Green biosynthesis of silver nanoparticles by Aspergillus niger and its antiamoebic effect against Allovahlkampfia spelaea trophozoite and cyst

Fungi represent an interesting candidate for the synthesis of nanoparticles. The biosynthesis of silver nanoparticles (AgNPs) has many industrial and biomedical indications. We aimed in this work to biologically synthesize silver nanoparticles using Aspergillus niger and to evaluate its effect against the newly identified Allovahlkampfia spelaea that causes resistant human keratitis. Aspergillus niger (soil isolate) was treated with silver nitrate to produce silver nanoparticles. AgNPs were characterized by Ultraviolet–Visible Spectroscopy, Transmission Electron Microscopy, and Fourier Transform Infrared Spectroscopy. The effect of the synthesized nanoparticles against Allovahlkampfia spelaea growth, encystation, excystation, and toxicity in host cells was evaluated. AgNPs exhibited significant inhibition of Allovahlkampfia spelaea viability and growth of both trophozoites and cysts, with a reduction of amoebic cytotoxic activity in host cells. AgNPs may give a promising future to the treatment of Allovahlkampfia spelaea infections in humans. [Display omitted] •Allovahlkampfia spelaea is a newly identified human parasite causing resistant keratitis.•Silver nanoparticles were biologically synthesized using Aspergillus niger; to investigate their antiparasitic effect against Allovahlkampfia spelaea.•They exhibited a significant inhibition of A. spelaea growth and viability of both trophozoites and cysts.•AgNPs could be a promising future in the treatment of human keratitis caused by this organism.