Fluid dynamic simulations of a microcavity bioreactor to promote organoid growth

Organoids are complex 3D multicellular tissues used to emulate cellular interactions within an organ. Fluid forces are a key element to grow organoids in vitro, they determine nutrient and oxygen supply, and generate shear stress. During cellular development shear stresses are necessary for organogenesis, proliferation, nutrient delivery and cell signaling. Organoids cultured without fluid in motion lack physiological shear forces and proper nutrient supply. However, organoid bioreactors with large fluid forces generate high shear stress which negatively affects cell viability and growth. Our objective was to design a fluidic device based on microcavity driven flow to provide an environment with physiological shear and improved nutrient supply. We used computer fluid dynamics to simulate cavity velocity as a function of microcavity length, height, and inlet velocity. We were able to simulate the conditions in which we obtained a flow of 0.01-0.1 Pa which allows us to obtain the correct parameters before micro-fabricating the device. After fabricating the device, we used particle image velocimetry of glass micro-beads to confirm the simulation values. In the future, we will culture stem cell organoids inside microcavities and measure their cell proliferations at 0.01-0.1 Pa.