Towards simulation of a bioreactor environment for biofabricated tissue maturation

Bioprinting of tissues and organs can be defined as layer-by-layer additive robotic biofabrication of three-dimensional functional living macrotissues and organ constructs using tissue spheroids as building blocks. The microtissues and tissue spheroids are living materials with certain measurable, evolving and potentially controllable composition, material and biological properties. Closely placed tissue spheroids undergo tissue fusion, a process that represents a fundamental biological and biophysical principle of developmental biologyinspired directed tissue self-assembly. After the tissue spheroids structuring, the tissue/organ newly made is then carried out into a bioreactor which should play an important role of providing an adequate environment to the growth and maturation of the bioproduct. Bioreactors are used to accelerate tissue maturation through the control of their mechanical, biochemical and electrical conditions. First of all, they should maintain the viability of the engineered tissue. Following, they are many times employed as equipment to the cell seeding and can be also applied to experimental and monitoring of maturation processes. The creation of a representative environment inside the bioreactor is too complex since it can enclose a large range of variables. Simulating this scenery is essential to the study. The success of tissues and organs bioprinting is straight linked to a set of an appropriate environment in the bioreactor that assures the feasibility, maturation, biomonitoring, tests, storing and transport of the involved elements on the generation of the new tissue such as the deposited cells and nutrients. As an example, the perfusion and fluid diffusion phenomena within the organs in maturation process in bioreactor is fundamental for understanding of the phenomenon. On the other hand, computational fluid dynamic software packets have been increasingly developed during the past decade and are powerful tool to calculate flow fields, shear stresses and mass transport within and around 3D constructs, including a bioreactor environment. This work presents a preliminary study that reproduces elements included in the bioreactor approach with some variables considered at the simulations based on the finite element method running on Ansys CFD software.