Microfluidic Chip for Odontoblasts in Vitro.

Odontoblast processes, which grow inside dentin tubules, are critical parts of odontoblasts, and they play an important role in dentin hypersensitivity. However, modeling the growth of odontoblast processes in vitro is difficult, which hinders the study of dentin hypersensitivity and other dental diseases. To our knowledge, no technique has yet been developed to induce the growth of odontoblast processes from a cell body in vitro. In the current study, we fabricated a microfluidic chip via soft lithography. The microchannels on the chip can mimic the microstructures of dentin tubules, and the microchambers that connect to the microchannels can be used for odontoblast culture. We successfully induced the growth of odontoblast processes from cell bodies by using this chip. In addition, we designed chips with different microchannel sizes (i.e., 2, 4, 6, and 8 μm) to investigate the relationship between the growth of odontoblast processes and the geometric constraint imposed by microchannels. Experimental results show that the growth of odontoblast processes can be successfully induced by 2 μm channels. However, odontoblasts will migrate in the 4, 6, and 8 μm channels. This finding indicates that 2 μm is the appropriate size for inducing the growth of odontoblast processes in vitro. This value is consistent with the size of dentin tubules in vivo. The fabricated microfluidic chip can serve as a powerful tool for investigating the physiology and pathology of odontoblast processes in the future and developing treatment solutions for dental diseases, such as dentin hypersensitivity.