The Influence of Metalized Graphene Oxide/Reduced Graphene Oxide and Sulfonated Polystyrene on Dental Pulp Stem Cell Differentiation and Protein Adsorption

Human dental pulp stem cells (DPSCs) can differentiate, showing potential for regenerative medicine. Designing artificial surfaces with properties appropriate for the initiation of extracellular matrix (ECM) adsorption and organization is a critical step in tissue engineering and can greatly impact protein adhesion. Sulfonated polystyrene (SPS), used as a scaffold for tissue development, stimulates protein adsorption due to the increased negative charge of sulfonate. Graphene and graphene oxide (GO) sheets enhance stem cell growth and differentiation because they are soft membranes with high in-plane stiffness and have the potential to be transferable and implantable platforms. This project functionalized GO and reduced GO (RGO) with gold or silver nanoparticles, mixing with SPS to investigate their combined impact on DPSC differentiation and protein adsorption, hypothesizing that this combination supplies more charges to better absorb the proteins to the surface and stimulate differentiation. Results indicate that proteins of cells plated on the gold-RGO/SPS surfaces were the most highly adsorbed and most densely packed. Additionally, the cell moduli data indicated that the metal-RGO solutions substantially induced a change in modulus even more than Dexamethasone, a glucocortoid known to enhance this process in DPSCs. This suggests that the metal-RGO solutions may be instrumental in osteogenic induction.