Names: Aaron Argyres and Mingu Kim

1. Names: Aaron Argyres and Mingu Kim High Schools: Clayton High School, Clayton, MO and David H. Hickman High School, Columbia, MO Mentor: Dr. Miriam Rafailovich Project Title: Increasing the Proliferation Rate and Inducing Osteogenic Differentiation of Dental Pulp Stem Cells with Graphene/Poly(4-vinylpyridine) Composite Substrates Tissue engineering could replace the established yet inefficient method of bone grafted dental implants, which is susceptible to various problems such as autoimmune rejection and malformation. Dental pulp stem cells (DPSC’s) are viable sources for tissue because of their ease of access and osteogenic differentiation capabilities. Our goal was to bioengineer graphene/poly(4-vinylpyridine) and graphene oxide/poly(4-vinylpyridine) composite substrates to increase the proliferation of DPSC’s and induce differentiation without the use of dexamethasone, a chemical differentiation factor, in a cost-efficient manner. We grew DPSC’s on varying concentrations of graphene/P4VP and graphene oxide/P4VP composites, as well as on pure P4VP and tissue culture plastic, which were controls. For each concentration, samples with dexamethasone were grown as controls for differentiation. Cell growth curves showed a statistically significant increase in cell proliferation by day 8 on the composite polymers of 1%-5% graphene and graphene oxide compared to the control. Furthermore, the cells grown on the graphene/P4VP composites induced biomineralization by day 28 even in the absence of dexamethasone, as shown by scanning electron microscopy. This biomineralization signified osteogenic differentiation. By analyzing atomic force microscopy images of the substrates, we developed possible models that explain our results. With further understanding of cell-substrate interactions, stem-cell based therapy for bone regeneration may become more practical and efficient.