Various embodiments of scaffolds are disclosed herein. In one embodiment, the scaffold includes a tubular polymeric structure, and a controlled gradient of solid-walled microtubules oriented radially or axially in the tubular polymeric structure. In another embodiment, the scaffold includes a nano-fibrous tubular polymeric structure, and an oriented and interconnected microtubular porous network formed in the nano-fibrous tubular polymeric structure. In still another embodiment, a composite scaffold is formed including a polymeric structure having an inner wall and an outer wall, and at least one electrospun layer positioned along at least one of the inner wall, or the outer wall, or in a middle of the porous polymeric structure.