 (1) ◽  
Author(s):  
Reem Emam ◽  
Nashwa Eassa

Mie-Gans (MG) fitting model theoretical model utilizing the phenomena of scattering light to determine the morphologies, shape, and size of metallic nanoparticles in solution. In the present work, the average radius of biosynthesized silver nanoparticles (AgNPs) was evaluated based on the fitting of their Ultraviolet-visible (UV-Vis) spectra by the MG fitting model for spherical and non-spherical particles. Biosynthesis of AgNPs using Lemon (Citrus Limon) leaves extract as a reducing agent and Gum Acacia as a capping and stabilizing agent was studied for various concentrations of Citrus Limon leaves extract. The investigation of structural and optical properties was carried out for the synthesized samples using X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), and UV-Vis spectroscopy. XRD confirmed the structure of AgNPs and revealed that the structure of these nanoparticles was face-centered cubic (fcc). FTIR measurements indicate the presence of citric acid in Citrus Limon leaf extract which is responsible for reducing bioreduced AgNPs. UV-Vis spectroscopy determined the surface plasmon resonance (SPR) for AgNPs; the peaks of resonances of samples appear at 436-461nm range. MG fitting evaluations show that most of AgNPs were spherical in shape with an average radius in the range of 39-47nm. Moreover, this model allows the estimation of the fraction of nonspherical and aggregated AgNPs. These unique characteristics of AgNPs have made them applicable in a large number of fields like water treatment, biomedical, energy science, catalysis, etc.

2011 ◽  
Vol 236-238 ◽  
pp. 1945-1948 ◽  
Author(s):  
Xiang Hua Gao ◽  
Li Qiao Wei ◽  
Jing Wang ◽  
Bing She Xu

Stable silver nanoparticles were synthesized from AgNO3through a simple green route using biodegradable and renewable starch as stabilizing agent. Nanoparticles have been studied for their formation, structure, morphology and size using UV–vis spectroscopy, X-ray diffraction (XRD) and HRTEM analysis. XRD showed that the nanoparticles were of face centered cubic structure. UV–Vis and HRTEM revealed that the spherical particles having radius 5-20 nm are mostly stabilized by starch. Further, antibacterial properties of these starch-stabilized nanoparticles show promising results for S.aureus in growth inhibition ring test.


Materials ◽  
2019 ◽  
Vol 12 (15) ◽  
pp. 2382 ◽  
Author(s):  
Muhammad Jamshed Khan ◽  
Suriya Kumari ◽  
Kamyar Shameli ◽  
Jinap Selamat ◽  
Awis Qurni Sazili

Nanoparticles (NPs) are, frequently, being utilized in multi-dimensional enterprises. Silver nanoparticles (AgNPs) have attracted researchers in the last decade due to their exceptional efficacy at very low volume and stability at higher temperatures. Due to certain limitations of the chemical method of synthesis, AgNPs can be obtained by physical methods including sun rays, microwaves and ultraviolet (UV) radiation. In the current study, the synthesis of pullulan mediated silver nanoparticles (P-AgNPs) was achieved through ultraviolet (UV) irradiation, with a wavelength of 365 nm, for 96 h. P-AgNPs were formed after 24 h of UV-irradiation time and expressed spectra maxima as 415 nm, after 96 h, in UV-vis spectroscopy. The crystallographic structure was “face centered cubic (fcc)” as confirmed by powder X-ray diffraction (PXRD). Furthermore, high resolution transmission electron microscopy (HRTEM) proved that P-AgNPs were covered with a thin layer of pullulan, with a mean crystalline size of 6.02 ± 2.37. The average lattice fringe spacing of nanoparticles was confirmed as 0.235 nm with quasi-spherical characteristics, by selected area electron diffraction (SAED) analysis. These green synthesized P-AgNPs can be utilized efficiently, as an active food and meat preservative, when incorporated into the edible films.


Nanomaterials ◽  
2020 ◽  
Vol 10 (9) ◽  
pp. 1777 ◽  
Author(s):  
Md. Mahiuddin ◽  
Prianka Saha ◽  
Bungo Ochiai

A green synthesis of silver nanoparticles (AgNPs) was conducted using the stem extract of Piper chaba, which is a plant abundantly growing in South and Southeast Asia. The synthesis was carried out at different reaction conditions, i.e., reaction temperature, concentrations of the extract and silver nitrate, reaction time, and pH. The synthesized AgNPs were characterized by visual observation, ultraviolet–visible (UV-vis) spectroscopy, dynamic light scattering (DLS), scanning electron microscopy (SEM), transmission electron microscopy (TEM), x-ray diffraction (XRD), energy dispersive x-ray (EDX), and Fourier transform infrared (FTIR) spectroscopy. The characterization results revealed that AgNPs were uniformly dispersed and exhibited a moderate size distribution. They were mostly spherical crystals with face-centered cubic structures and an average size of 19 nm. The FTIR spectroscopy and DLS analysis indicated that the phytochemicals capping the surface of AgNPs stabilize the dispersion through anionic repulsion. The synthesized AgNPs effectively catalyzed the reduction of 4-nitrophenol (4-NP) and degradation of methylene blue (MB) in the presence of sodium borohydride.


2021 ◽  
Vol 10 (3) ◽  
pp. 16-24
Author(s):  
Sherin Monichan ◽  
P. Mosae Selvakumar ◽  
Christine Thevamithra ◽  
M. S. A. Muthukumar Nadar ◽  
Jesse Joel

Silver nanoparticles has been used since ages, even till now it is exploited in almost all areas like medicine, textiles, industries, cosmetics, purification, dying and many more. There are many approaches which are used to synthesize silver nanoparticles. However, these approaches are either harmful to the environment or very costly. Therefore, green synthesis of silver nanoparticles (AgNPs) using leaves of Filicium decipiens eco-friendly and a very reliable method to procure AgNPs. Characterization of synthesized AgNPs were then done using UV-Vis spectroscopy and fluorescence which confirmed the formation of AgNPs, scanning electron microscope (SEM)confirmed its shape to be round and X-ray diffraction (XRD) determined its crystalline nature as face centered cubic structure. Furthermore, Dynamic Light Scattering (DLS) was also done in order to know the average diameter and zeta potential of AgNPs. However, it did not show potential results due to the aggregates formed during the green synthesis of AgNPs. In addition to this, anti-microbial test against bacteria such as gram negative (Escherichia. Coli) and gram positive (Bacillus.spc) were done using well-diffusion method and also its application of antimicrobial activity was tested over fabric to understand its application in textile industries. In both the cases, AgNPs showed more efficiency in gram negative bacteria than gram- positive.


2017 ◽  
Vol 2017 ◽  
pp. 1-11 ◽  
Author(s):  
Kero Jemal ◽  
B. V. Sandeep ◽  
Sudhakar Pola

Allophylus serratusmediated silver nanoparticles biosynthesis, characterization, and antimicrobial activity were described. The synthesis of silver nanoparticles was confirmed by visual observation: UV-Vis spectrum, X-ray diffraction (XRD), Scanning Electron Microscopy (SEM), Energy Dispersive Spectroscopy (EDS), and Fourier Transform Infra-Red (FTIR). UV-Vis spectroscopy studies showed that the absorption spectra of synthesized silver nanoparticles from leaf and callus extracts had absorbance peak range of 440 nm and 445 nm, respectively. The X-RD pattern revealed the presence of crystalline, dominantly spherical silver nanoparticles in the sample having size ranging from 42 to 50 nm. The XRD peaks 38.2°, 44.1°, 64.1°, and 77.0° for leaf extract and 38.1°, 44.3°, 64.5°, 77.5°, and 81.33° for callus extract can be assigned the plane of silver crystals (111), (200), (220), and (311), respectively, and indicate that the silver nanoparticles are face-centered, cubic, and crystalline in nature. SEM and EDS analysis also confirmed the presence of silver nanoparticles. The FTIR results showed the presence of some biomolecules in extracts that act as reducing and capping agent for silver nanoparticles biosynthesis. The synthesized silver nanoparticles showed significant antibacterial activity againstKlebsiella pneumoniaeandPseudomonas aeruginosa.


2021 ◽  
Vol 19 (2) ◽  
pp. 25-32
Author(s):  
Deegendra Khadka ◽  
Rachana Regmi ◽  
Mitesh Shrestha ◽  
Megha Raj Banjara

The application of silver nanoparticles in various sectors including health related field is remarkably profound. Nowadays, the research of synthesizing metal nanoparticles (MNPs) using plant extracts is fascinating field as it offers the eco-friendly and cost-effective method for nanoparticle synthesis. In this study, we synthesized silver nanoparticles (AgNPs) using methanolic extract of B.asiatica and C. fistula regarding their ethnomedical importance. The synthesized AgNPs were characterized by UV-Visible spectroscopy, Fourier transform infrared spectroscopy (FTIR) and X-ray diffractometer (XRD). UV-vis spectroscopy exhibited the characteristic Surface Plasmon Peak of silver nanoparticle~420 nm.FTIR data were measured to get a preliminary idea on the functional groups responsible for the stabilization of AgNPs. XRD data confirmed the natural crystal structure with a face centered cubic of AgNPs. The antibacterial activity of biosynthesized AgNPs was assessed by testing promptly available gram-positive Staphylococcus aureus and gram-negative Escherichia coli bacterial strain and antioxidant activity was calculated by DPPH assay. The overall outcomes of the studies concluded that the application of the biogenic synthesis of AgNPs of B. asiaticaas an antioxidant and antibacterial agent is more potent showing IC50 value 65.1±1.30 μg/mL and the highest zone of inhibition 15 mm in diameter against S. aureus.


2013 ◽  
Vol 662 ◽  
pp. 80-83 ◽  
Author(s):  
Mana Intarasawang ◽  
Kheamrutai Thamaphat

In the present study, we demonstrated an effective cost and environmentally benign method to synthesize the silver nanoparticles (AgNPs) using aquatic weed namely water hyacinth as a reducing agent. Ultraviolet irradiation was also combined in the process to enhance the reaction rate. The aqueous silver ions mixed with water hyacinth leaf extract under UV irradiation were reduced to AgNPs. The mixture color was changed from light yellow to yellowish-brown color within 5 min due to excitation of surface plasmon vibrations in AgNPs. The formation of AgNPs was confirmed by UV-visible spectroscopy, X-ray diffraction (XRD) spectrometry, energy dispersive X-ray (EDX) analysis and transmission electron microscopy (TEM). The AgNPs were found to be polycrystalline in nature and spherical particles with mean diameter of 12.54 ± 0.19 nm. The XRD pattern peaked at different diffraction angles corresponding to the (111), (200), (220), and (311) planes indicated that AgNPs have face-centered cubic (fcc) unit cell structure. This proposed method revealed that unwanted plant can utilize in nano-manufacturing as well.


2016 ◽  
Vol 4 (3) ◽  
pp. 254-258 ◽  
Author(s):  
Mona Hussein Ibraheim ◽  
A.A. Ibrahiem ◽  
T. R. Dalloul

Green synthesis of silver nanoparticles (AgNPs) from silver nitrate was carried out using aqueous Pomegranate juice extract (PJE) as a reducing agent. The formation of AgNPs was characterized by UV-visible (UV–vis) spectroscopy, transmission electron microscopy (TEM), Fourier transforms infrared spectroscopy and X-ray diffraction (XRD). Surface Plasmon resonance (SPR) of ∼420-423 nm confirmed the earlier formation of AgNPs. TEM and XRD analysis showed that the AgNPs with an average diameter of 23 nm are crystalline in nature and have face-centered cubic geometry. The antibacterial efficiency of AgNPs against Escherchia coli and Staphylococcus aureus showed high level of inhibition. Further, the zone of inhibition increased with the increase in the concentration of silver nanoparticles. These studies are quite useful as it shows the utility of green nanotechnology for the synthesis of silver nanoparticles without any toxic residuals and byproducts. The efficient antimicrobial activity of biosynthesized AgNPs proves the application potential in the area of nano-medicine.Int J Appl Sci Biotechnol, Vol 4(3): 254-258


Author(s):  
Anil Kumar Moola1 ◽  
Sundararajan Balasubramani ◽  
Ranjitha Kumari Bollipo Diana1 ◽  
Chari Nithya

We are reporting a novel approach for preparing silver nanoparticles with seed coat exudates of Celastrus paniculatus Willd, a medicinal plant traditionally used for the treatment of skin diseases, fever, leprosy and neurological disorders. HPTLC study revealed that aqueous, soluble seed coat exudates contain phenolics, alakaloids and flavonoids. The formation, crystalline nature and morphology of the nanoparticles were identified by UV–Vis spectroscopy, X-ray Diffraction (XRD) analysis, Transmission Electron Microscopy (TEM) and selected-area electron diffraction (SAED). Functional group stretching of aqueous soluble extracts was identified by using FTIR. Results revealed that nanosilver particles are spherical, range in size from 10 to 82 nm and crystalize in face-centered cubic structures. Surface-enhanced Raman spectra analysis showed that AgNP are capped with bioactive molecules from exudates and that they may act as precursors of the reduction of silver nitrate from the metallic state (Ag+) to the atomic state (Ag0). We also examined the minimal inhibitory concentration for bacteria Escherichia coli and Bacillus subtilis using a resazurin color assay. Nanosilver strongly inhibited the bacterial growth, leading to MIC values of 40μg/ml and 60μg/ml for the bacteria, respectively. The colony screening method and inhibition kinetics of biofilm formation in the Klebsiella pneumoniae strain were also studied using the tube method and a quantitative microplate assay. SEM analysis and quantification of the EPS revealed a fivefold decrease in concentration in treated compared to untreated. The inhibition response was duly reflected in SEM images.


Crystals ◽  
2020 ◽  
Vol 10 (11) ◽  
pp. 1008
Author(s):  
Pablo Miguel Ramos ◽  
Miguel Herranz ◽  
Katerina Foteinopoulou ◽  
Nikos Ch. Karayiannis ◽  
Manuel Laso

In the present work, we revise and extend the Characteristic Crystallographic Element (CCE) norm, an algorithm used to simultaneously detect radial and orientational similarity of computer-generated structures with respect to specific reference crystals and local symmetries. Based on the identification of point group symmetry elements, the CCE descriptor is able to gauge local structure with high precision and finely distinguish between competing morphologies. As test cases we use computer-generated monomeric and polymer systems of spherical particles interacting with the hard-sphere and square-well attractive potentials. We demonstrate that the CCE norm is able to detect and differentiate, between others, among: hexagonal close packed (HCP), face centered cubic (FCC), hexagonal (HEX) and body centered cubic (BCC) crystals as well as non-crystallographic fivefold (FIV) local symmetry in bulk 3-D systems; triangular (TRI), square (SQU) and honeycomb (HON) crystals, as well as pentagonal (PEN) local symmetry in thin films of one-layer thickness (2-D systems). The descriptor is general and can be applied to identify the symmetry elements of any point group for arbitrary atomic or particulate system in two or three dimensions, in the bulk or under confinement.


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