The rational designed graphene oxide-Fe₂O₃ composites with low cytotoxicity

Novel two-dimensional materials with a layered structure are of special interest for a variety of promising applications. In current research, the nanostructured graphene oxide-Fe₂O₃ composite (GO-Fe₂O₃) was firstly obtained via a carefully elaborated approach of vacuum freeze-drying. The scanning electron microscopy (SEM) and transmission electron microscope (TEM) images revealed that α-Fe₂O₃ nanoparticles loaded well on the surfaces of graphene. A series of characterization were performed to further elucidate the as-obtained nanomaterial's physicochemical properties. These results suggested the current route could be further extended to obtain the other kinds of two-dimensional materials based composites. For the sake of extending the potential application of herein achieved graphene composites, its cytotoxicity assessment on HeLa cells was systematically investigated. CCK-8 assay in HeLa cells treated by GO-Fe₂O₃ showed dose- (1-100μg/ml) and time- (24-48h) dependent cytotoxicity, which was comparable to that of GO. The excess generation of intracellular reactive oxygen species (ROS) induced by these nanomaterials was responsible for the cytotoxicity. TEM analysis vividly illustrated GO-Fe₂O₃ internalized by HeLa cells in endomembrane compartments such as lysosomes, and degraded through autophagic pathway. The detrimental biological consequence accompanied by cell internalization was limited. Based on the above results, it expected to render useful information for the development of new and popular strategies to design graphene-based composites, as well as deep insights into the mechanism of graphene-based composites cytotoxicity for further potential application.