Biosynthesis of size controlled silver nanoparticles by Fusarium oxysporum, their antibacterial and antitumor activities

Abstract The biosynthesis method is thought to be clean, nontoxic and environmentally acceptable. Many microorganisms produce extracellular or intracellular metal nanoparticles with different efficiency, size and shape. The goal in this study is to control the size of silver nanoparticles. The preliminary screening of microorganisms, Fusarium oxysporum was selected to control size of silver nanoparticles. Parametric optimization showed smallest particle size when F. oxysporum treated with 10 −2   M silver nitrate (metal ion concentration) at 50°C with 11 g wet biomass at pH 6 when fungal age 7 days when incubated for 72 h silver nanoparticles produced was characterized by TEM which revealed the formation of spherical, well-dispersed nanoparticles with size between 5 and 13 nm and FTIR gives the bands at 1619 and 1392.5 corresponding to the binding vibration of amide I and II bands of proteins, respectively. Antibacterial activity against Escherichia coli and Staphylococcus aureus showed maximum zone of inhibition of 2 mm and 1.6 mm, respectively, at 80 µL of silver nanoparticles. Cytotoxic activity was expressed as IC 50 that is found to be 121.23 µg cm −3 .