scholarly journals Influence of Nitrogen Source and Growth Phase on Extracellular Biosynthesis of Silver Nanoparticles Using Cultural Filtrates of Scenedesmus obliquus

2019 ◽  
Vol 9 (7) ◽  
pp. 1465 ◽  
Author(s):  
Osama Darwesh ◽  
Ibrahim Matter ◽  
Mohamed Eida ◽  
Hassan Moawad ◽  
You-Kwan Oh
Keyword(s):  
Silver Nanoparticles ◽  
Nitrogen Source ◽  
Antimicrobial Agents ◽  
Scenedesmus Obliquus ◽  
Nitrogen Sources ◽  
Nitrate Treatment ◽  
Extracellular Biosynthesis ◽  
Microalgal Culture ◽  
Transmission Electron ◽  
Green Microalga

In this study, silver nanoparticles (AgNPs) were green-synthesized extracellularly by the action of bioactive compounds in cultural filtrates of green microalga Scenedesmus obliquus (KY621475). The influences of six different nitrogen sources (i.e., NaNO3, CO(NH4)2, (NH4)2CO3, KNO3, NH4NO3, and (NH4)2SO4) on extracellular biosynthesis of AgNPs were observed by UV–Visible spectroscopy (380–425 nm) and confirmed using high-resolution transmission electron microscopy (HRTEM). The highest biomass production was observed in the case of urea and ammonium carbonate treatments, which, surprisingly, showed negative activity for AgNPs biosynthesis. Considering their coupling and compatible presence in cultural filtrates, reductases (especially nitrate reductase) as reduction agents are assumed to play a key role in the extracellular biosynthesis of AgNPs. The cultural filtrates of the potassium and sodium nitrate treatments produce AgNPs of relatively small size (5–10 and 4–10 nm, respectively), smaller than those produced by filtrate of ammonium nitrate treatment. The antimicrobial activity of produced AgNPs was a function mainly of particle size, which was influenced by the nitrogen source of the microalgal culture. The AgNPs produced from the KNO3 and NaNO3 cultural filtrates performed the best as antimicrobial agents.

scholarly journals Microbial Synthesis and Characterization of Silver Nanoparticles using Alternaria alternata

2019 ◽  
pp. 1-7 ◽  
Author(s):  
Sarafadeen O. Kareem ◽  
Oluwagbenga T. Familola ◽  
Adejare R. Oloyede ◽  
Enock O. Dare
Keyword(s):  
Silver Nanoparticles ◽  
Alternaria Alternata ◽  
Structural Integrity ◽  
Xrd Analysis ◽  
Potential Candidate ◽  
Extracellular Biosynthesis ◽  
Agno3 Solution ◽  
Transmission Electron ◽  
Mycelial Mass ◽  
Cell Free Filtrate

In this study, extracellular biosynthesis of silver nanoparticles (AgNPs) was carried out using Alternaria alternata. AgNPs were synthesized using vegetative and cell-free filtrate methods. Silver nitrate (AgNO3) solution was reduced with fungal mycelial mass and cell-free filtrate at a ratio of 1:4 (v/v). Further, the effects of biosynthesis parameters (reaction time, reaction temperature, light and dark incubation, and static and agitated conditions) weredetermined. The structural integrity of the synthesized AgNPs was investigated through UV-visible spectrophotometry, X-ray diffraction (XRD) analysis, and transmission electron microscopy (TEM). Parameter optimization revealed that cell-free filtrate AgNP synthesis at 40 °C with constant agitation and incubation in darkness for 120 h using 1 mM AgNO3resulted in the highest absorbance value (at 400 nm). Further, TEM images showed that the synthesized AgNPs were spherical, homogeneous, and well dispersed while the XRD peaks confirmed the purity of the AgNPs obtained. The diameters of the AgNPs were found to range from 7.48 to 12.15 nm. This study identifies Alternaria alternata as a potential candidate for use in the industrial biosynthesis of AgNPs.

scholarly journals Biosynthesis of Anisotropic Silver Nanoparticles byBhargavaea indicaand Their Synergistic Effect with Antibiotics against Pathogenic Microorganisms

2015 ◽  
Vol 2015 ◽  
pp. 1-10 ◽  
Author(s):  
Priyanka Singh ◽  
Yeon Ju Kim ◽  
Hina Singh ◽  
Ramya Mathiyalagan ◽  
Chao Wang ◽  
...  
Keyword(s):  
Silver Nanoparticles ◽  
Vibrio Parahaemolyticus ◽  
Size Range ◽  
Average Diameter ◽  
Pathogenic Microorganisms ◽  
X Ray Diffraction ◽  
X Ray ◽  
Extracellular Biosynthesis ◽  
Predominant Component ◽  
Transmission Electron

The strainBhargavaea indicaDC1 isolated from four-year-oldP. ginsengrhizospheric soil was used to perform rapid and extracellular biosynthesis of anisotropic silver nanoparticles. The ultraviolet-visible (UV-vis) spectra of the reaction mixture containing silver nanoparticles showed a peak at 460 nm, corresponding to the surface plasmon absorbance of silver nanoparticles. Field-emission transmission electron microscopy (FE-TEM) structural characterization revealed the nanobar, pentagon, spherical, icosahedron, hexagonal, truncated triangle, and triangular nanoparticles, with the size range from 30 to 100 nm. The energy-dispersive X-ray (EDX) analysis and elemental mapping results also confirmed that the silver was the predominant component of isolated nanoparticles. The X-ray diffraction (XRD) results correspond to the purity of silver nanoparticles and dynamic light scattering (DLS) result indicated that the average diameter of particles was 111.6 nm. In addition, enhancement in antimicrobial activity of commercial antibiotics was observed against various pathogenic microorganisms such asVibrio parahaemolyticus, Salmonella enterica, Staphylococcus aureus, Bacillus anthracis, Bacillus cereus, Escherichia coli, andCandida albicans.

Efficacy of Silver Nanoparticles Synthesized from Hymenocallis species (Spider Lilly) Leaf Extract as Antimicrobial Agents

2019 ◽  
Vol 12 (5) ◽  
pp. 4644-4647
Author(s):  
K.K. Gupta ◽  
Neha Kumari ◽  
Neha Sinha ◽  
Akruti Gupta
Keyword(s):  
Silver Nanoparticles ◽  
Leaf Extract ◽  
Antimicrobial Agents ◽  
Color Change ◽  
Bacterial Species ◽  
Antimicrobial Property ◽  
Biogenic Synthesis ◽  
E Coli ◽  
Light Yellow ◽  
Antibiotic Property

Biogenic synthesis of silver nanoparticles synthesized from Hymenocallis species (Spider Lilly) leaf extract was subjected for investigation of its antimicrobial property against four bacterial species (E. coli, Salmonella sp., Streptococcus sp. & Staphylococcus sp.). The results revealed that synthesized nanoparticles solution very much justify the color change property from initial light yellow to final reddish brown during the synthesis producing a characteristics absorption peak in the range of 434-466 nm. As antimicrobial agents, their efficacy was evaluated by analysis of variance in between the species and among the different concentration of AgNPs solution, which clearly showed that there was significant variation in the antibiotic property between the four different concentrations of AgNPs solution and also among four different species of bacteria taken under studies. However, silver nanoparticles solution of 1: 9 and 1:4 were proved comparatively more efficient as antimicrobial agents against four species of bacteria.

Hydroxylamines as One-Atom Nitrogen Sources for Metal-Catalyzed Cycloadditions

Synthesis ◽  
2021 ◽  
Author(s):  
Xinjun Luan ◽  
Jingxun Yu
Keyword(s):  
Transition Metal ◽  
Nitrogen Source ◽  
Nucleophilic Reagent ◽  
Nitrogen Sources ◽  
Short Review ◽  
Indole Derivatives ◽  
Electrophilic Amination ◽  
Intramolecular Cycloaddition ◽  
Transition Metal Catalyzed ◽  
Metal Catalyzed

AbstractTransition-metal-catalyzed C–N bond formation is one of the most important pathways to synthesize N-heterocycles. Hydroxylamines can be transformed into a nucleophilic reagent to react with a carbon cation or coordinate with a transition metal; it can also become an electrophilic nitrogen source to react with arenes, alkenes, and alkynes. In this short review, the progress made on transition-metal-catalyzed cycloadditions with hydroxylamines as a nitrogen source is summarized.1 Introduction2 Cycloaddition To Form Aziridine Derivatives2.1 Intramolecular Cycloaddition To Form Aziridine Derivatives2.2 Intermolecular Cycloaddition To Form Aziridine Derivatives3 Cycloaddition To Form Indole Derivatives4 Cycloaddition To Form Other N-Heterocycles4.1 Aza-Heck-Type Amination Reactions4.2 Nitrene Insertion Amination Reactions4.3 Intramolecular Nucleophilic and Electrophilic Amination Reactions5 Conclusion and Outlook

scholarly journals The Antimicrobial and Anti-Inflammatory Effects of Silver Nanoparticles Synthesised from Cotyledon orbiculata Aqueous Extract

Nanomaterials ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 1343
Author(s):  
Caroline Tyavambiza ◽  
Abdulrahman Mohammed Elbagory ◽  
Abram Madimabe Madiehe ◽  
Mervin Meyer ◽  
Samantha Meyer
Keyword(s):  
Staphylococcus Aureus ◽  
Silver Nanoparticles ◽  
Metallic Nanoparticles ◽  
Methicillin Resistance ◽  
Antimicrobial Activities ◽  
Transmission Electron ◽  
Anti Inflammatory ◽  
Anti Inflammation ◽  
Important Medicinal Plant ◽  
Pro Inflammatory Cytokines

Cotyledon orbiculata, commonly known as pig’s ear, is an important medicinal plant of South Africa. It is used in traditional medicine to treat many ailments, including skin eruptions, abscesses, inflammation, boils and acne. Many plants have been used to synthesize metallic nanoparticles, particularly silver nanoparticles (AgNPs). However, the synthesis of AgNPs from C. orbiculata has never been reported before. The aim of this study was to synthesize AgNPs using C. orbiculata and evaluate their antimicrobial and immunomodulatory properties. AgNPs were synthesized and characterized using Ultraviolet-Visible Spectroscopy (UV-Vis), Dynamic Light Scattering (DLS) and High-Resolution Transmission Electron Microscopy (HR-TEM). The antimicrobial activities of the nanoparticles against skin pathogens (Staphylococcus aureus, Staphylococcus epidermidis, Methicillin Resistance Staphylococcus aureus, Pseudomonas aeruginosa and Candida albicans) as well as their effects on cytokine production in macrophages (differentiated from THP-1 cells) were evaluated. The AgNPs from C. orbiculata exhibited antimicrobial activity, with the highest activity observed against P. aeruginosa (5 µg/mL). The AgNPs also showed anti-inflammatory activity by inhibiting the secretion of pro-inflammatory cytokines (TNF-alpha, IL-6 and IL-1 beta) in lipopolysaccharide-treated macrophages. This concludes that the AgNPs produced from C. orbiculata possess antimicrobial and anti-inflammation properties.

scholarly journals The Synergistic Effect of Biosynthesized Silver Nanoparticles and Phage ZCSE2 as a Novel Approach to Combat Multidrug-Resistant Salmonella enterica

Antibiotics ◽  
2021 ◽  
Vol 10 (6) ◽  
pp. 678
Author(s):  
Abdallah S. Abdelsattar ◽  
Rana Nofal ◽  
Salsabil Makky ◽  
Anan Safwat ◽  
Amera Taha ◽  
...  
Keyword(s):  
Silver Nanoparticles ◽  
Color Change ◽  
Antibacterial Properties ◽  
Multidrug Resistant ◽  
Inhibitory Effect ◽  
Health Concern ◽  
Resistant Bacteria ◽  
Mortality And Morbidity ◽  
Novel Approach ◽  
Transmission Electron

The emergence and evolution of antibiotic-resistant bacteria is considered a public health concern. Salmonella is one of the most common pathogens that cause high mortality and morbidity rates in humans, animals, and poultry annually. In this work, we developed a combination of silver nanoparticles (AgNPs) with bacteriophage (phage) as an antimicrobial agent to control microbial growth. The synthesized AgNPs with propolis were characterized by testing their color change from transparent to deep brown by transmission electron microscopy (TEM) and Fourier-Transform Infrared Spectroscopy (FTIR). The phage ZCSE2 was found to be stable when combined with AgNPs. Both minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) were evaluated for AgNPs, phage, and their combination. The results indicated that MIC and MBC values were equal to 23 µg/mL against Salmonella bacteria at a concentration of 107 CFU/mL. The combination of 0.4× MIC from AgNPs and phage with Multiplicity of Infection (MOI) 0.1 showed an inhibitory effect. This combination of AgNPs and phage offers a prospect of nanoparticles with significantly enhanced antibacterial properties and therapeutic performance.

scholarly journals Green Synthesized Silver Nanoparticles Immobilized on Activated Carbon Nanoparticles: Antibacterial Activity Enhancement Study and Its Application on Textiles Fabrics

Molecules ◽  
2021 ◽  
Vol 26 (13) ◽  
pp. 3790
Author(s):  
Pratama Jujur Wibawa ◽  
Muhammad Nur ◽  
Mukhammad Asy’ari ◽  
Wijanarka Wijanarka ◽  
Heru Susanto ◽  
...  
Keyword(s):  
Silver Nanoparticles ◽  
Antibacterial Activity ◽  
Activated Carbon ◽  
Aloe Vera ◽  
Particle Size Analysis ◽  
Size Analysis ◽  
E Coli ◽  
Transmission Electron ◽  
Average Size ◽  
Green Synthesized Silver Nanoparticles

This research aimed to enhance the antibacterial activity of silver nanoparticles (AgNPs) synthesized from silver nitrate (AgNO3) using aloe vera extract. It was performed by means of incorporating AgNPs on an activated carbon nanoparticle (ACNPs) under ultrasonic agitation (40 kHz, 2 × 50 watt) for 30 min in an aqueous colloidal medium. The successful AgNPs synthesis was clarified with both Ultraviolet-Visible (UV-Vis) and Fourier Transform Infrared (FTIR) spectrophotometers. The successful AgNPs–ACNPs incorporation and its particle size analysis was performed using Transmission Electron Microscope (TEM). The brown color suspension generation and UV-Vis’s spectra maximum wavelength at around 480 nm confirmed the existence of AgNPs. The particle sizes of the produced AgNPs were about 5 to 10 nm in the majority number, which collectively surrounded the aloe vera extract secondary metabolites formed core-shell like nanostructure of 8.20 ± 2.05 nm in average size, while ACNPs themselves were about 20.10 ± 1.52 nm in average size formed particles cluster, and 48.00 ± 8.37 nm in average size as stacking of other particles. The antibacterial activity of the synthesized AgNPs and AgNPs-immobilized ACNPs was 57.58% and 63.64%, respectively (for E. coli); 61.25%, and 93.49%, respectively (for S. aureus). In addition, when the AgNPs-immobilized ACNPs material was coated on the cotton and polyester fabrics, the antibacterial activity of the materials changed, becoming 19.23% (cotton; E. coli), 31.73% (polyester; E. coli), 13.36% (cotton; S. aureus), 21.15% (polyester; S. aureus).

scholarly journals Size Control of Synthesized Silver Nanoparticles by Simultaneous Chemical Reduction and Laser Fragmentation in Origanum majorana Extract: Antibacterial Application

Materials ◽  
2021 ◽  
Vol 14 (9) ◽  
pp. 2326
Author(s):  
Entesar Ali Ganash ◽  
Reem Mohammad Altuwirqi
Keyword(s):  
Silver Nanoparticles ◽  
Irradiation Time ◽  
Chemical Reduction ◽  
Size Control ◽  
Reduction Process ◽  
Laser Wavelength ◽  
X Ray Diffraction ◽  
Ag Nps ◽  
Transmission Electron ◽  
Origanum Majorana

In this work, silver nanoparticles (Ag NPs) were synthesized using a chemical reduction approach and a pulsed laser fragmentation in liquid (PLFL) technique, simultaneously. A laser wavelength of 532 nm was focused on the as produced Ag NPs, suspended in an Origanum majorana extract solution, with the aim of controlling their size. The effect of liquid medium concentration and irradiation time on the properties of the fabricated NPs was studied. While the X-ray diffraction (XRD) pattern confirmed the existence of Ag NPs, the UV–Vis spectrophotometry showed a significant absorption peak at about 420 nm, which is attributed to the characteristic surface plasmon resonance (SPR) peak of the obtained Ag NPs. By increasing the irradiation time and the Origanum majora extract concentration, the SPR peak shifted toward a shorter wavelength. This shift indicates a reduction in the NPs’ size. The effect of PLFL on size reduction was clearly revealed from the transmission electron microscopy images. The PLFL technique, depending on experimental parameters, reduced the size of the obtained Ag NPs to less than 10 nm. The mean zeta potential of the fabricated Ag NPs was found to be greater than −30 mV, signifying their stability. The Ag NPs were also found to effectively inhibit bacterial activity. The PLFL technique has proved to be a powerful method for controlling the size of NPs when it is simultaneously associated with a chemical reduction process.

scholarly journals Biosynthesis of Silver Nanoparticles Mediated by Entomopathogenic Fungi: Antimicrobial Resistance, Nanopesticides, and Toxicity

Antibiotics ◽  
2021 ◽  
Vol 10 (7) ◽  
pp. 852
Author(s):  
Tárcio S. Santos ◽  
Tarcisio M. Silva ◽  
Juliana C. Cardoso ◽  
Ricardo L. C. de Albuquerque-Júnior ◽  
Aleksandra Zielinska ◽  
...  
Keyword(s):  
Silver Nanoparticles ◽  
Filamentous Fungi ◽  
Entomopathogenic Fungi ◽  
Antimicrobial Agents ◽  
Insect Pests ◽  
Insect Control ◽  
Biological Synthesis ◽  
Biological Methods ◽  
Potential Use

Silver nanoparticles are widely used in the biomedical and agri-food fields due to their versatility. The use of biological methods for the synthesis of silver nanoparticles has increased considerably due to their feasibility and high biocompatibility. In general, microorganisms have been widely explored for the production of silver nanoparticles for several applications. The objective of this work was to evaluate the use of entomopathogenic fungi for the biological synthesis of silver nanoparticles, in comparison to the use of other filamentous fungi, and the possibility of using these nanoparticles as antimicrobial agents and for the control of insect pests. In addition, the in vitro methods commonly used to assess the toxicity of these materials are discussed. Several species of filamentous fungi are known to have the ability to form silver nanoparticles, but few studies have been conducted on the potential of entomopathogenic fungi to produce these materials. The investigation of the toxicity of silver nanoparticles is usually carried out in vitro through cytotoxicity/genotoxicity analyses, using well-established methodologies, such as MTT and comet assays, respectively. The use of silver nanoparticles obtained through entomopathogenic fungi against insects is mainly focused on mosquitoes that transmit diseases to humans, with satisfactory results regarding mortality estimates. Entomopathogenic fungi can be employed in the synthesis of silver nanoparticles for potential use in insect control, but there is a need to expand studies on toxicity so to enable their use also in insect control in agriculture.

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