A team of researchers at MIT and Children’s Hospital Boston has built cardiac patches studded with tiny gold wires that could be used to create pieces of tissue whose cells all beat in time, mimicking the dynamics of natural heart muscle. The development could someday help people who have suffered heart attacks.
The study, reported this week in Nature Nanotechnology, promises to improve on existing cardiac patches, which have difficulty achieving the level of conductivity necessary to ensure a smooth, continuous “beat” throughout a large piece of tissue.
The unique new approach uses gold nanowires scattered among cardiac cells as they’re grown in vitro. The researchers believe the technology may eventually result in implantable patches to replace tissue that’s been damaged in a heart attack.
To build new tissue, biological engineers typically use miniature scaffolds resembling porous sponges to organize cells into functional shapes as they grow. Traditionally, however, these scaffolds have been made from materials with poor electrical conductivity.
The team took as their base material alginate, an organic gum-like substance that is often used for tissue scaffolds. They mixed the alginate with a solution containing gold nanowires to create a composite scaffold with billions of the tiny metal structures running through it.
Then, they seeded cardiac cells onto the gold-alginate composite, testing the conductivity of tissue grown on the composite compared to tissue grown on pure alginate. Because signals are conducted by calcium ions in and among the cells, the researchers could check how far signals travel by observing the amount of calcium present in different areas of the tissue.
There, they observed a dramatic improvement among cells grown on the composite scaffold: The range of signals conduction improved by about three orders of magnitude.
The researchers plan to pursue studies in vivo to determine how the composite-grown tissue functions when implanted into live hearts.
Also: Learn about an implantable axial rotary heart pump .
