Figure 3.

The MTT assay used to test the cytotoxicity of various control liposomal formulations on cervical cancer cells. The cellular toxicity that is induced by control (empty) liposomes of different (a) sizes and (b) charges is represented following an incubation period of 24, 48 and 72 h with HeLa cells. The positively-charged liposomes displayed noticeable toxicity at 48 h exposure and at the same dilution factor that was used for diluting liposomal encapsulated ATO. Neutral liposomes were found to show the least toxicity. Data are presented as mean ± SD of three replicate experiments; ** p < 0.01. PC: phosphatidylcholine.