| dc.description.abstract | Regeneration of functional dentin remains challenging in regenerative dentistry since it requires a precise control of odontoblast polarization and differentiation. Both biophysical and biochemical factors have been proposed to play critical roles in regulating odontoblast behaviors, while currently there is no feasible platform to examine their effects. Therefore, an in vitro platform which enables the isolation of single biophysical/biochemical factor seems necessary. A gelatin-derived nanofibrous matrix-based micropattern system was developed by combining electrospinning, photolithography and laser ablation techniques. This system provides a clean and biomimetic background that allows for single odontoblast entrapment and observation.
Micropatterns with various biophysical properties were fabricated to examine their influence on isolated human dental pulp stem cells (hDPSCs). Nanofibrous topography promoted a more in vivo-like cell morphology and stronger odontogenic differentiation of single hDPSCs when compared to a smooth topography. A large micropattern size also increased hDPSC differentiation. However, hDPSC polarization wasn’t observed on any of these 2D micropatterns. Therefore, a 3D tubular architecture was generated and hDPSCs were successfully induced to polarize in vitro with a odontoblast-like cell morphology and increased differentiation ability. Afterwards, rotated microenvironments were created and it’s found that gravity was a contributory factor in inducing hDPSC polarization.
In addition, influences of various biochemical factors were explored on the novel platform. Results showed intercellular communication efficiently promoted hDPSC differentiation but failed to enhance hDPSC polarization. Eight types of growth factors, including TGF-β, BMP-2, BMP-4, EGF, HGF, FGF2, Wnt5a and Shh, promoted hDPSC polarization within appropriate concentration ranges, while higher concentrations damaged the cell limitation effect of micropatterns. Besides, rat BMSCs seeded to the NF-MT scaffolds displayed similar polarization behaviors but distinct differentiation capacity with hDPSCs. Moreover, the addition of several inhibitors confirmed that the cytoskeletal integrity and integrin-mediated cell adhesion were prerequisites for hDPSC polarization and differentiation.
In summary, we generated an novel platform for single hDPSC study and successfully induced hDPSC polarization in vitro. This platform allowed us to explore the effects of various biophysical and biochemical factors on hDPSC polarization and differentiation, which may benefit the development of next-generation dentin regenerative strategies. | en |
