'Velcro-like' scaffold holds promise for artificial heart grafts

Canadian engineers have created a biocompatible scaffold that could make it easier to grow artificial heart tissue for repairing damaged hearts.

Scientists have been able grow heart cells in the laboratory for a number of years, however the absence of the support cells found in a real heart means that these cells often bear little resemblance to those found in the body.

To address this, a team from the University of Toronto in Canada has developed a scaffold mesh that can be used to build larger tissue structures than is possible with existing methods.

The group, led by biomedical engineer Prof Milica Radisic, used a special polymer called POMaC to create a 2D mesh for the cells to grow around.

This resembles a honeycomb in shape, except that the holes are not symmetrical. Instead, they are wider in one direction than in another. This provides a template that causes the cells to line up together. When stimulated with an electrical current, the heart muscle cells contract together, causing the flexible polymer to bend.

Next, the team bonded T-shaped posts on top of the honeycomb. When a second sheet is placed above, these posts act like tiny hooks, poking through the holes of the honeycomb and clicking into place. The concept the same as the plastic hooks and loops of Velcro.

The assembled sheets are said to have functioned almost immediately.

“As soon as you click them together, they start beating, and when we apply electrical field stimulation, we see that they beat in synchrony,” said Radisic. The team has created layered tissues up to three sheets thick in a variety of configurations. 

The ultimate goal of the project is to create artificial tissue that could be used to repair damaged hearts. The modular nature of the technology should make it easier to customise the graft to each patient.

“If you had these little building blocks, you could build the tissue right at the surgery time to be whatever size that you require,” Radisic daid in a statement. These artificial tissues could be used to test out new drugs in a realistic environment.

Radisic and her team are now collaborating with medical researchers in order to design in vivo experiments that will take the project one step closer to the clinic.