The invention provides for translating two-dimensional microfabrication technology into the third dimension. Two-dimensional templates are fabricated using high-resolution molding processes. These templates are then bonded to form three-dimensional scaffold structures with closed lumens. The scaffolds can serve as the template for cell adhesion and growth by cells that are added to the scaffolds through the vessels, holes or pores. These scaffolds can be formed by layering techniques, to interconnect flat template sheets to build up a fully vascularized organ.