Graphene oxide-based substrate: physical and surface characterization, cytocompatibility and differentiation potential of dental pulp stem cells.

Objective: The aim of this study was to evaluate the cytotoxicity and differentiation potential of a graphene oxide (GO)-based substrate using dental pulp stem cell (DPSC).
Methods: GO was obtained via chemical exfoliation of graphite using the modified Hummer's method and dispersed in water-methanol solution. 250μL of 1.5mg/mL solution were added to a cover slip and allowed to dry (25°C, 24h). GO-based substrate was characterized by Raman spectroscopy, AFM and contact angle. DPSC were seeded on GO and glass (control). Cell attachment and proliferation were evaluated by polymeric F-actin staining, SEM and MTS assay for five days. mRNA expression of MSX-1, PAX-9, RUNX2, COL I, DMP-1 and DSPP were evaluated by qPCR (7 and 14 days). Statistical analyses were performed by either Mann-Whitney, one or two-way Anova followed by and Tukey's post hoc analysis (α=0.05).
Results: Peaks at 1587cm(-1) and 1340cm(-1) (G and D band) and ID/IG of 0.83 were observed for GO with Raman. AFM showed that GO was randomly deposited and created a rougher surface comparing to the control. Cells successfully adhered on both substrates. There was no difference in cell proliferation after 5 days. Cells on GO presented higher expression for all genes tested except MSX-1 and RUNX2 for 7 days.
Significance: GO-based substrate allowed DPSC attachment, proliferation and increased the expression of several genes that are upregulated in mineral-producing cells. These findings open opportunities to the use of GO alone or in combination with dental materials to improve their bioactivity and beyond.
(Copyright © 2016 The Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.)