Dhakshinamoorthy PG. Biosynthesis of silver nanoparticles using

In previous studies, pomegranate juice and its ellagitannins inhibited proliferation and induced apoptosis in HT- 29 colon cancer cells. reported that ellagitannins inhibit the COX-2 (cyclooxygenase; COX-1 and COX-2), AKT (Protein Kinase B) NF-κB (Nuclear Factor Kappa-B) into the anticancer mechanism in the HT- 29 human colon cancer cell line and provide a direction for future studies into its role in the treatment and prevention of colon cancer. The pomegranate juice, seed, peel extract can also be considered as a natural reducing and capping agent to produce various biogenic nanoparticles i.e., silver (). It also provides a direction for future studies of this plant derived nanoparticles by drug formulation its role in the treatment of various diseases.

of silver nanoparticles using Cymbopogan Citratus (Dc) Stapf. Extract

of silver nanoparticles using tea leaf extract and evaluation of their

David E. Extracellular synthesis of silver nanoparticles using leaves

Abstract:
Biofilms are three-dimensional structures that contains billions of genetically identical bacteria submerged in a self-produced extracellular matrix, which protect bacteria from antibiotics and the human immunological defenses. More than 85 % of chronic and/or recurrent human infections are linked to bacterial biofilms. In addition, spore-forming pathogenic bacteria represent an additional community threat because of their intrinsic refractory behavior against antibiotics, phagocytes and their easy utilization in bioterrorist attacks. Therefore, every day the available microbicide arsenal against biofilms and spores becomes scarcer. Accordingly, nano-material biotechnology emerges as a promising alternative for reducing the detrimental effects of microbial-related diseases. Here we describe the development of novel nanostructured coating systems with improved photocatalytic and antibacterial activities. These systems comprise, in one case, layers of SiO2 followed by layers of mesoporous or dense TiO2-anatase, and doping with silver nanoparticles (Ag NPs). In the other case, we developed Copper NPs and its oxides by a chemical method based on a bottom up approach and its stabilization using aminosilanes as surface modifiers. The activity of CuNPs and AgNPs (MNPs) was measured against spores and vegetative (planktonic and sessile) forms of the relevant human pathogens Enterohemorrhagic Escherichia coli (etiological agent of Hemolytic Uremic Syndrome), Listeria monocytogenes (etiological agent of septic abortion), Bacillus anthracis (etiological agent of Anthrax), Clostridium perfringens (etiological agent of food-associated diarrhea and Gas Gangrene), cystic-fibrosis related Pseudomona aeruginosa and methicillin-resistant Staphylococcus aureus ( etiological agent of sepsis and myocardiopathies). The planktonic and sessile growth (measured as the final cellular yield at 600 nm and crystal violet staining, respectively) of each pathogen, as well as the sporocide effect on C. perfringens and B. anthracis spores, was very significant at submillimolar concentrations of MNPs (95 % of vegetative growth inhibition and sporocide effect, p

of silver nanoparticles using Cassia roxburghii DC. Aqueous extract,

Abstract:
Biofilms are three-dimensional structures that contains billions of genetically identical bacteria submerged in a self-produced extracellular matrix, which protect bacteria from antibiotics and the human immunological defenses. More than 85 % of chronic and/or recurrent human infections are linked to bacterial biofilms. In addition, spore-forming pathogenic bacteria represent an additional community threat because of their intrinsic refractory behavior against antibiotics, phagocytes and their easy utilization in bioterrorist attacks. Therefore, every day the available microbicide arsenal against biofilms and spores becomes scarcer. Accordingly, nano-material biotechnology emerges as a promising alternative for reducing the detrimental effects of microbial-related diseases. Here we describe the development of novel nanostructured coating systems with improved photocatalytic and antibacterial activities. These systems comprise, in one case, layers of SiO2 followed by layers of mesoporous or dense TiO2-anatase, and doping with silver nanoparticles (Ag NPs). In the other case, we developed Copper NPs and its oxides by a chemical method based on a bottom up approach and its stabilization using aminosilanes as surface modifiers. The activity of CuNPs and AgNPs (MNPs) was measured against spores and vegetative (planktonic and sessile) forms of the relevant human pathogens Enterohemorrhagic Escherichia coli (etiological agent of Hemolytic Uremic Syndrome), Listeria monocytogenes (etiological agent of septic abortion), Bacillus anthracis (etiological agent of Anthrax), Clostridium perfringens (etiological agent of food-associated diarrhea and Gas Gangrene), cystic-fibrosis related Pseudomona aeruginosa and methicillin-resistant Staphylococcus aureus ( etiological agent of sepsis and myocardiopathies). The planktonic and sessile growth (measured as the final cellular yield at 600 nm and crystal violet staining, respectively) of each pathogen, as well as the sporocide effect on C. perfringens and B. anthracis spores, was very significant at submillimolar concentrations of MNPs (95 % of vegetative growth inhibition and sporocide effect, p

synthesis of silver nanoparticles using Argemone Mexicana leaf extract

Extracellular biosynthesis of silver nanoparticles ..

Several studies have shown that the combination of silver nanoparticles with antibiotics leads to an enhanced effect of the antibiotics against microorganisms., This action is most probably due to an increase in cell wall penetration by these antibiotics with the nanoparticles. Combinations of antibiotics with nanoparticles have many advantages that minimize the side effects of broad-spectrum antibiotics; these benefits include increasing the concentration of the local antibiotic at the target site and facilitating the binding of antibiotics to microorganisms. Moreover, nanoparticle–antibiotic conjugates lower the amounts of both the drugs and the nanoparticles in the dosage; this property reduces the side effects of the medication while increasing its antimicrobial properties. In our study, the synergistic effect of silver nanoparticles with different commercial antibiotics was investigated against six pathogenic microorganisms by using the disc diffusion method. represents the antimicrobial activity of partially purified silver nanoparticles and silver nitrate of the same concentration (1 mM) against S. enterica, E. coli, V. parahaemolyticus, B. anthracis, and B. cereus. The appearance of zones of inhibition indicated that the biosynthesized silver nanoparticles had stronger antimicrobial properties against the tested microorganisms than did silver nitrate when both treatments were used at the same concentration. In addition, the synergistic effect of the antibiotics (lincomycin, oleandomycin, novobiocin, vancomycin, penicillin G, and rifampicin) in conjugation with biosynthesized silver nanoparticles increased the sensitivity of the tested microorganisms. The results show that S. enterica, E. coli, and V. parahaemolyticus () were completely resistant to the antibiotics; however, the addition of the silver nanoparticle solutions to the discs rendered the bacterial strains sensitivity to those discs and thereby resulted in the formation of zones of inhibition (). The maximum increase in fold area has been calculated for antibiotics with silver nanoparticles with respect to standard antibiotics. The average of maximum increase in fold area against the antibiotic-resistant microorganisms S. enterica, E. coli, and V. parahaemolyticus () observed in this study was highest for novobiocin (4.82 fold), then for lincomycin, oleandomycin, and rifampicin (4.23 fold), then for vancomycin (3.98 fold), and finally for penicillin G (3.66 fold). Various researchers have demonstrated the combined effect of biosynthesized silver nanoparticles with commercial antibiotics.,, The results demonstrate that the silver nanoparticles obtained by B. frigoritolerans DC2 enhance the antimicrobial activity of commercial antibiotics against S. enterica, E. coli, and V. parahaemolyticus.

for the synthesis of silver nanoparticles using plant extracts, ..

Title of Talk: Plant-mediated biosynthesis of silver nanoparticles by leaf extracts of Lasienthra africanum and a study of the influence of kinetic parameters

of metal nanoparticles using plant extracts.

In the present study, silver nanoparticles were successfully synthesized in the culture supernatant of B. frigoritolerans DC2. The formation of silver nanoparticles by the reduction of AgNO3 was indicated by the color change of the reaction mixture (). As the biosynthesis proceeded over 48 hours, the color changed from light yellow to dark brown. This brown color could be due to the excitation of surface plasmon vibrations; if so, this would indicate the formation of silver nanoparticles in the reaction mixture. On the other hand, no color change was observed in the control flask that contained medium with only the 1 mM AgNO3 solution and had been kept under the same conditions as the other flask (). Because the nanoparticle synthesis was extracellular, the need for downstream processing that would have been otherwise essential for intracellular synthesis was avoided and thereby made the process simpler and more cost-effective. The exact mechanism behind the extracellular synthesis of silver nanoparticles in the supernatant remains to be elucidated. However, reports have suggested that the extracellular enzyme secreted by microorganism in the culture supernatant is responsible for the reduction of silver ions to silver nanoparticles., The study based on extracellular synthesis of silver nanoparticles by Bacillus licheniformis showed that the nitrate reductase enzyme extracellularly secreted by the bacteria in the medium was responsible for the synthesis of silver nanoparticles.