Toxicity evaluations of superparamagnetic iron oxide nanoparticles: cell "vision" versus physicochemical properties of nanoparticles.

In the last few decades, nanoparticles (NPs) have been recognized as promising candidates for starting a new revolution in science and technology due to their unusual properties, attracting the attention of physicists, chemists, biologists, and engineers. The aim of this study is to evaluate the toxicities (at both cellular and molecular levels) of three forms of superparamagnetic iron oxide nanoparticles (SPIONs) of various surface chemistries (COOH, plain, and NH(2)) through the comparison with gene expression patterns of three cell types (i.e., human heart, brain, and kidney). For this purpose, both an MTT assay and a DNA microarray analysis were applied in three human cell lines--HCM (heart), BE-2-C (brain), and 293T (kidney)--under the exposure to SPIONs-COOH, SPIONs-NH(2), and bare SPIONs. The specific gene alteration and hierarchical clustering revealed that SPIONs-COOH altered genes associated with cell proliferative responses due to their reactive oxygen species (ROS) properties. It was also found that the cell type can have quite a significant role in the definition of suitable pathways for detoxification of NPs, which has deep implications for the safe and high yield design of NPs for biomedical applications and will require serious consideration in the future.