Abstract
The purpose of this study was to investigate the effects of mesoporous bioactive glass nanoparticle (MBN)/graphene oxide (GO) composites on the mineralization ability and differentiation potential of human dental pulp stem cells (hDPSCs). MBN/GO composites were synthesized using the sol-gel method and colloidal processing to enhance the bioactivity and mechanical properties of MBN. Characterization using FESEM, XRD, FTIR, and Raman spectrometry showed that the composites were successfully synthesized. hDPSCs were then cultured directly on the MBN/GO (40:1 and 20:1) composites in vitro. MBN/GO promoted the proliferation and alkaline phosphatase (ALP) activity of hDPSCs. In addition, qRT-PCR showed that MBN/GO regulated the mRNA levels of odontogenic markers (dentin sialophosphoprotein (DSPP), dentine matrix protein 1 (DMP-1), ALP, matrix extracellular phosphoglycoprotein (MEPE), bone morphogenetic protein 2 (BMP-2), and runt-related transcription factor 2 (RUNX-2)). The mRNA levels of DSPP and DMP-1, two odontogenesis-specific markers, were considerably upregulated in hDPSCs in response to growth on the MBN/GO composites. Western blot analysis revealed similar results. Alizarin red S staining was subsequently performed to further investigate MBN/GO-induced mineralization of hDPSCs. It was revealed that MBN/GO composites promote odontogenic differentiation via the Wnt/β-catenin signaling pathway. Collectively, the results of the present study suggest that MBN/GO composites may promote the differentiation of hDPSCs into odontoblast-like cells, and potentially induce dentin formation.
Highlights
Stem cell-based dentin regeneration may provide an alternative to the conventional conservative treatment of teeth in cases of trauma or caries [1]
field emission scanning electron microscope (FESEM) revealed that spherical mesoporous bioactive glass nanoparticle (MBN) were coated by a planar sheet of graphene oxide (GO) (Figure 1)
GO did not appear to have any effect on the mRNA levels of bone morphogenetic protein 2 (BMP-2) and runt-related transcription factor 2 (RUNX-2) on day 14, whereas the mRNA levels of dentine matrix protein 1 (DMP-1), dentin sialophosphoprotein (DSPP), alkaline phosphatase (ALP), and matrix extracellular phosphoglycoprotein (MEPE) were significantly increased in cells grown on MBN/GO 40:1 and 20:1 composites. These results indicate that GO promoted odontogenic differentiation in Human dental pulp stem cells (hDPSCs) in a manner similar to that observed in the case of osteoblastic differentiation
Summary
Stem cell-based dentin regeneration may provide an alternative to the conventional conservative treatment of teeth in cases of trauma or caries [1]. Gronthos et al [3] transplanted hDPSCs into the subcutaneous cavity of immunocompromised mice and observed the formation of dentin-pulp-like complexes. Since this initial observation, dentin regeneration using hDPSCs has been actively investigated in the field of dentin-pulp tissue engineering. Graphene and its derivatives have excellent biocompatibility and biostability, and have been shown to enhance cell attachment, proliferation, and differentiation in various stem cell studies. Their effects on osteogenic differentiation have been reported in a number of previous studies [9,10]
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