Growth and accelerated differentiation of mesenchymal stem cells on graphene-oxide-coated titanate with dexamethasone on surface of titanium implants

Objective. In this study, the objective is to construct graphene-oxide-coated titanate on titanium foils as drug vehicle to enhance cell proliferation and osteo-differentiation of rat bone mesenchymal stem cells (rBMSCs). Methods. Graphene oxide (GO) sheets obtained using the modified Hummer's method and characterized by AFM were coupled with bioactive titanate on Ti implants (GO-Ti) pretreated by alkali, followed by reduction (rGO-Ti). They were characterized by Raman spectroscopy, XPS, SEM, FTIR and contact angle. After dexamethasone (DEX) was loaded onto them (DEX-GO-Ti and DEX-rGO-Ti), cell proliferation of rBMSCs on them was evaluated by CCK-8 and F-actin staining, and differentiation through alkaline phosphatase activity, mRNA expression, and calcium nodules. Results. The obtained GO sheets were monolayers from AFM. Raman spectra exhibited two prominent peaks at D and G bands, and the I(D)/I(G) ratios increased from 0.96 to 1.68 after reduction. XPS proved the existence of oxygenated functional groups for GO-Ti and the reduction of their intensity for rGO-Ti. From SEM, GO and rGO were evenly coated on nanostructures. DEX-GO-Ti absorbed most amount of DEX and released in a sustained manner. CCK-8 results showed that DEX-GO-Ti showed excellent performance on promoting cell proliferation. RMBSCs on DEX-GO-Ti presented greatly high expression of calcium, proteins and mRNA related to osteogenic differentiation. Significance. GO coated titanate nanostructrues on surfaces of Ti foils by a simple self assembly method, showed excellent vechiles for DEX. The construct promoted proliferation and accelerated osteogenic differentiation of rBMSCs, and would be prosperous for their further applications. (C) 2017 The Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.