Functionalization of graphene oxide nanosheets can reduce their cytotoxicity to dental pulp stem cells

Background. The dental pulp is a heterogeneous soft tissue that supplies nutrients and acts as a biosensor to identify pathogenic stimuli. Regeneration of the dental pulp is one of the desirable topics for researchers. Graphene oxide nanosheets (nGOs) help overexpression of the genes related to odontogenic differentiation of stem cells from dental pulps and increases attachment and proliferation of dental pulp stem cells. Despite its benefits, nGO may be considered as a threat to the environment and human health. Therefore, the purpose of this study was to evaluate the biocompatibility potential of graphene oxide (nGO), chitosan functionalized graphene oxide (nGO-CS), and carboxylated graphene (nGO-COOH) when exposed to human dental pulp stem cells (hDPSCs). Material and Methods. Some different aspects of biocompatibility of nGO, nGO-CS, and nGO-COOH were synthesized, and several intracellular effects induced by different concentrations of graphene-based nanosheets, including cell viability, intracellular oxidative damages, and various factors such as LDH, GSH, SOD, MDA, and MMP, were studied on hDPSCs. Results. According to results, IC50 was determined as 232.01, 467.81, and ≥1000 μg/mL for nGO, nGO-CS, and nGO-COOH, respectively. These results demonstrated the lower toxicity and higher cytocompatibility of nGO-CS and nGO-COOH compared to nGO. nGO-COOH not only has any adverse effect on the cell membrane and mitochondrial activity but also shows slight antioxidant activity at some concentrations. Conclusion. The findings help design safe and cytocompatible nGO derivatives for biomedical applications in dental fields.