Fig. 2

Validation of new MFD and characterization of BMSCs. Micrographs of a organ chamber, b pillars and c resistive channels after photolithography and d picture of MFD with BMSC-CM insert. e Micrograph of seminiferous tubules within organ chamber during culture. f The graph presents the flow rate in resistive channels with different medium levels in the reservoir tank (MATLAB R2018a). Surface plot represents the velocity field inside the microsystem where the red arrows indicate the flow direction (COMSOL Multiphysics v5.6). g Micrograph of passage three spindle-shaped BMSCs adhering to culture plate. h Adipogenic and i osteogenic differentiation of BMSCs (ORO, 20x; ARS, 100x, respectively, *p < 0.01). j Characteristic surface antigenic expression of BMSCs by FCM