Development of a mist-based printhead for droplet-based bioprinting of ionically crosslinking hydrogel bioinks
In this paper, a novel droplet-based printhead is developed for 3D bioprinting of ionically crosslinking hydrogel bioinks. Contrary to previous approaches to droplet-based bioprinting, many of which use a liquid crosslinking agent to construct scaffolds, the developed system delivers the crosslinker in mist form within the printhead. A mechanism is developed to remove excess mist within the printhead, which prevents scaffold instability caused by the accumulation of liquid on the printing stage. The developed printhead is compatible with commercial systems and offers good droplet gelation and co-droplet adhesion.
It is shown that the gelation rate can be controlled by adjusting the delivery rate of the mist. As a result, it is shown that the delivery rate of the mist has an impact on the shape fidelity and mechanical properties of the printed constructs. The printability and swelling properties of printed constructs crosslinked using different mist delivery rates are studied. Moreover, the impacts of printing parameters including printhead height, mist outlet pressure and printhead channel dimensions on the mist distribution and therefore the gelation rate within the printhead is investigated.
Additionally, using high-speed imaging, the effects of mist concentration and droplet velocity on the dynamics of droplet impact onto the surface is characterized. Finally, it is shown that the printed constructs using the developed printhead show a low level of cytotoxicity and high level of cell viability. This development advances the applicability of droplet-based bioprinting to construct complex and biocompatible scaffolds for tissue and organ regeneration.
S. Badr, B. MacCallum, E. Madadian, G. Kerr, E. Naseri, D. MacDonald, A. Bodaghkhani, R.A. Tasker, A. Ahmadi,
Development of a mist-based printhead for droplet-based bioprinting of ionically crosslinking hydrogel bioinks,
Bioprinting, Volume 27, 2022, e00207, ISSN 2405-8866,
https://doi.org/10.1016/j.bprint.2022.e00207.