Biofabrication by 3-D printing of bioinks requires that the user adjusts the printing pressure such that the resulting flow through the printing needle matches the speed of movement of the printing head. Because most bioinks are highly shear-thinning, small pressure changes result in large changes of the flow speed. Moreover, the user perhaps needs to know the shear stresses inside the printing needle that act upon the cells.

The research group of Stephan Gekle (Department of Physics, University of Bayreuth) in collaboration with our group (Richard Gerum) has developed a web-based tool (link) to compute the pressure-flow relationship of shear-thinning bioinks as well as the flow and shear stress profile insde the printing needle.

References

S. J. Muller, E. Mirzahossein, E. N. Iftekhar, C. Bacher, S. Schrufer, D. W. Schubert, B. Fabry, S. Gekle
Flow and hydrodynamic shear stress inside a printing needle during biofabrication.
PLoS ONE 15(7): e0236371