scholarly journals Green Synthesis of Silver Nanoparticles Using Hibiscus sabdariffa Leaves Extract

2021 ◽  
Vol 3 (1) ◽  
pp. 76-81
Author(s):  
Siti Husnaa Mohd Taib ◽  
Kamyar Shameli ◽  
Roshafima Rasit Ali ◽  
Zahra Izadiyan ◽  
Zatil Izzah Ahmad Tarmizi
Keyword(s):  
Silver Nanoparticles ◽  
Hibiscus Sabdariffa ◽  
Ag Nps ◽  
Tem Analysis ◽  
Force Microscopy ◽  
Atomic Force ◽  
Transmission Electron ◽  
Vis Spectroscopy ◽  
Size Of Particles ◽  
Average Size

The present paper reports the synthesis of silver nanoparticles (Ag-NPs) by a green method using Hibiscus sabdariffa (H. sabdariffa) leaves extract as reductant and stabilizer. The synthesized Ag-NPs were characterized by ultraviolet-visible (UV-vis) spectroscopy, transmission electron microscopy (TEM), atomic force microscopy (AFM) and Fourier transform infrared spectroscopy (FTIR). UV-vis spectrum of synthesized Ag-NPs showed a peak at 378 nm. TEM analysis revealed that the particles were spherical and irregular in shape and has average size around 56.52 nm. This structure and size of particles were confirmed by AFM analysis. The UV-vis and FTIR spectrum provides evidence of the presence of caffeic acid component as a representative biomolecule in stabilising the nanoparticles based on previous studies. Hence, this study advocates that H. sabdariffa have potential for synthesizing nanoparticles.

scholarly journals On the Operational Aspects of Measuring Nanoparticle Sizes

Nanomaterials ◽  
2018 ◽  
Vol 9 (1) ◽  
pp. 18 ◽  
Author(s):  
Jean-Marie Teulon ◽  
Christian Godon ◽  
Louis Chantalat ◽  
Christine Moriscot ◽  
Julien Cambedouzou ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Ag Nps ◽  
Force Microscopy ◽  
Average Value ◽  
Atomic Force ◽  
Transmission Electron ◽  
Scanning Transmission ◽  
Experimental Protocols ◽  
Operational Aspects

Nanoparticles are defined as elementary particles with a size between 1 and 100 nm for at least 50% (in number). They can be made from natural materials, or manufactured. Due to their small sizes, novel toxicological issues are raised and thus determining the accurate size of these nanoparticles is a major challenge. In this study, we performed an intercomparison experiment with the goal to measure sizes of several nanoparticles, in a first step, calibrated beads and monodispersed SiO2 Ludox®, and, in a second step, nanoparticles (NPs) of toxicological interest, such as Silver NM-300 K and PVP-coated Ag NPs, Titanium dioxide A12, P25(Degussa), and E171(A), using commonly available laboratory techniques such as transmission electron microscopy, scanning electron microscopy, small-angle X-ray scattering, dynamic light scattering, wet scanning transmission electron microscopy (and its dry state, STEM) and atomic force microscopy. With monomodal distributed NPs (polystyrene beads and SiO2 Ludox®), all tested techniques provide a global size value amplitude within 25% from each other, whereas on multimodal distributed NPs (Ag and TiO2) the inter-technique variation in size values reaches 300%. Our results highlight several pitfalls of NP size measurements such as operational aspects, which are unexpected consequences in the choice of experimental protocols. It reinforces the idea that averaging the NP size from different biophysical techniques (and experimental protocols) is more robust than focusing on repetitions of a single technique. Besides, when characterizing a heterogeneous NP in size, a size distribution is more informative than a simple average value. This work emphasizes the need for nanotoxicologists (and regulatory agencies) to test a large panel of different techniques before making a choice for the most appropriate technique(s)/protocol(s) to characterize a peculiar NP.

scholarly journals Detection Limits of DLS and UV-Vis Spectroscopy in Characterization of Polydisperse Nanoparticles Colloids

2013 ◽  
Vol 2013 ◽  
pp. 1-10 ◽  
Author(s):  
Emilia Tomaszewska ◽  
Katarzyna Soliwoda ◽  
Kinga Kadziola ◽  
Beata Tkacz-Szczesna ◽  
Grzegorz Celichowski ◽  
...  
Keyword(s):  
Light Scattering ◽  
Dynamic Light Scattering ◽  
Point Of View ◽  
Spectroscopy Analysis ◽  
Force Microscopy ◽  
Atomic Force ◽  
Transmission Electron ◽  
Vis Spectroscopy ◽  
The One

Dynamic light scattering is a method that depends on the interaction of light with particles. This method can be used for measurements of narrow particle size distributions especially in the range of 2–500 nm. Sample polydispersity can distort the results, and we could not see the real populations of particles because big particles presented in the sample can screen smaller ones. Although the theory and mathematical basics of DLS technique are already well known, little has been done to determine its limits experimentally. The size and size distribution of artificially prepared polydisperse silver nanoparticles (NPs) colloids were studied using dynamic light scattering (DLS) and ultraviolet-visible (UV-Vis) spectroscopy. Polydisperse colloids were prepared based on the mixture of chemically synthesized monodisperse colloids well characterized by atomic force microscopy (AFM), transmission electron microscopy (TEM), DLS, and UV-Vis spectroscopy. Analysis of the DLS results obtained for polydisperse colloids reveals that several percent of the volume content of bigger NPs could screen completely the presence of smaller ones. The presented results could be extremely important from nanoparticles metrology point of view and should help to understand experimental data especially for the one who works with DLS and/or UV-Vis only.

scholarly journals Microwave-Assisted Green Synthesis of Silver Nanoparticles Using Juglans regia Leaf Extract and Evaluation of Their Physico-Chemical and Antibacterial Properties

Antibiotics ◽  
2018 ◽  
Vol 7 (3) ◽  
pp. 68 ◽  
Author(s):  
Mahsa Eshghi ◽  
Hamideh Vaghari ◽  
Yahya Najian ◽  
Mohammad Najian ◽  
Hoda Jafarizadeh-Malmiri ◽  
...  
Keyword(s):  
Silver Nanoparticles ◽  
Leaf Extract ◽  
Juglans Regia ◽  
Antibacterial Properties ◽  
Infrared Analysis ◽  
Ag Nps ◽  
Stabilizing Agents ◽  
Agno3 Solution ◽  
Transmission Electron ◽  
Vis Spectroscopy

Silver nanoparticles (Ag NPs) were synthesized using Juglans regia (J. regia) leaf extract, as both reducing and stabilizing agents through microwave irradiation method. The effects of a 1% (w/v) amount of leaf extract (0.1–0.9 mL) and an amount of 1 mM AgNO3 solution (15–25 mL) on the broad emission peak (λmax) and concentration of the synthesized Ag NPs solution were investigated using response surface methodology (RSM). Fourier transform infrared analysis indicated the main functional groups existing in the J. regia leaf extract. Dynamic light scattering, UV-Vis spectroscopy and transmission electron microscopy were used to characterize the synthesized Ag NPs. Fabricated Ag NPs with the mean particle size and polydispersity index and maximum concentration and zeta potential of 168 nm, 0.419, 135.16 ppm and −15.6 mV, respectively, were obtained using 0.1 mL of J. regia leaf extract and 15 mL of AgNO3. The antibacterial activity of the fabricated Ag NPs was assessed against both Gram negative (Escherichia coli) and positive (Staphylococcus aureus) bacteria and was found to possess high bactericidal effects.

scholarly journals Biogenic silver nanoparticles from Trichodesma indicum aqueous leaf extract against Mythimna separata and evaluation of its larvicidal efficacy

2017 ◽  
Vol 57 (2) ◽  
pp. 194-200 ◽  
Author(s):  
Abdul A. Buhroo ◽  
Gousul Nisa ◽  
Syed Asrafuzzaman ◽  
Ram Prasad ◽  
Razia Rasheed ◽  
...  
Keyword(s):  
Silver Nanoparticles ◽  
Leaf Extract ◽  
Average Particle ◽  
Particle Sizes ◽  
Mythimna Separata ◽  
Ag Nps ◽  
Leaf Extracts ◽  
Tem Analysis ◽  
Vis Spectroscopy ◽  
Aqueous Leaf Extract

AbstractThe present exploration is focused on the bio-fabrication of silver nanoparticles (Ag NPs) usingTrichodesma indicumaqueous leaf extract as a reducing agent. The synthesized Ag NPs were productively characterized by UV-vis spectroscopy, XRD, and TEM studies. The photosynthesis of Ag NPs was done at room temperature for 24 h and at 60°C. The green synthesis of spherical-shaped Ag NPs bio-fabricated fromT. indicumwith a face centred cubic structure showed average particle sizes of 20–50 nm, which is inconsistent with the particle size calculated by the XRD Scherer equation and TEM analysis. We further explored the larvicidal efficacy of biosynthesized Ag NPs with leaf extracts ofT. indicumagainstMythimna separata. The results showed that Ag NPs (20–50 nm) ofT. indicumpossess good larvicidal activity againstM. separatawith an LC50of 500 ppm. Thus, we can advocate that Ag NPs of 20–50 nm size extracted fromT. indicummay be considered in the pest management programme ofM. separatain future.

scholarly journals Optimization of biogenic synthesis of silver nanoparticles from flavonoid-rich Clinacanthus nutans leaf and stem aqueous extracts

2020 ◽  
Vol 7 (7) ◽  
pp. 200065 ◽  
Author(s):  
Siti Nur Aishah Mat Yusuf ◽  
Che Nurul Azieyan Che Mood ◽  
Nor Hazwani Ahmad ◽  
Doblin Sandai ◽  
Chee Keong Lee ◽  
...  
Keyword(s):  
Silver Nanoparticles ◽  
Functional Groups ◽  
Silver Ions ◽  
Cost Effective ◽  
Aqueous Extracts ◽  
Tem Analysis ◽  
Transmission Electron ◽  
Vis Spectroscopy ◽  
The Face ◽  
Clinacanthus Nutans

Background : Silver nanoparticles (AgNPs) are widely used in food industries, biomedical, dentistry, catalysis, diagnostic biological probes and sensors. The use of plant extract for AgNPs synthesis eliminates the process of maintaining cell culture and the process could be scaled up under a non-aseptic environment. The purpose of this study is to determine the classes of phytochemicals, to biosynthesize and characterize the AgNPs using Clinacanthus nutans leaf and stem extracts. In this study, AgNPs were synthesized from the aqueous extracts of C. nutans leaves and stems through a non-toxic, cost-effective and eco-friendly method. Results : The formation of AgNPs was confirmed by UV-Vis spectroscopy, and the size of AgNP-L (leaf) and AgNP-S (stem) were 114.7 and 129.9 nm, respectively. Transmission electron microscopy (TEM) analysis showed spherical nanoparticles with AgNP-L and AgNP-S ranging from 10 to 300 nm and 10 to 180 nm, with average of 101.18 and 75.38 nm, respectively. The zeta potentials of AgNP-L and AgNP-S were recorded at −42.8 and −43.9 mV. X-ray diffraction analysis matched the face-centred cubic structure of silver and was capped with bioactive compounds. Fourier transform infrared spectrophotometer analysis revealed the presence of few functional groups of phenolic and flavonoid compounds. These functional groups act as reducing agents in AgNPs synthesis. Conclusion : These results showed that the biogenically synthesized nanoparticles reduced silver ions to silver nanoparticles in aqueous condition and the AgNPs formed were stable and less toxic.

scholarly journals Silver Nanoparticles: Biosynthesis Using an ATCC Reference Strain ofPseudomonas aeruginosaand Activity as Broad Spectrum Clinical Antibacterial Agents

2016 ◽  
Vol 2016 ◽  
pp. 1-7 ◽  
Author(s):  
Melisa A. Quinteros ◽  
Ivana M. Aiassa Martínez ◽  
Pablo R. Dalmasso ◽  
Paulina L. Páez
Keyword(s):  
Silver Nanoparticles ◽  
Broad Spectrum ◽  
Nitrate Solution ◽  
Human Neutrophils ◽  
Resistant Bacteria ◽  
Klebsiella Pneumonia ◽  
Bacterial Strains ◽  
Ag Nps ◽  
Tem Analysis ◽  
Vis Spectroscopy

Currently, the biosynthesis of silver-based nanomaterials attracts enormous attention owing to the documented antimicrobial properties of these ones. This study reports the extracellular biosynthesis of silver nanoparticles (Ag-NPs) using aPseudomonas aeruginosastrain from a reference culture collection. A greenish culture supernatant ofP. aeruginosaincubated at 37°C with a silver nitrate solution for 24 h changed to a yellowish brown color, indicating the formation of Ag-NPs, which was confirmed by UV-vis spectroscopy, transmission electron microscopy, and X-ray diffraction. TEM analysis showed spherical and pseudospherical nanoparticles with a distributed size mainly between 25 and 45 nm, and the XRD pattern revealed the crystalline nature of Ag-NPs. Also it provides an evaluation of the antimicrobial activity of the biosynthesized Ag-NPs against human pathogenic and opportunistic microorganisms, namely,Staphylococcus aureus,Staphylococcus epidermidis,Enterococcus faecalis,Proteus mirabilis,Acinetobacter baumannii,Escherichia coli,P. aeruginosa, andKlebsiella pneumonia. Ag-NPs were found to be bioactive at picomolar concentration levels showing bactericidal effects against both Gram-positive and Gram-negative bacterial strains. This work demonstrates the first helpful use of biosynthesized Ag-NPs as broad spectrum bactericidal agents for clinical strains of pathogenic multidrug-resistant bacteria such as methicillin-resistantS. aureus,A. baumannii, andE. coli. In addition, these Ag-NPs showed negligible cytotoxic effect in human neutrophils suggesting low toxicity to the host.

Properties of Silver Nanoparticles Prepared by the Electric Spark Dispersion Method

2013 ◽  
Vol 872 ◽  
pp. 74-78 ◽  
Author(s):  
S.P. Zhuravkov ◽  
Evgeny Plotnikov ◽  
Dmitry Martemiyanov ◽  
Nikolay A. Yavorovsky ◽  
Ulrich Hasse ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Silver Nanoparticles ◽  
Structural Characteristics ◽  
Silver Particles ◽  
Dispersion Method ◽  
Force Microscopy ◽  
Atomic Force ◽  
Transmission Electron ◽  
Light Scattering Spectroscopy

The morphological and structural characteristics of nanoscale silver particles obtained by the method of electric spark dispersion of metal granules in the liquid aprotic medium were obtained using atomic force microscopy, transmission electron microscopy, and dynamic light scattering spectroscopy. The specific surface, morphology, structure and the distribution by size of the particles are presented.

Study of Defects in p-type Layers in III-nitride Laser Diode Structures Grown by Molecular Beam Epitaxy

2006 ◽  
Vol 955 ◽  
Author(s):  
Huixin Xiu ◽  
Pedro MFJ Costa ◽  
Matthias Kauer ◽  
Tim M Smeeton ◽  
Stewart E Hooper ◽  
...  
Keyword(s):  
Molecular Beam Epitaxy ◽  
Molecular Beam ◽  
Extended Defects ◽  
Tem Analysis ◽  
Force Microscopy ◽  
Atomic Force ◽  
Transmission Electron ◽  
P Type ◽  
Nitride Laser ◽  
Cladding Layers

ABSTRACTThis paper reports on the study of defects in p-type layers in III-nitride laser structures grown by molecular beam epitaxy. Characterization of the heterostructures was carried out using atomic force microscopy and transmission electron microscopy. The results show that a high density of extended defects – possibly inversion domains – exist in the p-type cladding layers of as-grown structures with either AlGaN/GaN superlattices or bulk AlGaN cladding layers. TEM analysis of operated and aged devices does not reveal any significant structural modification of the p-type material which might be the cause of deterioration in the lasing performance or failure.

scholarly journals Use of Atomic Force Microscopy and Transmission Electron Microscopy for Correlative Studies of Bacterial Capsules

2008 ◽  
Vol 74 (17) ◽  
pp. 5457-5465 ◽  
Author(s):  
Oleg Stukalov ◽  
Anton Korenevsky ◽  
Terry J. Beveridge ◽  
John R. Dutcher
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Atomic Force Microscopy ◽  
Shewanella Oneidensis ◽  
Geobacter Sulfurreducens ◽  
Phase Imaging ◽  
Tem Analysis ◽  
Force Microscopy ◽  
Atomic Force ◽  
Transmission Electron

ABSTRACT Bacteria can possess an outermost assembly of polysaccharide molecules, a capsule, which is attached to their cell wall. We have used two complementary, high-resolution microscopy techniques, atomic force microscopy (AFM) and transmission electron microscopy (TEM), to study bacterial capsules of four different gram-negative bacterial strains: Escherichia coli K30, Pseudomonas aeruginosa FRD1, Shewanella oneidensis MR-4, and Geobacter sulfurreducens PCA. TEM analysis of bacterial cells using different preparative techniques (whole-cell mounts, conventional embeddings, and freeze-substitution) revealed capsules for some but not all of the strains. In contrast, the use of AFM allowed the unambiguous identification of the presence of capsules on all strains used in the present study, including those that were shown by TEM to be not encapsulated. In addition, the use of AFM phase imaging allowed the visualization of the bacterial cell within the capsule, with a depth sensitivity that decreased with increasing tapping frequency.

scholarly journals Synthesis and Photonics Applications of Afzelechin Conjugated Silver Nanoparticles

Coatings ◽  
2021 ◽  
Vol 11 (11) ◽  
pp. 1295
Author(s):  
Shahid Ali ◽  
Muhammad Rahim ◽  
Perveen Fazil ◽  
Malik Shoaib Ahmad ◽  
Azeem Ullah ◽  
...  
Keyword(s):  
Silver Nanoparticles ◽  
Band Gap ◽  
Band Gap Energy ◽  
Visible Absorption ◽  
Force Microscopy ◽  
Atomic Force ◽  
Uv Visible ◽  
Size And Morphology ◽  
Average Size ◽  
20 Nm

The silver nanoparticles were synthesized, functionalized with afzelechin and characterized using UV-Visible spectroscopy. A difference of 20 nm was observed in surface plasmon resonance of bare and functionalized silver nanoparticles which indicates afzelechin conjugation with silver nanoparticles. The atomic force microscopy (AFM) technique was used for the determination of the size and morphology of synthesized silver nanoparticles. The afzelechin conjugated silver nanoparticles were spherical and their sizes ranged from 3 to 10 nm with an average size of 8 nm while the bare silver nanoparticles were also spherical and their sizes ranged from 3 to 10 nm with an average size of 6 nm. The average sizes were also calculated by fitting their UV-Visible absorption spectra. Fitting is based on the Mie and Mie Gans models, which deduced that afzelechin conjugated silver nanoparticles were 96.5% spherical and 3.5% spheroidal with an average size of 5 nm while bare silver nanoparticles were 100% spherical with an average size of 4 nm. Both the fitting model as well as the AFM results showed a difference of 3 nm between the sizes of afzelechin conjugated silver nanoparticles while 2 nm differences was observed for bare silver nanoparticles. The band gap energy of afzelechin conjugated silver nanoparticles and bare silver nanoparticles were calculated via Tauc’s equation and were found to be 5.1 eV and 5.4 eV, respectively. A difference of 0.3 eV was observed in band gap energies of afzelechin conjugated silver nanoparticles and bare silver nanoparticles.

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