Perfusion 3D Bioprinting with Gelatin and Hydrogel for Vascular Tissue Engineering

Abstract

Vascular disease is one of the leading causes of morbidity and mortality in developed countries, and thereby necessitates the replacement of diseased artery or vein through surgical intervention. Tissue engineering offers an alternative approach of designing biomaterials for small diameter artery regeneration. Vascular graft infections occur infrequently, with an incidence that varies by surgical site but in general ranges from 0.5% to 6%. Infections of vascular grafts are associated with significant mortality and morbidity risk. Vascularization is also a major problem in tissue engineering, especially for engineering tissues that are thicker than approximately 200 μm. Insufficient vascularization limits the oxygen and nutrient transfer to cells, which can lead to hypoxia and formation of non-uniform tissue structures. Vasculature-like structures are usually multilayer and hollow. They have a complex shape with varying diameters throughout the body. Thus, it is quite difficult to imitate this complex 3D structure using materials similar to native vessels such as hydrogels. Though a few techniques have been explored to fabricate this complex 3D structure, direct bioprinting of such a complex 3D structure on a solid platform in a single step has not been realized. Natural vascular tissues serve as a unique experimental tool for investigating fundamental mechanisms of vascular function and maturation process under 3D flow conditions. The methods have great potential in vascularized tissue fabrication as the vascular channel is simultaneously created while cells and matrix are printed around the channel in desired 3D patterns