One of the big challenges doctors face after patients suffer debilitating heart attacks is finding a way to repair the permanent damage caused to the organ. Research is booming in the development of regenerative cells or tissues to help repair damaged organs, but there are significant dangers in embarking upon major surgeries on already weak patients. To avoid this, a team at the University of Toronto has developed a regenerative tissue patch that can be injected within the body without the need for invasive surgery.

The University of Toronto team has recently made great leaps forward in developing polymer scaffolds that can grow human tissue and muscle cells, but finding a suitable way to get that tissue into the human body has remained a challenge.

"If an implant requires open-heart surgery, it's not going to be widely available to patients," says Professor Milica Radisic. After a heart attack the organ is so weakened that is it often too risky to perform such an invasive procedure. "It's just too dangerous," she says.

After three years of research, Radisic and her research partner, PhD candidate Miles Montgomery, produced an injectable patch that can unfold into a bandage-like shape after emerging from a needle.

The team then seeded this patch with real heart cells and successfully injected it into both rats and pigs. The polymer-based cell scaffold is based on a technique the team has previously developed and it is designed to break down over time, leaving only the new tissue.

"When we saw that the lab-grown cardiac tissue was functional and not affected by the injection process, that was very exciting," says Montgomery. "Heart cells are extremely sensitive, so if we can do it with them, we can likely do it with other tissues as well."

Human clinical trials for the technology are still some time away, with more research needed to discover how stable the patches are over the long-term, but the team is optimistic the invention could be widely applied across a variety of organs, including the heart and the liver.

"You could customize this platform, adding growth factors or other drugs that would encourage tissue regeneration," says Radisic. "I think this is one of the coolest things we've done."

The research was published in the journal Nature Materials.

Watch a short video below of the patch unfolding after emerging from a needle.