Fig. 3

Bioprinting of the alginate-based inks. A–F Simulated and printed constructs. The pattern is picked in a way that no contaminants can enter from the top in a direct way. Still, open porosity, yet no direct path is implemented for the 50% filled constructs to retain oxygen permeability. A and D depict the simulated constructs generated in the slicing software from the respective G-Code. A represents the top view, where no direct path through the construct can be perceived. D shows the same constructs at a tilted angle where the open structure can be observed. B and E show the final printed constructs at a filling factor of 50% in the same viewing angles as A and D, showing both the blocked and the open pathways as stated before. C and F show the constructs with complete filling of 100%, with no easy pathways for oxygen or contaminants. G and H are optical micrographs depicting two crossing lines of printed alginate-based ink with 0% and 15% t-ZnO loading, respectively. The insets show a magnification of an individual line. The more jagged contour of the lines in H are caused by protruding t-ZnO arms. I: Graphs of an amplitude sweep for alginate-based inks with 0% to 15% t-ZnO. The moduli increase with the content of t-ZnO. J: Flow curves of alginate-based inks with 0% to 15% t-ZnO. Both static and dynamic yield stress do not change from 0 to 5% t-ZnO content. A significant increase in static and dynamic yield stress can be seen for 15% t-ZnO