A Modular Three-Dimensional Bioprinter for Printing Porous Scaffolds for Tissue Engineering

Linnea Warburton, Leo Lou, Boris Rubinsky

Research output: Contribution to journalArticlepeer-review

8 Scopus citations

Abstract

Three-dimensional (3D) bioprinting is a fabrication method with many biomedical applications, particularly within tissue engineering. The use of freezing during 3D bioprinting, aka "3D cryoprinting," can be utilized to create micopores within tissue-engineered scaffolds to enhance cell proliferation. When used with alginate bio-inks, this type of 3D cryoprinting requires three steps: 3D printing, crosslinking, and freezing. This study investigated the influence of crosslinking order and cooling rate on the microstructure and mechanical properties of sodium alginate scaffolds. We designed and built a novel modular 3D printer in order to study the effects of these steps separately and to address many of the manufacturing issues associated with 3D cryoprinting. With the modular 3D printer, 3D printing, crosslinking, and freezing were conducted on separate modules yet remain part of a continuous manufacturing process. Crosslinking before the freezing step produced highly interconnected and directional pores, which are ideal for promoting cell growth. By controlling the cooling rate, it was possible to produce pores with diameters from a range of 5 μm to 40 μm. Tensile and firmness testing found that the use of freezing does not decrease the tensile strength of the printed objects, though there was a significant loss in firmness for strands with larger pores.

Original languageEnglish (US)
Article number031205
JournalJournal of Heat Transfer
Volume144
Issue number3
DOIs
StatePublished - Mar 1 2022

Bibliographical note

Funding Information:
Funding is gratefully acknowledged from the NSF Engineering Research Center for Advanced Technologies for Preservation of Biological Systems (ATP-Bio) NSF EEC #1941543. L.W. was supported by the National Science Foundation Graduate Research Fellowship Program. Special thanks to Gabriel Lopez (UC Berkeley) for aiding in the tensile testing and to Cristina Bilbao-Sainz (USDA) for aiding with the texture profile analysis.

Funding Information:
• NSF Engineering Research Center for Advanced Technologies for Preservation of Biological Systems (ATP-Bio) NSF EEC (Grant No. 1941543; Funder ID: 10.13039/100000001).

Publisher Copyright:
© 2022 American Society of Mechanical Engineers (ASME). All rights reserved.

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