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Chand, et al.
The results for the cylindrical nozzle were
MWSS cylindrical = − 0.76 8.37x+ + 4.75y − (5) confounded due to the drastic changes in mass flow
19.94x + 2 5.74xy − 6.07y 2 rate, and hence, further simulations with a constant mass
flow rate are needed. Three-dimensional simulations of
4. Conclusions the bioink thread profile under experimental conditions,

Our aim was to investigate the effect of crucial bioprinting simulations involving cells, and experimental verification
parameters – nozzle geometry, nozzle diameter, inlet of the results to validate the usefulness of the computational
pressure, and bioink rheology, specifically, shear-thinning simulation are proposed as future work.
properties – on the MWSS and thus cell viability through Acknowledgments
computational simulation. In addition, we simulated the
effect of printing speed on the thread profile along with Beni Shimwa Muhire acknowledges NYU Abu Dhabi’s
outlet velocity and pressure. The main conclusions of our Virtual Summer 2021 Visiting Undergraduate Research
study can be summarized as follows: Program for the opportunity to work on this project.
• In general, the MWSS for the tapered conical nozzle
is lower than the conical nozzle, and the cylindrical Funding
nozzle has the lowest MWSS. However, the cells This research received no specific grant from any funding
experience higher shear stress for a greater portion of agency in the public, commercial, or not-for-profit sectors.
the nozzle length in the cylindrical nozzle.
• The flow rate of bioink is crucial in the investigation Conflicts of interest
of shear stress. Higher pressure needs to be applied in
the cylindrical nozzle to attain the same flow rate as The authors declare no conflicts of interest.
the other two nozzles, resulting in higher shear stress. Authors’ contributions
Increasing the pressure is a possible confounding
factor because it increases mass flow rate which R.C. carried out design of experiment, ran steady
decreases the time spent by the cell under high shear and transient simulation, and drafted and revised the
stress. manuscript. B.M. ran steady simulation and cowrote the
• Increasing the nozzle diameter increases mass flow manuscript. S.V. was responsible for ideation, manuscript
rate and decreases the wall shear stress, but it may review and editing, as well as overall supervision.
negatively affect the printing resolution.
• Our findings do not suggest that increasing the inlet References
pressure has a more prominent negative effect than
decreasing the outlet diameter. 1. Vijayavenkataraman S, Yan WC, Lu WF, et al., 2018, 3D
• We demonstrated that computational simulations Bioprinting of Tissues and Organs for Regenerative Medicine.
can be used to generate a thread profile of printed Adv Drug Deliv Rev, 132:296–332.
strand and our simulations suggest that the ideal https://doi.org/10.1016/j.addr.2018.07.004
printing speed is independent of nozzle geometry for 2. Magalhães IP, Oliveira PM, Dernowsek J, et al., 2019,
a constant nozzle diameter at a constant inlet mass
flow rate. Investigation of the Effect of Nozzle Design on Rheological
• We presented empirical relationships based on our Bioprinting Properties Using Computational Fluid Dynamics.
simulations, which would facilitate comparisons Matéria (Rio de Janeiro), 24:714.
amongst different bioinks and experimental setups. https://doi.org/10.1590/s1517-707620190003.0714
Most importantly, the effects of these bioprinting 3. Wang Z, Abdulla R, Parker B, et al., 2015, A Simple and High-
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bioprinting parameters, which would not be possible in https://doi.org/10.1088/1758-5090/7/4/045009
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while bioprinting. As such, the efficiency of bioprinting https://doi.org/10.3390/ijms22083971
processes can be increased and the development of novel 5. Biazar E, Najafi SM, Heidari KS, et al., 2018, 3D Bio-printing
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