scholarly journals Anti-Bacterial and Anti-Candidal Activity of Silver Nanoparticles Biosynthesized Using Citrobacter spp. MS5 Culture Supernatant

Biomolecules ◽  
2020 ◽  
Vol 10 (6) ◽  
pp. 944
Author(s):  
Aftab Hossain Mondal ◽  
Dhananjay Yadav ◽  
Asghar Ali ◽  
Neelofar Khan ◽  
Jun O Jin ◽  
...  

The present study described the extracellular synthesis of silver nanoparticles (AgNPs) using environmental bacterial isolate Citrobacter spp. MS5 culture supernatant. To our best knowledge, no previous study reported the biosynthesis of AgNPs using this bacterial isolate. The biosynthesized AgNPs were characterized using different techniques like UV-Vis spectroscopy, fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), transmission electron microscopy (TEM), scanning electron microscopy (SEM) equipped with energy dispersive X-ray (EDX). The analysis of UV-Vis spectra revealed absorption maxima at 415 nm due to surface plasmon resonance (SPR) indicated the formation of AgNPs and FTIR spectrum confirmed the participation of proteins molecule in AgNPs synthesis. XRD and EDX spectrum confirmed the metallic and crystalline nature of AgNPs. TEM and SEM showed spherical nanoparticles with a size range of 5–15 nm. The biosynthesized AgNPs showed effective independent as well as enhanced combined antibacterial activity against extended spectrum β-lactamase (ESBL) producing multidrug resistant Gram-negative bacteria. Further, effective antifungal activity of AgNPs was observed towards pathogenic Candida spp. The present study provides evidence for eco-friendly biosynthesis of well-characterized AgNPs and their potential antibacterial as well as antifungal activity.

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.


2020 ◽  
Vol 6 (4) ◽  
pp. 294
Author(s):  
Ezzeldin Ibrahim ◽  
Jinyan Luo ◽  
Temoor Ahmed ◽  
Wenge Wu ◽  
Chenqi Yan ◽  
...  

Biosynthesis of silver nanoparticles (AgNPs) using endophytic bacteria is a safe alternative to the traditional chemical method. The purpose of this research is to biosynthesize AgNPs using endophytic bacterium Bacillus endophyticus strain H3 isolated from onion. The biosynthesized AgNPs with sizes from 4.17 to 26.9 nm were confirmed and characterized by various physicochemical techniques such as Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), UV-visible spectroscopy, transmission electron microscopy (TEM) and scanning electron microscopy (SEM) in addition to an energy dispersive spectrum (EDS) profile. The biosynthesized AgNPs at a concentration of 40 μg/mL had a strong antifungal activity against rice blast pathogen Magnaporthe oryzae with an inhibition rate of 88% in mycelial diameter. Moreover, the biosynthesized AgNPs significantly inhibited spore germination and appressorium formation of M. oryzae. Additionally, microscopic observation showed that mycelia morphology was swollen and abnormal when dealing with AgNPs. Overall, the current study revealed that AgNPs could protect rice plants against fungal infections.


2021 ◽  
Vol 3 ◽  
Author(s):  
Kenneth Ssekatawa ◽  
Denis K. Byarugaba ◽  
Charles D. Kato ◽  
Eddie M. Wampande ◽  
Francis Ejobi ◽  
...  

Antibiotics have been the nucleus of chemotherapy since their discovery and introduction into the healthcare system in the 1940s. They are routinely used to treat bacterial infections and to prevent infections in patients with compromised immune systems and enhancing growth in livestock. However, resistance to last-resort antibiotics used in the treatment of multidrug-resistant infections has been reported worldwide. Therefore, this study aimed to evaluate green synthesized nanomaterials such as silver nanoparticles (AgNPs) as alternatives to antibiotics. UV-vis spectroscopy surface plasmon resonance peaks for AgNPs were obtained between 417 and 475 nm. An X-ray diffraction analysis generated four peaks for both Prunus africana extract (PAE) and Camellia sinensis extract (CSE) biosynthesized AgNPs positioned at 2θ angles of 38.2°, 44.4°, 64.5°, and 77.4° corresponding to crystal planes (111), (200), (220), and (311), respectively. A dynamic light-scattering analysis registered the mean zeta potential of +6.3 mV and +0.9 mV for PAE and CSE biosynthesized nanoparticles, respectively. Fourier transform infrared spectroscopy spectra exhibited bands corresponding to different organic functional groups confirming the capping of AgNPs by PAE and CSE phytochemicals. Field emission scanning electron microscopy imaging showed that AgNPs were spherical with average size distribution ranging from 10 to 19 nm. Biosynthesized AgNPs exhibited maximum growth inhibitory zones of 21 mm with minimum inhibitory concentration and minimum bactericidal concentration of 125 and 250 μg/ml, respectively, against carbapenem-resistant bacteria.


Nanomaterials ◽  
2020 ◽  
Vol 10 (10) ◽  
pp. 2082 ◽  
Author(s):  
Salem S. Salem ◽  
Ehab F. EL-Belely ◽  
Gniewko Niedbała ◽  
Maryam M. Alnoman ◽  
Saad El-Din Hassan ◽  
...  

An endophytic strain of Streptomyces antimycoticus L-1 was isolated from healthy medicinal plant leaves of Mentha longifolia L. and used for the green synthesis of silver nanoparticles (Ag-NPs), through the use of secreted enzymes and proteins. UV–vis spectroscopy, Fourier-transform infrared (FT-IR), transmission electron microscopy (TEM), X-ray diffraction (XRD), and dynamic light scattering (DLS) analyses of the Ag-NPs were carried out. The XRD, TEM, and FT-IR analysis results demonstrated the successful biosynthesis of crystalline, spherical Ag-NPs with a particle size of 13–40 nm. Further, the stability of the Ag-NPs was assessed by detecting the surface Plasmon resonance (SPR) at 415 nm for one month or by measuring the NPs surface charge (−19.2 mV) by zeta potential analysis (ζ). The green-synthesized Ag-NPs exhibited broad-spectrum antibacterial activity at different concentrations (6.25–100 ppm) against the pathogens Staphylococcus aureus, Bacillus subtilis Pseudomonas aeruginosa, Escherichia coli, and Salmonella typhimurium with a clear inhibition zone ranging from (9.5 ± 0.4) nm to (21.7 ± 1.0) mm. Furthermore, the green-synthesized Ag-NPs displayed high efficacy against the Caco-2 cancerous cell line (the half maximal inhibitory concentration (IC50) = 5.7 ± 0.2 ppm). With respect to antibacterial and in-vitro cytotoxicity analyses, the Ag-NPs concentration of 100 ppm was selected as a safe dose for loading onto cotton fabrics. The scanning electron microscopy connected with energy-dispersive X-ray spectroscopy (SEM-EDX) for the nano-finished fabrics showed the distribution of Ag-NPs as 2% of the total fabric elements. Moreover, the nano-finished fabrics exhibited more activity against pathogenic Gram-positive and Gram-negative bacteria, even after 10 washing cycles, indicating the stability of the treated fabrics.


Catalysts ◽  
2021 ◽  
Vol 11 (11) ◽  
pp. 1377
Author(s):  
Chandra Kishore Somasundaram ◽  
Raji Atchudan ◽  
Thomas Nesakumar Jebakumar Immanuel Edison ◽  
Suguna Perumal ◽  
Rajangam Vinodh ◽  
...  

Herein, Sargassum coreanum (marine algae)-mediated silver nanoparticles (AgNPs) were successfully synthesized by a simple reduction method. The synthesized AgNPs were characterized using ultraviolet-visible spectroscopy, attenuated total reflection Fourier transformed infrared spectroscopy, X-ray diffractometry, field emission scanning electron microscopy (FESEM) with energy-dispersive X-ray (EDX) spectroscopy, and high-resolution transmission electron microscopy (HR-TEM) analysis. The acquired colloidal AgNPs were strongly absorbed around 420 nm and displayed brown color under visible light. The XRD pattern of AgNPs exposed their face-centered cubic geometry along with crystalline nature. The HRTEM images of synthesized AgNPs confirmed the mean particle size of 19 nm with a distorted spherical shape, and the calculated interlayer distance (d-spacing value) was about 0.24 nm. Further, the catalytic degradation of methylene blue using sodium borohydride and AgNPs was monitored using UV–vis spectroscopy. The result revealed that AgNPs performed as a superior catalyst, which completely degraded MB in 20 min. The rate constant for MB degradation was calculated to be 0.106 min−1, demonstrating that the marine algae-mediated AgNPs had outstanding catalytic activity. This approach is easy and environmentally benign, which can be applied for environmental-based applications such as dye degradation and pollutant detoxification.


2018 ◽  
Vol 83 (5) ◽  
pp. 515-538 ◽  
Author(s):  
Andreia Corciova ◽  
Bianca Ivanescu

Nanotechnology is one of the most studied domains, and nanoparticle synthesis, especially of silver nanoparticles, has gained special importance due to their properties, biocompatibility and applications. Today, the processes of nanoparticles synthesis tend toward the development of inexpensive, simple, non-toxic and environmentally friendly methods. Thus, the use of plants in the synthesis of silver nanoparticles has attracted considerable interest because biomolecules can act as both reducing and stabilizing agents. This survey aims at discussing the conditions for obtaining silver nanoparticles using plants and their characterization by several methods, such as FTIR and UV?Vis spectroscopy, X-ray diffraction, and scanning and transmission electron microscopy. In addition, it examines some of the most common biological uses of silver nanoparticles: antibacterial, antioxidant and cytotoxic.


Nanomaterials ◽  
2020 ◽  
Vol 10 (2) ◽  
pp. 219 ◽  
Author(s):  
Ezzeldin Ibrahim ◽  
Muchen Zhang ◽  
Yang Zhang ◽  
Afsana Hossain ◽  
Wen Qiu ◽  
...  

Nanoparticles are expected to play a vital role in the management of future plant diseases, and they are expected to provide an environmentally friendly alternative to traditional synthetic fungicides. In the present study, silver nanoparticles (AgNPs) were green synthesized through the mediation by using the endophytic bacterium Pseudomonas poae strain CO, which was isolated from garlic plants (Allium sativum). Following a confirmation analysis that used UV–Vis, we examined the in vitro antifungal activity of the biosynthesized AgNPs with the size of 19.8–44.9 nm, which showed strong inhibition in the mycelium growth, spore germination, the length of the germ tubes, and the mycotoxin production of the wheat Fusarium head blight pathogen Fusarium graminearum. Furthermore, the microscopic examination showed that the morphological of mycelia had deformities and collapsed when treated with AgNPs, causing DNA and proteins to leak outside cells. The biosynthesized AgNPs with strong antifungal activity were further characterized based on analyses of X-ray diffraction, transmission electron microscopy, scanning electron microscopy, EDS profiles, and Fourier transform infrared spectroscopy. Overall, the results from this study clearly indicate that the biosynthesized AgNPs may have a great potential in protecting wheat from fungal infection.


Biomolecules ◽  
2019 ◽  
Vol 9 (9) ◽  
pp. 419 ◽  
Author(s):  
Shreya Joshi ◽  
Savitha De Britto ◽  
Sudisha Jogaiah ◽  
Shin-ichi Ito

The current challenges of sustainable agricultural development augmented by global climate change have led to the exploration of new technologies like nanotechnology, which has potential in providing novel and improved solutions. Nanotools in the form of nanofertilizers and nanopesticides possess smart delivery mechanisms and controlled release capacity for active ingredients, thus minimizing excess run-off to water bodies. This study aimed to establish the broad spectrum antifungal activity of mycogenic selenium nanoparticles (SeNPs) synthesized from Trichoderma atroviride, and characterize the bioactive nanoparticles using UV–Vis spectroscopy, dynamic light scattering (DLS), Fourier transform infrared (FT-IR), X-ray diffraction (XRD), scanning electron microscopy-energy dispersive X-ray spectroscopy (SEM-EDS), and high-resolution transmission electron microscopy (HR-TEM). The synthesized nanoparticles displayed excellent in vitro antifungal activity against Pyricularia grisea and inhibited the infection of Colletotrichum capsici and Alternaria solani on chili and tomato leaves at concentrations of 50 and 100 ppm, respectively. The SEM-EDS analysis of the bioactive SeNPs revealed a spherical shape with sizes ranging from 60.48 nm to 123.16 nm. The nanoparticles also possessed the unique property of aggregating and binding to the zoospores of P. infestans at a concentration of 100 ppm, which was visualized using light microscope, atomic force microscopy, and electron microscopy. Thus, the present study highlights the practical application of SeNPs to manage plant diseases in an ecofriendly manner, due to their mycogenic synthesis and broad spectrum antifungal activity against different phytopathogens.


Author(s):  
AJI JOVITHA AT ◽  
DEIVASIGAMANI B

Objective: The present study attempted to synthesize AgNPs from mangrove bark Rhizophora mucronata and analyze characteristics. The synthesized AgNPs analyzed with UV–vis spectroscopy, high-resolution transmission electron microscopy (HRTEM), and energy-dispersive X-ray (EDX) for confirming the nanoparticles. Methods: The dried R. mucronata bark was powdered and kept in at 55°C for 15 min in a water bath and cooled at room temperature to get the extract. The R. mucronata bark extract was treated with silver nitrate and kept overnight in the dark environment which will turn the solution to dark brown color. The silver nanoparticles were characterized using UV–visible absorption at room temperature. Further characterization was also done with X-ray diffraction, high-resolution transmission electron microscope measurements, and DLS analysis. Results: The synthesized AgNPs were analyzed with various analytical methods that revealed the abundant presence of silver nanoparticles. The UV–vis spectroscopy analysis exposed the surface plasmon resonance peak of 422 nm. High-resolution transmission electron microscopy (HRTEM) analysis indicated the size ranging from 10 nm to 200 nm in diameter and a spherical shaped poly dispersal of the particles. The energy-dispersive X-ray (EDX) and DLS also confirmed the presence of silver atoms. Conclusion: Silver nanoparticles of Rhizophora mucronata bark revealed a well-defined structure and may be used in antimicrobial function in further researches.


2016 ◽  
Vol 8 (1) ◽  
pp. 1523-1532 ◽  
Author(s):  
Sujata D Wangkheirakpam ◽  
Wangkheirakpam Radhapiyari Devi ◽  
Chingakham Brajakishore Singh ◽  
Warjeet S Laitonjam

The leaf extract of Strobilanthes flaccidifolius Nees. was used for the synthesis of silver nanoparticles through a green technique of synthesis. The nanoparticles was characterized by UV-VIS spectroscopy which proves the formation silver nanoparticles. FTIR (Fourier Transmission infra red spectroscopy) study was carried out to assess the biomolecule as indigo precursors, Energy dispersion X-ray analysis(EDX) data further proves it. EPR (Electron paramagnetic resonance technique) shows the free radical in silver neutral state and XRD(X-ray diffraction technique) also repots silver neutral formation.The morphology and the shape of the silver nanoparticles were determined by Scanning electron microscopy(SEM) and Tunneling electron microscopy (TEM).The nanoparticles adopted spherical morphology and the size ranging from 6nm to 54.11nm and average size was determined as 12.15± 5.3nm.The nanoparticles had antimicrobial activity


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