New insights regarding the selectivity and the uptake potential of nanoceria by human cells

Abstract

Lately, cerium oxide nanoparticles (CeO2-NPs, nanoceria) have gained a great interest for applications in diagnose and treatment of many diseases, including cancer. Herein, we have synthesized CeO2-NPs and performed in vitro studies on HeLa (human cervical cancer) and HFL-1 (normal human fetal lung fibroblast) cell lines. The nanosized CeO2-NPs, 6–16nm in diameter, were obtained by a simple, precipitation method. In order to identify the crystalline phases and to estimate the average particle sizes, an X-ray diffraction investigation was performed. The structural and morphological characterization of the nanoceria was assessed by Raman Spectroscopy, Transmission Electron Microscopy (TEM), thermogravimetric analysis, and Zeta potential analysis. The in vitro tests were aimed at studying the CeO2-NPs cellular cytotoxicity, uptake, and ability to induce generation of reactive oxygen species on the HeLa and HFL-1 cells. The results obtained demonstrate a selective behaviour of the CeO2-NP towards both cell lines. The nanoparticles are, to a large extent, internalized in the HeLa cells, while very little nanoceria internalization is observed on the HFL-1 cells. Also, the CeO2-NPs are more cytotoxic to HeLa cells compared to HFL-1. Moreover, the level of reactive oxygen species upon exposure to CeO2-NPs is significantly higher on the HeLa cells. Such findings might have implications in targeted cancer therapies. The more nanoceria exhibit selective properties toward tumor cells and avoid interaction with non-tumor cells, the more potential they have to become an efficient system for targeted drug delivery.