A Platform for the Continuous Culture of Endothelial Cells Under Physiological Flow Conditions in Simulated Microgravity

Microphysiological systems (MPS) are valuable in vitro models that recreate the structure and function of human tissues. Specifically, tissue- or organ-on-chips that incorporate microfluidic technology replicate the in vivo mechanical and biochemical environment while enabling real-time monitoring of cellular growth and development. These systems can be particularly useful for spaceflight studies, as they can be sent into space, such as to the International Space Station (ISS), to investigate the impact of space travel on the human body. A major impediment to the success of the MPS is the formation of bubbles, which can be pronounced in microgravity. This paper describes the design, assembly, and operation of a microphysiological cell culture system for use in simulated microgravity (e.g., run on a random positioning machine or clinostat). The incorporation of an orientation-independent bubble trap into the fluidic circuit has been shown to be highly effective for removing air bubbles in microgravity and enabling long-term endothelial cell culture. This closed-loop, orientation-independent microfluidic system can be used for bubble-free operation of tissue chips or organ-on-chips to simulate the combined effects of microgravity and flow or for deployment in space missions.