http://www.sciencemag.org/news/2018/06/lab-created-miniguts-grow-larger-when-you-load-them-springs

Scientists around the world are harnessing organoids, tissue clusters derived from stem cells that mimic the 3D structure of our organs in miniature, to model diseases and test new drugs. But most organoids are nowhere near large and complex enough to replace missing or damaged parts of human organs. In a new study, researchers have shown that adding loaded springs to human gut organoids may make them grow bigger and exhibit features of adult organs as they mature in the abdomens of mice.

As our intestines develop, they’re pulled and stretched inside the body; previous studies have shown that those forces influence their emerging structure. So the researchers aimed to apply similar forces to intestinal tissue grown from human stem cells that had been developing for 10 weeks inside of mice. Each was implanted with a spring about a centimeter long, compressed inside a gelatin capsule that gradually dissolved to let loose the spring’s outward force.