Comparative Study on Different Concentration of Hydrogel-based Scaffolds and Dental Stem Cell for the Development of Patient-specific 3D Printing Bioink

Objectives: Recently, 3D printing technology using stem cell as 'bioink' has offered a greater reproducibility and user-controllability compared with other tissue model. Therefore, the purpose of this study is to evaluate the potential use of patients' own dental stem cells in combination with scaffold as '3D printing bioink' to reproduce more accurate, dynamic in-vivo like environment that occurs during early stages of healing in the peri-implant region.
Methods: Periodontal ligament stem cell line obtained from healthy subjects were used in this study. Then, injectable hydrogel-based scaffolds were mixed with PDL cell line and resultant mixture were placed onto machined titanium disc under osteogenic induction medium. Conventional cell seeding procedure on titanium disc was also performed. In vitro assessment including Scanning electron microscope (SEM), quantitative RT-PCR was performed at different time scales. The potential use of '3D printing bioink' with different concentration of hydrogel-based scaffolds and PDL stem cell was then evaluated by comparing the results with that of conventional cell seeding procedure.
Results: Even distribution of the cells with uniformed cell to cell distance and better cytocompatibility were observed when '3D printing bioink' was applied onto titanium discs whereas cells were sparsely identified with conventional cell seeding procedure. Concentration-dependent effects of hydrogel-based scaffolds were also identified. The results of quantitative analysis using RT-PCR also revealed that more reliable, reproducible results were identified with 3D environment than with conventional cell seeding procedure.
Conclusions: Patient's own dental stem cells in combination with scaffold can be successfully used as future 3D priting bioink and further utilized for development of more reliable patient-specific in vitro assessment tools for the evaluation of implant surface.