Fig. 9.

Developmental tissue engineering scaffold requirements. (A) Diffusion of nutrients and oxygen for cell survival as well as soluble factors fundamental for epithelial-mesenchymal interactions. (B) Possibility for cells to remodel the artificial ECM and correctly organize in space to develop the regenerated tissue/organ. (C) Biodegradability of the scaffold that should be, in time, substituted with the newly formed ECM of the mature tissue/organ. (D) Adequate mechanical properties. (E) Promotion of vascularization and innervation to allow for the mature tissue/organ survival and functionality. Epithelial and mesenchymal cells are depicted in yellow and green; light blue lines represent a generic 3D developmental tissue engineering scaffold.