FIG. 5.

LIVE/DEAD fluorescence images of chondrocytes and viability results. LIVE/DEAD fluorescence image merged with bright-field microscopy images of microgel-encapsulated cells when the end of outlet tubing was kept outside the isolation bag (a) and when the outlet tubing was kept inside the isolation bag (b). LIVE/DEAD fluorescence images of chondrocytes embedded in left-over macrogel after the encapsulation experiment (c). Effects of the oxygen and encapsulation process on cell viability (d): The significant difference between groups where the tubing was left inside and outside of the isolation bag suggests critical effects of oxygen on the cell viability. The non-significant difference of viability between the microgel encapsulated cells and left-over cells in the syringe indicates no negative effects of the microfluidic photocrosslinking process on the cell viability. Note that the viability of cells before the encapsulating process was tested by trypan blue staining. Effects of encapsulation on cell viability (e): Many unencapsulated cells in the collected sample came from the setting up period before applying UV light. These unencapsulated cells had a lower viability than the encapsulated ones, potentially due to the fluid flow shear stress in the microfluidic system or the collision between the microgels and the cells. *p < 0.05. n = 2.