Australasian Science: Australia's authority on science since 1938

Patch Mends a Broken Heart

An Australian and British team has developed a polymer patch that improves the conduction of electrical impulses across damaged heart tissue. The flexible patch, which has been effective in animal models, is long-lasting and can be attached to the heart without stitches.

“Heart attacks create a scar which slows and disrupts the conduction of electrical impulses across the heart,” says Prof Sian Harding of Imperial College London. “This leads to potentially fatal disturbances of the heart rhythm. Our electrically conducting polymer patch is designed to address this serious problem.”

The patch, which was described in Science Advances, has three components:

  • a film of chitosan (a polysaccharide found in crab shells that’s often used as a food additive);
  • polyaniline (a conducting polymer that’s grown on top); and
  • phytic acid (a substance found in plants that’s added to the polyaniline to switch it to its conducting state).

“Conducting polymers work when they are dry, but most become non-conducting in a very short time when placed in bodily fluids,” says lead author Dr Damia Mawad of The University of NSW. “Our sutureless patch represents a big advance. We have shown it is stable and retains its conductivity in physiological conditions for more than 2 weeks compared with the usual 1 day of other designs.

“No stitches are required to attach it, so it is minimally invasive and less damaging to the heart, and it moves more closely with the heart’s motion.”

The patch is made to adhere to the cardiac tissue by shining a green laser on it, in a patented technique developed by Dr Antonio Lauto of Western Sydney University.

Team members at the British Heart Foundation’s Imperial Cardiovascular Regenerative Medicine Centre tested the patch by implanting it into rats. They found it improved the conduction of electrical impulses across the heart scar tissue.

“We envisage heart attack patients eventually having patches attached as a bridge between the healthy and the scar tissue to help prevent cardiac arrhythmia,” Mawad says.

Prof Molly Stevens of Imperial College adds: “The patch can help us better understand how conductive materials interact with heart tissue and influence the electrical conduction in the heart, as well as better understand the physiological changes associated with heart attacks”.