Could this patch help mend a broken heart?

Researchers in Ireland have developed a prototype patch that they say does the same job as crucial aspects of heart tissue.

The patch was designed to withstand the mechanical demands of heart tissue and mimic the electrical signaling properties that allow the heart to pump blood throughout the body. The researchers believe it brings medtech one step closer to a functional design that could mend a broken heart.

Cardiac patches lined with heart cells can be applied surgically to restore heart tissue in patients who have had damaged tissue removed after a heart attack and to repair congenital heart defects in infants and children. Ultimately, though, the goal is to create cell-free patches that can restore the synchronous beating of the heart cells, without impairing the heart muscle movement. The bioengineers report their work in the journal Advanced Functional Materials.

“Researchers are continuously looking to develop new treatments which can include stem cell treatments, biomaterial gel injections and assistive devices,” said senior author Michael Monaghan, an assistant professor at Trinity College Dublin, in a news release. “Ours is one of few studies that looks at a traditional material, and through effective design allows us to mimic the direction-dependent mechanical movement of the heart, which can be sustained repeatably. This was achieved through a novel method called ‘melt electrowriting’ and through close collaboration with the suppliers located nationally we were able to customize the process to fit our design needs.”

This work was performed in the Trinity Centre for Biomedical Engineering, based in the Trinity Biomedical Sciences Institute in collaboration with Spraybase, a subsidiary of Avectas Ltd.

The mechanical demands of heart muscle cannot be met using polyester-based thermoplastic polymers, which are predominantly the approved options for biomedical applications, according to the researchers. However, the functionality of thermoplastic polymers could be leveraged by its structural geometry. They made a patch that could control the expansion of a material in multiple directions and tune this using an engineering design approach.

The patches were manufactured via melt electrowriting, a core technology of Spraybase, which the company says is reproducible, accurate and scalable. The patches were also coated with the polymer polypyrrole to provide electrical conductivity while maintaining cell compatibility. The patch withstood repeated stretching, which is a dominant concern for cardiac biomaterials, and showed good elasticity, to accurately mimic that key property of heart muscle.

“Essentially, our material addresses a lot of requirements,” Monaghan said. “The bulk material is currently approved for medical device use, the design accommodates the movement of the pumping heart, and has been functionalized to accommodate signaling between isolated contractile tissues. This study currently reports the development of our method and design, but we are now looking forward to furthering the next generation of designs and materials with the eventual aim of applying this patch as a therapy for a heart attack.”