Evaluation of the Cytotoxicity and Oxidative Stress Response of CeO2-RGO Nanocomposites in Human Lung Epithelial A549 Cells.

Maqusood Ahamed,M A Majeed Khan,Hisham A Alhadlaq,Mohd Javed Akhtar,Zabnallah M Alaizeri

doi:10.3390/nano9121709

Abstract

Graphene-based nanocomposites have attracted enormous interest in nanomedicine and environmental remediation, owing to their unique characteristics. The increased production and widespread application of these nanocomposites might raise concern about their adverse health effects. In this study, for the first time, we examine the cytotoxicity and oxidative stress response of a relatively new nanocomposite of cerium oxide-reduced graphene oxide (CeO2-RGO) in human lung epithelial (A549) cells. CeO2-RGO nanocomposites and RGO were prepared by a simple hydrothermal method and characterized by relevant analytical techniques. Cytotoxicity data have shown that RGO significantly induces toxicity in A549 cells, evident by cell viability reduction, membrane damage, cell cycle arrest, and mitochondrial membrane potential loss. However, CeO2-RGO nanocomposites did not cause statistically significant toxicity as compared to a control. We further observed that RGO significantly induces reactive oxygen species generation and reduces glutathione levels. However, CeO2-RGO nanocomposites did not induce oxidative stress in A549 cells. Interestingly, we observed that CeO2 nanoparticles (NPs) alone significantly increase glutathione (GSH) levels in A549 cells as compared to a control. The GSH replenishing potential of CeO2 nanoparticles could be one of the possible reasons for the biocompatible nature of CeO2-RGO nanocomposites. Our data warrant further and more advanced research to explore the biocompatibility/safety mechanisms of CeO2-RGO nanocomposites in different cell lines and animal models.

Highlights

Graphene is a single atom thick two-dimensional sheet of sp2 hybridized carbon atoms with multifaceted properties, such as elasticity, flexibility, high conductivity, and ease of functionalization [1,2]
One of the most successful approaches has been the use of graphene derivatives such as graphene oxide (GO) and reduced graphene oxide (RGO)
The phase purity and crystal structure of CeO2 NPs, RGO, and CeO2-RGO nanocomposites were examined by a X-ray diffractometer (XRD, PanAnalytic X’Pert Pro) employing Cu-Kα radiation

Summary

Introduction

Graphene is a single atom thick two-dimensional sheet of sp hybridized carbon atoms with multifaceted properties, such as elasticity, flexibility, high conductivity, and ease of functionalization [1,2]. Despite the great potential of graphene in biomedical applications, its unmodified state has poor solubility in biological media, which makes nanomedicine study in this context complicated [6,7]. Studies on the biological response of metal oxide-based RGO nanocomposites at the cellular and molecular levels are scarce This is the first study that explores the cytotoxic and apoptotic potential of CeO2-RGO nanocomposites in human lung cancer epithelial (A549) cells. Information on the physicochemical properties of CeO2-RGO nanocomposites and their cellular response with possible toxicity mechanisms are critically important to study, in order to outline the potential application of this nanocomposite in the field of biomedicine

Materials and Methods

Characterization

Cell Culture

Toxicity Experiments

Oxidative Stress