Cellular uptake and toxicity of AU55 clusters

The cellular uptake and cytotoxicity of 4, 12, and 18 nm gold nanoparticles (Au55)in human K562 leukemia cells were investigated. Eleven different cancer and healthy human cell lines were employed for investigating the cytotoxic effects for Au55. In vitro cytotoxicity was investigated by the MIT assay, a calorimetric method according to which a tetrazolium-based compound is reduced in formazan by living cells. It was observed that gold nanoparticles protected with various surface modifiers were not toxic to human cells, despite being takes up into the cells. The metastatic melanomas MV3 and BLM showed the most significant sensitivity to Au55 from the eleven cells examined. The results confirmed a strong toxicity toward various human cancer and healthy cell lines in contrast to larger gold nanoparticles.