Borate modified bioglass containing scaffolds for dental tissue engineering applications

Moonesi Rad, Reza
Dental tissue engineering has gained increasing attention in recent years. Dentures or implants are used as replacements of the lost teeth. High cost of these restorations and rejection possibility of the implants are their main drawbacks. For this reason, a regenerative approach for repairing of the damaged dentin-pulp complex or generating a new tissue is needed. The properties associated with bioglass like biocompatibility and bioactivity are very attractive for dental applications. In this thesis, bioactive glass nanoparticles (BG-NPs) modified with borate at different ratios (7%, 14%, and 21%) were synthesized using combination of sol-gel/co-precipitation and quick alkali-mediated sol-gel methods. Their effect on the odontogenic differentiation of human dental pulp stem cells (hDPSCs) was investigated. Additionally, 3D cellulose acetate/pullulan/gelatin (CA/PULL/GEL) based dentin-like constructs containing 10 or 20% BG-NPs was studied to explore their potential for dentin regeneration. SEM and XRD analyses showed that synthesized BGs were nano-sized and amorphous in nature, respectively. Characteristic functional groups of BGs were observed in FTIR and FT-Raman spectral analysis. ICP analysis revealed that BGs synthesized possessed the expected and compositions close to the theoretical ones. The purpose of modification of bioglass with borate was to achieve increased biodegradability. Increase of B2O3 in BG content positively affected the bioactivity of BG. Higher ion release in SBF resulted in higher amounts of calcium phosphate deposited on BG discs. Three-dimensional porous scaffolds with tubular pore structures were successfully produced using two methods: thermally induced phase separation/porogen leaching (TIPS/PL) and freeze-drying/metal mold pressing (FD/MMP) and crosslinked with glutaraldehyde. KCl was added as porogen for increasing porosity of the scaffolds in TIPS/PL method. Bioactivity tests showed apatite like depositions on scaffolds. BG addition enhanced bioactivity of the scaffolds. Furthermore, borate modification resulted in higher deposition than observed in scaffolds with BG. Scaffolds without BG possessed the highest porosity percentage. Addition of 10% BG improved the mechanical properties of scaffolds. For cell culture studies hDPSCs were isolated from patient’s extracted tooth and flow cytometry analysis showed that isolated hDPSCs were mesenchymal origin. 6.25 mg/ml was chosen as the optimum BG concentration from dose dependent cytotoxicity study and used for differentiation tests. All of BG groups enhanced odontogenic differentiation of hDPSCs and presence of borate increased cell viability. hDPSCs proliferated on scaffolds prepared by both methods and presence of borate modified BGs increased cell viability observed on scaffolds. Immunohistochemical and histochemical stainings showed that scaffolds positively affected the odontoblastic differentiation of the hDPSCs. In this thesis, results showed that borate modified BG-NPs and dentin-like constructs hold promise for use in dental tissue engineering applications.
Citation Formats
R. Moonesi Rad, “Borate modified bioglass containing scaffolds for dental tissue engineering applications,” Ph.D. - Doctoral Program, Middle East Technical University, 2018.