Development of Three-dimensional Models of Bone and Oral Mucosa

Objectives: To develop and characterise three-dimensional tissue-engineered models of bone and oral mucosa in order to construct a full-thickness composite osteo-mucosal model.
Methods: Bone cells were expanded in vitro, seeded onto porous hydroxyapatite/tricalcium phosphate (HA/TCP) scaffold discs and cultured in a spinner bioreactor to enhance the nutrient transport. Two different types of bone cells were investigated including primary human osteoblasts and rat osteosarcoma cells. Regular assessments of the bone reconstructs were carried out throughout the study both quantitatively by using PrestoBlue cell viability assay and qualitatively by Scanning Electron Microscopy (SEM).
The oral mucosa model was constructed separately by air-liquid interface culture of oral keratinocytes on fibroblast-populated collagen gels. The engineered mucosa was then transferred and laminated onto the engineered bone surface at the endpoint of its culture to form a full-thickness osteo-mucosal model which was fixed and processed for histological examinations.
Results: PrestoBlue fluorescence spectroscopy showed that the engineered bone remained vital throughout the study if cultured within the bioreactor in a dynamic condition. SEM images showed that bone cells were evenly distributed across the scaffold and progressively expanded in numbers with osteoid-like new bone formation inside the interconnected macro pores.The histological examination of the oral mucosal model showed presence of a continuous multilayer epithelium on top of a connective tissue layer densely populated with viable fibroblasts.
Conclusions: Tissue-engineered models developed in this study resembled the natural bone and oral mucosa and have the potential to be used as relevant models to include both bone and oral mucosa for various in vitro applications including biological evaluation of biomaterials and disease modelling.