Graphene Induces Osteoblastic Differentiation on Substrates With Tunable Stiffness

Objectives: To investigate the potential of graphene to induce osteogenic differentiation of dental pulp stem cells (DPSC) seeded on substrates with different modulus of elasticity.
Methods: Single layer graphene was manufactured on by chemical vapour deposition (CVD) at 1000 °C within a mixture of hydrogen and methane. The graphene was deposited on polydimethylsiloxane (PDMS) films prepared with different proportions of Sylgard 184 and 527 (5:1, 1:1 and 1:5). DPSC were seeded on PDMS and graphene-coated PDMS (Gp-PDMS) and maintained with basal culture medium. After 10 days, the genetic expression of bone-related genes (JUNB, RUNX2, COL-I and OCN) and mechanical sensitive genes (integrin α5, vinculin, FAK, LYN, SMAD1 and MYH10) were evaluated by RT-PCR (n=9, each group). Statistical analysis was performed with Mann–Whitney test (a=0.05).
Results: Graphene-coated PDMS increased the gene expressions of JUNB, RUNX2, COL-I and OCN as compared with non-coating group (p<0.05). Notably, the OCN gene expression increased by 6 folds in 5:1 and 1:1 compared with PDMS alone. Similar significant increases were observed for integrin α5, vinculin, FAK, LYN, SMAD1 and MYH10.
Conclusions: Single layer graphene can increase the expression of the genes studied disregarding the stiffness of underlying PDMS substrate.