Simulation of a 3D Bioprinted Human Vascular Segment

The ultimate goal of bioprinting is the production of living and functional tissue and organs for transplantation in a reasonable time scale. To achieve this goal, the best process would be organ printing. It enables creation of tissue with a high level of cell density; can solve the problem of vascularization in thick tissues; organ printing can be done in situ. Organ printing is a computer-aided 3D tissue engineering of living organs with layer-by-layer deposition of tissue spheroids compounded by pre-sorted cells and hydrogel with principles of self-assembly. This process can be divided in 3 technological steps: i) Development of the design files (blueprint) for the organs; ii) Actual printing; iii) Post processing or organ conditioning and accelerated tissue and organ maturation. This work presents an initial study about the post-processing concerning the maturation phase. It was adopted a clinical image of computer tomography (CT) of a human heart. A branch of this heart was selected and handled. This image was converted into a 3D virtual mesh able to be used in the simulations. Two conditions were considered: a 3D branch formed by spheres analogously to the tissue spheroids representing a fresh organ bioprinted and the second one taking into account the surface of the branches representing a more maturated structure. Some analysis were executed to verify the fusion process among the tissue spheroids when the spheres are under fusion to each other and the distance between them decreased at long the time. Velocity and pressure were analyzed through four selected sections in the vascular branch where there is fluid flow through the spheres that form threedimensionally the structure as a fresh organ bioprinted by a 3D bioprinter.