Stanford Researchers Develop Novel Bioink

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Stanford University Guest Post

Figure (adapted):  A) Schematic depicting the drawbacks of commonly used bioinks for each stage of the printing process. These drawbacks can be overcome by new biomaterials development. B) Schematic of the two material components of MITCH-Alginate and its dual-stage crosslinking. In the first stage, noncovalent binding between two complementary peptides forms a weak gel upon mixing of the two polymer components. In the second stage, ionic crosslinking occurs between calcium ions in solution and the alginate backbone of component 1.C) Macroscopic photograph and D) confocal microscopy image of prelabeled hASCs (red) and 3T3 cells (green) printed with MITCH-Alginate into a pattern of perpendicular lines (top-down view).

Materials scientists out of Stanford University have developed a novel bioink to combat some of the drawbacks faced by commonly used bioinks. This team identified the three most pressing drawbacks as settling of cells within the bioink, poor cell viability, and cell dehydration during the printing process. In order to combat these issues, the bioink uses two stages of crosslinking: the first stage uses physical, nonpermanent crosslinks to create an extrudable, weak hydrogel that prevents cells from settling in the print cartridge and provides mechanical protection to the cells during printing; the second stage of crosslinking occurs in the saline bath and uses electrostatic interactions to stiffen the bioink and provide additional structural support and maintain cell hydration. These hydrogels are unique in their ability to allow for an even distribution of cells, to protect cells from harmful mechanical forces during the printing process, and to be printed into a fluid bath to ensure full cell hydration while printing. The beta version of the BioBots printer was used to develop this material and has since been upgraded to the BioBot 1 for further biomaterials development and testing.

Dubbin, K., Hori, Y., Lewis, K. K. and Heilshorn, S. C. (2016), Dual-Stage Crosslinking of a Gel-Phase Bioink Improves Cell Viability and Homogeneity for 3D Bioprinting. Advanced Healthcare Materials. doi: 10.1002/adhm.201600636

Post by: Karen Dubbin, PhD Student at Stanford University (LinkedIn)