scholarly journals Hydrothermal Assisted Synthesis and Biological Evaluation of Biogenic Silver Nanoparticles

Author(s):  
Anthony Ekennia ◽  
Dickson N. Uduagwu ◽  
Njemuwa N. Nwaji ◽  
Olawale J. Olowu ◽  
Obianuju L. Nwanji ◽  
...  

Abstract We report on hydrothermal synthesis of biogenic silver nanoparticles (AgNPs) using aqueous leaf extract of Alchornea laxiflora for threefold applications in antibacterial screening against Escherichia coli and Staphylococcus aureus, tyrosinase inhibition of mushroom tyrosine enzymes with 3,4-dihydroxyphenylalanine as a substrate and photocatalytic degradation of malachite green dye. The mode of action for the tyrosinase application and kinetics of both the tyrosinase and photocatalytic activities were provided. The localized surface resonance bands of the AgNPs were observed within the range of 424 – 435 nm from the electronic spectral analysis. Fourier transform-infrared studies reveal the functional groups of plant metabolites such as phenolic compounds and amines on the nanoparticles. The Energy Dispersive X-ray result reveals the presence of silver and other elemental compositions from the plant extract. X-ray diffraction result showed a face-centred cubic crystalline structure for the AgNPs. The SEM analyses reveal that the nanoparticles are spherical in shape with average size range of 20-52 nm. The AgNPs exhibited a dose dependent tyrosinase inhibition activity with IC50 of 20.83 µg/ml and a competitive mode of inhibition. The results of photocatalytic degradation of malachite green dye depicted rapid photo inspired degradation of 86 % in less than a min and at reaction rate of 0.136 min-1. The silver nanoparticles showed enhanced antibacterial activities compared to the precursors: silver nitrate and aqueous extract of Alchornea laxiflora.

2020 ◽  
Vol 20 (7) ◽  
pp. 4143-4151 ◽  
Author(s):  
Yun Wang ◽  
Xudong Zhang ◽  
Yuzhuo Bai ◽  
Wei Li ◽  
Xu Li ◽  
...  

The current investigation reports the structural and biological evaluation of silver nanoparticles (AgNPs) biosynthesized from the pericarp extract of Cucumis melo L. (muskmelon). The AgNPs were characterized by ultraviolet-visible (UV-Vis) spectrophotometry, XRD (X-ray diffraction), SEM (scanning electron microscopy) and EDAX (energy-dispersive X-ray spectroscopy). The XRD analysis showed that biosynthesized AgNPs were having FCC (face centered cubic) crystalline structures. Further, the SEM and EDAX showed spherically shaped AgNPs having an average size of 25 nm. The AgNPs effectively inhibited the growth of Bacillus subtilis and Escherichia coli. Moreover, the cytotoxic assay of AgNPs revealed effective cytotoxicity against different cancer cells, such as HeLa, HCT-116, PC-3 and Jurkat in a dose reliant way. The cell viability was noticed to range from 50% to 60% with IC50 values ranging from 150 μg/mL to 224 μg/mL. The lower cell viability indicates the toxic effects of biosynthesized AgNPs against these malignant cells. Thus, the current study shows that these biosynthesized AgNPs could be utilized in various medical applications in near future.


Polymers ◽  
2021 ◽  
Vol 13 (13) ◽  
pp. 2033
Author(s):  
Marwa F. Elkady ◽  
Hassan Shokry Hassan

An efficient, environmentally compatible and highly porous, silver surface-modified photocatalytic zinc oxide/cellulose acetate/ polypyrrole ZnO/CA/Ppy hybrid nanofibers matrix was fabricated using an electrospinning technique. Electrospinning parameters such as solution flow rate, applied voltage and the distance between needles to collector were optimized. The optimum homogenous and uniform ZnO/CA/Ppy polymeric composite nanofiber was fabricated through the dispersion of 0.05% wt ZnO into the dissolved hybrid polymeric solution with an average nanofiber diameter ranged between 125 and 170 nm. The fabricated ZnO-polymeric nanofiber was further surface-immobilized with silver nanoparticles to enhance its photocatalytic activity through the reduction of the nanofiber bandgap. A comparative study between ZnO polymeric nanofiber before and after silver immobilization was investigated using X-ray diffraction (XRD), scanning electron microscope (SEM), transmission electron microscopy (TEM), Fourier transform infrared (FTIR) and thermal gravimetric analysis (TGA). The photocatalytic degradation efficiency of the two different prepared nanofibers before and after nanosilver immobilization for malachite green (MG) dye was compared against various experimental parameters. The optimum degradation efficiency of nanosilver surface-modified ZnO-polymeric nanofibers was recorded as 93.5% for malachite green dye after 1 h compared with 63% for ZnO-polymeric nanofibers.


2021 ◽  
Vol 21 (11) ◽  
pp. 5784-5793
Author(s):  
K. Geetha ◽  
R. Udhayakumar

In this study, spinel NiCexFe2–XO4 (x = 0.0 - 0.5) nanoparticles (NPs) was synthesized by microwave combustion technique (MCT) utilizing the fuel of Aloe vera plant extract. The establishment of spinel cubic crystal structure was ensured by powder X-ray diffraction (PXRD) technique. The particles like nanostructured morphology were confirmed by high-resolution scanning electron microscope (HRSEM). Energy dispersive X-ray (EDX) studies confirmed the formation of spinel ferrite structure and ensured that no other elements were present. Magnetic parameters such as remanant magnetisation (Mr), coercivity (He) and saturation magnetization (Ms) were calculated from the magnetic hysteresis (M-H) loops, which exhibited ferromagnetic behaviour. The photocatalytic behavior was investigated by visible light treatment for the photocatalytic degradation (PCD) of rhodamine B (Rh-B) dye and the sample NiCe0.3Fe1.7O4 exhibits higher PCD efficiency (93.88%) than other compositions. The antibacterial activities of gram-positive S. aureus, B. subtilis, gramnegative K. pneumonia and E. coli have been investigated using undoped and Ce3+ substituted NiFe2O4 NPs and observed higher activity, which indicated that, they can be used in the bio-medical applications.


2018 ◽  
Vol 34 (6) ◽  
pp. 3140-3144
Author(s):  
Ritu Vershney ◽  
Komal Chelaramani ◽  
Arpan Bhardwaj ◽  
Nayma Siddiqui ◽  
Suresh Kumar Verma

The synthesis of Ni doped titania (TiO2) nanoparticles were achieved via simple novel sol gel technique, in which Titanium-n-butoxide and NiCl2 were taken as precursors. Effect of different wt% of dopant in TiO2 was studied on photocatalytic degradation of Aniline blue and Toluidine Blue. The study suggested the increased photocatalytic degradation with increased time duration. The synthesized samples were analyzed by surface electron microscopy (SEM) and X-ray diffraction studies. The antibacterial activity was investigated against Gram-positive Staphylococcus aureus bacteriae. Studies revealed that on increasing the dopant concentration, the diameter of zone of inhibition also increased upto 1.5 wt%.


2019 ◽  
Vol 8 (1) ◽  
pp. 590-599 ◽  
Author(s):  
Kaushik Roy ◽  
Ambikesh K. Srivastwa ◽  
Chandan K. Ghosh

Abstract In this report, we present a simple and unexplored procedure for green synthesis of silver nanoparticles featuring exudation of Euphorbia acruensis along with the study of its antibacterial and anticoagulant properties. Analytical techniques like ultraviolet visible spectroscopy (UV-Vis), X-ray diffraction (XRD) and high resolution transmission electron microscopy (HRTEM) were used to analyse the production, crystallinity and morphology of bio-reduced silver nanoparticles. The antibacterial study was performed by following standard disc diffusion method. Most importantly, the anticoagulant and thrombolytic activities of biogenic silver nanoparticles were evaluated by addition of nanoparticles to human blood samples under practical conditions. These green synthesized silver nanoparticles were found to have potent antibacterial, anticoagulant and thrombolytic properties which make them an attractive choice for future medical applications.


2013 ◽  
Vol 57 (8) ◽  
pp. 3688-3698 ◽  
Author(s):  
Soumitra Mohanty ◽  
Prajna Jena ◽  
Ranjit Mehta ◽  
Rashmirekha Pati ◽  
Birendranath Banerjee ◽  
...  

ABSTRACTWith the emergence of multidrug-resistant mycobacterial strains, better therapeutic strategies are required for the successful treatment of the infection. Although antimicrobial peptides (AMPs) and silver nanoparticles (AgNPs) are becoming one of the popular antibacterial agents, their antimycobacterial potential is not fully evaluated. In this study, we synthesized biogenic-silver nanoparticles using bacterial, fungal, and plant biomasses and analyzed their antibacterial activities in combination with AMPs against mycobacteria.Mycobacterium smegmatiswas found to be more susceptible to AgNPs compared toM. marinum. We found that NK-2 showed enhanced killing effect with NP-1 and NP-2 biogenic nanoparticles at a 0.5-ppm concentration, whereas LLKKK-18 showed antibacterial activity only with NP-2 at 0.5-ppm dose againstM. smegmatis. In case ofM. marinumNK-2 did not show any additive activity with NP-1 and NP-2 and LLKKK-18 alone completely inhibited the bacterial growth. Both NP-1 and NP-2 also showed increased killing ofM. smegmatisin combination with the antituberculosis drug rifampin. The sizes and shapes of the AgNPs were determined by transmission electron microscopy and dynamic light scattering. AgNPs showed no cytotoxic or DNA damage effects on macrophages at the mycobactericidal dose, whereas treatment with higher doses of AgNPs caused toxicity and micronuclei formation in cytokinesis blocked cells. Macrophages actively endocytosed fluorescein isothiocyanate-labeled AgNPs resulting in nitric oxide independent intracellular killing ofM. smegmatis. Apoptosis and cell cycle studies showed that treatment with higher dose of AgNPs arrested macrophages at the G1-phase. In summary, our data suggest the combined effect of biogenic-AgNPs and antimicrobial peptides as a promising antimycobacterial template.


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