It also enabled the team to 3D print stem cells into precise shapes in petri dishes before they began to mature. The organoids developed better and more consistently. The improved growing conditions could one day help with the manufacture of replacement tissues.

Why stress relaxation matters

“What turned out to matter most was how the material relaxes over time—something we call stress relaxation,” said Zev Gartner, Ph.D., professor of Pharmaceutical Chemistry at UCSF and senior author of the paper, which was published in Nature Materials on Mar. 10. “It needs to give way at the same pace that tissues are reshaping themselves.”