Mycosynthesis and characterization of silver nanoparticles and their activity against some human pathogenic bacteria

Abstract

The aim of this study was to biosynthesis silver nanoparticles from the fungus Nigrospora sphaerica isolated from soil samples and to examine their activity against five human pathogenic strains of bacteria viz. Escherichia coli, Proteus mirabilis, Pseudomonas aeruginosa, Salmonella typhi and Staphylococcus aureus using disc diffusion method. The synergistic effect of silver nanoparticles in combination with commonly used antibiotic Gentamycin against the selected bacteria was also examined. The synthesized silver nanoparticles from free-cell filtrate were characterized by using UV-Vis spectrophotometer analysis, Fourier transform infrared spectroscopy (FTIR) and scanning electron microscope (SEM). UV-Vis spectrophotometer analysis showed a peak at 420 nm indicating the synthesis of silver nanoparticles, FTIR analysis verified the detection of protein capping of silver nanoparticles while SEM micrographs revealed that the silver nanoparticles are dispersed and aggregated and mostly having spherical shape within the size range between 20 and 70 nm. The synthesized silver nanoparticles exhibited a varied growth inhibition activity (15-26 mm diam inhibition zones) against the tested pathogenic bacteria. A remarkable increase of bacterial growth inhibition (26-34 mm diam) was detected when a combination of silver nanoparticles and Gentamycin was used. A significant increase in fold area of antibacterial activity was observed when AgNPs in combination with Gentamycin was applied. The synthesized silver nanoparticles produced by the fungus N. sphaerica is a promising to be used as safe drug in medical therapy due to their broad spectrum against pathogenic bacteria.

Silver Nanoparticles as Potential Antibacterial Agents

“…Alteration of membrane permeability and respiration [26,[28][29][30][31][32][33][34][35][36][37][38][39][40][41][42][43][44] …”

“…Alteration of membrane [28,41,47] Listeria monocytogenes Morphological changes, separation of the cytoplasmic membrane from the cell wall, plasmolysis [47] Micrococcus luteus Alteration of membrane [28] Nitrifying bacteria inhibits respiratory activity [31] Pseudomonas aeruginosa Irreversible damage on bacterial cells; Alteration of membrane permeability and respiration [17,28,32,33,36,[41][42][43][44][48][49][50] Proteus mirabilis Alteration of cell wall and cytoplasm. [43,44] …”

Mycosynthesis of silver and gold nanoparticles: Optimization, characterization and antimicrobial activity against human pathogens

“…Because of these advances over other methods, the myco-based extracellular synthesis method is often considered a better resource for higher productivity of nanoparticles (Du et al, 2011;Muhsin and Hachim, 2014).…”

Green synthesis of silver nanoparticles using fresh water green alga Pithophora oedogonia (Mont.) Wittrock and evaluation of their antibacterial activity

“…The use of environmentally benign materials like plant extract (Sinha and Paul 2014), bacteria (Seshadri et al 2012), fungi (Muhsin and Hachim 2014) and marine algae (Kannan et al 2013) for the synthesis of silver nanoparticles offers numerous benefits of eco-friendliness and compatibility for pharmaceutical and other biomedical applications as they do not use toxic chemicals for the synthesis protocol. Green synthesis are found to be superior over physical and chemical method as it is economically feasible, environmental friendly, scaled up for mass-scale production without any complexity (Goodsell 2004).…”