Figure 5: Dynamic cell culture with different medium flow rates for 7 days. Fluorescence images of MG-63 cell nuclei from the 4 different levels of the in vitro 3D module. Note that the best results for cell survival in the core region (levels 2 and 3) can be observed at perfusion flow rates of 30–45 μL/min. Interestingly, cell death could be detected at a higher flow rate of 60 μL/min, especially on level 4. Fluorescence images: nuclei of vital cells = green, nuclei of dead cells = red (Axio Scope.A1, magnification 10x, bar 100 μm).