Objective   To investigate the cytotoxicity among different size of hematite nanoparticles by 50% inhibitory concentration(IC₅₀)and oxidative effects.

  Methods   CHL cell was used in this study.Three sizes of Fe₂O₃ nanoparticles 8, 13, and 37 nm were administered to the cell cultures with different doses and times as experimental groups.The IC₅₀ and growth-inhibitory curves of cells were assayed by cell counting.The concentration of malondialdehyde(MDA)was determined by thiobarbituric acid reactive substance method and the activity of superoxide dixmutase(SOD)was determined by xanthine oxidase method.

  Results   (1) When cells were exposed to three sizes of nanopar ticles respectively within a dose range, the cells inhibitory(CI)rate decreased as the dose increasing with a relationship of dose-effect response, which however disappeared beyond the dose range.(2)Within the range of dose-effect as above, the IC₅₀ of three sizes of nanoparticles were calculated: IC₅₀(8 nm)=279.586 μg/mL, IC₅₀(13 nm)=254.739 μg/ml, IC₅₀(37nm)=56.1237 μg/ml.(3)The hematite nanoparticles can induce the oxidative stress condition in CHL cells in relation to time, but no notable correlation between the index of MDA, SOD and the size and doses.

  Conclusion   There is difference of cytotoxicity among different sizes of hematite nanoparticles.Meanw hile the hematite nanoparticles can induce oxidative stress condition in CHL cell, which maybe correlative to its cytotoxicity according to time and effect relationship.