Desenvolvimento de uma nova plataforma Organ-on-a-Chip para a biomimetização do microambiente da medula óssea

Abstract

Around the world, Drug research and development faces a situation of low efficiency in their projects. The biggest contribution to this is the utilization of standard cell culture plataforms in vitro and animal models. In this scenario, the Organ-on-a-chip technology, based on microfluidics and tissue engineering, emerges as a promising platform for the in vitro biomimicking organs, including bone marrow. The main objective of this thesis is to design a microphysiological system based on marrow histology and microarchitecture with focus on the study of cell behavior under physiological and pathological conditions, mainly the study of acute lymphocytic leukemia. For this purpose, the first step of this project was the geometry microdevice conceptualization. The next step was to verify the microdevice as a platform capable providing physiological and fluid perfusion conditions analogous to what the marrow cells experience in vivo. The flow velocity profile and the oxygen distribution were calculated from the implementation of the computational model using the finite element software Comsol Multiphysics® v5.6, specifically through the system of equations of transport phenomena and cell dynamics. For the construction of the computational model, the hydrogel matrix representative hydraulic parameter of porosity was calculated using a scanning electron microscope and the free software ImageJ. After the simulation, the microdevice was manufactured using microfabrication techniques based on 3D printing in acrylic resin and molding by soft lithography, with polydimethylsiloxane as the base material. As this microfabrication method is relatively new in Organ-on-a-chip applications, two steps were performed, one to evaluate the generated patterns, through measurements using an electronic magnifying glass and a profilometer, and then the verification if the material is cytotoxic, using a test that measures cellular metabolic activity. At the end, a preliminary study of three-dimensional static cell culture was carried out on the new microphysiological platform. Jy cells that emulate the leukemia cells of acute lymphocytic leukemia were cultured in a standard type I collagen matrix, where cell viability and morphology were evaluated. The obtained results indicate that the protocols and the computational model implemented for the project of the microphysiological system generated a biomimetic platform that provides the cells with a mechanical, physical and biochemical microenvironment with biological relevance, configuring itself as a first approach for the representation of what they experience in vivo in the bone marrow. The platform denoted by Integrated Marrow Niches-on-a-chip may prove to be a useful tool for drug screening and the study of new therapeutic approaches acute acute lymphocytic leukemia.