How do you mend a broken heart? You’re operating on a heart and it’s got a tear in it. How do you seal it?
Sutures? Staples? These are the traditional answers, but they aren’t good ones. Both involve piercing tissue and creating holes, which is bad news for an organ that’s constantly moving, and vigorously pumping blood. Holes lead to clots. They also bleed.
And if you specialise in doing heart surgeries on babies, as Pedro del Nido from Children’s Hospital does, you can add small size and delicate tissues to those other challenges. “The holy grail for heart surgeons, especially for those who work on babies, is to attach things without damaging the normal underlying tissue,” he says.
A glue, then. The trouble is that a heart adhesive must be strong enough to hold despite the heart’s constant beating, but flexible enough to allow those same beats to happen. It has to work in wet conditions—something that most glues aren’t designed to do. It needs to repel water so it doesn’t dissolve. It must thicken slowly or blood will wash it away. It can’t thicken immediately because you want to be able to position and adjust it. It has to be biodegradable.