Biogenic antimicrobial silver nanoparticles produced by fungi

• Published in: Applied microbiology and biotechnology 2013, Vol.97 (2), p.775-782
• Main Authors: Rodrigues, Alexandre G., Ping, Liu Yu, Marcato, Priscyla D., Alves, Oswaldo L., Silva, Maria C. P., Ruiz, Rita C., Melo, Itamar S., Tasic, Ljubica, De Souza, Ana O.
• Format: Article
• Language: English
• Subjects: Anti-Bacterial Agents - chemistry; Anti-Bacterial Agents - metabolism; Anti-Bacterial Agents - pharmacology; Antimicrobial agents; Applied Microbial and Cell Physiology; Aspergillus - metabolism; Aspergillus tubingensis; Biomedical and Life Sciences; Bionectria ochroleuca; Biotechnology; Candida; Coasts; E coli; Electrophoresis; Filtrate; Fungi; Gram-positive bacteria; Hypocreales - metabolism; Life Sciences; Metal Nanoparticles - chemistry; Microbial Genetics and Genomics; Microbiology; Microorganisms; Nanoparticles; Pathogens; Pseudomonas aeruginosa; Pseudomonas aeruginosa - drug effects; Silver; Silver - metabolism; Studies; X-ray diffraction; Zeta potential
• ISSN: 0175-7598; 1432-0614
• DOI: 10.1007/s00253-012-4209-7

Aspergillus tubingensis and Bionectria ochroleuca showed excellent extracellular ability to synthesize silver nanoparticles (Ag NP), spherical in shape and 35 ± 10 nm in size. Ag NP were characterized by transmission electron microscopy, X-ray diffraction analysis, and photon correlation spectroscopy for particle size and zeta potential. Proteins present in the fungal filtrate and in Ag NP dispersion were analyzed by electrophoresis (sodium dodecyl sulfate polyacrylamide gel electrophoresis). Ag NP showed pronounced antifungal activity against Candida sp, frequently occurring in hospital infections, with minimal inhibitory concentration in the range of 0.11–1.75 μg/mL. Regarding antibacterial activity, nanoparticles produced by A. tubingensis were more effective compared to the other fungus, inhibiting 98.0 % of Pseudomonas. aeruginosa growth at 0.28 μg/mL. A. tubingensis synthesized Ag NP with surprisingly high and positive surface potential, differing greatly from all known fungi. These data open the possibility of obtaining biogenic Ag NP with positive surface potential and new applications.