In vitro effect of AgNP nanoparticles on Acanthamoeba castellani parasite

Keratitis is a vision-threatening corneal infection caused by the protozoan Acanthamoeba castellani, for which there is currently no viable and safe therapy in either people or animals. As a result, more effective and safer anti-amoebic agents are urgently needed. The study aims to determine the effect of silver nanoparticles (AgNPs) on clinical strains of Acanthamoeba spp. 78 Acanthamoeba Keratitis (AK) patients' corneal smear were collected using a sterile swab from different hospitals in Basrah province, Iraq. Silver nanoparticles (AgNPs) were synthesized using Rosmarinus officinalis leaf extract, and used with serial concentrations to evaluate their in vitro cytotoxicity. AgNPs exhibited an absorbance peak at 455 nm. The FTIR analysis identified the chemical constituents in the extract that contribute to AgNP synthesis and surface stabilization. AgNPs displayed a size of 25.70 nm and a Z-average of 106.3 nm using Zeta sizer. The X-ray diffraction (XRD) analysis was comparable to the positions of the standard of Ag and AgO. Zeta potential analysis revealed a peak at -41.7 mV. Field Emission Scanning Electron Microscope (FE-SEM) images demonstrated AgNPs nanoscale with an average size of 40-50 nm. AgNPs showed considerable potential to eliminate both trophozoite and cyst stages of the parasite; trophozoites readily appeared to absorb silver nanoparticles, while cyst stages suffered destruction in their resistant walls.