Synthetic Heart Tissue Sticks Like Velcro

Not ideal for fastening children's shoes
Zhang et al, Science Advances, 2015

A team of researchers has developed a material that beats like a heart in the body but from which layers can be stacked or peeled away, according to a study published today in Science Advances.

When researchers make synthetic heart tissue, they usually combine biodegradable man-made chemicals with living cells grown in a lab. These tissues do work, but they’re limited. Some production methods make the final shape of the cells unpredictable, or the tiny scaffolds of cells can’t stack on top of each other; bioprinted tissues are pretty good, but doctors can’t separate out the different layers.

It might sound strange to want to disassemble the layers of a synthetic heart, but it’s pretty important. Researchers can treat the different layers with protective molecules to make them better adapted for, say, a patient with a lot of inflammation. In a research setting, separating the layers allows researchers to test the effects of different factors, such as time, location, and different coating molecules, on the tissue’s durability, according to Milica Radisic, a chemical engineer at the University of Toronto and one of the study authors. That could help researchers make even better versions of the material in the future.

The Velcro you see on shoes or clothing has two different components. One side of the fabric has a series of tiny loops made of fiber; the other has hooks. When you put them together to fasten a garment, most (but not all) of the hooks attach through the loops.

Radisic’s Tissue-Velcro is based on the same premise. One side of each layer has an array of loops made of the biodegradable polymer, and the other side has T-shaped hooks of the same material. Each layer can be synthesized individually, with whatever additional molecules the researchers are interested in testing. When the layers are slapped together or ripped apart, the molecules and the polymer stay intact.

When the researchers put Tissue-Velcro in neonatal mice, they found that the material conformed perfectly into a hole in the heart tissue while still retaining its structural integrity. After a few days, the tissue started beating, and continued to do so when it was coated with a layer of endothelial cells, which protects the polymer from breaking down in the body or causing inflammation.

But scientists aren’t planning to use this in human heart transplants anytime soon—its primary application is in heart research, at least for now. In future studies the researchers hope to use Tissue-Velcro to understand how individual cell survival or death affects heart function.