The Role of Titania Surface Coating by Atomic Layer Deposition in Improving Osteogenic Differentiation and Hard Tissue Formation of Dental Pulp Stem Cells

Abstract

Recent studies have focused on modifying implant surface properties to improve bone regeneration and osseointegration. Herein, the role of titania surface coating in enabling dental pulp stem cells (DPSCs) differentiation and hard tissue formation is studied. Atomic layer deposition is applied at lower temperature to coat a nanolayer of titania onto hard and soft polybutadiene substrates without altering their moduli, to probe the effects of surface chemistry and substrate modulus. In the absence of titania, DPSCs prefer to attach and proliferate on the hard substrate, where particle‐like biomineralization is present after 28 days in culture, whereas no biomineralization is observed on the soft substrate. Applying titania surface coating results in the improvement of adhesion and proliferation, regardless of substrate modulus, whereas cell and substrate moduli remain the same as control without titania coating. Furthermore, templated biomineralization is observed given the bone‐like tissue composition by Raman analysis, in consistent with real time‐polymerase chain reaction (RT‐PCR) results showing upregulation of osteopontin (OPN) and bone sialoprotein (BSP), representing osteogenic differentiation. The results indicate that titania surface coating improved the ability to nucleate banded collagen fibers which in turn templated mineral deposits, and further induced the osteogenesis of DPSCs, regardless of its substrate modulus.