▎ 摘　　要

Graphene, a single sp(2) bonded carbon, is now a burgeoning interest with various fascinating properties in a large number of biomedical applications. Consequently, the impact of graphene-based functional nanohybrid and its potential risk to human health have raised considerable public concerns. In this present study, we have synthesized cerium oxide (CeO2) anchored reduced graphene oxide (RGO) nanohybrid and a detailed study on its nanotoxicity profile has also been scrutinized. To confirm the efficient synthesis of nano-CeO2/RGO nanohybrid, the systematic characterization has been carried out using FTIR, Raman and UV-Vis spectroscopic analysis. The successful imprint of CeO2 nanoparticles (NPs) on RGO nanosheet was also evident from the scanning electron microscopy (SEM) and transmission electron microscopy (TEM) micrographs. A dose-dependent in vitro nanotoxicity of the nanohybrid has been assessed by using monocyte macrophage cells-Raw264.7 and colon cancer cells-HCT116 as compared with RGO and CeO2. The results conferred that as compared with single nanostructures (RGO or CeO2), nanohybrid showed excellent biocompatibility and no such prominence morphological alteration of the cell structure. Moreover, after exposure of different nanomaterials to HCT116 cells, the possible cellular interaction was investigated through reactive oxygen species (ROS) measurements using flow cytometry analysis dicholoro-dihydro-fluorescen dia-acetate (DCF) assay. These results conveyed that nanohybrid adapts an oxidative stress mechanism upon cellular interaction where it utilizes the scavenging property of CeO2, which induces the cell proliferation. Overall, the nano-CeO2/RGO nanohybrid exhibits a prolonged biocompatibility and cell viability, which is highly desired for biomedical applications.