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Osteocytes, the most abundant cells in bone, are embedded in a mineralized matrix for mechanosensing and regulating of bone remodeling.It has been validated that osteocytes are very sensitive to the changes of biochemical components and mechanical stimulations of the external microenvironment.Previously, we have clarified that the cytoskeleton organization and connexin 43 expressions, which are essential for osteocyte mechanosensing and transduction, has been alternated under microgravity conditions.So it is hypothesized that the mechanosensitivity of osteocyte is changed under microgravity conditions.In order to verify the hypothesis and obtain reliable experimental results, a novel integrated microfluidic device for simulated bone matrix-based osteocyte culture and fluid flow stimulation was constructed and an apparent microgravity level was provided by a special superconducting magnet.Based on this, the mechanosensitivity of osteocytes to fluid flow stress under microgravity conditions could be investigated.Microfluidic device is a promising platform for osteocyte mechanobiology because of its excellent performance in the precise control of fluid perfusion as well as in keeping the organized cells in a tissue-relevant context.The device used in this study was designed using AutoCAD software and fabricated using soft lithopgraphy with polydimethylsiloxane (PDMS).The device with a size of 2×2×0.3 cm2 composed with two-layered functional structures, cell culture layer and control layer.The cell culture layer contains sixteen parallel functional units.Each unit has a middle channel for cell culture, two side channels for fluid perfusion, and two groups of optimized micropillar arrays each located between the cell culture channel and the side channels.The simulated bone matrix composed of type-Ⅰ collagen and hydroxyapatite (Figure 1A and B) was constructed in the cell culture channel using biomineralization method.The control layer with branch channels activated by an external programmed syringe pump was used to generate oscillatory flow with altered frequency and amplification.Four levels of fluid flow stress each with four parallel experiments were conducted simultaneously in one device.This novel microfluidic device provides a specific platform for assessment of mechanosensitivity of osteocytes in apparent microgravity condition provided by the superconducting magnet.