Cationic
carbosilane dendrimers are branched molecules with antimicrobial properties. Their activity has been tested against Acanthamoeba polyphaga, a causative agent of
Acanthamoeba keratitis, a severe ocular disease in humans. A. polyphaga trophozoites and
cysts were exposed to different noncytotoxic cationic
carbosilane dendrimers with proven antiamoebic activity. The effects of treatment on cell surface and cell ultrastructure were examined by scanning and transmission electron microscopy, respectively. Two of the
dendrimers tested induced dramatic alterations of cellular ultrastructure in both trophozoites and
cysts, including vacuolization, depletion of cytoplasmic contents, and reduced cell size. Additionally, we observed severe alterations of the plasma membrane with membrane blebbing in trophozoites and disruption in
cysts. These alterations were also observed with
chlorhexidine, a
drug used for treatment of
Acanthamoeba keratitis. Our results support that these compounds may target membranes, and their action is critical for parasite integrity.