Neutral buoyancy as a simple approach to implement microgravity

Abstract It is well recognized that interesting biological phenomena occur in various organisms, including humans/animals, plants, and bacteria, in the microgravity environment of space. However, there are limitations to investigating these phenomena in real space and under conditions simulating microgravity on Earth. In this study, we developed a simulated microgravity system based on neutral buoyancy. It has been demonstrated that this system facilitates the suspension of cell spheroids for sufficient periods for cell culture and effectively replicates the cellular behaviors observed in actual microgravity environments, such as maintenance of stemness and suppression of osteogenic differentiation, with simultaneous promotion of chondrogenic and adipogenic differentiations in stem cells. Therefore, it serves as a simple and effective platform for various microgravity research endeavors.