Odontogenic responses of human dental pulp cells to collagen/nanobioactive glass nanocomposites

Objectives. Collagen-based nanocomposite incorporating nanobioactive glass (Col/nBG) was developed as a scaffolding matrix for dentin-pulp regeneration. The effects of the novel matrix on the proliferation of human dental pulp cells (hDPCs) and their differentiation into odontoblastic lineage were investigated. Methods. Nanocomposite scaffold was prepared by incorporating nBG within the Col solution and then reconstituting them into a membrane form. Cell growth by MTS assay, adhesion by scanning electron microscopy (SEM), and odontoblastic differentiation by alkaline phosphatase (ALP) activity, mineralization, and the mRNA expression of differentiation-related genes of DPCs on each scaffold were evaluated. Results. The introduction of nBG significantly improved the bone mineral-like apatite formation in the simulated body fluid, suggesting excellent acellular bone-bioactivity. The hDPCs cultured on the Col/nBG nanocomposite have shown active growth behavior during culture for 14 days. The mRNA levels of major organic extracellular matrix of dentin, collagen type I and III were highly expressed in the Col/nBG matrix. Moreover, the alkaline phosphatase (ALP) activity and the mineralized nodule formation were increased in the Col/nBG nanocomposite compared to those in Col. Odontoblatic differentiation genes, including dentin sialophosphoprotein, dentin matrix protein I, ALP, osteopontin and osteocalcin were significantly stimulated in the Col containing nBG. Moreover, the key adhesion receptor integrin components alpha 2 and beta 1, specifically binding to collagen molecule sequence, were upregulated in Col/nBG compared to Col, suggesting that odontogenic stimulation was closely related to the integrin-mediated process. Significance. In our study, the nanocomposite Col/nBG matrix induced the growth and odontogenic differentiation more effectively than Col alone, providing a promising scaffold condition for regeneration of dentin-pulp complex tissue. (C) 2012 Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.