Effective cell growth potential of Mg-based bioceramic scaffolds towards targeted dentin regeneration

E Kontonasaki,C Hadjichristou,M Bousnaki,A Bakopoulou,Petros Koidis,E Papachristou,G.S Theodorou,K.M Paraskevopoulos,A Theocharidou,L Papadopoulou,N Kantiranis

doi:10.1515/bjdm-2015-0039

Abstract

New emerging approaches in tissue engineering include incorporation of metal ions involved in various metabolic processes, such as Cu, Zn, Si into bioceramic scaffolds for enhanced cell growth and differentiation of specific cell types. The aim of the present work was to investigate the attachment, morphology, growth and mineralized tissue formation potential of Dental Pulp Stem Cells (DPSCs) seeded into Mg-based glass-ceramic scaffolds with incorporated Zn and Cu ions. Bioceramic scaffolds containing Si 60%, Ca 30%, Mg 7.5% and either Zn or Cu 2.5%, sintered at different temperatures were synthesized by the foam replica technique and seeded with DPSCs for up to 21 days. Scanning Electron Microscopy with associated Energy Dispersive Spectroscopy (SEM-EDS) was used to evaluate their ability to support the DPSCs's attachment and proliferation, while the structure of the seeded scaffolds was investigated by X-Ray Diffraction Analysis (XRD). Zn-doped bioceramic scaffolds promoted the attachment and growth of human DPSCs, while identically fabricated scaffolds doped with Cu showed a cytotoxic behaviour, irrespective of the sintering temperature. A mineralized tissue with apatite-like structure was formed on both Cu-doped scaffolds and only on those Zn-doped scaffolds heat-treated at lower temperatures. Sol-gel derived Zn-doped scaffolds sintered at 890oC support DPSC growth and apatite-like tissue formation, which renders them as promising candidates towards dental tissue regeneration.

Highlights

Scaffold-based approach for dental tissue regeneration involves the use of an appropriate scaffolding material where cells, triggered by specific molecular or environmental cues, become able to “create” tissues of the desired architecture
Ceramic scaffolds consisting of calcium/phosphate glasses, such as β-TCP and HA have been applied for tooth or specific dental tissue regeneration due to their compositional resemblance to hydroxyapatite, the mineral phase of enamel, dentin and cementum, while other bioactive glasses and glass ceramic compositions have shown promising results
Scaffold Morphology The scaffolds derived from the Cu compositions were very brittle and multiple fractured struts and pores were observed in the respective SEM micro-photographs (Fig. 1, a and b)

Summary

Introduction

Scaffold-based approach for dental tissue regeneration involves the use of an appropriate scaffolding material where cells, triggered by specific molecular or environmental cues, become able to “create” tissues of the desired architecture. Ceramic scaffolds consisting of calcium/phosphate glasses, such as β-TCP and HA have been applied for tooth or specific dental tissue regeneration due to their compositional resemblance to hydroxyapatite, the mineral phase of enamel, dentin and cementum, while other bioactive glasses and glass ceramic compositions have shown promising results. Despite the effective use of Mg in bone tissue regeneration, Mg-containing glass-ceramics have been only recently proposed for dental tissue regeneration[6] and have been proven effective to induce differentiation of human mesenchymal stem cells (MSCs) 7. The sustained release of Si and Mg during the gradual degradation of the scaffolds can significantly enhance proliferation, differentiation and bio-mineralization of stem cells as well as human dental pulp stem cells (DPSCs) in vitro[8].

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