IN THE present study, Nickel oxide (NiO) nanoparticles (NiONPs) were bio-synthesized extracellularly by the fungus Fusarium verticillioides (F. verticillioides) using Nickel Nitrate Hexahydrate Ni(NO3)2.6H2O as a starting material. The formed NiONPs were precipitated in the form of a dark precipitate after adding the fungal filtrate to Ni(NO3)2.6H2O solution. The properties of this formed precipitate were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM) and Fourier transformed infrared (FTIR). The XRD pattern indicated that the NiONPs had a face-centered cubic (FCC) structure and their average crystallite size was found to be 8-17.7 nm. The average particle size found to be 8.5-20.7 nm from TEM image, which was compatible with XRD result. The FTIR analysis bands revealed the chemical composition bonding of the formed nano-NiO compound.
The antifungal activity of the formed NiONPs was tested against some human pathogenic fungi which were isolated from mycotic keratitis patients, inpatient department of ophthalmology hospital, Tanta University, Egypt. The best results obtained against Candida albicans, C. tropicalis and Aspergillus niger where the minimum inhibitory concentration (MIC) was 12.5, 25 and 25 mg/ml, respectively. Further confirmation of NiONPs biological activity was employed by measurement of their concentration at different intervals within skin, blood and liver of experimental animals, showing a promising absorption and washing out rates from mice tissues; these results indicated that the NiONPs did not accumulated within mice bodies.