The next critical step in fabricating the multilayered hierarchical structure mimicking vascular graft was the coating of the lumen to mimic the tunica intima layer of natural blood vessels. To achieve this, the perfusion technique was employed, which offers a versatile approach for various applications, such as drug delivery, tissue engineering, and organ-on-a-chip systems. The SEM images of the complete three-layered tubular structure, mimicking the vascular grafts are depicted in Figure , showcasing the successful gelatin coating and its attachment to the surface. During the perfusion process, the aim was to ensure that both the surface and pores of the graft were adequately coated with gelatin. Notably, the gelatin solution could penetrate the electrospun layer through the pores in the 3D printing structure, promoting efficient coverage and attachment of gelatin onto the fibers.