Abstract
ZnO nanoparticles have an advantage over soluble polymers as drug carriers because they can remain in the body for considerable periods of time. Many studies have demonstrated that Zinc Oxide (ZnO) nanoparticles hold promise as anti-cancer agents. The mechanism for cytotoxicity caused by ZnO is not completely understood. The toxic effect of ZnO nanoparticles with a mean diameter of 20 nm was investigated for the heart tissue of male Wistar rats. Microscopic examination revealed that the nanoparticles caused tissue damage and resulted in alterations. The results demonstrated the toxicity of ZnO nanoparticles and showed that nanoparticle dosage is a critical factor that influences their toxic effects.