Post myocardial infarction (heart attack), damaged heart tissue doesn’t tend to heal very well. Not only is the pumping action weakened due to muscle cells dying, but the electrical signaling through the heart can also be impeded.
Scientists at Trinity College Dublin have now developed remarkable new patches that mimic the electrical conductivity of heart tissue while being able to withstand the physical forces that a moving heart produces. Such patches may one day be used to help overcome some of the consequences of heart attacks and provide a matrix within which new cells can make home.
“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,” said Michael Monaghan, senior author of a paper appearing in journal Advanced Functional Materials. “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.”
Polyester-based thermoplastic polymers are a common biocompatible material used in medicine these days, but its normal state is not rugged enough to withstand being repeatedly flexed by the heart. The Trinity team collaborated with a company called Spraybase to apply a technique called melt electrowriting in order to create special geometries within the material that can be designed to have the material move in expected ways.
They were able to make patches that mimic the elasticity of native heart tissue and, by applying a coating of a conductive polymer, they were able to mimic the conductivity of the heart. Moreover, the material allows for compatibility with new and growing cells, so gives hope as a potential for active treatment of damaged hearts.
From the study abstract:
Here, an electroconductive cardiac patch that conforms to the mechanics of human myocardium is fabricated. By melt electrospinning writing (MEW), it is possible to fabricate an auxetic patch that can overcome the limited range of elasticity seen in conventional square patch designs. The auxetic patches can accommodate the strains and stresses exhibited by the human myocardium during diastole and systole. It is shown that the geometry of the auxetic patches can be fine‐tuned to reflect anisotropic mechanical properties.
Study in Advanced Functional Materials: Electroconductive Melt Electrowritten Patches Matching the Mechanical Anisotropy of Human Myocardium