Current Challenges of Bioprinted Tissues Toward Clinical Translation.

Bioprinting is a recently developed technology that has great potential to manufacture artificial tissues and organs for transplantation. Recent studies have demonstrated promising results of small-scale bioprinted tissues with vascular structure and signs of their particular tissue functions. However, the recreation of a complex and multifunctional vascular network and the limitation of oxygen and nutrient diffusion in a human-scale tissue are still challenges in the current stage of this technology. Bioprinting technology has evolved different approaches to better create vascular networks in a small scale and high resolution. The use of patterned biomaterials and growth factors as well as the coculture of endothelial cells with other cell types has also been used to improve the angiogenesis and decrease the time for vascularization. Finally, the incorporation of materials for providing oxygen and suppressing cellular metabolism provides another strategy to overcome the limitations of oxygen and nutrient diffusion for bioprinted tissues.