Cellular Nanofiber Structure with Secretory Activity-Promoting Characteristic for Multicellular Spheroid Formation and Hair Follicle Regeneration.

Multicellular spheroid can mimic the in vivo microenvironment and maintain the unique functions of tissues, which has attracted great attention in tissue engineering. However, the traditional culture microenvironment with structural deficiencies complicates the culture and collection process and tends to lose the function of multicellular spheroids with the increase of cell passage. In order to construct efficient and functional multicellular spheroids, in this study, a chitosan/polyvinyl alcohol nanofiber sponge which has an open-cell cellular structure is obtained. The hair follicle regeneration model was employed to evaluate hair follicle inducing ability of dermal papilla (DP) multicellular spheroids which formed on cellular structure nanofiber sponge. Through the structural fine-tuning, the nanofiber sponge has appropriate elasticity for creation of a 3D dynamic microenvironment to regulate cellular behavior. The cellular structure nanofiber sponge tilts the balance of cell-substratum and cell-cell interactions to a state, which is more conducive to the formation of controllable multicellular spheroids in a short time. More importantly, it improves the secretory activity of high-passaged DPCs and restores its intrinsic properties. Experiments using BALB/c nude mice show that cultured DP multicellular spheroids could effectively enhance hair follicle inducing ability. This novel system provides a simple and efficient strategy for multicellular spheroids formation and hair follicle regeneration.