In the new technique, these cells are injected directly into the body along with hydrogel microspheres that help them stay together and form connections with nearby blood vessels. The spheres have special properties that allow them to act like a liquid when they are closely packed together, so they can be injected through a syringe and then regain their solid structure once inside the body. “These microspheres provide the hepatocytes with a niche where they can stay localized and become connected to the host circulation much faster,” says MIT postdoc Vardhman Kumar, lead author of a paper on the work.

The researchers have shown that the cells can remain viable in the bodies of mice for at least two months, generating many of the enzymes and other proteins that the liver produces. In the study, they were injected into the fat tissue of the belly, but they could also be delivered to other sites.

“The way we see this technology is it can provide an alternative to surgery, but it can also serve as a bridge to transplantation where these grafts can provide support until a donor organ becomes available,” Kumar says. While patients would likely need to take immunosuppressive drugs, the researchers are exploring how they might get the hepatocytes to evade the immune system or use the microspheres to deliver immunosuppressants locally.