When the researchers pumped nutrient-rich media through the gel's template-fashioned vascular system, the entrapped liver cells boosted their production of albumin and urea, natural components of blood and urine, respectively, which are important measures of liver-cell function and health. There was also clear evidence of increased cell survival around the perfused vascular channels.
And theoretical modeling of nutrient transport in these perfused gels showed a striking resemblance to observed cell-survival patterns, opening up the possibility of using live-cell data to refine computer models to better design vascular architectures.
Though these engineered tissues were not equivalent to a fully functioning liver, the researchers used cell densities that approached clinical relevance, suggesting that their printed vascular system could eventually be used to further research in lab-grown organs and organoids.
"The therapeutic window for human-liver therapy is estimated at one to 10 billion functional liver cells," Bhatia said. "With this work, we've brought engineered liver tissues orders of magnitude closer to that goal, but at tens of millions of liver cells per gel we've still got a ways to go.
"More work will be needed to learn how to directly connect these types of vascular networks to natural blood vessels while at the same time investigating fundamental interactions between the liver cells and the patterned vasculature. It's an exciting future ahead."
With promising indications that their vascular networks will be compatible with all types of cells and gels, the team believes their 3D printing method will be a scalable solution for a wide variety of cell- and tissue-based applications because all organ vasculature follows similar architectural patterns.
"Cell biologists like the idea of 3D printing to make vascularized tis
|Contact: Evan Lerner|
University of Pennsylvania